FAQs

Is there specific guidance where a particular zone starts, or is the whole booth regarded as one zone?

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 […]

What are the regulations regarding intrinsically safe electronic devices inside a paint booth?

What are the regulations regarding intrinsically safe electronic devices inside a paint booth?

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 […]

What is the proper way to get an even finish when painting a metallic hood without getting the stripe effect when applying the clearcoat?

What is the proper way to get an even finish when painting a metallic hood without getting the stripe effect when applying the clearcoat?

Finish Application

If the stripping is happening only after you start applying the clear coat it is possible that the basecoat is not completely flashed off when the clear in applied. This can cause the metallic to shift. Another possibility is that the basecoat has been applied unevenly, with the wrong reducer, equipment, or air pressure and the stripping is in the base but not visual until the clear is applied. I would need to know a lot of information to help narrow down what the problem may be.

How many air changes are required for a 16 by 14 by 40 paint booth?

How many air changes are required for a 16 by 14 by 40 paint booth?

Air Changes There is no code or standard that requires a specific air change for paint spray booths. It is more common for the ventilation performance of a spray booth to be specified by the average velocity through the booth or in the vicinity of […]

What is the best placement of sensor tubes coming from the magnahelic gauge for a downdraft paint booth?

What is the best placement of sensor tubes coming from the magnahelic gauge for a downdraft paint booth?

Measuring Pressure The answer depends on what pressure differential you are trying to measure. If you are measuring cabin pressure compared to building pressure, the high-pressure sensor tube should be mounted in the cabin away from any booth openings. The low-pressure tube should be left […]

Are manometers or other pressure drop devices required by law on exhaust filters?

Are manometers or other pressure drop devices required by law on exhaust filters?

National Fire Protection Association

A means is required to make sure that you are moving the required amount of air for paint spraying. Your choices depend upon the code or standard adopted by your local authority. If NFPA 1 Fire Code is being enforced then the requirements spelled out in NFPA 33 Standard for Spray Application Using Flammable or Combustible Materials 2011 Edition would apply. NFPA 33 states that “Spray areas equipped with overspray collection filters shall have an effective means to ensure that the performance requirements of Section 7.2 are met.” [33:7.2.1] NFPA 33 also offer explanatory material that says that “Acceptable means to comply with 7.2.1 include, but are not limited to, visible gauges, audible alarms, approved interlocks, or an effective inspection program.” [33:A7.2.1] says that “Acceptable means to comply with 7.2.1 include, but are not limited to, visible gauges, audible alarms, approved interlocks, or an effective inspection program.” [33:A7.2.1]

International Fire Code (IFC)

If the IFC is being enforced then the requirements spelled out in Chapter 24 would apply. The IFC states that “Visible gauges, audible alarms or pressure-activated devices shall be installed to indicate or ensure that the required air velocity is maintained.” [IFC:2404.7.8.3]

Therefore, some means is required to ensure that the required air movement is maintained within the spray area. Both codes give you options. The intent of these requirements is to alert the operator of the point where the filters are loaded and can no longer pass the required amount of air. At that point, the filters need to be replaced.

What are the potential hazards when painting with the doors open?

What are the potential hazards when painting with the doors open?

“We are using a spray gun between 20-60 psi when the production doors are open on the unit. Do the filters on the doors provide a significant protection factor when dealing with Isocyanates?” The paint booth should have the doors closed during paint spraying. The […]

How do I maintain a specific spray temperature inside the paint booth?

How do I maintain a specific spray temperature inside the paint booth?

I live in Malaysia with the temperature of 32 degree Celsius, how do I maintain the spray temperature of 23 degrees Celsius inside the painting booth? Do I need to install a chiller and humidifier? Due to the conditions in Malaysia the temperature set-point being […]

Is there a “magic number” on the manometer at which paint booth filters should be changed?

Is there a “magic number” on the manometer at which paint booth filters should be changed?

Regardless of the filter used, it is a matter of how much total resistance is designed into the fan in question and the relative condition of the fan. All fan units are designed to operate within a range of resistance, that includes the ductwork, plenum and filters. Without the exact fan curve data that should have been supplied in the operator’s manual for a particular booth, the best one can do is base the change out resistance on industry “norms”.

The exhaust filters of most spray booths are designed to be changed at approximately 0.5 to 0.75-inch water column, but with variable frequency drive systems this may be extended to 1 inch or beyond for a single-stage exhaust filter.

On intake filters, the change-out final resistance depends in part on the type of booth: non-pressurized or pressurized; and with pressurized booths, whether it is a recirculation or has independent supply and exhaust fans.

For non-pressurized booths, such as a traditional crossdraft, a preventative maintenance schedule of three to six times annually is most common since the manometer or magnehelic is used to measure the exhaust fan only.

For pressurized booths, there may be a separate manometer or magnehelic for the supply air or recirculation air plenums, and a photohelic that would measure the differential pressure of the intake and exhaust air balance. Recirculation filters would typically be changed at 0.5 to 1.0-inch water column dependent on fan capability. Air make-up filters in a separate fan unit would be changed similarly. For diffusion filters in a pressurized booth, a preventative maintenance schedule is probably the most preferred method of maintenance: once per year for booths that have MERV8 or higher supply air filters, and twice per year for filters with lower efficiency ratings.

Again, these are generalized and not specific to the equipment in use at this application. More critical than any speculative or default method of determining filter change parameters would be to consult the operator’s manual or the manufacturer for the specific equipment.

Is there a minimum airflow guideline for non-spraying times?

Is there a minimum airflow guideline for non-spraying times?

We would like to turn down the airflow in our spray booth during non-spraying times (i.e. warming it up in the morning). There is no specific airflow requirement for non-spraying modes such as prep or unoccupied times. Generally, users will revert back to standard building […]