The third installment in our ongoing series of FAQ posts! Here’s a few more of the most popular questions & answers about spray booths.
It’s very important to be as informed as possible when you make the commitment to purchase a paint booth. It’s definitely no small investment, as we’ve talked about in this blog before. But how do you take your seemingly endless list of questions and decide where to begin? Well, for starters it’s always a good idea to make an effort to educate yourself as much as possible on the basics of key paint booth issues, so we’ve decided to put together a list of the most commonly asked questions we’ve received from our customers to make the learning process for you a bit easier.
Q. Downdraft, Semi-Downdraft, Side Downdraft and Crossdraft — What’s the difference? Which one is better? How do I decide amongst them?
A. Downdraft, semi-downdraft, side downdraft and crossdraft are all styles of airflow in a paint booth.
• Good – Crossdraft: Air is pulled through one end of the booth from the shop or plant. The air flows parallel to the floor, over the product, and into the filter bank on the opposite side of the booth. The filter bank captures particulate, and the air is exhausted into the atmosphere though ducting.
• Better – Semi-downdraft: Air is introduced to the booth through the ceiling in the first 25-30% of the booth. The exhaust fan continues to pull the air through the working chamber, causing the air to change directions and become parallel to the floor. Air is then drawn over the product, through the exhaust chamber at the booth rear, and vented to the atmosphere through ducting.
• Even Better – Side Downdraft: Air enters the booth through a full-length ceiling plenum, and flows downward over the product. When the air reaches the floor, it is pulled into the floor-level filtered exhaust plenums on each side of the booth, and exhausted into the atmosphere through ducting.
• Best – Downdraft: Air flows vertically from the ceiling intake plenum at the top of the booth, over the product, and into the filtered exhaust pit in the floor. It’s then exhausted into the atmosphere.
Downdraft airflow is generally accepted as the best type of airflow for a paint booth. It does an excellent job of controlling overspray and contamination, and provides a safe, clean environment in which to paint. Because of the cost of a pit and volume of airflow, it is also the most expensive style.
When deciding upon an airflow style, you will want to select the style that fits within your budget and meets your quality needs.
For a complete breakdown on the design of each airflow model, here’s a link to the GFS Finishing Academy page on this topic: Spray Booth Airflow Designs
Q. What is recirculation? How can I benefit from having this feature in my booth?
A. Recirculation can be added to a booth to cut energy costs during the cure cycle. With recirculation, once air has passed through the working chamber during the cure cycle, 80% of the air is pulled through the filters and back into the air replacement unit. At that point the air is then combined with 20% fresh air, reheated and returned to the working chamber. The 20% air that is not returned to the air replacement unit is filtered and exhausted directly into the atmosphere through ducting.
The ability to recirculate the heated air, rather than heat the ambient air, provides a great savings in energy and fuel costs. This option can be easily added to GFS control panels.
Q. What is temperature rise? Why is it important?
A. The temperature rise is the discharge air temperature from the unit, above the ambient outside air temperature. For example: if a facility is located in an area where the winter low temperature is -10˚ F and the desired temperature is 70˚ F, a unit with a 90˚ rise would provide 80˚ process air with -10˚ outside air.
The temperature rise is a very important factor when selecting an air replacement unit. If you receive a quote that doesn’t show you a temperature rise on the air replacement unit, encourage your supplier to provide you with this information.
Q. What does GFS recommend for a cure temperature?
A. Although this is highly dependent on the specific type of coating being used, GFS recommends a typical cure temperature of 140˚ F. When selecting an air replacement unit, it is recommended that you attain the proper information to ensure the air replacement unit can reach the desired curing temperature. GFS also suggests contacting your paint distributor for the recommended cure temperature for the paint you use.
Q. What kind of maintenance will I need to do on my booth and how often?
A. A primary function of a spray booth is to reduce the likelihood of fires and explosions. Regular maintenance of the booth system contributes to the fire prevention effort by removing flammable accumulations and dust. A well-maintained and clean booth will also allow for the best possible paint finishes.
Most booth manufacturers will provide you with a recommended maintenance schedule for your booth. It’s important to follow these recommendations to keep your booth operating in the best condition. GFS also offers a preventative maintenance program. Tailored to meet your needs, service engineers will provide maintenance and cleaning to ensure that your equipment maintains optimal performance. The program can include anything from the general maintenance of the booth to cleaning, and the replacement of filters.
It’s important to make sure that your booth manufacturer has people on hand to answer any questions you may have about the operation and maintenance of your booth, and to provide additional support if necessary. Booth maintenance is critical to the safety of your employees and quality of your paint finish.