So, You Want a Paint Booth
7 things to consider before offering coating application services
- By Michael L. Thayer, CHMM
- May 05, 2009
These days you can find just about anything on the Internet. Did you know that wikiHow.com even explains how to construct a homemade paint booth with a few items readily available from any big box home improvement store? Unfortunately, industrial painting operations, which provide durable and aesthetically pleasing finishes to many products, are much more complex than hanging some plastic sheeting and grabbing a spray gun.
Such a project includes not only the upfront issues of obtaining environmental permits but also recordkeeping and reporting, employee training, industrial hygiene and employee safety, hazardous waste generation, and many others that must be managed during operations. All of these requirements should be fully analyzed and weighed against the benefit of the overall project.
Many areas, especially those that are heavily urbanized, specify the amount of volatile organic compounds (VOCs) allowed in coatings. Houston, for example, limits many paints to a maximum 3.5 pounds of VOC per gallon (419 g/L) for many types of coatings (this limit doesn’t allow you to dilute the coating with water or a non-VOC solvent to comply). Using paints outside these limits may require use of a thermal oxidizer or may limit usage to very low levels.
Other requirements may apply to an entire country: the U.S. Environmental Protection Agency requires that certain conditions be met for coatings that contain various metals over prescribed concentrations. Similarly, the E.U. Solvent Emissions Directive (SED) may also impact paint selection and operational flexibility in Europe.
Do not assume that your paint supplier will provide you with compliant coatings for your area or know specific regulatory requirements; the burden of compliance is on the end user.
All application devices are not created equal. The high volume-low pressure (HVLP) spray gun, which at 10 psig / 0.07 MPa reduces atomization and emissions, is the most widely accepted. Airless and air-assisted airless spray guns usually are allowed. Electrostatic paint sprayers can be used but not effectively in all situations. Rollers or brushes may be exempt from most environmental requirements.
Do not assume that your equipment supplier will provide you with compliant spray painting guns or know specific regulatory requirements; the burden of compliance is on the end user.
Design, operation, and location
Beyond the size of the booth, which should be dictated by the size and geometry of the parts to be coated, there are design elements and operational issues that must be considered and compared against regulatory requirements.
It has to be built in a manner that maintains proper airflow across the painting area, toward the filter media, and out of the building through a stack. Specific requirements will dictate the minimum and maximum airflow face velocities at intake openings and filters. Good engineering design typically dictates that stacks discharge vertically at a minimum height of 1.5 times the height of the building and that rain protection devices not obstruct the vertical flow of the discharged air.(see Stack Height Chart)
Paint booth particulate filters must meet minimum removal efficiencies and be replaced as necessary to maintain optimal performance. Recently adopted EPA standards specify a particulate removal efficiency of 98 percent for certain coating operations.
The location of the booth within the facility also must be considered. Regulatory requirements may dictate minimum property line setback distances. Local building and fire codes must be addressed.
Do not assume that your equipment supplier will provide you with a compliant paint booth or know specific regulatory requirements; the burden of compliance is on the end user.
Usage rates and air permits
The higher the paint usage rates, the higher the VOC and particulate emissions rates. The higher the emissions rates, the more complicated the permitting process. The more complicated the permitting process, the more expensive and time consuming the entire process becomes.
Before you can begin operations, you have to:
- Prepare a permit application, which details the proposed paint booth and addresses all of the applicable environmental requirements and demonstrates how the operation will comply. Filling out this document can take from several days to several weeks and months depending on site complexity.
- Submit the application for review. The application plus any required fees must be submitted to the appropriate regulatory agency. Typically, the agency will let you know if the application is administratively complete and begin its technical review. Once the agency is satisfied that the operation will not violate applicable regulations, it will issue a construction permit. Simple permits or permits by rule may require up to a month for agency approval; more complicated permits, or those with higher emission limits, may take 6-9 months or longer and may involve opportunity for public comment. Most permits require that the best emission controls be used and that the impact of any emissions be considered on off-site properties.
- Be ready for agency inspection following construction. The agency may inspect the operation to verify its compliance with the application and construction permit and issue a final operating permit. In some cases, a joint construction and operating permit will be issued.
- Keep up with recordkeeping and reporting requirements. The operating permit describes the conditions under which the source must operate and also details emissions limits and any recordkeeping and reporting requirements. Maintaining paint logs (hours of operation and specific paint, solvent, and thinner usage rates) are common practices. This data typically is used to calculate emissions on whatever mass per time-scale basis is required in the permit (lbs/hr, lbs/week, tons/year, etc.). Annual emissions inventories and fees likely will be required, such as Toxic Release Inventory (U.S.), National Pollutant Release Inventory (Canada), and National Atmospheric Emissions Inventory (U.K.).
Personnel must be trained on the proper use and maintenance of the paint application equipment as well as any general operation and maintenance issues associated with the booth for which they are responsible. Appropriate personnel should be trained on any of the environmental requirements for which they are specifically responsible, such as maintaining accurate paint logs.
Industrial hygiene and employee safety
Painters will need to wear some type of respiratory protection, which can be determined through an industrial hygiene assessment. They must undergo medical examination and clearance, be fit tested, and be trained and required to follow all regulatory guidelines regarding the use of respiratory protection.
Hazardous and non-hazardous waste generation can be expected to increase with the operation of a paint booth. As with air compliance issues, there are a myriad of environmental regulations dedicated to the generation, storage, and disposal of wastes. Depending upon the specific location and types and quantities of wastes generated, a facility may be subject to employee training, recordkeeping and reporting, limited onsite storage quantities and times, and written plan development.
So, you still want a paint booth?
Michael L. Thayer, CHMM, is the corporate health, safety, and environmental manager for Air and Water Compliance at National Oilwell Varco headquartered in Houston, Texas.