The main purpose of a paint booth or spray booth is to contain hazardous materials such as overspray and volatile organic compounds (VOCs) and to prevent fumes, chemicals, gases and vapors from spreading in the workshop or outside. In addition to protecting the environment, complying with local regulations and ensuring the safety of your employees and facilities, enclosing the painting process in a booth allows for better quality paint work that’s free of contaminants (for example dust).
In order to choose a suitable high quality painting booth, you will need to know the dimensions of the parts or products to be painted and choose a booth large enough to house and handle them. You will also need to make sure there is enough space and air in your booth.
Once you have chosen the size, you will need to choose the filter type according to the application process:
Liquid applications generally use a dry filter paint booth with an exhaust fan that draws excess paint to a filter bank, located in the booth walls or in the floor pit, that captures particles.
Powder application processes generally require several layers of filtration, ending with either a baghouse filter or a powder collector, without requiring the evacuation of air outside the building.
What is the structure of a paint booth?
A paint booth is a ventilated and, if necessary, heated space that allows painters to work in safe hygienic conditions in accordance with the current regulations. A paint booth can be open or enclosed; it is adapted to the dimensions of the parts to be painted. There are paint booths for vehicles, industrial applications, inflatable pain booths, etc.
A paint booth is made up of:
A structure of panels that channel the air.
A motorized fan unit to evacuate the air that’s been polluted by the fumes of the sprayed paint. It is equipped with special filters.
an extraction chimney that evacuates air outside the building.
a specific electrical control cabinet that controls the booth.
How to choose the size of a paint booth?
You will need to take into account the dimensions of the biggest part to be painted, including racking, pallet or trolley. Then add a minimum of 60 cm (2 feet) to the height and 1.5 m (5 feet) to the length and width to determine the size of booth you need.
If you are going to paint several parts simultaneously, count about 90 cm (3 feet) between the parts.
What types of ventilation are there for paint booths?
Good ventilation is essential for the health of your operators, but is also important for the final result of the painting process. A paint booth has a constant supply of fresh filtered air from outside and an evacuation of polluted air. The ventilation system includes a ventilation fan and an exhaust fan.
In order to determine the best air flow for ventilation, you will need to carefully examine the parts to be painted: the shape and weight of parts will be decisive for your choice.
Different types of air flow can move in different ways:
Vertical air flow: vertical flow from the ceiling filter to the grating. Advantages: mainly cleanliness. The air is sucked around the object and expelled underneath. Overspray and contaminants are drawn down, away from the object. The risk of contamination is reduced and the painter is less exposed. Generally finishes dry better, and parts require less correction and polishing. Disadvantages: tunnels or pits are required for this system to work, otherwise the booth must be raised, which leads to significant costs.
Diagonal air flow: diagonal flow from the ceiling filter to a suction wall or partial grating. Advantages: air circulation is more uniform around the object. Paint and contaminants are sucked up and moved away from the finished paint job. Additionally, the booth does not require concrete shafts, which reduces costs. Disadvantages: these booths are the most expensive due to the construction methods used. On the other hand, the booth doesn’t need tunnels, pits or elevated floors.
Horizontal air flow: horizontal flow from a supply cabinet to a suction wall. The advantages and disadvantages are the same as for diagonal air flow.
Cross air flow: air is drawn in through the main doors of the workspace, exhaust is put out through the rear walls. The air is sent directly to the area to be painted. Advantages: these booths are economical because they require little construction material and little work to build. Disadvantages: the air flow follows a linear path on the object. Contaminants are more likely to land on the parts to be painted because of the greater distance they have to travel to the exit. The operator painting also hinders the air flow, which can lead to excess paint in some areas.
Types of ventilation:
vertical air flow
diagonal air flow
horizontal air flow
cross air flow
What type of heating can be used in paint booths?
Heating is an important element to keep in mind before you buy a paint booth because the cheapest booths are often the most expensive to upgrade or customize.
Horizontal air flow booths cannot have door heating.
Installing heating on cross air-flow booths will require major modifications, and a heat recycling system in some of these cabins could be expensive. It is better to consider heating before making a purchase.
Booths with vertical air flow are easier to modify to in order to add a heat source. It may be more expensive and complicated to recycle the heat from this kind of booth, however, because of the evacuation at the rear of the booth, which might require additional ducts.
If you decide to opt for an unheated booth, leave room around the booth for a possible additional heating system later. Also make sure that your building has the necessary power supply and that your city can provide you with the authorization to add heating. If the volume of the parts to be painted is large, consider recycling heat as you will save a significant amount.
What filtration method should you choose for your paint booth?
In a paint booth, it is important to filter the air because the air is constantly being supplied and evacuated. A filter is necessary to achieve a good paint finish and in order to protect the environment. It is important to continuously monitor your booth filters to avoid performance losses.
There are several types of filters in a filtration system:
Pre-filters: they are located in front of the fan and ensure the purification of the incoming air.
Extraction filters: they are located either on the slatted floor (vertical or diagonal flow) or in the side wall (diagonal or horizontal flow). These filters retain paint fallout and other waste.
Output filters: these are not always present in paint booths. They filter the output air. Depending on the product and your painting frequency, you can choose if you want to install them or not.
There are also high-performance filters specially designed for spray booths to prevent workers from inhaling or ingesting powder.
What is the current safety standard for paint booths?
There are different international norms according to where you will be working, so it is important to look into this before you purchase a paint booth. US Occupational Safety and Health Administration (OSHA) for example has a number of specific requirements.
Generally safety standards make it mandatory that the booth include:
Ventilation by one or more fans
A dry air filtration OR air cleaning system.
Measurement and monitoring devices
An alarm system
Paint booth trend: connected booths
As in many fields today, there are now paint booths that include a connected system. The operator monitors the work on a touch screen. The workshop manager can thus follow the work in real time. The manager can not only supervise production, but also the booth process parameters such as temperature, humidy, etc.
My cousin owns an auto body shop, and he has been thinking of doing full body paint jobs for RVs and buses. You mentioned that good ventilation is essential for his operator’s health, and for better results. It would be great to let him know about this information before he bys his spray booth.