Publication : 09 22 2021
In partnership with CAMFIL

The maintenance of paint booth filters is still a tricky area for many in the industry but is essential to perform quality work in a healthy environment. With the Camfil specialists, we try to demystify the whole thing to answer the most frequent questions on the subject.

For proper filter selection and maintenance, you must first identify the type of paint booth you are working with.

What is the difference between paint booth models?

Downdraft paint booths are generally the painter's favorite. They provide the most particle-free finish. Air enters through the intake plenum, whether heated or not, descends over the product and exhausts through a pit or series of pits in the floor. The exhaust air is carried out of the booth and then up into the atmosphere.

Crossdraft paint booths are the most common and economical option. The air is drawn in through a front opening or front filtered doors across the product and then exhausted out through the back wall. Once out the back wall, it is then vented to the atmosphere.

Semi-Downdraft paint booths are a very economical option for those who want heat in the booth. The booth typically fitted with an intake plenum on the front top of the booth, which is where the heated make-up air enters the booth. The air flows down and across the product exiting through the back wall. Once out the back wall, it is then vented to the atmosphere.

What paint filters should I use?

You should also know that each type of booth requires different types of filters, specific to each one. Here is an overview of the Camfil filters to use for each type of booth:

Downdraft Spray Booth

Semi-Downdraft Spray Booth

Crossdraft Spray Booth

Prep Station

How often should paint booth filters be changed?

Changing paint booth filters on a regular basis is essential to the proper operation of the booth.

The frequency of replacement depends on many factors: hours of use, coatings used, the design of the spray booth, particle concentrations in the air supplying the booth, air velocity and of course, the quality of the filters used.
For example, in a Crossdraft booth, since the SERAP filtration capacity is lower, they need to be changed more regularly than the other 3 (CDM-R1, CDMP-R1, CSRP-1). Being much thinner, SERAP filters clog and get dirty faster. For this reason, we recommend using a CDM-R1 instead, since in addition to requiring less frequent maintenance than the SERAPs, they will do a superior job of filtering dust, volatile components, and overspray. In TAP tests, even when stacking up to 3 or 4 SERAP filters, we can see that dust passes through very easily at the slightest vibration, so much so that with superior quality filters like the CDM-R1, we can simulate a vibration for much longer without a single dust particle passing through.

The following replacement frequency reflects the industry average:
Crossdraft Intake Panel Filters: normally changed every 1 to 3 months
Paint Arrestors: normally changed every 1 to 2 weeks
Prefilters: normally changed every 2 to 4 months
Downdraft Ceiling Filters: normally changed every 6 to 12 months, (proper pre-filter maintenance will extend the life of downdraft ceiling filters)

What is the main difference between the different grades of Downdraft cabin ceiling filters?

Diffusion Capabilities: Premium diffusion media, such as Camfil's CDM-600 media, not only offers the best filtration efficiency in the industry (particle removal), but also the best ability to balance the cabin airflow. The premium ceiling media is designed to provide a constant level of back pressure in the plenum to ensure that when air begins to enter the booth, it does so evenly across the width of the ceiling. The booth then operates with a "laminar" airflow, which is necessary for the best painting results. Low pressure drop diffusion media (such as Camfil's CDM-560 media) still offer extremely high filtration efficiency, but their dust holding capacity (which reduces their life) and diffusion properties are slightly reduced, making them more suitable for prep stations.

Why is it important to change paint chamber filters?

First, delaying filter changes can create a poor balance in the booth, which will ultimately lead to poor paint transfer efficiency, increased coating usage, reduced exhaust media life, and ultimately rework on the vehicle.

Over-saturated exhaust filters create a build-up of paint overspray inside the ducts, on the fan and blower, causing many problems such as engine overload. This could get to the point of having to have the chimney cleaned and the air duct fans changed, or even break some of the components of the ventilation system. Diligence in replacing filters is essential to extending the life of paint booth equipment.

Also, filters that have been neglected for too long do a poor job of trapping surrounding dust, especially when there is "overspray" buildup on the fans, which causes vibration. The accumulated dust then infiltrates the painter's work. The painter is then forced to do additional work to polish the part, thus wasting time and adding to the time required to complete the job. Remember, better filter maintenance = less polishing!

All in all, it is important to ask the specialists about the life span of the filters we install in our paint booths. The higher quality filters offer a better filtration quality and last much longer than the others. It is also important to know that a high-bearing body will have to change its filters much more often.

Content translated and adapted by Les Entrepôts A.B. Inc.

Source : Filter Products & Accessories for Prep Stations, Crossdraft and Downdraft Spraybooths - Product Application Guide [15/09/2021]