A few years ago the state of Maryland enacted legislation to require the installation of specialized emissions control technology to capture excess mercury emissions from power plants. And according to the latest published reports it appears that the initiative has been a success. Coal-burning power plants in Maryland are now required to install new pollution controls that reduce mercury emissions by 80 percent.

But appearently that is not enough to keep the air quality in the state safe enough for all. Why?

A serious health threat still exists because neighboring states have yet to crack down on the toxic pollutant, an environmental group’s report says. The neighboring states, particularly Pennsylvania, Ohio and West Virginia are among the worst in the nation for mercury emissions, ranking second, third and fourth highest, respectively, in the country. All are within Maryland’s “airshed,” where pollutants put into the air in one state are carried by prevailing winds into neighboring states.

Robert M. Summers, acting secretary of the environment, noted in a news release that 73 percent of the mercuy air pollution measured in Maryland is coming from outside the state’s borders.

He and others called on the Environmental Protection Agency to follow through with an air-quality standard it is set to propose in March that would curb mercury and other toxic air pollution from power plants.  The federal standard, if proposed as drafted, would reduce mercury emission by more than 90 percent, advocates say.

The report – and a recent press conference – are meant to put public pressure on EPA to go through with the regulation in the face of pushback from industry and its supporters in Congress, where legislation to block new EPA rules is said to be in the works.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

Often our customers find it difficult to determine exactly what kind of Filter Media they require for their specific Dust collection system. Other times they know the particular type of filter media they need, but are unable to determine the exact size they need for their Baghouse.

To assist our customers, we at Baghouse.com have prepared this article to help you select the right filter media to match your specific needs.

If you would like to speak directly with one of our dust collection experts for additional help in selecting your Filter Media, or if you would like to receive a free Baghouse Filters quote, please call us at  800 351 6200 or Contact Us using our online form.


Step 1 – Filter Media Selection

Choose the media from which your filter bags will be constructed of based on the type of application they will be used for. Take the following things into consideration prior to selecting your filter media:

•    Temperature – Do your bags need to withstand extreme temperatures?
•    Material – What is the filter being used for?
•    Chemistry – Can your filter withstand the chemical makeup of the dust particles
•    Resistance- Is the filter media able to resist the abrasion of the dust particles

Choosing the correct filter media is an important and sometimes difficult process. To assist you in the identification of the right media for your bags, keep the following in mind: Filter bag performance is directly related to how well it can tolerate the environment in which it is being used. How efficiently it can remove the dust particles from its fabric and its ability to be cleaned by the dust collector is also important. You must first learn to identify the type of filter media currently used in your application. Below you will find a list of typical construction methods:

•    Woven felts
•    Non-woven felts
•    Natural fibers
•    Synthetics (Thermoset or Thermoplastics such as Polypropylene “PPRO” – Polyphenylene sulfide “PPS” – Polyester “PE”)

For additional information on media types please examine our Filter Fabrics Chart below. A simple test to determine if a material is a thermoplastic is to take a small swatch and put a flame to it. A thermoplastic material will begin to melt when exposed to direct heat. The selection criterion eliminates materials based on temperature and chemical characteristics. The first cut is usually made based on temperature. Then the chemical characteristics of the gas stream are considered to further refine the search. Next, the efficiency of the material further dictates the construction of the material such as the weight, oz/sq. ft., fiber and surface treatments/membranes. Last but not least, if there are still two or more candidates it comes down to a price versus performance trade off.

Dust Collector Filter Fabrics


Popular Materials


Polyester FeltPolyester Felt - Baghouse Filter Fabric

Recommended continuous operation temperature: 275°F
Maximum (short time) operation temperature: 300°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Fair
Resistance to mineral acids: Fair+
Resistance to organic acids: Fair
Resistance to oxidizing agents: Good
Resistance to organic solvents: Good
Available weights: 10 oz. – 22 oz.

Polypropylene Felt - Dust Collector Filter Fabric

Polypropylene Felt

Polypropylene Felt

Recommended continuous operation temperature: 190°F
Maximum (short time) operation temperature: 210°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): Excellent
Resistance to alkalis: Excellent
Resistance to mineral acids: Excellent
Resistance to organic acids: Excellent
Resistance to oxidizing agents: Good
Resistance to organic solvents: Excellent
Available weights: 12 oz. – 18 oz


High Temperature Materials


Conex® / Nomex® Felt (Aramid) - Dust Collector Filter Fabric

Conex® / Nomex® Felt (Aramid)

Conex® / Nomex® Felt (Aramid)

Recommended continuous operation temperature: 400°F
Maximum (short time) operation temperature: 425°F
Supports combustion: No
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Good
Resistance to mineral acids: Fair
Resistance to organic acids: Fair+
Resistance to oxidizing agents: Poor
Resistance to organic solvents: Good
Available weights: 10 oz. – 22 oz.

P84® Felt Polyimide - Dust Collector Filter Fabric

P84® Felt Polyimide

P84® Felt Polyimide

Recommended continuous operation temperature: 475°F
Maximum (short time) operation temperature:500°F
Supports combustion: No
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Fair
Resistance to mineral acids: Good+
Resistance to organic acids: Good+
Resistance to oxidizing agents: Good+
Resistance to organic solvents: Excellent
Available weights: 14 oz. – 18 oz.

Ryton® Felt / PPS - Dust Collector Filter Fabric

Ryton® Felt / PPS

Ryton® Felt / PPS

Recommended continuous operation temperature: 375°F
Maximum (short time) operation temperature: 400°F
Supports combustion: No
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Excellent
Resistance to mineral acids: Excellent
Resistance to organic acids: Excellent
Resistance to oxidizing agents: Fair
Resistance to organic solvents: Excellent
Available weights: 16 oz. – 18 oz.

Dust Collector Filter Specialty Materials


Homopolymer Acrylic Felt - Dust Collector Filter Fabric

Homopolymer Acrylic Felt

Homopolymer Acrylic Felt

Recommended continuous operation temperature: 250°F
Maximum (short time) operation temperature: 275°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): Good+
Resistance to alkalis: Fair
Resistance to mineral acids: Good+
Resistance to organic acids: Excellent
Resistance to oxidizing agents: Good
Resistance to organic solvents: Good+
Available weights: 15 oz. – 18 oz.

Epitropic Felt Antistatic - Dust Collector Filter Fabric

Epitropic Felt Antistatic

Epitropic Felt Antistatic

Recommended continuous operation temperature: 275°F
Maximum (short time) operation temperature: 300°F
Supports combustion: Yes
Biological resistance (bacteria, mildew): No Effect
Resistance to alkalis: Fair
Resistance to mineral acids: Fair+
Resistance to organic acids: Fair
Resistance to oxidizing agents: Good
Resistance to organic solvents: Good
Available weights: 14 oz. – 16 oz.

Step 2 – Dust Collector Filter Measurements

Accurate measurements lead to the best fit. It’s likely that your dust collector has been modified over the years due to permitting issues or changes in your process which called for a reconfiguration of the Baghouse. In this case OEM configurations will not fit and you will need to obtain accurate measurements for your filters before ordering replacement filter bags. If you currently have filter bags installed that are functioning properly, you can remove one of these bags to get the proper measurements for your replacement order. A spare bag that has not been used yet can also be measured if available. However, be sure to verify the bag measured is the same as the bags currently being used in the dust collector. If you are removing a used bag to measure, please be sure to use all necessary precautionary measures set in place prior to removal i.e. gloves, protective garments and respiratory equipment if needed. It is best not to rely only on the numbers off the unit of OEM filter specifications because of possible changes to the configurations. Of course the best solution is to mail the manufacturer a new or used bag that can be used a guide sample.

Flat Width: Place the filter on a flat surface such as a large table or cement floor. With the filter stretched out, press down on the side. Using a measuring tape, very accurately record the width. Be sure to hold the filter down firmly on an even surface when taking this measurement.

Diameter: When measuring the tube sheet hole of a pulse jet style dust collector, first make sure the hole has not been damaged or warped in any way. Clean the surface thoroughly with a wire brush then using a micrometer, measure the hole in both directions. If the measurements are at all different locate another hold and repeat this process.

Length: Remove the filter from the unit. Preferably with the assistance of another person, stretch the filter out. While maintaining tension on the filter record the length from the longest point at each end using a measuring tape. Do not include and straps, metal caps or other hanging hardware in the measurement, just the length of the filter itself.

Step 3 – Top & Bottom Construction

The top and bottom construction of a filter bag involves a variety of possible configurations. Identifying the type of cleaning process used by your dust collector will help to determine which configuration is needed. The most common types of dust collectors are “Pulse-Jet” “Shaker” “Reverse Air”. The chart below can help you identify which type of dust collector filter you are using.

Filter Configuration Chart

Pulse-Jet Dust Collectors (Reverse jet) – Found in almost every industrial environment. They are the most popular design and are seen in nearly all industry segments. Pulse-Jet Units can be divided into two major groups Top load or bottom load units sometime called top entry (walk-in plenum) or bottom entry (common in bin vents) because of the point of entry used to change out the filters.

Typical filter configuration for a top load unit:
Snap Band Top (double-beaded ring)
Disk Bottom (w/o wear strip)

Typical filter configuration for a bottom load unit:
Raw End Top
Disk Bottom (w/o wear strip)

Shaker Dust Collectors (Mechanical Cleaning) – Usually found in older applications where unscheduled down time is not a major concern.

Typical filter Top Configurations
Loop Top
Grommet Top
Strap or Tail Top
Metal Hanger or Cap

Typical Filter Bottom Configurations
Corded Cuff with Clamp
Snap Band
(Double-Beaded Ring)

Reverse-Air Dust Collectors – Usually found in very large air handling environments such as power generation and cement plants although they do have uses in a variety of industries. Sometimes called a structural bag, these filters usually have a series of support rings spaced every few feet throughout the length of the bag.

Typical Top Configurations
Compression band w/Metal Cap & Hook

Typical Bottom Configurations
Compression band
Snap Band
Cord w/Metal Clamp

Snap Band - Dust Collector Filter Configuration

Snap Band

Raw Edge - Dust Collector Filter Configuration

Raw Edge

Cord - Dust Collector Filter Configuration


Hanger - Dust Collector Filter Configuration


Grommet - Dust Collector Filter Configuration


Loop - Dust Collector Filter Configuration


Strap - Dust Collector Filter Configuration


Support Ring - Dust Collector Filter Configuration

Support Ring

Rubber O-Ring - Dust Collector Filter Configuration

Rubber O-Ring

Disk - Dust Collector Filter Configuration


Disk With Wear Strip - Dust Collector Filter Configuration

Disk With Wear Strip

Flange - Dust Collector Filter Configuration


Hem - Dust Collector Filter Configuration


Sewn Flat - Dust Collector Filter Configuration

Sewn Flat

Envelope - Dust Collector Filter Configuration


Step 4 – Additional Options

Ground Wires – Use to comply with Factory Mutual requirements for static dissipation. Ground wire can be made from stainless steel or copper however this technique only works on a localized area of the filter. For optimal static dissipation look at conductive fiber filter made with Epitropic or Stainless Steel fibers.

Wear Cuffs – Used to combat abrasion at the bottom of the bag either from a sandblasting effect or from bag-to-bag abrasion due to turbulence in the bag house. Usually 2 to 4 inches in length and made of a material similar to that of the body of the filter bag.

Special Finishes – There are many finish options that can be added to the filter media at the time it is manufactured. Please refer to the materials selection area for further details. If you want to order a specific brand or special type of finish please add that request into the additional comments section when ordering.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

This article has been designed to educate customers by giving a brief overview of all the Dust Collection Systems available today. A detailed explanation of the benefits and drawbacks of each type of system can be found in further articles on Baghouse.com

What is a Dust Collector?

After the contaminated air is captured by a Dry Dust Collection system, either by means of a Central Collection System, or in a unit Collector. The dust filled air then needs to be treated and the contaminates removed, before the air can be recirculated back into the facility or dispersed into the atmosphere. The Dust Collector separates the particles from the airstream and sends it on to its final destination.

Why are Dust Collectors Needed?

