This is the first installment in the all-new Hodess Cleanroom Construction blog. With this segment of our site, we’re hoping to provide articles and thoughts to help people address problems with all aspects of cleanrooms. Our goal is to create a place where we can share with you the wealth of lessons learned from designing and building cleanrooms for the past 35 years. That experience is key in my role as President of Hodess Cleanroom Construction. Going forward, we hope this blog serves a resource for the industry’s innovators to refer to.
Cleanrooms today have changed significantly from 35 years ago. The equipment, finishes, and filtration technologies have advanced at a rapid pace. In 1981, we still saw HEPA filters in wood frames or galvanized steel housings. The paper technologies, potting systems, use of aluminum frames and housing—all have drastically reduced the risk of not meeting particle count requirements. Throughout the early 1980’s, we struggled to hit the particle counts and with a lot more air (90fpm +/-20FPM) than we use today. Leaks in the HEPA’s and housing were more pronounced. There wasn’t the abundance of aluminum pre-gasketed ceiling made for cleanrooms.
In my first cleanroom, the ceiling grid had to be custom designed and manufactured to meet the load requirements. Today, there are so many systems available that reduce leakage and help insure cleanroom cleanliness. Non-shedding wall and floor systems have also come a long way. As a result of these advances, we are using less air and generally certifying 1 to 2 classes cleaner than an earlier design with little issue. If I have learned anything from my successful time in this business, it’s that as the industry evolves, so does your approach.
Build Clean programs were nonexistent in 1981. We started developing them as we realized just “one final cleaning” did not work, as trapped dirt would work its way out over time. These programs and better final gowning procedures have further reduced particulate levels and made room certification easier. Today, we see multilevel protocol, cleaning in many specifications, and we have standard precautions. Practices like degreasing duct at the shop and bagging all duct ends help us further insure a cleanroom certifies quickly.
Back in the 1980s, Fed Spec 209 C-E was the design gospel. It spelled out coverages, velocities, and other parameters to design and certify cleanrooms. Three and a half decades later, we follow the ISO 14644 standard, which follows metric measurement requirements that replaces the old classification system from Fed Spec 209. The ISO standard has also been changing. Up until the current version, it has contained recommended air changes per hour to get to a specific ISO class.
The latest standard is projected to not even include this information. We’re moving towards dilution calculations based on the process, gowning, and other factors. However, even 30 years after the standards were rewritten, Hodess still gets requests for Class 100 vs ISO 5 rooms. Old habits are hard to kick but the industry is making a major effort to change the labels. As we have for 35 years, we’ll evolve with them.