How to Know if You Need an Air Make Up Unit for Your Paint Booth
What Air Make Up Units Are
Air make up Units are air replacement systems for spray booths. They provide heated air to the booth that is equal to the air that is removed due to your exhaust fan running. Air make ups can also be equipped with advanced controls to allow for the booth to add a bake cycle to your painting process. Having air to replace the air removed and the potential to have a low temperature bake cycle is nice but it is also quite expensive, often it can cost as much and even more than the whole spray booth itself. With cost in mind when do we know if it is necessary or worth adding heated make up air to your paint booth, that’s what we’ll cover in this post.
Variable 1 Is there a need for increased production in your manufacturing process
Often your painting operation can be the bottleneck for your facilities production. The key variable is what is the dry time for your product and how much space do you have for your product to dry. If you do not have space for an item to dry in open shop air due to needing floor space or if you want more product done in shorter time heated air with a bake cycle can be just what is needed. To know the potential production increase you can read your technical data sheet for your coatings. WIthin this sheet will be a section that states the difference in dry time when using room or ambient temperature vs a bake temperature (this temperature is typically in the mid to low 100 degree range). The difference in these times is the difference in dry time and hence indicates the change in production. If your original dry time is 4 hours unheated and 2 hours heated you can essentially double your production.
Variable 2 – Air available in your shop
- We recommend having enough shop air to run a booth at least 20 minutes before you deplete the air from your building. This is so that you can have your shop doors closed and operate the booth without worry about busting a window from too much negative pressure. Additionally, the increased workload on your heaters of your building that would be required to re warm the building to ambient temperature is high, an air make up is designed for high production of heated air not maintaining a steady state which is typically what a regular shop heater is designed for. To know how long you can run the booth before running out of heated air you calculate the cfm of a booth by taking the width x height x 100 for a cross draft or length x width x 50 for a downdraft, this will give you the approximate cubic feet a minute draw of the booth. You then calculate the cubic feet of your building by multiplying width x height x length. Take the cubic feet of your building and divide by the cfm draw of your spray booth the result is the number of minutes before you would deplete your building of all air. As stated if that number is less than 20 (20 minutes) you should consider an air make up