There are many reasons why having a proper Dust Collection System installed in your facility is needed, a few important reasons are:

•    To protect employees and society from exposure to pollution,
•    To recover valuable products from the dust filled air
•    To facilitate compliance with health and air emission standards.

Types of Dust Collectors

The five principal types of industrial dust collectors that will be discussed in this article are:

•    Cyclone Collectors (Inertial separators)
•    Baghouses (Fabric collectors)
•    Wet scrubbers
•    Electrostatic precipitators
•    Unit collectors

Cyclone Collectors (Inertial Separators)

Inertial separators
work by making use of one or more of the following forces centrifugal, gravitational, and inertial in order to separate dust from the airstream. Once separated, the dust is removed to a hopper by gravity for temporary storage. While this type of collect can be used in applications where particle sizes are large and only a “rough” air filtration is desired, the main usage for this type of collector is as a precleaner, to remove larger particles and debris and avoid overloading and damaging more efficient dust collectors.

The three types of Inertial Separators are:

•    Settling Chambers
•    Baffle Chambers
•    Centrifugal Collectors

A Settling Camber is a large box installed into the ductwork.  The sudden larger area for the airstream to pass through causes the air stream to slow down, which in turns causes the larger particles to settle to the bottom of the chamber. This type of collector is rarely used as the primary dust collector due to it’s large space requirements, and low efficiency. However, the fact that it can be fashioned from almost any material and its simple design, which requires little maintenance, leads it to being a wise choice as a precleaner for a more efficient Dust Collector.

A Baffle Chamber has a fixed baffle plate that causes the airflow to rapidly change its direction, first turning downward, and then making a 180 degree turn back up. In the process, the larger particles fall to the bottom of the chamber and can be collected from there. As with Settling Chambers this type of collector is best used as a precleaner for another more efficient collector further in the collection system. Also like a Settling Chamber its relatively simple design and low maintenance needs make it an excellent choice for the beginning of any large scale collection system.

Centrifugal Collectors create a vortex in the airstream within an enclosure, similar to water going down a drain. Normally this is done by having the airstream enter the collect at an angle, which causes it to spin. As the airstream is spun around the collector, the particles strike the wall and fall into the hopper below.

Within this category there are two main types of systems in use:

•    Single Cyclone systems
•    Multiple Cyclone systems

A Single Cyclone Collector creates a dual vortex, a main downward vortex to disperse the coarser matter, and a secondary upward vortex to remove the finer particles on the return to the outlet to the duct system.

A Multiple Cyclone Collector works in the same manner as the Single Cyclone variety albeit with several small dynamiter cyclones instead of just one. The multiple cyclones work in parallel and share the same air input and output.

Between the two, the Multiple Cyclone Collector will operate more efficiently because of being longer in length and smaller in dynamiter. The smaller dynamiter cause the centrifugal force generated to be greater, and the longer length allows for more contact with the surface of the collector by the particles thereby causing more particles to be removed from the airstream. However, a greater loss of pressure is found in Multiple Cyclone Collectors than in Single Cyclone Collectors.

Again as with the other kinds of Inertial Separators, this systems main advantage is the lack of moving parts thus requiring less maintenance and repair. While it can be designed to remove a specific size range of particles, it still remains best used as a precleaner to eliminate coarse particles and ease the load on more efficient Dust Collectors further along in the system.

Advantages & Disadvantages – Centrifugal Collectors

Types Advantages Disadvantages
Cyclones Have no moving parts Have low collection efficiency for respirable particulates
Can be used as precleaners to remove coarser particulates and reduce load on more efficient dust collectors Suffer decreased efficiency if gas viscosity or gas density increases
Can be designed to remove a specific size range of particles Are susceptible to erosion
Have drastically reduced efficiency due to reduction in airflow rate
Cannot process sticky dust
Multiple Cyclones Have no moving parts Have low collection efficiency for respirable particulates
Are more efficient than single-cyclone separators Are prone to plugging due to smaller diameter tubes
Have low pressure drop when used as a precleaner Improper gas distribution may result in dirty gas bypassing several tubes
Cannot process sticky dust
For a given gas volume, occupy more space than single-cyclone separators

Common Operating Problems & Solutions – Cyclone Collectors

Symptom Cause Solution
Erosion High concentrations of heavy, hard, sharp-edged particles Install large-diameter “roughing” cyclone upstream of high-efficiency, small-diameter cyclone.
Line high-efficiency cyclone with refractor or erosion-resistant material.
Corrosion Moisture and condensation in cyclone Keep gas stream temperature above dewpoint.
Insulate cyclone.
Use corrosion-resistant material such as stainless steel or nickel alloy.
Dust Buildup Gas stream below dewpoint Maintain gas temperature above dewpoint.
Very sticky material Install vibrator to dislodge material.
Reduced Efficiency or Dirty Discharge
Leakage in ductwork of cyclone Clean cyclone routinely.
Check for pluggage and leakage and unplug or seal the ductwork.
Close all inspection ports and openings.
Reduced gas velocity in cyclone Check the direction of fan rotation; if rotation is wrong, reverse two of the tree leads on motor.

Common Operating Problems and Solutions – Multiclones

Symptom Cause Solution
Erosion High concentrations of heavy, hard, sharp-edged particles Install cast iron tubes.
Install a wear shield to protect tubes
Overloaded tubes Uneven gas flow and dust distribution Install turning vanes in elbow, if elbow precedes inlet vane.
Loss of volume in tubes
Uneven pressure drop across tubes
Plugging in inlet vanes, clean gas outlet tubes, and discharge hopper Low gas velocity Install turning vanes in elbow inlet
Uneven flow distribution Insulate multiclone
Moisture condensation Install bin-level indicator in collection hopper.
Overfilling in discharge hopper Empty hopper more frequently.
Reduced efficiency or dirty gas stack Leakage in ductwork Seal all sections of ductwork and multiclone to prevent leaks
Leakage in multiclone

Startup/Shutdown Procedures – Centrifugal Collectors

Type Startup Shutdown
Cyclones 1. Check fan rotation. 1. Allow exhaust fan to operate for a few minutes after process shutdown until cyclone is empty.
2. Close inspection doors, connections, and cyclone discharge. 2. If combustion process is used, allow hot, dry air to pass through cyclone for a few minutes after process shutdown to avoid condensation.
3. Turn on fan. 3. Turn off exhaust fan.
4. Check fan motor current. 4. Clean discharge hopper.
5. Check pressure drop across cyclone.
Multiclones 1. Conduct same startup procedures as cyclones. 1. Conduct same shutdown procedures as cyclones.
2. At least once a month, measure airflow by conducting a pitot traverse across inlet to determine quantity and distribution of airflow.
3. Record pressure drop across multiclone.
4. If flow is significantly less than desired, block off rows of cyclone to maintain the necessary flow per cyclone.

Preventative Maintenance Procedures – Centrifugal Collectors

Type Frequency Procedure
Cyclones Daily Record cyclone pressure drops.
Check stack (if cyclone is only collector).
Record fan motor amperage.
Inspect dust discharge hopper to assure dust is removed.
Weekly Check fan bearings.
Check gaskets, valves, and other openings for leakage.
Monthly Check cyclone interior for erosion, wear, corrosion, and other visible signs of deterioration.
Multiclones Daily Same as cyclones.
Weekly Same as cyclones.
Monthly Check multiclone interior for erosion, wear, corrosion, and improper gas and dust distribution.
Inspect individual cyclones and ducts for cracks caused by thermal expansion or normal wear.

Fabric Dust Collectors

Fabric Collectors (commonly known as a Baghouse) are among the most widely used dust collection systems. They benefit from having the potential to be one of the most efficient (up to 99% of very fine particles) and cost effective dust collection systems you can choose.

The way they work

The Gas stream enters into the Baghouse via the location’s duct system. Once inside the dust filled gases come into contact with the filter bags within. As the gases pass through the filters the dust particles are trapped on the filter media. Over time a layer of cake dust is built up on the surface of the filter bags. This is the secret to this filter medium’s high efficiency potential. Once the cake dust has formed, it further impedes the passage of dust through the filters in four different ways:

•    Inertial Collection: The incoming Gas stream strikes the filter media, which is located perpendicular to the Gas flow before changing direction causing the dust particles to remain on the filter.
•    Interception: Particles that do not cross the fluid streamlines come in contact with fibers because of the fiber size.
•    Brownian movement: By means of diffusion, there is an increased chance of contact between the filter and the dust particles due to their molecular motion.
•    Electrostatic Forces: An increased attraction can occur between the dust particles and the filter media when an electrostatic charge is found on the dust particles.

Air to Cloth Ratio

An understanding of the term Air to Cloth Ratio is vital to understand the mechanics of any Baghouse system regardless of the exact type used. This ratio is defined as the amount of air or process gas entering the Baghouse divided by the sq. ft of cloth in the Baghouse. An example of an Air to Cloth Ratio is provided below courtesy of http://www.usairfiltration.com

(Bag diameter in inches x pi x bag length in inches)
Total Cloth area = 144 x total number of bags
A standard 6” bag has a 5-7/8” diameter
This bag is 12’ long
There are a total of 132 bags in the Baghouse
= (5-7/8” x 3.1416 x 144”) ÷ 144 x 132
= (5.875” x 3.1416 x 144”) ÷ 144 x 132
= (2657.79) ÷ 144 x 132
= 18.46 SF of cloth per bag x 132 bags
Total cloth area = 2,436 sq. ft.
Assume the Baghouse is handling 13,000 ACFM of air
Air to cloth ratio = ACFM ÷ total cloth area
= 13,000 ÷ 2,436
= 5.34 : 1

Different Baghouse designs

There are three main types of Baghouse systems currently in use today. The same basic mechanics are present in all of them, the main difference being how filter bags are cleaned.

•    Mechanical Shaker
•    Reverse Air
•    Reverse Jet (Or Pulse Jet)

A Mechanical Shaker is a design where the filter bags are suspended from the top of the Baghouse by horizontal beams and fastened to a cell plate on the bottom. When the Gas stream enters at the bottom of the Baghouse it is then forced up through the inside of the tubular filter bags, thereafter passing unto the airflow outlet at the top. The cleaning of this type of Baghouse is done by a shaking of the top horizontal bar that the filter bags are attached to.  This is caused by a motor driven shaft and cam system that sends waves down the surface of the filter bags causing the dust to fall off the interior of them into the hopper below.  This Baghouse has a relatively low Air to Cloth Ratio requiring large amounts of space. Despite this draw back, the simple design remains a noted advantage, leading to this system being widely used in the mineral processing industry.

In a Reverse Air Baghouse, filter bags are connected to a cell plate on the bottom of the Baghouse and are suspended from an adjustable hanger frame on top. The Gas stream, as in the Mechanical Shaker design enters into the Baghouse and passes through the filter bags from the bottom leading to the dust collecting again on the interior of the filter bags, thereafter leaving through the outlet port at the top.  Again the main difference in this style of Baghouse system when compared to others is the cleaning mechanism. In this system, a cleaning cycle starts with injecting clean air into the Collector in the reverse direction of the normal flow. This causes the compartment to become pressurized. The pressure causes the bags to collapse slightly releasing the cake dust to crack and fall off to be collected by the hopper below.  Since it is necessary to shut down normal airflow to the Baghouse during the cleaning cycle, this type of Baghouse is normally compartmentalized so as to allow for only a partial shutdown of the system.

With a Reverse Jet or Pulse Jet Baghouse, the same basic design is found as in the other types of Baghouse design, however, with a few very important differences. In a Pulse Jet Baghouse, the baghouse filter bags are individually overlaid on a metal cage, which is then attached to a cell plate at the top of the compartment. The Gas stream enters the Baghouse at the bottom and is forced through the outside to the inside of the filter bags after which the Gas stream exits the compartment from the outlet port at the top. The main advantage of this Baghouse is that it does not require a shutdown of any kind to run a cleaning cycle. A digital sequential timer is attached to the one of the filter bags inside the Baghouse. This timer signals a solenoid valve to start the cleaning cycle when it detects a certain amount of build up on the bag. It consists of a small burst of compressed air being fired down through the filter bags. Which cause the excess cake dust to fall off into hopper at the bottom of the Baghouse where it can be collected. The cleaning cycle of the Pulse Jet collectors provides a more complete cleaning and reconditioning of the filter bags than in the Shaker, and Reverse Air designs. Also the short nature of the cleaning cycle also leads to a reduction in the recirculation and redeposit of dust. Finally, enabled by the continuous cleaning feature of the design, this kind of collection system has a higher Air to Cloth Ratio so the space requirements are much lower than in other systems.

