Spray finishing refers to operations where organic or inorganic materials are utilized in a dispersed form to coat, treat or clean surfaces. This is a broad definition and can include activities involving the use of flammable liquids (e.g., paint) in a spray booth or spray area, electrostatic coating and similar operations.
Spray finishing is a very detailed activity and an effective way to create a high-quality finish. However, because these operations involve the use of flammable and hazardous liquids, it can create a number of safety hazards that threaten a business’s property and employees. This Risk Insights provides an overview of spray finishing exposures and ways organizations can control workplace hazards.
When it comes to spray finishing, there are two main hazards to consider:
- Fire and explosion—If sprayed chemicals meet an ignition source, they can ignite and spread very quickly, even causing an explosion. Utilizing a spray booth is critical, as it contains the spray in an environment free of ignition sources.
- Employee exposure—Spraying chemicals outside a booth allows chemicals to spread, possibly exposing nearby employees to potentially toxic fumes. Even inside a booth, though, employees may need additional protection.
Again, to control hazards, spray finishing should be done inside a properly designed booth. When it comes to using a spray booth, there are very specific requirements that must be met, particularly as they relate to the following:
- Location—The spray booth should be located where there are egress options if there is a fire. The booth should be located away from other operations and separated by fire-rated construction.
- Construction—The wall, ceilings and floors of the spray booth should be connected and made of noncombustible materials. Additionally, construction of the spray booth should promote the proper airflow, and there should be at least 3 feet of space on all sides of the booth. Spray booths should also be free of any pockets that could collect flammable residue.
- Fire protection—Spray booths must be protected by an automatic fire protection system that is appropriate for the hazard. If the spray booth cannot be connected to an automatic sprinkler system, a fixed fire suppression system can be used. It should be noted that sprinkler heads are ineffective if overspray is allowed to build up. To prevent this, cover sprinkler heads with a thin paper bag or cellophane that is not made of plastic and has a thickness of 0.003 inches or less. Protective coverings for fire sprinklers must be replaced regularly to avoid residue buildup, which could negatively impact sprinkler function.
- Electrical—Wiring and fixtures in and around the booth are potential ignition sources, necessitating explosion-proof wiring. In terms of how this wiring is laid out, many factors affect the exact requirements and distances, so it’s recommended that a qualified person oversees the installation of a new spray booth. Potential sources of ignition should be kept away from the spray booth. In place of explosion-proof lighting, bulbs can be kept behind vapor-tight, wired and tempered glass located outside the spray booth. Other ignition sources must be accounted for as well. “No Smoking” and “No Open Flames” signs should be posted in spray areas, as well as near any mixing and or storage rooms.
- Ventilation—Spray booths must be equipped with ventilation that’s capable of removing flammable vapors and confining them to a safe place. The ventilation must be running any time spraying is done.
- Housekeeping—Spray booths must be kept free of accumulating materials, as this can increase fire hazards. When cleaning is done, the ventilation system must be on. Filters must be inspected daily, and, if they don’t allow for the proper airflow, they must be replaced. Contaminated waste and filters must be removed and kept in a designated and approved area. Some of these chemicals may cause the discarded filters to self-combust, so it’s critical to keep them in a noncombustible container that’s equipped with a tight-fitting lid. Waste material should be removed regularly from the facility by a qualified company. Any tools used for cleaning must not generate sparks or create undue fire hazards.
Spraying chemicals can also lead to employee exposure concerns. As such, it’s critical to understand the hazards associated with the use of chemicals and take the proper precautions to protect your employees.
Industrial hygiene testing, such as air monitoring, may need to be done to understand your employees’ exposure levels. Respiratory protection (e.g., air purifying respirators or supplied air) may be needed. Additionally, personal protective equipment may be needed, including gloves, eye protection and chemical-resistant suits.
Spray finishing can create serious fire and explosion hazards and even expose employees to hazardous chemicals. A properly designed and maintained spray booth is a critical to ensure safe spray finishing operations.
For more information on managing risk, consult with an expert at Robertson Insurance & Risk Management today.