DRY FILTER PAINT BOOTH CONVERSION
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| Overview: | Dry filter systems for paint booths are used to remove paint-based particulates from spray booth air emissions. Their only waste stream is a spent filter containing particulate waste. These systems replace water curtain spray paint booths, which generate large quantities of wastewater and paint
sludge. The wastewater typically requires off-site treatment, and the paint
sludge is frequently disposed as a hazardous waste.
There are many types of dry filter systems, however, all operate on the same principle: particulate-laden air flowing towards the filter media is forced to change directions rapidly. The particulate, having more inertia than the surrounding air, impacts the filter media and is removed from the airflow. The scrubbed air is vented into the atmosphere. Before installing this technology, several system issues should be considered in the conversion of a paint spray booth. These issues include characteristics and applicability of dry filter systems, required fan size, dry filter surface area, paint booth duty cycles, and paint usage rates. An additional issue for consideration is the existence and variation of emission regulations in this country. Generally, the filter system must be chosen such that it meets all local, state and federal emission regulatory standards. Many types of dry filter particulate emissions control systems (PECS) and filters are available. Four principal types of filters are currently used: fiberglass cartridges, multi-layer honeycombed paper rolls or pads, accordion-pleated paper sheets, and clothe rolls or pads. Each type of filter has different characteristics for particulate capacity, removal efficiency, cost, and replacement time. Filter performance is characterized by three basic parameters: particulate capacity, resistance to airflow, and particulate removal efficiency. Paint characteristics, such as overspray particulate size distribution, should be compared to the filter’s performance parameters to obtain an effective match between components. Filter replacement is required when the filter becomes heavily laden with captured particulates, resulting in a reduction in removal efficiency and an increase in the pressure differential across the filter face. A filter system gaining prominence in the Air Force is the Styrobaffle Paint Arrestor. These filters are Styrofoam-like in composition, and are less expensive, last longer and are easier to dispose of than traditional fiberglass filters. When these filters are ready to be disposed, they may be simply dissolved in used paint gun cleaning solvent, which is then normally recycled. The waste stream generated in a dry filter paint booth is a spent filter laden with paint booth particulate emissions. No other media is contaminated during the collection of the particulate waste; hence, the quantity of waste generated is minimized in comparison to the water curtain spray paint booth. For instance, when using lead or zinc chromate paints, the dry filter can eliminate approximately 50 to 90% of the hazardous waste that is generated by a water curtain spray paint booth. The removal and replacement of the spent filters is a simple procedure. The method for disposal of the spent filters will depend on the particular constituents of the paint used. Many facilities now segregate operations involving hazardous and non-hazardous painting into separate paint booths in order to expedite waste handling and disposal. The Styrobaffle Paint Arrestors are highly recommended where applicable and are best used as the first stage of a two or three-layer air system. However, they do not meet National Emissions Standards for Hazardous Air Pollutants (NESHAP) requirements and can not be used where the Aerospace NESHAP requirements are enforced. The Aerospace NESHAP applies to many, but not all, Air Force bases. | |||||||||||||||||||||||||||
| Compliance Benefit: | Use of a dry filter paint booth
eliminates the wastewater and paint sludge (i.e., less hazardous waste is
generated) that are generated with a water curtain. This benefit helps
facilities meet the requirements of waste reduction under RCRA, 40 CFR 262; the
Pollution Prevention Act (42 USC 13101-13109); and Executive Order (EO)
13148, Greening the Government Through Leadership in Environmental
Management; and may also help facilities reduce their
generator status and reduce their regulatory burden under RCRA, 40 CFR
262 (i.e., recordkeeping, reporting, inspections, transportation,
accumulation time, emergency prevention and preparedness, emergency
response). In addition, the dry filter paint booth uses less water and
electricity, which helps facilities to meet the water conservation requirements
of EO 13123, Greening the Government Through Efficient Energy
Management. Conversion to a dry filter system may also decrease a facility’s
need for an industrial wastewater discharge permit (local issue).
The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved. | |||||||||||||||||||||||||||
| Materials Compatibility: | Powder paint is typically not
used in dry filter paint booths because this type of paint is usually
recycled, which is not economical when using a dry filter paint
booth.
Facilities that must comply with the NESHAP for Aerospace Manufacturing and Rework must use a two-stage dry filter system. If the booth is new and the paint contains chromium or cadmium, then a three-stage dry filter system must be used. | |||||||||||||||||||||||||||
| Safety and Health: | The concerns with the dry filter
systems are with the variety of paints that are used and the potential
contaminant exposure. When using lead and zinc chromate paints, inhalation
of lead or zinc can irritate the respiratory tract and can be poisonous.
Some lead compounds are known to be carcinogenic. Solvent-based paints can
irritate the lungs and mucous membranes. Prolonged exposure can affect
respiration and the central nervous system. Proper personal protective
equipment (PPE) and filter handling procedures designed to minimize the
release of paint dust into the air should be used.
Consult your local industrial health specialist, your local health and safety personnel, and the appropriate MSDS prior to implementing this technology. | |||||||||||||||||||||||||||
| Benefits: |
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| Disadvantages: |
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| Economic Analysis: | Converting a water curtain spray
booth to a dry filter paint booth can be easily accomplished and can be
done in-house. The cost of conversion usually ranges from $200 to $2,000,
depending on the size and condition of the old water curtain spray booth.
Purchasing a new dry filter paint booth can cost between $2,000 and
$20,000. The conversion from a water curtain spray booth to a dry filter
paint booth can save several thousand dollars in operating and maintenance
costs per year.
Assumptions (from Columbus Industries, Inc.):
Annual Operating Cost Comparison for Dry Filter Paint Booth Conversion and Water Curtain Spray Booth
Economic Analysis Summary:
Click Here to view an Active Spreadsheet for this Economic Analysis and Enter Your Own Values. To return from the Active Spreadsheet, click the Back arrow on the Tool Bar. | |||||||||||||||||||||||||||
| NSN/MSDS: | None identified.
| Approving Authority: | Appropriate authority for
making process changes should always be sought and obtained prior to procuring or
implementing any of the technologies identified herein.
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| Points of Contact: | For more information |
| Vendors: |
This is not meant to be
a complete list, as there are other manufacturers of this type of
equipment.
Columbus Industries, Inc. |
| Chemco Manufacturing
Company, Inc. 3225 Commercial Ave. Northbrook, IL 60062-1920 Phone: (800) 323-0431 | |
| Fluid Air Products
(Government Distributor) 12834 Gravois Road St. Louis, MO 63127 Phone: (314) 729-7000 or (800) 365-7565 FAX: (314) 729-7099 Contact: Bob Hunt Email: bhunt@fluidair.com | |
| Related Links: |
Do You Use A Water Curtain Paint Booth? - Navy Environmental Quality Initiative (EQI) Wet-to-Dry Filter Paint Booth Conversions - P2 Equipment Program | Sources: | Columbus
Industries, Ashville, OH |
| Supplemental: |
Picture of Wet to
Dry Filter Paint Spray Booth Conversion - P2 Equipment Program 
Picture of Wet to
Dry Filter Paint Spray Booth |