Cartridge Collectors

Unlike Baghouse collectors which feature the use of woven or felt filter bags, Cartridge Collectors use perforated metal cartridges that are cylindrical shaped and open on one or both ends lined with a pleated nonwoven filtering media. Once installed, one end of the cartridge is sealed off and the open end is used for the clean exhaust. Similar to a Baghouse, the Gas stream is forced through the outside of the cartridge to the inside where it then exits back into the system. Cartridge Collectors are also compatible with Reverse or Pulse Jet cleaning. Large numbers of these Collectors can be installed and used for continuous filtration for a location’s dust collection system.

Advantages and Disadvantages – Baghouses

Types Advantages Disadvantages
Shaker Baghouses Have high collection efficiency for respirable dust Have low air-to-cloth ratio (1.5 to 2 ft/min)
Can use strong woven bags, which can withstand intensified cleaning cycle to reduce residual dust buildup Cannot be used in high temperatures
Simple to operate Require large amounts of space
Have low pressure drop for equivalent collection efficiencies Need large numbers of filter bags
Consist of many moving parts and require frequent maintenance
Personnel must enter Baghouse to replace bags, creating potential for exposure to toxic dust
Can result in reduced cleaning efficiency if even a slight positive pressure exists inside bags
Reverse Air Baghouses Have high collection efficiency for respirable dust Have low air-to-cloth ratio (1 to 2ft/min)
Are preferred for high temperatures due to gentle cleaning action Require frequent cleaning because of gentle cleaning action
Have low pressure drop for equivalent collection efficiencies Have no effective way to remove residual dust buildup
Cleaning air must be filtered
Require personnel to enter baghouse to replace bags, which creates potential for toxic dust exposure
Pulse Jet (Reverse Jet) Baghouses Have a high collection efficiency for respirable dust Require use of dry compresses air
Can have high air-to-cloth ratio (6 to 10ft/min) May not be used readily in high temperatures unless special fabrics are used
Have increased efficiency and minimal residual dust buildup due to aggressive cleaning action Cannot be used if high moisture content or humidity levels are present in the exhaust gases
Can clean continuously
Can use strong woven bags
Have lower bag wear
Have small size and fewer bags because of high air-to-cloth ratio
Some designs allow bag changing without entering Baghouse
Have low pressure drop for equivalent collection efficiencies

Common Operating Problems and Solutions – Baghouses*

Symptom Cause Solution
High Baghouse pressure drop Baghouse undersized consult vendor
Install double bags
Add more compartments or modules
Bag cleaning mechanism not properly adjusted Increase cleaning frequency
Clean for longer duration
Clean more vigorously
Shaking not strong enough (S) Increase shaker speed
Compartment isolation damper valves not operating properly (S, RA) Check linkage
Check valve seals
Check air supply of pneumatic operators
Compressed air pressure too low (PJ) Increase pressure
Decrease duration and frequency
Check compressed-air dryer and clean it if necessary
Check for obstructions in piping
Repressurizing pressure too low (RA) Speed up repressurizing fan.
Check for leaks
Check damper valve seals
Pulsing valves failed (PJ) Check diaphragm
Check pilot valves
Bag tension too tight (RA) Loosen bag tension
Bag tension too loose (S) Tighten bags
Cleaning timer failure Check to see if timer is indexing to all contacts
Check output on all terminals
Not capable of removing dust from bags Check for condensation on bags
Send dust sample and bags to manufacturer for analysis
Dryclean or replace bags
Reduce airflow
Excessive reentrainment of dust Empty hopper continuously
Clean rows of bags randomly instead of sequentially (PJ)
Incorrect pressure-drop reading Clean out pressure taps
Check hoses for leaks
Check for proper fluid level in manometer
Check diaphragm in gauge
Dirty Discharge at stack Bags leaking Replace bags
Isolate leaking compartment or module
Tie off leaking bags and replace them later
Bag clamps not sealing Smooth out cloth under clamp and re-clamp
Check and tighten clamps
Failure of seals in joints at clean/dirty air connection Caulk or weld seams
Insufficient filter cake Allow more dust buildup on bags by cleaning less frequently.
Use precoating on bags (S, RA).
Bags too porous Send bag in for permeability test and review with manufacturer
High compressed-air consumption (PJ) Cleaning cycle too frequent Reduce cleaning cycle, if possible
Pulse too long Reduce pulsing duration
Pressure too high Reduce supply pressure, if possible
Diaphragm valve failure Check diaphragm and springs
Check pilot valve
Reduced compressed-air pressure (PJ) Compressed-air consumption too high See previous solutions
Restrictions in compressed-air piping Check compressed-air piping
Compressed-air dryer plugged Replace dessicant in the dryer
Bypass dryer temporarily, if possible
Replace dryer
Compressed-air supply line too small Consult design
Compressor worn out Replace rings
Check for worn components
Rebuild compressor or consult manufacturer
Pulsing valves not working Check pilot valves, springs, and diaphragms
Timer failed Check terminal outputs
Moisture in Baghouse Insufficient preheating Run the system with hot air only before process gas flow is introduced
System not purged after shutdown Keep fan running for 5 to 10 min after process is shut down
Wall temperature below dewpoint Raise gas temperature
Insulate unit
Lower dewpoint by keeping moisture out of system
Cold spots through insulation Eliminate direct metal line through insulation
Water/moisture in compressed air (PJ) Check automatic drains
Install aftercooler
Install dryer
Repressurizing air causing condensation (PJ) Preheat repressurizing air
Use process gas as source of repressurizing air
Material bridging in hopper Moisture in Baghouse See previous solutions
Dust stored in hoppers Remove dust continuously
Hopper slope insufficient Rework or replace hoppers
Screw conveyor opening too small Use a wide, flare trough
High rate of bag failure, bags wearing out Baffle plate worn out Replace baffle plate
Too much dust Install primary collector
Cleaning cycle too frequent Slow down cleaning
Inlet air not properly baffled from bags Consult vendor
Shaking too violent (S) Slow down shaking mechanism
Repressurizing pressure too high (RA) Reduce pressure
Pulsing pressure too high (PJ) Reduce pressure

* S =  Shaker
RA = Reverse Air
PJ  = Pulse Jet

Startup/Shutdown Procedures – Baghouses

Startup Shutdown
1. For processes generating hot, moist gases, preheat Baghouse to prevent moisture condensation, even if Baghouse is insulated. (Ensure that all compartments of shaker or reverse-air Baghouses are open.) 1. Continue operation of dust-removal conveyor and cleaning of bags for 10 to 20 minutes to ensure good removal of collected dust.
2. Activate Baghouse fan and dust-removal conveyor.
3. Measure Baghouse temperature and check that it is high enough to prevent moisture condensation.

Preventive Maintenance Procedures – Baghouses

Frequency    Procedure


•    Check pressure drop.
•    Observe stack (visually or with opacity meter).
•    Walk through system, listening for proper operation.
•    Check for unusual occurrences in process.
•    Observe control panel indicators.
•    Check compressed-air pressure.
•    Assure that dust is being removed from system.


•    Inspect screw-conveyor bearings for lubrication.
•    Check packing glands.
•    Operate damper valves.
•    Check compressed-air lines, including line filters and dryers.
•    Check that valves are opening and closing properly in bag-cleaning sequence.
•    Spot-check bag tension.
•    Verify accuracy of temperature-indicating equipment.
•    Check pressure-drop-indicating equipment for plugged lines.


•    Check all moving parts in shaker mechanism.
•    Inspect fans for corrosion and material buildup.
•    Check drive belts for wear and tension.
•    Inspect and lubricate appropriate items.
•    Spot check for bag leaks.
•    Check hoses and clamps.
•    Check accuracy of indicating equipment.
•    Inspect housing for corrosion.


•    Inspect baffle plate for wear.
•    Inspect bags thoroughly.
•    Check duct for dust buildup.
•    Observe damper valves for proper seating.
•    Check gaskets on doors.
•    Inspect paint, insulation, etc.
•    Check screw conveyor for wear or abrasion.


•    Check fan belts.
•    Check welds.
•    Inspect hopper for wear

Wet Scrubbers

Another effective method of dust collection is the use of Wet Scrubbers (Air Washers). These systems use a scrubbing liquid (usually water) to filter out finer dust particles.  After being filtered the Gas Stream is then sent through a mist eliminator (demister pads) to remove the excess moisture from the Gas stream. Afterward the Gas stream exits the collector through the outlet port and returns back into the system. Wet Scrubbers are ideal:

•    For the collection of explosive material
•    Where “slurry” produced could be reused (either in other parts of process or sold)
•    Where chemical reactions could be generated with other collection methods
•    To absorb excess air

Wet scrubbers have the advantage of low start up costs and low space requirements. They are well suited for treating high temperature and high humidity Gas streams. They also are able to process both air and “sticky” particulates.  The main disadvantages are that they are costly to operate, require a precleaner for any heavy dust loads, cause water pollution that then needs to be addressed, and can erode with high air velocities.

There are a vast variety of different designs and applications of this type of filtration system but all of them have three basic operations they perform:

•    Gas-humidification: The gas-humidification process conditions fine particles to increase their size so they can be collected more easily.
•    Gas-liquid contact: This is the entire basis for the operation of this type of system. The method of contact between the liquid is done in four main ways:

•    Inertial impaction takes place when the Gas stream is forced to flow around the droplets in its path. The stream separates and flows around the droplet. However the larger particles continue to be carried by inertial force in a straight path coming in direct contact with the liquid.
•    Interception: Finer particles while not directly coming in contact with the droplets, do however brush up against the side of them causing them to be absorbed into the liquid.
•    Diffusion occurs when a fine mist is created from the liquid being used. As the particles pass through the mist they make contact with the surfaces of the droplets by means of the Brownian effect, or diffusion.
•    Condensation nucleation is the effect of a gas being cooled below its dew point while within a moisture rich environment, causing the vapor to condense of the surface of the particles thereby encapsulating them.

•    Liquid separation: After going through the cleaning phase the remaining liquid and contaminates must be removed before the Gas stream can be sent back into the system. This is accomplished by means of a Mist Eliminator (Demister Pads). Which remove the liquid and dust mixture from the Gas stream and send it to a collector. Once in the collector, the solid waste settles to the bottom where it is removed by means of a drag chain system to be deposited in a dumpster or another collection area.
Wet Scrubbers are further categorized by pressure drop (in inches water gauge) as follows:

•    Low-energy scrubbers (0.5 to 2.5)
•    Low- to medium-energy scrubbers (2.5 to 6)
•    Medium- to high-energy scrubbers (6 to 15)
•    High-energy scrubbers (greater than 15)
The large amount of different Wet Scrubbers in use makes it impossible to comment on every single design in this article. However a brief overview of the most common types will enable you to understand the basic operational procedures present in all of them.

Low Energy Scrubbers:

•    The most basic design is that of a Gravity Spray Tower Scrubber. In this system the contaminated air enters at the bottom of the cylindrically shaped scrubber and rises through a mist of water sprayed from nozzles at the top. The dirty water collects at the bottom of the tank and the clean air (mist) exits from the top of the collector. This collector has a relatively low efficiency compared to other kinds of Wet Scrubbers. However it’s main advantage is it can handle very heavy dust loads without getting backed up.

•    Dynamic wet precipitators also called Wet Fan Scrubbers are a popular design used for medium energy scrubbing applications. In this system the Gas stream passes through a larger fan that is constantly kept wet with the cleaning liquid. The particles are trapped in the liquid and are then by means of centrifugal force thrown off the spinning fan blades unto the sides of the collector where they eventually settle at the bottom enabling them to be collected.

•    Orifice Scrubbers work in a very similar way to inertial separators but with one important difference, Orifice Scrubbers use a water surface to capture the dust particles. When the Gas stream enters the collector it is rapidly redirected when it comes in contact with the water surface. Causing the dust particles to be removed from the Gas stream. A greater efficiency can be obtained by the addition of liquid spray nozzles to further separate the contaminates from the Gas stream. While these are an effective filtration system one should note that they tend to be ineffective against fine particles as these tend to be redirected off of the water surface by the high surface tension.

