Case Study | AAF ArrestAll®
In 2012, Green River Community College and the State of Washington initiated a plan to build a new state-of-the-art community college focused on training skilled woodworking professionals. The goal was to teach aspiring woodworkers the art of woodworking, design and craftsmanship while providing hands on training.
Wood dust particles and chemicals used in finishing can present several health and safety hazards to students if not properly controlled. Concentrations of small wood dust particles are not visible to the naked eye and are considered highly flammable. These particles, if not controlled, can accumulate in machines and present a potential fire hazard.
Green River Community College looked to AAF to help design and install a collection system to meet the safety and performance needs of their students. Design considerations for the woodworking classroom needed to comply with the National Fire Protection Association’s (NFPA) 664: Standard for the Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities, while also meeting a sound limitation of 65 dBA. Additionally, Green River was looking for a collection system that did not require compressed air usage.
The woodworking classroom and dust collector design presented several challenges. First, the classroom was outfitted with several pieces of dust-producing equipment spread throughout the large open room to allow for students and teachers to move from station to station. The dust collection system and ducting had to be designed to minimize interference with the classroom environment.
Secondly, the dust collector would be located indoors, which meant sound abatement was critical, and had to comply with Washington State’s noise requirements. There was no compressed air available at the site, so the dust collector needed to operate without the need for compressed air. Most importantly, the students’ safety had to be assured, as wood dust is highly flammable and can present explosion hazards.
AAF’s applications engineering team recommended an AR4-15 ArrestAll® shaker collector and an integral after filter. With the ArrestAll® design, the industrial fan never contacts dust laden air, meeting the NFPA 664 guidelines. Consequently, if the primary filters fail, the secondary safety filters capture bypassed particulate. This keeps students safe while preventing combustible dust from reaching the fan. Secondly, AAF’s integral Varicel® after filter systems are 95% on 0.3 micron particles, and meet the 99.99% efficiency on 10 micron requirement, as called out in NFPA 664. Integral spark detection and spray nozzles in the ductwork along with high speed abort gates add additional layers of protection to prevent any deflagration from occuring.Utilizing a 90 degree sound trap on the return air also reduced noise below 65 dBA, meeting Washington State’s noise requirements.
The school now has an industrial dust collection system that keeps students and instructors safe and maintains good housekeeping, while also complying with OSHA, NFPA and EPA regulations. With the safety and performance features included in the supplied dust collection system, the students and teachers can do their work without having to worry about the safety concerns or nuisance dust often encountered in woodworking applications.