Is there a rule of thumb or formula to determine or calculate spray booth air supply velocity w.r.t. the amount of paint required for a particular part? Paint booth air velocity and paint gun pressure are independent of each other. Paint companies want 80 to […]
We have seen a full range of paint booth contamination scenarios. Typically, when businesses put in new equipment, they also change a lot of other things in the shop, which can result in contamination in the spray booth.
For example, one shop we worked with started getting little blue fibers in their paint all of a sudden. They talked to their paint reps and jobbers, but they still could not figure it out. What they learned was that a change they made in their shop processes resulted in this booth contamination. When they changed their paint booths, they also changed their uniforms — to a new blue color. They discovered that these new shirts were pilling and the fibers were landing in the paint jobs. A quick remedy would have been to wear paint suits, which help protect the painter and prevent contamination. Following a basic safety practice could have saved them months of rework.
Another time, a manufacturer set up all of their mixing operations inside their paint booths on the intake side. Multiple tables, paint cans, guns, towels, rags, hoses and a variety of other items had been in their spray booth for a long period of time. Since the intake air passed over the top of all of it, everything they were painting was covered in dirt and contaminants from their mixing operations inside the booth.
Other scenarios that could be remedied with common safety practices include not changing filters regularly, and sometimes even from storing and eating food in a paint booth, causing food particles to show up in the paint.
Outside of that, the worst damage can be seen from silicone entering the paint environment. This can be caused by cleaners used in other parts of a shop, especially if there is a detail department. Ideally, you should always use silicone-free cleaners. Some new cleaners will claim to be silicone-free, yet they include an additive that reacts the same way as silicone. Spraying just a small amount of that into a shop will cause fisheyes in the finish. To prevent this problem, keep your detail areas completely separate from the paint shop — in a different building or walled off.
We recommend GFS Wave® exhaust paint booth filters from Global Finishing Solutions®. They are polyester filters with a large surface volume. The ridges or “waves” on the filter media capture and retain overspray, acting as a 3D loading system. Flat exhaust filters get clogged very […]
Is there specific guidance where a particular zone starts, or is the whole booth regarded as one zone?
We are a joinery company and have a booth with a 3.0m wide dry back extract for lacquer finishing. Our insurance company has raised concerns regarding the zoning within the room.
In both the US and Europe the interior volume of a spray booth is considered to be a single area classification.
In the US, NFPA 33 Standard for Spray Application Using Flammable or Combustible Materials 2011 Edition, provides guidance on the electrical area classifications in and around a spray booth. It states that the interior of a spray booth or spray room is considered Class I, Division 1. The external volume within 915 mm (3 feet) of openings, including closed doors, is Class I, Division 2. Chapter 6 provides diagrams for the various styles of booths as well as for open spraying.
In Europe, the standard is EN 12215 Coating plants – Spray booths for application of organic liquid coating materials – Safety requirements. In the 2009 Edition, the Zone classification is based upon the concentration of flammables. It states that if you are between 25% and 50% of the LEL, then the interior of the spray booth is Zone 1. If you are less than 25% of the LEL, then the interior is Zone 2. In all cases, the external volume within 1 m of permanent openings is classified Zone 2. This information is taken from Section 18.104.22.168 and Figures A.1 and A.2.
In addition to following industry codes and standards, we recommend that you consult with the local authority to ensure you are in compliance with local codes and standards.
If allowed, what type of certification and enclosure does a communications device require to go into a paint booth? National Fire Protection Association The interior of a paint spray booth or room must meet the requirements for a Class 1 Division 1 area as defined […]