Low to Medium Energy Scrubbers:

•    Wet Cyclone Scrubbers are nearly identical to their normal cyclone collector counterparts. In a Wet Cyclone Scrubber the Gas stream enters the collector and is then forced into a cyclone movement by the strategic placement of stationary scrubbing vanes. Liquid is introduced at the top of the collector allowing the dust particles to stick to the wet walls of the collector when they are thrown off by the vortex. As with dry Cyclone Collectors, this type of system has the benefit of few to no moving parts and it is efficient for particles up to 5um and above.

Medium to High Energy Scrubbers:

•    Packed Bed Scrubbers consist of a bed of packing media, which is then sprayed with water. The packing media allows for a very wide distribution of the water, which in turn allows the Gas stream to have the maximum contact with the water during its passage though the collector. Air enters at the bottom of the collector where it first makes contact with the water in the recirculation tank. Then it is forced up through the various layers of the filtering media, and after being sent through a Mist Eliminator is sent back into the system via the exit port at the top.

Within the category of Packed Bed Scrubbers there are three different variations on the implementation of this filtering mechanism they are:

•    Cross-flow scrubbers are designed to minimize height for low-profile applications. In this design the packed media is laid as sheets perpendicular to the Gas stream. The Gas stream enters in one side of the Scrubber and flows horizontally through it passing though the packing media and then exiting out the opposite side
•    Co-current flow scrubbers
•    Counter-current flow scrubbers

High energy Scrubbers:

•    Venturi Scrubbers make use of the Venturi effect to accelerate the Gas stream to speeds of 12,000 to 36,000 ft/min. The Gas stream enters into the Scrubber through a Venturi shaped inlet where it is sprayed with water. The water hitting the extremely high speed air causes it to instantly atomize. The very fine water droplets attach to the dust particles and form a slurry, which then falls to the bottom of the collector. After passing through a Mist eliminator the Gas stream is sent back into the system.

Advantages and Disadvantages – Wet Scrubbers

Advantages Disadvantages
Have low capital costs and small space requirements Have high operating and maintenance costs
Have low capital costs and small space requirements Require corrosion-resistant materials if used with acidic gases
Are able to collect gases as well as particulates (especially “sticky” particulates) Require a precleaner for heavy dust loadings
Have no secondary dust sources Cause water pollution; require further water treatment
Are susceptible to erosion at high velocities
Collect wet products
Require freeze protection

Common Operating Problems and Solutions – Wet Scrubbers

Problem Solution
Wet/dry buildup Keep all areas dry or all areas flooded.
Use inclined ducts to a liquid drain vessel.
Ensure that scrubber is installed vertically.
Maintain liquid seal.
Dust buildup in fan Install clean water spray at fan inlet.
Excessive fan vibration Clean fan housing and blades regularly.
Liquid pump failure Divert some of the recycle slurry to a thickener, settling pond, or waste disposal area and supply clean water as makeup.
Increase the water bleed rate.
Worn valves Use wear-resistant orifice plates to reduce erosion on valve components.
Jammed valves Provide continuous purge between valves and operating manifold to prevent material buildup.
Erosion of slurry piping Maintain pumping velocity of 4 to 6 ft/s to minimize abrasion and prevent sedimentation and settling.
Plugged nozzles Replace nozzles or rebuild heads.
Change source of scrubbing liquid.
Supply filtered scrubbing liquid.
Buildup on mist eliminators For vane-type demisters, spray the center and periphery intermittently to clean components.
For chevron-type demisters, spray the water from above to clean the buildup.

Startup/Shutdown Procedures – Wet Scrubbers

Prestart Checklist Shutdown
1. Start fans and pumps to check their rotation. 1. Shut down fan and fan spray. Insulate scrubber from operation.
2. Disconnect pump suction piping and flush it with water from an external source. 2. Allow liquid system to operate as long as possible to cool and reduce liquid slurry concentrations.
3. Install temporary strainers in pump suction line and begin liquid recycle. 3. Shut off makeup water and allow to bleed normally.
4. With recycle flow on, set valves to determine operating conditions for desired flow rates. Record the valve positions as a future baseline. 4. When pump cavitation noise is heard, turn off pump and pump gland water.
5. Record all system pressure drops under clean conditions. 5. Open system manholes, bleeds, and other drains.
6. Perform all recommended lubrications.
7. Shut down fan, drain the system, and remove temporary strainers.
1. Allow vessels to fill with liquid through normal level controls. Fill large-volume basins from external sources.
2. Start liquid flow to all pump glands and fan sprays.
3. Start recycle pumps with liquid bleed closed.
4. Check insulation dampers and place scrubber in series with primary operation.
5. Start fan and fan inlet spray. Leave inlet control damper closed for 2 min to allow fan to reach speed.
6. Check gas saturation, liquid flows, liquid levels, fan pressure drop, duct pressure drops, and scrubber pressure drop.
7. Open bleed to pond, thickener, or other drain systems so slurry concentration can build slowly. Check final concentration as cross-check on bleed rate.

Preventative Maintenance Procedures – Wet Scrubbers

Frequency Procedure


•    Check recycle flow.
•    Check bleed flow.
•    Measure temperature rise across motor.
•    Check fan and pump bearings every 8 hours for oil level, oil color, oil temperature, and vibration.
•    Check scrubber pressure drop.
•    Check pump discharge pressure.
•    Check fan inlet and outlet pressure.
•    Check slurry bleed concentration.
•    Check vibration of fan for buildup or bleeds.
•    Record inlet and saturation temperature of gas stream.
•    Use motor current readings to detect flow decreases. Use fan current to indicate gas flow.
•    Check pressure drop across mesh and baffle mist eliminators. Clean by high-pressure spraying, if necessary.

•    Check wet/dry line areas for material buildup. Clean, if necessary.
•    Check liquid spray quantity and manifold pressure on mist eliminator automatic washdown.
•    Inspect fans on dirty applications for corrosion, abrasion, and particulate buildup.
•    Check bearings, drive mechanisms, temperature rise, sprocket alignment, sprocket wear, chain tension, oil level, and clarifier rakes.
•    Check ductwork for leakage and excessive flexing, Line or replace as necessary.
•    Clean and dry pneumatic lines associated with monitoring instrumentation.

•    Verify accuracy of instruments and calibrate.
•    Inspect orifice plates.
•    Clean electrical equipment, including contacts, transformer insulation, and cooling fans.
•    Check and repair wear zones in scrubbers, valves, piping, and ductwork.
•    Lubricate damper drive mechanisms and bearings. Verify proper operation of dampers and inspect for leakage.

Electrostatic Precipitators

Electrostatic Precipitators use electrostatic forces to collect dust from the Gas stream. Several high power Direct Current Discharge Electrodes are places inside the collector. The incoming Gases pass by the first set of Discharging Electrodes (ionizing section) that give the particles a negative charge (ionization). The now ionized particles travel pass the next set of electrodes (the collection section) that carry a positive charge. The positively charged plates attract the negatively charged particles causing them to collect on the plates. Cleaning is accomplished by vibrating the electrodes either continuously, or at a timed interval, causing the captured dust to fall off into a hopper below. All of this can be done while the system is operating normally.

Electrostatic Precipitators are best used in an ambient capture type system with low particle loads. Without an automated self-cleaning feature, this type of collector can very easily reach its maximum particle retention limit, which will result in a system failure. Further, for a high dust load system a great amount of dust storage is needed. Media Filtration (Baghouse) or Pleated Filtering Media (Cartridge Collectors) provide a much great surface area for dust storage than Electrostatic Precipitator systems do.  However the advantages of this system are great for their intended applications. They have the ability to be extremely efficient (in excess of 99.9% in some cases), can function within vary large temperature ranges (between 700 °F and -1300°F), and can have large flow rates with minimal pressure and temperature changes. They are also very well suited for the collection of fine dust particles as well as materials like acids and tars which other system may have difficulty with.

All electrostatic Precipitators have four main components:

•    A Power supply to provide the system with electricity
•    An Ionizing section to negatively charge the incoming particles
•    A cleaning system designed to remove collected particles from the Electrode collection plates
•    A housing to enclose the Precipitator section

Within the category of Electrostatic Precipitator Collectors, there are two main types of systems:

•    High Voltage Single State Precipitators (Cottrell type)
•    Low Voltage Dual State Precipitators (Penny type)
High Voltage Single State Precipitators are further divided between two main designs:

Plate Precipitators are made up of several flat parallel plate collectors that are usually between 8 and 12in apart. Placed directly in the middle of each set of directly adjacent plates are a series of high voltage (40,000-70,000 volts) DC Discharge Electrodes. As the Gas stream passes through the plates it is ionized by the Discharge Electrodes and then immediately deposited unto the collection plates. The plates are then cleaned by vibrating the plates causing the debris to fall into a hopper or collection bin below. The majority of Single State Precipitators in use today are of the plate variety.

Tubular Precipitators operate in the same manner as Plate Precipitators however in a different configuration. This design uses a tubular shaped collection device with the Discharge Electrodes placed in the middle of the tube. As the Gas stream flows through the tube it is first ionized by the Discharge Electrode in the center, and then the charged particles are attracted to the inside of the positively charged tube. The cleaning mechanism can be one nearly identical to that of Plate Precipitators or it can be used as part of a Wet Static Precipitator system, wherein the sides of the Precipitator are flushed with water thereby cleaning them.
Tubular Precipitators are widely used in the mineral processing industry. They are highly valuable for use in high temperature Gas streams (boiler exhaust gas on power plants) because of their ability to adjust to the expansion and contraction of metal parts in the system. In addition this type of collector is also able to handle vapor collection, containing adhesive, “sticky”, radioactive, and extremely toxic compounds.

Low Voltage Dual Stage Precipitators contain several grounded plates about one inch from each other with another intermediate plate that also contains a charge. This system uses a much lower voltage than the High Voltage type (a 13,000-15,000 volt DC supply with intermediate supply of 7,500 compared to 40,000 to 70,000). This type of system is widely used to collect fumes and particles generated by welding, grinding or burning operations. They are also used in hooded and ducted welding machines and welding booths.
Low Voltage Dual Stage Precipitators have the advantages of being highly efficient, the possibility of a self contained washing system, and a longer service life since cleaning is only required on a monthly basis. However because maintenance requires removing the Precipitator Frames and the manual cleaning of the cleaning assemblies which are quite delicate, this type of Precipitator requires a great amount more care and caution to be used when performing maintenance.

Advantages and Disadvantages – Electrostatic Precipitators

Advantages Disadvantages
Have collection efficiencies in excess of 99% for all particulates, including sub-micron-sized particles Have high initial investment costs
Usually collect dust by dry methods Do not respond well to process changes such as changes in gas temperature, gas pressure, gas flow rate, gaseous or chemical composition, dust loading, particulate size distribution, or electrical conductivity of the dust
Have lower pressure drop and therefore lower operating costs Have a risk of explosion when gas stream contains combustibles
Can operate at high temperatures (up to 1200º F) and in colder climates Product ozone during gas ionization
Can remove acids and tars (sticky dust) as well as corrosive materials Require large space for high efficiency, and even larger space for dust with low or high resistivity characteristics
Allow increase in collection efficiency by increasing precipitator size Require special precautions to protect personnel from exposure to high-voltage
Require little power Require highly skilled maintenance personnel

Unit Collectors

For certain applications, Unit Collectors are a better choice for a facilities needs than a conventional Central Collection System. These collectors control contamination at their source. They benefit from low initial cost, direct return of captured material to the main material flow, and very low space requirements. These collectors are best used when the dust source is isolated, portable or changes position often. Some examples of instances where this type of collector might be useful are dust-producing operations, such as bins and silos or remote belt-conveyor transfer points.

Depending on the particular desired application is there are a number of different designs available to choose from with a capacity of 200 to 2,000 ft3/min. The two main types are:

•    Fabric Collectors
•    Cyclone Collectors

Unit Fabric Collectors are very similar to their bigger relatives used in a Central Collection System. They usually employ either a Mechanical Shaker, or a Pulse Jet system for cleaning. This type is well suited for the collection of fine particles such as in the mineral processing industry.
Unit Cyclone Collectors also operate on the same principles are the kind used in Central Collection Systems. Dust is collected and deposited into a hopper, which then can be removed later for cleaning. This type of collector is best used in the collection of coarse of larger particles.

Central Collection System

Every Dust Collection System must have a Central Collection System in place in order to send the contaminated air to the filtration system. A Central Collection System consists of a series of collection inlets, and the necessary duct work to transport the dust laden Gas stream to the collector and afterward on to be either recirculated back into the facility or dispersed into the atmosphere. The pressure in this duct system is supplied by the Fan and Motor System.

Fan and Motor

Choosing the right Fan and Motor System requires a number of different factors to be taken into consideration including but not limited to:

•    Volume required
•    Fan static pressure
•    Type of material to be handled through the fan (For example, a Radial Blade Fan should be used with fibrous material or heavy dust loads, and a nonsparking construction must be used with explosive or flammable materials.)
•    Limitations in space
•    Acceptable levels of noise caused by the fan
•    Required operational temperature (For example, sleeve bearings are suitable to 250º F; ball bearings to 550º F.)
•    Adequate size to handle pressure and volume requirements with minimum horsepower usage
•    Whether any corrosive materials are going to be handled and what protective coatings may be needed
•    Ability of fan to accommodate small changes in total pressure while maintaining the necessary air volume
•    Need for an outlet damper to control airflow during cold starts (If necessary, the damper may be interlocked with the fan for a gradual start until steady-state conditions are reached.)

Also to be considered is what type of drive system for the fan you plan to use. A Direct Drive fan is run directly off of a drive shaft from the motor, this provides for lower space needs, but places the fan at a constant unchangeable speed. While Belt Driven fan, which uses a belt to flywheel configuration needs more space, it can allow for the fan speed to be easily changed which is vital for some applications.

There are two main types of fan designs that are used in industrial applications:

•    Centrifugal fans
•    Axial-flow fans

A Centrifugal Fan (also called a Squirrel-cage fan for its resemblance rodent exercise devices) is a fan build with blades (or ribs) surrounding a central hub.  The air enters into the side of the fan and then turns 90° and is accelerated and thrown out of the fan by means of centrifugal force.  The diverging shape of the scroll also converts a portion of the velocity pressure into static pressure. The fan is driven by means of a drive shaft that extends out from the center hub of the fan.

There are three main types of Centrifugal fan blades that can be used:

•    Forward Curved Blades
•    Backward Curved Blades
•    Straight Radial Blades

Forward Curved Bladed Fans have blades that are curved in the direction of the rotation of the fan. These fans are highly sensitive to particulate buildup and are used for high airflow, low pressure applications.

Backward Curved Bladed Fans contain blades that are positioned away from the fans rotation direction. These fans will provide an efficient operation, and can be used in Gas streams with light to medium particle concentration. While they can be fitted with wear protection, this type of blade can still become backed up if the particle load gets to be too heavy. This fan type is most often employed in medium speed, high pressure, and medium airflow applications.

Straight Radial Bladed Fans provide the best choice for heavy particle loads. This design features a series of blades that extend straight out from the center hub. This design is used for high pressure, high speed and low volume applications.

Fan dampeners

Fan dampeners are metal plates that can be adjusted to reduce the energy usage of the fan. Placed on the Outlet port of a fan, they are used to impose a flow resistance to control the Gas stream. They also can be placed on the Inlet port, which can perform the same function, as well as redirect how the Gas stream enters into the fan.

Axial Flow Fans

Axial Flow Fans have blades that are mounted unto a center drive shaft. They induce the air to move parallel to the shaft the blades are mounted on by the screw-like action of the propellers. The air is blown across the axis of the fan hence the name Axial Flow Fans. This type of fan is commonly used in systems with low resistance levels.

The three main different designs of Axial Flow Fans are:

•    Propeller
•    Tube Axial
•    Vane Axial

Propeller Fans is the most simple fan design. It is used to move large an amount of air against very low static pressure from the rest of the system. General and Dilution ventilation are two common uses for this type of axial fan.

The Tube Axial design is very similar to a normal propeller type fan, except that the propeller is enclosed in an open ended cylinder. This design is more efficient than simple propeller types and is often used in moving Gas streams filled with condensable fumes or pigments.

Vane Axial Fans are nearly identical to Tube Axial Fans. But these contain specially attached vanes that are designed to straighten the Gas stream as is passes through the fan. These can produce high static pressures relative to this type of fan. However these fans are in most applications used only for clean air.

Fan Rating Table

Once all of the preceding material has been examined, the final step in the selection of the proper fan for your system is to consult a Fan Rating Table. This is used to list all of the specifications for the various fans produced by a certain manufacturer. When reviewing a Fan Rating Table one must keep these few points in mind:

•    The rating tables show all of the possible pressures and speeds that can be achieved within the limits of the fan’s normal operation range.
•    A fan that operates at a single or fixed speed and has a fixed blade setting will only have one possible rating. The only way to gain multiple ratings is by varying the speed and the blade setting.
•    It may be possible to obtain the same fan in different construction classes
•    Increasing the exhaust volume will in turn increase the static and total pressure in the system

Fan installation

Once a system has been installed in the field, inevitably certain differences between design and field installation will require a field test to be done to find the exact measurements of static pressure and volume. This step is crucial in order for a proper fan system to be selected. A few brief points are good to keep in mind during the installation process that can cause your real world values to change from the original design specifications:

•    Elbows and bends near the fan’s discharge will increase the systems resistance thereby lowering your fan’s performance
•    Make sure to install the impeller in the proper direction desired.
•    Certain types of fittings such as elbows, mitered elbows and square ducts, can cause a nonuniform airflow which in turn will again lower performance
•    Build up of debris in the inlets, blades, passages as well as obstructions should be checked and remedied
•    In a belt driven system one must check the motor sheave and fan sheave are properly aligned and that proper belt tension is present

Electric Motors

An Electric Motor is what supplies the power necessary to operate the fan (Blower) in the Dust Collection System.  Electric Motors are usually grouped as either Induction, or Synchronous designs. Induction designs are the only ones that are used in Dust Collection Systems today.
Induction Motors normally operate on three phase AC current. The two most common types used in Dust Collection Systems are:

•    Squirrel Cage Motors are generally used where a constant speed is desired
•    Slip Ring Motors by contrast are general purpose or continuous rated motors that are used in applications where there is a need for an adjustable speed in the motor.

Another important design consideration is whether the Motor is one of these two enclosure designs:

•    Drip Proof and Splash Proof Motor are types of Open Enclosed Motors, which use a kind of electric motor enclosure that has vents to allow airflow but to prevent liquids and solids from entering the motor. This design is not suitable for application where particles that can damage the interior of a motor are found in the ambient atmosphere around the motor.
•    Totally Enclosed Motors have an exterior fan mounted unto the backside of the motor drive end. The fan blows air over the motor enclosure to provide additional cooling for the motor. Since the actual motor is totally enclosed this design provides the best protection against dust and other contaminates that might damage the motor if allowed inside.
Both Types can also be constructed in explosion and dust ignition proof models to protect against accidental ignition of dust particles.
The following factors need to be considered when choosing which motor meets your needs:

•    Horsepower and RPMs
•    Power supply needs such as voltage, single or three phase AC and frequency
•    The environment in which the motor will have to operate (humidity, temperature, open flames or corrosive elements
•    What kind of load is going to be placed on the motor (fan and other drive mechanisms) and power company restrictions on cold starts.
•    Sufficient power supply for cold starts
•    Overload protection needed for the particular motor

Fan & Motor Troubleshooting Chart

Symtom Probable Cause Solution
Insufficient airflow, low ft3/min Fan
Forward curved impeller installed backwards Reinstall impeller
Fan running backwards Change fan rotation by reversing two of the three leads on the motor
Impeller not centered with inlet collar(s) Make impeller and inlet collar(s) concentric
Fan speed too low Increase fan speed by installing smaller diameter pulley
Elbows or other obstructions restricting airflow Redesign ductwork
Install turning vanes in elbow
Remove obstruction in ductwork
No straight duct at fan inlet Install straight length of ductwork, at least 4 to 6 duct diameters long, where possible
Increase fan speed to overcome this pressure loss
Obstruction near fan outlet Remove obstruction or redesign ductwork near fan outlet
Sharp elbows near fan outlet Install a long radius elbow, if possible
Install turning vanes in elbow
Improperly designed turning vanes Redesign turning vanes
Projections, dampers, or other obstructions near fan outlet Remove all obstructions
Duct System
Actual system more restrictive (more resistant to flow) than expected Decrease system’s resistance by redesigning ductwork
Dampers closed Open or adjust all dampers according to the design
Leaks in supply ducts Repair all leaks in supply duct
Too much airflow, high ft3/min Fan
Backward inclined impeller installed backwards (high horsepower) Install impeller as recommended by manufacturer
Fan speed too fast Reduce fan speed
Install larger diameter pulley on fan
Duct System
Oversized ductwork; less resistance Redesign ductwork or add restrictions to increase resistance
Access door open Close all access and inspection doors
Low static pressure, high ft3/min Fan
Backward inclined impeller installed backwards (high horsepower) Install impeller as recommended by manufacturer
Fan speed too high Reduce fan speed
Install larger diameter pulley on fan
Duct System
System has less resistance to flow than expected Reduce fan speed to obtain desired flow rate
Gas Density
Gas Density lower than anticipated (due to high temperature gases or high altitudes) Calculate gas flow rate at desired operating conditions by applying appropriate correction factors for high temperature or altitude conditions
Low static pressure, low ft3/min Duct System
Fan inlet and/or outlet conditions not same as tested Increase fan speed
Install smaller diameter pulley on fan
Redesign ductwork
High static pressure, low ft3/min Duct System
Obstructions in system Remove obstructions
Duct system too restricted Redesign ductwork
Install larger diameter ducts
High horsepower Fan
Backward inclined impeller installed backwards Install impeller as recommended by manufacturer
Fan speed too high Reduce fan speed
Install larger diameter pulley on fan
Duct System
Oversized ductwork Redesign ductwork
Access door open Close all access/inspection doors
Gas Density
Calculated horsepower requirements based on light gas (e.g., high temperature or high altitude) but actual gas is heavy (eg.,cold startup) Replace motor
Install outlet damper, which will open gradually until fan comes to its operating speed
Fan Selection
Fan not operating at efficient point of rating Redesign system
Change fan
Change motor
Fan does not operate Electrical
Blown Fuses Replace Fuses
Electricity turned off Turn on Electricity
Wrong voltage Check for proper voltage on fan
Motor too small and overload protector has broken circuit Change motor to a larger size
Broken belts Replace belts
Loose pulleys Tighten or reinstall pulleys
Impeller touching scroll Reinstall impeller properly

Dust Disposal

After the Airstream has been cleaned, the dust that has been collected must be disposed of in a proper way to ensure that recontamination is avoided.  In many cases where the collected material is of value, it can be returned to the product stream and reused. However this is not practical in all applications. Minimizing secondary dust problems is also a key component in an effective dust disposal system. Operations such as loading and unloading of the collected material, or the transportation of wet slurry can present further contamination problems that need to be addressed.
All Disposal Systems have to accomplish these four objectives without further contaminating the environment, in order to be effective in their role in the Dust Collection System:

•    Collected material from the hopper must be removed
•    Transportation to storage
•    Storage of the collected material
•    Treatment necessary before final disposal

Removal Of Dust From The Hopper

The hopper must be emptied of the collected dust on a regular basis to prevent overfilling. Often this process is done while the collector is still operating. If this is the case, rotary air locks, or tipping valves need to be used in order to maintain a positive air seal and thus avoid massive pressure loss that would be detrimental to the normal operation of the system. Some materials display what is called a bridging tendency, which is a tendency to stick together and form long strands that can over time build up into bridge like formations that can impede the normal operations within a hopper. If material of this kind is present in the system, special equipment such as bin vibrators, rappers, or air jets should be used to ensure that the material that has a bridging tendency does not interfere with normal operation of the hopper.

Dust Transportation

Once the dust has been removed from the collector, it must be transported to a storage area where is can be given any final treatments needed before it is disposed of.  There are four main systems that can be used to transport the collected material to holding there are:

•    Screw conveyers
•    Air conveyers
•    Air Slides
•    Pressurized piping system for wet material (Slurry)

Screw conveyers use rotating shaft to move material to the desired location. These systems are very effective methods of dust transportation.  However several areas of concern in this type of system are that they tend to have a noted lack of easy access for maintenance purposes, the castings and bearings can wear out easily when used with abrasive materials with air leaks being the end result.

Air Conveyers are used mainly for dry dust applications. Making use of a high velocity low air volume principle, these collectors are a great choice because of their few moving parts and their ability to move dust both vertically and horizontally. The main concerns with this system are that the piping can over time suffer from excessive wear from abrasive compounds. They also require large initial investments of capital and have higher operating costs.

Air Slides are widely used for light dust loads with nonabrasive materials. Air fluidization of the dust is the main operating principle behind this system. This system while able to transport great amounts of material has the downside of only being able to do so in a horizontal direction. Areas of concern are the need to maintain a constant down pitch in the ductwork, and greater maintenance costs.

Pressurized piping systems are needed when transporting the slurry made from using a Wet Scrubber design. This system is used to send the slurry to a settling pond for further treatment. Great care must be taken by the operators of this system to ensure that no leakage occurs which would result in an environmental hazard caused by water pollution.

Dust Storage

Storage tanks and Silos are the most common storage locations for dry dust compounds after their collection.  These sites are then fitted to allow loading of the material into enclosed trucks or rail cars below.
When using a wet collection system often times a settling pond is needed.  In a settling pond the captured particles are separated by means of the process of decantation.  The slurry from the Wet Scrubbers is left to sit in a large pond or basin, allowing the captured particles to over time slowly settle to the bottom of the pond; afterwards the clean water is discharged. Again certain factors to consider in the use of a settling pond are that the water holding area can only be decanted in the warmer, dryer part of the year, and in most instances two settling ponds are needed to operate efficiently.

Final Disposal

When deciding on a final disposal method, one must remember that great care needs to exercised in order to avoid recirculation of the dust by the wind. Sometimes in because of this concern, and for easier transportation, the captured material is processed into pellets before final disposal.  Generally four different options are available for the final disposal of the collected material:
•    Placement in a landfill
•    Recycling
•    Byproduct utilization
•    Collected material may be suitable for backfilling land fills and quarries

Selection of a Dust Collector

The differences in design, operation, efficiency, space requirement, construction, and maintenance needs, as well as the initial start up, operating, and maintenance costs differ greatly between various products and systems. However in choosing which system will meet your needs the best, the following point should be considered:

Dust concentration and Particle size – Within any kind application the specific sizes and dust concentrations can vary enormously. Therefore, knowing the exact range of particle size and concentration levels that will be present will be vital in your choosing the proper Collection System.

Degree of collection required – How intensive of a filtration action is needed is determined by several factors. The exact dangers and hazards of the contaminates to be captured, its potential as a public health risk or nuisance, site location, the allowable emission rate by the regulatory body for the given substance, characteristics of the dust, and any recyclable value.

Characteristics of the Gas stream – Differences in Gas stream temperatures and humidity levels can great affect certain types of collectors. For example Gas temperatures above 180° F (82°C) will destroy many types of filter media (Filter Bags) used in Fabric Collectors (Baghouses). Water vapor or steam can blind certain types of Filter Media. Corrosive and other chemicals can erode certain metals and other materials used in the construction of many Collectors.

Types of Dust – Certain types of Collectors have a great deal of physical contact between the particles and the Collector itself. A number of different materials such as silica or metal ore are quite abrasive and can cause erosion through prolonged contact with the Collector. Other “sticky” compounds can attach themselves to the interior surfaces of the collector and cause blockages. The size and distinct shape of some types of dust render certain collection methods useless. When certain types of materials are fluidized into the air they become highly combustible. Under these circumstances Electrostatic Precipitators are instantly ruled out, along with most Inertial Separators.

Disposal Methods – Differences in disposal methods betweens different locations. Collectors can be arranged to unload their collected matter either in a continuous mode or at a predetermined time interval. Removal of collected matter from dry systems can also result in secondary causes of dust pollution and contamination. While using a Wet Scrubber System will eliminate this concern, proper handling of slurry created during the cleaning cycle will involve an entirely different set of problems, such as precautions against water pollution, and proper care and maintenance of the retention ponds.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

At least 281 combustible dust fires and explosions occurred in general industry between 1980 and 2005 in the United States, which caused at least 119 fatalities and 718 injuries; including seven catastrophic dust explosions in the past decade, involving multiple fatalities and significant community economic impact; and occurred in a wide range of industries and involved many types of combustible dusts.

According to a report by the US Chemical Safety Board (CSB) a major factor that lead to the high amount of incidents was the overall lack of education regarding the danger of Dust Explosions. Without this information, plant operators are not able to implement proper safety precautions, and adequately train their personal about the precautions they need to take to minimize the chance of a Dust Explosion occurring in their facility.  This article has been prepared to help bring awareness to the dangers of Dust Explosions, and what precautions can be taken to avoid them.

What Is A Dust Explosion?

A factory that has been destroyed by a Dust Explosion

A Dust Explosion that begins in the Dust Collection System can lead to the destruction of an entire facility.

Most solid organic materials, in addition to many metals and inorganic nonmetallic materials, when reduced to a finely divided size, and sufficiently dispersed into the atmosphere will explode under the right conditions. Many combustible dusts are intentionally manufactured for a wide range of applications such as Metallic Powder Coatings, or certain foodstuffs such as Corn Starch, Flour, and Granulated Sugar. Others are produced during the manufacture and transport of materials such as wood processing, and stone quarrying. Additionally, during the manufacturing process for many materials, actions such as milling, polishing, and transportation may create substantial amounts of dust that can later accumulate on a wide range of surfaces.

Any industry that produces materials of a fine particle size that are combustible, and many that simply though their day-to-day operation create large amounts of secondary dust are at risk for Dust Explosions. Industries such as Metal, Food, Plastic, and Wood Processing are just a few that are at risk for this kind of industrial accident.

The Anatomy of a Dust Explosion

The Beginnings

The basics of combustion deal with the so called “Fire Triangle” that illustrates the importance of the three main factors that need to be present for combustion to take place. These three are Fire, Heat (Ignition Source) and Oxygen. With regards to Dust Explosions, we need to add another two ingredients to create what has been termed the “Dust Explosion Pentagon” Dispersion and Confinement. When all five of these factors are present in the right balance, a dust explosion will occur. The more of these factors that can be controlled or be kept below the combustion threshold, the less likely there will be an incident.

When a material is finely divided into a dust or power form it in most cases it becomes much more likely to combust than it would in a solid state. The reason for this is because when a material is smaller in size, and is dispersed into the air, it creates a much larger surface area to ignite. For example, a 1 kg sphere of a material with a density of 1g/cm3 would be about 27 cm across and have a surface area of 0.3 m3. However, if it was broken up into spherical dust particles 50µm in diameter (about the size of flour particles) it would have a surface area of 60 m² This greatly increased surface area allows the material to burn much faster, and the extremely small mass of each particle allows it to catch on fire with much less energy than the bulk material, as there is no heat loss to conduction within the material.

The source of ignition in a Dust Explosion is often times very difficult if not impossible to determine with absolute certainty. This is because in an industrial setting there is such a larger amount of possible ignition sources that after an incident, it cannot always be pinpointed with absolute certainty.  Some possible sources include, Open Flames, Electrostatic Discharge, Friction, Chemical Reactions, Arcing (From machinery or other equipment) and Hot Surfaces.

Primary and Secondary Explosions

Primary Dust Explosions, in an industrial setting, usually involve a dust cloud (Dispersed Dust) that is ignited by an ignition source. This explosion while possibly involving a substantial amount of dust is often not the most devastating. That is because this initial explosion can cause a pressure wave that can dislodge settled dust from other areas within a facility (Such as on the top of structural elements like beams and columns, high shelving, and machinery, or other areas that dust and debris may collect) causing it to disperse and then cause a much larger explosion that is termed a Secondary Dust Explosion. The majority of fatalities, and damage caused by dust explosion incidents, are actually caused by Secondary Dust Explosions.

Conditions That Lead To A Dust Explosion

The same CSB report cited earlier, after having discussed several different Industrial Dust Explosion Incidents, concluded that while all had many different factors that contributed to the respective incidents, all had the following circumstances in common:

* Facility management failed to conform to NFPA (National Fire Protection Agency) standards that would have prevented or reduced the effects of the explosions.
* Company personnel, government standards enforcement officials, insurance underwriters, and health and safety professionals inspecting the facilities failed to identify dust explosion hazards or recommend protective measures.
* The facilities contained unsafe accumulations of combustible dust and housekeeping to remove such accumulations was inadequate.
* Workers and managers were often unaware of dust explosion hazards.
* Procedures and training to eliminate or control combustible dust hazards were inadequate.
* Previous fires and other warning events were accepted as normal, and their causes were not identified and resolved.
* Dust collectors were inadequately designed or maintained to minimize explosions.
* Process changes were made without adequately reviewing them for potential hazards.

Listed here are a few of the summery reports published by the CSB. As you will see the above-mentioned factors all played a role in the eventual incidents.

Organic Dust Fire and Explosion: Massachusetts (3 killed, 9 injured)

In February 1999, a deadly fire and explosion occurred in a foundry in Massachusetts. The Occupational Safety Health Administration (OSHA) and state and local officials conducted a joint investigation of this incident. The joint investigation report1 indicated that a fire initiated in a shell molding machine from an unknown source and then extended into the ventilation system ducts by feeding on heavy deposits of phenol formaldehyde resin dust. A small primary deflagration occurred within the ductwork, dislodging dust that had settled on the exterior of the ducts. The ensuing dust cloud provided fuel for a secondary explosion, which was powerful enough to lift the roof and cause wall failures. Causal factors listed in the joint investigation report included inadequacies in the following areas:

* Housekeeping to control dust accumulations;
* Ventilation system design;
* Maintenance of ovens; and,
* Equipment safety devices.

Organic Dust Fire and Explosion: North Carolina (6 killed, 38 injured)

In January 2003, devastating fires and explosions destroyed a North Carolina pharmaceutical plant that manufactured rubber drug-delivery components. Six employees were killed and 38 people, including two firefighters, were injured. The U.S. Chemical Safety and Hazard Investigation Board (CSB), an independent Federal agency charged with investigating chemical incidents, issued a final report2 concluding that an accumulation of a combustible polyethylene dust above the suspended ceilings fueled the explosion. The CSB was unable to determine what ignited the initial fire or how the dust was dispersed to create the explosive cloud in the hidden ceiling space. The explosion severely damaged the plant and caused minor damage to nearby businesses, a home, and a school. The causes of the incident cited by CSB included inadequacies in:

* Hazard assessment;
* Hazard communication; and
* Engineering management.

The CSB recommended the application of provisions in National Fire Protection Association standard NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids, as well as the formal adoption of this standard by the State of North Carolina.

Organic Dust Fire and Explosion: Kentucky (7 killed, 37 injured)

In February 2003, a Kentucky acoustics insulation manufacturing plant was the site of another fatal dust explosion. The CSB also investigated this incident. Their report3 cited the likely ignition scenario as a small fire extending from an unattended oven, which ignited a dust cloud created by nearby line cleaning. This was followed by a deadly cascade of dust explosions throughout the plant. The CSB identified several causes of ineffective dust control and explosion prevention/mitigation involving inadequacies in:

* Hazard assessment;
* Hazard communication;
* Maintenance procedures;
* Building design; and,
* Investigation of previous fires.

Metal Dust Fire and Explosion: Indiana (1 killed, 1 injured)

Finely dispersed airborne metallic dust can also be explosive when confined in a vessel or building. In October 2003, an Indiana plant where auto wheels were machined experienced an incident, which was also investigated by the CSB. A report has not yet been issued, however, a CSB news release told a story similar to the previously discussed organic dust incidents: aluminum dust was involved in a primary explosion near a chip melting furnace, followed by a secondary blast in dust collection equipment.

Prevention, Safety and Mitigation

Now that we have discussed many of the contributing factors that can lead to a Dust Explosion, we are going to highlight several areas that if given the proper attention, will lead to a safer working environment, and lessen the potential for property damage bodily harm.

Hazard Analysis

We have discussed the great danger that Dust Explosions can pose to life and property. Now we have listed several areas that if given the proper attention will greatly reduce the probability of a dust explosion occurring, and should one occur, lessen the severity of said explosion, possibly saving lives and lessening the damage to the facility in the process.

Facility Dust Hazard Assessment

Being aware that the possibility of a Dust Explosion exists is the first step to avoiding one. As mentioned previously, most dusts or powders will burn and if dispersed in the air in the right proportions and may explode. The same CSB study quoted earlier found that despite the long history of Dust Explosions in industry, in many cases the hazards involved with explosive dusts were largely ignored by plant operators, as well as by outside insurance auditors and government inspectors. Therefore, recognizing the great potential for this kind of accident during the initial design of the facility and while doing regular hazard analysis, are crucial

Here are some of the items to look for when conducting a facility hazard analysis with regard to the potential for Dust Explosions.

Dust Combustibility

Above all else, it must be determined whether or not that various types of dust produced in the facility are indeed combustible. As stated before, most materials in dust or powder form will burn when dispersed into the air in the right proportions. However, those proportions vary with each material. Therefore, it is vital for those responsible to gather as much data as possible about the particular materials present in the facility. One potential source of said data is the particular material’s MSDS or Material Safety Data Sheet. In some cases, additional information such as combustibility test results will be available from chemical manufacturers. However as noted before, many times a manufacturer MSDS may be lacking sufficient data regarding the combustibility of the material in dust or powder form. Therefore additional testing may be necessary to determine this information.

Electrical Considerations

Areas that require a special electrical equipment classification due to the presence (or potential presence) of dubitable dust need to be identified during a facility hazard analysis. There are several published sources of guidelines and/or regulations regarding special electrical equipment classification. These include: The OSHA Electrical standard (29 CFR Part 1910
Subpart S), NFPA 70, the National Electrical Code®, and NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (classified) Locations for Electrical Installations in Chemical Process Areas.

Several of these guidelines identify three different groups of combustible dusts, (Metal, Carbonaceous and Other) and the different safety considerations that are needed for each. For example Metal dusts are considered electrically conductive; therefore special care needs to be taken to ensure that no electrical current can pass through layers of the dusts causing short circuits and arcs, which could then lead to an ignition. Additionally, in certain industrial settings, other high-energy ignition sources such as welding arcs may be present and need to be accounted for.

Potential For Dust Accumulation

The exact amount of dust accumulation necessary for an explosion to occur can vary greatly. As discussed earlier variables such as particle size, methods of dispersion, ventilation system models, air currents, physical barriers and volume of the area where the airborne dust exists can all vary in each different type of dust. With the site-specific data at hand, potential areas of concern can be identified. And the hazard analysis can then be tailored to the specific circumstances in each area and the full range of variables affecting the hazard.

Even seemingly small amounts of accumulated dust can cause catastrophic damage. The CSB estimated, for example, that the explosion that devastated a pharmaceutical plant in 2003 and killed six employees was caused by dust accumulations mainly under 0.25 inches deep. The NFPA warns that more than 1/32 of an inch of dust over 5 percent of a room’s surface area presents a significant explosion hazard.

Many different locations throughout a facility can be a potential starting point for a conflagration. An area where dust is concentrated is an obvious place to start. In Dust Collectors for example, a combustible mixture of diffused dust and air can be found whenever the Collector is operating. Additionally, locations where dust can settle whether occupied, or concealed spaces (such as in ceiling rafters, the tops of shelving, etc). When conducting the Hazard Analysis, careful consideration needs to be given to all possible scenarios in which any previously identified settle dust can be dispersed into the air, either though normal operations, or potential failure modes.

Precautionary Measures

After hazards have been assessed and hazardous locations are identified, one or more of the following prevention, protection and/or mitigation methods may be applied.

Dust Control

Controlling the amount of dust generated, where it is generated, and the dispersion of it throughout the facility, is key to reducing the likelihood of an explosion from occurring. The following steps should be taken in this regard:

* Minimize the amount of dust that escapes from processing equipment and ventilation systems.
* Install a Dust Collection System and monitor it closely to ensure it is operating properly.
* Where possible, install materials (Surfaces) that collect dust poorly and facilitate easy cleaning.
* Inspect and note all hidden or concealed spaces where dust accumulation might occur.
* Maintain a set schedule for cleaning all dust prone areas, and follow it closely.
* Use cleaning methods that do not themselves generate dust clouds when ignition sources are present.
* Locate Relief Valves away from dust hazard zones.
* Maintain a comprehensive dust control program, with hazard dust inspections, testing, housekeeping, and control initiatives.

In several of the cases highlighted earlier, the initial explosion spread by means of ductwork that connected various equipment (usually the Dust Collection System, and/or different parts of the ventilation system) throughout the plant. It is therefore vital that these ductwork systems be fitted with isolation values and inspected regularly to remove excess sitting dust accumulations.

Additionally, certain dust generating operations (such as the use of abrasives, blasting, grinding, or buffing) fall under OSHA  (or similar governmental agencies) ventilation requirements.

Ignition Control

Along with Dust Control, controlling all possible ignition sources also plays a major role in any comprehensive Dust Control Program. Along with Electrical Considerations, there are many other areas that merit attention with regard to ignition potential. Here are several key recommendations for controlling possible Dust Ignition sources.

* Proper Installation, Classification, Operation, and Maintenance of all Electrical Equipment and Wiring (Class II wiring methods and equipment such as “dust ignition-proof” and “dust-tight” should be employed)
* Employ adequate Static Electricity control methods such as Grounding Wires/Rods, etc.
* Limit Smoking, Open Flames, and Sparks in work area.
* Limit or isolate sources of mechanical sparks and friction
* Separate foreign materials that may ignite combustibles from process materials.
* Limit contact between heated surfaces and heating system from combustible dusts.
* Install spark arrestors/spark traps in all dust collector ductwork.

Further resources including US regulation, guidelines, and recommendations can be found in the following sources:

* NFPA 654, Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids
* OSHA’s Powered Industrial Trucks standard (29 CFR 1910.178).

Damage Control

Despite the best efforts of all parties involved, incidents may still occur. It is therefore, the wise course of action is to prepare for the worst, and implement a strategy that will reduce the severity of such an incident should it occur. The following is a list of recommended steps to take to minimize the impact of a Dust Explosion:

* Separate, and Segregate the Hazard to the extent possible. Place distance between the hazard and the work area, and isolate the hazard with barriers where possible.
* Install deflagration venting.
* Install pressure relief valves on applicable equipment.
* Employ Spark/Ember detection systems, and extinguishing equipment.
* To the extent possible, install explosion protection system, including sprinkler systems, and other assorted specialized suppression techniques.

Proper Employee & Management Training

Even with all of the aforementioned precautions, without a workforce, both employees and management, that have been properly educated about the dangers of Dust Explosions, and safety procedures to reduce the likelihood of their occurrence, and control, and limit the damage should they occur, there still remains high degree of probability for a Dust Explosion occurring.


Workers that are trained in preventing, and proper incident response techniques are integral to the safe operation of any facility. They are the people closest to the hazard, if these ones are trained to recognize and prevent these types of occurrences from taking place, they can accomplish much in this regard. These ones should also be encouraged to feel free to report unsafe working conditions, or areas where there could be an improvement in safety standards. Therefore all employees, whether they are working directly in hazard areas or not, should be adequately trained in safe work practices applicable to their job tasks, as well as on the overall plant programs for dust control and ignition source control. Periodic refresher courses should also be arranged to keep these safety issues fresh in their minds, and up to date with any possible changes to the hazard conditions themselves.


A qualified team of managers should be responsible for conducting a facility analysis (or for having one done by qualified outside persons) prior to the introduction of a hazard and for developing a prevention and protection scheme tailored to their operation. Supervisors and managers should be aware of and support the plant dust and ignition control programs. Their training should include identifying how they can encourage the reporting of unsafe practices and facilitate abatement actions.


The dangers of Dust Explosion are quite real; they have caused great amounts of damage to property, and have cost many lives. The importance of implementing a comprehensive dust control program, including hazard analysis, implementation of proven dust control and ignition control techniques, damage mitigation, and employee and management training cannot be overstated.

View this video report by the CSB

About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

PHILADELPHIA (January 4, 2011) – Four Prisons in the State of Pennsylvania have reached a settlement with the Environmental Protection Agency of alleged Clean Air Act violations. The settlement with the Commonwealth of Pennsylvania’s Department of Corrections and the Department of General Services, includes provisions that will include new pollution control technology being installed, and  additional reporting requirements at the four correctional facilities in Muncy, Bellefonte, Huntingdon and Somerset, Pa.

“Today’s settlement will improve the air quality in four Pennsylvania communities,” said Shawn M. Garvin, EPA Mid-Atlantic Regional Administrator.  “It’s important that all sources of air emissions, including prisons, comply with environmental regulations to ensure that the standards are met in nearby communities.”

The exact terms of the settle require each location to make improvements to its boiler plants to reduce emissions, including particulate matter, sulfur dioxide and nitrous oxides. These pollutants can cause respiratory problems, exacerbate cases of childhood asthma, and create haze.  Under the agreement, the Department of Corrections will also pay a civil penalty of $300,000.

The specific new improvements that are scheduled to be installed include a new Baghouse (Dust Collector) to reduce particulate matter at the Rockview facility. Other locations will switch from coal-fired boilers to cleaner gas-fired versions. In some locations the new gas-fired boilers will be installed, in others existing equipment will be used in a larger capacity, while phasing out the older coal-fired equipment.

This settlement has reporting obligations to ensure the prisons stay on schedule with the terms of the agreement.  Should the facilities’ boilers fail to meet the requirements, they will be subject to stipulated penalties, ranging from $1,000 to $10,000 per day contingent on the type and length of the violation.

The settlement is subject to a 30-day public comment period and final court approval.

A full list of the proposed changes can be found below:

  • Baghouse to control particulate matter will be installed at the Rockview facility;
  • New gas-fired boiler units at the Laurel Highlands facility will be constructed;
  • Coal-fired boiler units at the Muncy facility will be shut down and replaced by an existing natural gas- fired boiler; and
  • The Huntingdon facility is required to either add particulate matter controls, or convert to gas-fired boiler units.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

2010 marks the second year in a row that no new coal-fire power plants were constructed in the United States according to the Washington Post. However coal-fired plants remain the largest generator of electricity in the U.S. supplying approximately 50% of all power generated each year. Increasingly however factors such as the economy, lower natural gas prices, and environmentalist opposition, have effectively halted the growth of the coal industry.

Recent technological advancements in the extraction and production of natural gas have unlocked for use large domestic supplies previously thought unusable. This in turn has driven the cost of natural gas down dramatically. Reserves of natural gas found in Shale Rock formations, (or Shale Gas) are thought to be enormous, rivaling the oil reserves of the Middle East.

With many in the industry looking to natural gas as the future, including American Electric Power (AEP) America’s largest electricity generator, interest in new coal plants seems to be waning. Additionally according to a report from Deutsche Bank, if gas prices stay below $6, more plants will be converting from coal to gas.

“Coal is a dead man walkin’,” says Kevin Parker, global head of asset management and a member of the executive committee at Deutsche Bank. “Banks won’t finance them. Insurance companies won’t insure them. The EPA is coming after them…And the economics to make it clean don’t work.”

This however does not mean that the coal industry is dead. The coal industry still manged to have enough weight last year to kill the climate legislation (cap and trade) in the US Senate, showing it still has a lot of influence in politics and public opinion. Plus, even as it declines, it remains the number one source of electricity in America.

Further challenges await the coal industry this year from a different front. Beginning this year, the Environmental Protection Agency has new regulations scheduled to take effect to lower greenhouse gas emissions of power plants emitting over 75,000 tons of carbon dioxide per year. Such a rule would force industry to install state-of-the-art emissions controls on new construction in order to obtain the necessary air permits. Along with increased pressure from Washington, this means that existing coal-fired plants will be coming under heavy scrutiny to ensure that they are meeting all current Federal and State emissions regulations. With large fines, and negative publicity being the price of failing to meet the new standards.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

By Dominick DalSanto
Environment Expert & Author

The term Industrial Dust Collection for many simply draws a blank in their minds. “What is that?” they may say. Or they might simply think that it has something to do with “Big Vacuum Cleaners”. But little do those outside of the industry itself appreciate how many benefits this multimillion dollar industry brings to all of us. Here are just 5 reasons why we should be care about Dust Collection technology and the effects it has on our lives.

1. Dust Collection Protects Human Life

There are literally thousands of industrial processes that create dust pollution, including Steel Mills, Food Processing, Woodworking, Cement Plants, and other Manufacturing.  By capturing harmful particulate matter emitted from these industrial sources, prevent the release of a wide range of dangerous compounds into the atmosphere, thereby preventing human exposure to this harmful material.

2. Dust Collection Protects Our Environment

Since the industrial revolution began almost 200 years ago, mankind’s industrial progress has caused much harm to our planet. By passing contaminated air through a Dust Collector Filter before it is released into the environment, industrial sites can prevent the contamination of water sources, such as rivers lakes and streams, as well as keep our air clean, safe and breathable for animal, plant and human life alike.

3. Proper Dust Collector Systems Help Keep Workers Healthy

Ironworkers from 1930 working on the Empire State Building

One of the greatest dangers facing industrial workers is exposure to contaminated air. Another overlooked danger of large amounts of dust pollution, is the very real threat of a dust explosion occurring. When certain kinds of dusts are dispersed into the air in the right proportions, it can lead to a very violent explosion that can  cause a massive loss of life. Through the operation of a Baghouse (Trade term for a Dust Collector), job site hazards are reduced, and worker safety is increased.

4.  Dust Control Helps Keep Manufacturing Costs Down, Leading To Cheaper Products For You

With a adequate Dust Control program in place, industry can avoid many costly accidents (Such as Dust Explosions) and attain a higher quality product.

5. Countless Products Could Not Be Manufactured With It

Many industrial processes are only possible through the application of Dust Collection/Separation and related technology. These include most forms of Food Production, Metal Processing, Pharmaceutical Manufacturing and more.

Yes our industry, which may at times to the public seem to be irrelevant, is in fact one of the most vital industrial processes we have in our modern industrial era.

What other ways does the Dust Collection Industry benefit society?

This list is by no means exhaustive, no does it claim to be. We would like to hear from you. Please leave your comments below.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

By Gilda Martinez
Staff Writer Baghouse.com

The rapid economic growth and industrialization in many developing countries is calling for a sustainable management of the natural resources. Despite the urgency of this problem, not many people are aware of this growing issue. Although great efforts are being done by many environmentally conscience companies in the developed world, this article will analyze problems and solutions, how increasingly industrialized countries, in particular India, are using the same tools to keep their air clean, how the governments have changed their focus, policy, etc to fix the problem and how these areas provide a booming market for providers of Industrial Pollution Controls, specifically Dust Collection.

The Growing Air Pollution Problem In India

It is the case in the country of India that smog and pollution have become an integral part of life in this urbanized land. A drive through any city in the country would result in a fine blanket of black dust on oneself. Take for example, the city of Kolkata, which is considered the most polluted city in the country. Dust and smog particles envelop the entire city, which leads to breathing problems throughout. Chimneys of small factories spew seven tones of particulate matter across the urban area. Much of this pollution is because Kolkata is the only metro area that allows small industrial units to use coal-fired boilers.

While Kolkata tops the list of polluted cities in India, Mumbai, Bangalore and Chennai follow it closely. According to a recent study by the Calcutta Metropolitan Development Authority (CMDA), commissioned by the state Pollution Control Board, around 10,000 small industrial units have been identified, which use coal-fired boilers, many of them, lacking current pollution control technologies. All together these units burn an estimated 85 tones of coal everyday. The CMDA has mapped areas, which have the maximum usage of coal.

Most of these units are located in suburban Kolkata such as Dunlop Bridge, Baranagar, Cossipore, Maniktala, Topsia, Tangra and Tiljala. These units are used to power the manufacture and production of ceramics, plywood, tanning and leather finishing units, dyeing, and bleaching and rubber goods. These units contribute nearly 30 per cent of the particulate matter in the atmosphere.

There are 6 main pollutants of concern according to Central Pollution Control Board (CPCB). They are Suspended Particulate Matter (SPM) of less than 10 and 2.5 microns (PM10 and PM2.5), Nitrogen Oxides (NOx) and Ozone. Only adding to the situation is that most of India has a Tropical or Sub-Tropical climate and with generally warmer temperatures there is a tendency for pollutants to be trapped closer to the ground, leading to an even greater danger for Humans.

What Is Being Done To Combat Pollution in India

As part of a major air-cleansing drive, the state government has decided to make the units switch from solid to liquid fuel to fire the boilers. The state Pollution Control Board is currently in talks with industry associations to devise mechanisms to prevent and control pollution by industrial units.
Many air quality monitoring agencies have set up as the first step in a larger effort to keep their air clean. For example Delhi has set up several real time air quality monitoring stations to track certain specified air pollutants and toxins in that city. The system uses Lidar (light detection and ranging) technology, which releases and captures a laser beam and measures the before-after difference to gauge the concentrations of various pollutants in the air.

In Sialkot, the government ensured the installation of dust collectors at buffing machine to arrest the buffing dust, in addition to constructing screen grit chambers to trap the sludge from the effluent through the introduction of de-salting tables to minimize the quantity of salt in the effluent.

The city Nagpur is looking to take similar measures regarding its environmental problems. The measures suggested include increasing stack height on sponge iron plants from 30 meters to 80 meters, de-sulpherisation of coal used by the industrial units and scrubbing of SO2 (sulphur dioxide) from smelters, furnaces and DRI furnaces.

Similarly, the adoption of properly sized Filter Bags and Electrostatic Precipitators (ESPs) with higher efficiency, use of clean fuel by the thermal power plants and aluminum smelters, reduction of kiln accretion and implementation of the recommendations of IIT Kharagpur for sponge iron plants have been reccomended by many agencies involved in researching this problem.

These measures are expected to improve the air quality greatly. However there still remains a major problem, the same problem that other newly industrialized countries (such as Brazil) are also facing, and that has to do with automobile traffic. The volume of personal vehicles is astounding. More than 5.6 million vehicles drive on Delhi’s roads every day and another two million come to the metropolis from towns like Haryana and Uttat Pradesh.The Government wants to regulate traffic, and encourage people to take public transportation instead of taking their personal cars into the city.

Future Outlook of Pollution Control in India

With its rapid development which is expected to grow in 7 -8%, especially the industrial sector, the overall growth of the Indian economy is creating a large, booming market for Industrial Pollution Control technologies. The environmental issues, the recent governmental developments, and the lack of local expertise, are leaving the door wide open for companies and manufactures specialized in Industrial Filtration to expand into this booming market.

Locally while there are a large number of Air Filtration (Baghouse Filters) technologies manufacturers, these firms are still unable to keep up with the increasing demand for their products and services. Therefore, American, European, and Chinese companies are keeping an eye on India for potential new markets for their own products and services.

We hope this article has made readers more aware of not only the environmental situation facing India and other similar developing countries, but also how the development of environmental technologies is becoming a vital part of these nation’s growing economies.

One only has to look at how the US Department of Homeland Security and its TSA (Travel Safety Association) are making headlines recently for implementing controversial security measures at American airports, thereby changing the way we travel, to see clearly the effect that governmental agencies can have on our everyday life.

One agency that often gets overlooked has done more to change the United States (and through its influence the world) than most people realize. The US Environmental Protection Agency (EPA), recently celebrated its 40th anniversary.

As part of a larger week of commemorating 40 years of protecting the environment, the Aspen Institute – an international nonprofit dedicated to fostering enlightened leadership and open-minded dialogue has listed the top 10 ways that the EPA has strengthen America. The list highlights how environmental activism benefits not only the Earth, and the people that live on it from a social, moral, and public health perspective, but also how by having avoided widespread contamination of the nation’s resources, it has lead to a stronger, more economically viable future for the nation as a whole over time.

Aspen Institute President and CEO Walter Isaacson had these comments on the history of the EPA and its effect. “Over its 40-year history, EPA has evolved into the world’s preeminent environmental regulatory agency through a balanced, three-pronged strategy, combining excellent science, regulatory enforcement, and engagement of all stakeholders in developing new solutions to environmental problems. EPA’s balanced, multifaceted structure and operation sets the standard around the world for applying strong science, as well as economic incentives and disincentives, to achieve positive environmental outcomes while allowing businesses to grow and prosper,”

The following are highlights of EPA’s 40 year history identified in the report:

·         Removing Lead from Gasoline—and from the Air

·         Removing the Acid from Rain

·         Clearing Secondhand Smoke

·         Vehicle Efficiency and Emissions Control

·         Controlling Toxic Substances

·         Banning Widespread Use of DDT

·         Rethinking Waste as Materials

·         A Clean Environment for All/Environmental Justice

·         Cleaner Water

·         The “Community Right to Know” Act

A full copy of the report can be found at www.aspeninstitute.org.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.

WASHINGTON D.C. – In a recent year end report detailing annual enforcement and compliance results, the U.S. Environmental Protection Agency (EPA) through enforcement of regulation, and compliance actions forced polluters to pay more than $110 million in civil penalties and commit to spend an estimated $12 billion on pollution controls, cleanup, and environmental projects that benefit communities. The total accumulated effect of all enforcement, and subsequent reductions in emissions due to infrastructure improvements is expected to prevent the release of nearly 1.4 Billion pounds.

“At EPA, we are dedicated to aggressively go after pollution problems that make a difference in our communities through vigorous civil and criminal enforcement,” stated Cynthia Giles, assistant administrator for EPA’s Office of Enforcement and Compliance Assurance. “Our commitment to environmental enforcement is grounded in the knowledge that people not only desire, but expect, the protection of the water they drink, the air they breathe and the communities they call home.”

EPA Activities In 2010

Enforcement of the Clean Air Act provisions, are expected o alone account for the reduction of of approximately 400 Million pounds of air pollution per year. It is estimated that those reductions will save between $6.2 Billion and $15 Billion each year in health care costs. Additionally through FY (Fiscal Year) 2010 EPA actions have ensured that over 1 Billion pounds of water pollution will be reduced, eliminated or handled properly, and approximately $8 Billion in investigates will be made in pollution control and environmental improvement projects. EPA’s civil enforcement actions also led to commitments to treat, minimize or properly dispose of more than an estimated 11.8 billion pounds of hazardous waste.

EPA Criminal Enforcement

With diligent effort to vigorously prosecute accused environmental criminals, the EPA in FY 2010 opened 346 new environmental crime cases. The results are that 289 defendants were charged with committing environmental crimes, with 198 being convicted a$41 Million being levied in fines and restitution.

Interactive Data Access Tools Increase Transparency.

This year’s annual results include an enhanced mapping tool that allows the public to view detailed information about the enforcement actions taken at more than 4,500 facilities that concluded in FY 2010 on an interactive map of the United States and its territories. The map shows facilities and sites where civil and criminal enforcement actions were taken for alleged violations of U.S. environmental laws regulating air, water, and land pollution. The mapping tool also displays community-based activities like the locations of the environmental justice grants awarded in FY 2010 and the Environmental Justice Showcase Communities.

The release of the EPA’s enforcement and compliance results and the accompanying mapping tool are part of EPA’s commitment to transparency. They are intended to improve public access to data and provide the public with tools to demonstrate EPA’s efforts to protect human health and the environment in communities across the nation.


About the Author

| Dominick DalSanto is an Author & Environmental Technologies Expert, specializing in Dust Collection Systems. With nearly a decade of hands-on working experience in the industry, Dominick’s knowledge of the industry goes beyond a mere classroom education. He is currently serving as Online Marketing Director & Content Manager at Baghouse.com. His articles have been published not only on Baghouse.com , but also on other industry related blogs and sites. In his spare time, Dominick writes about travel and life abroad for various travel sites and blogs.