SAVVY FACILITY MANAGERS know that industrial vacuum cleaners are critical in maintaining the purity of “clean” environments like pharmaceutical cleanrooms and gowning areas. In these and other controlled areas, specialized vacuums collect—and ideally retain— dust, powders, and other contaminants.

What isn’t as widely known is the impact that the vacuum cleaner’s filtration system has on its effectiveness and on overall facility cleanliness. In fact, inadequately filtered vacuums may exhaust collected contaminants and particles back into the working environment, jeopardizing product purity and employee safety.

All vacuum filtration systems are not created equal; High-Efficiency Particulate Air (HEPA) and Ultra-Low Penetration Air (ULPA) filtered vacuum cleaners that appear comparable may actually vary a great deal when it comes to maintaining filtration efficiency in the long-term. Although true HEPA and ULPA filters must test well when first manufactured, poorly designed filters will decline in performance—sometimes quite dramatically—over time.

In order to make informed purchase decisions and ensure that the proper levels of cleanliness are maintained, contamination control specialists must possess a basic understanding of vacuum cleaner filtration technology and, more importantly, its effect on their facilities.

Combating Airborne Particulates

In pharmaceutical cleanrooms, all airborne particles including invisible ones are considered contaminants. These particles must be removed from the facility in order to secure the safety of the products being manufactured as well as the safety of cleanroom personnel.

As Figure 1 shows, the human eye cannot see particles smaller than 50 to 60 microns in diameter (for comparison, the diameter of a human hair is approximately 80 to 100 microns). In addition, particles that are ten microns or less are considered respirable and can settle deep into workers’ lungs, often causing adverse health effects. Respirable particles make up more than 99% of the seven million particles taken in with every breath.

To safeguard your facility against these invisible threats, you must take particle size into account when purchasing a cleanroom vacuum. Consider the smallest particle size you will have to collect then choose either a HEPA- or ULPA-filtered model. A HEPA-filtered model is ideal if you must collect and retain particles down to 0.3 microns; choose an ULPA-filtered model if you must collect and retain particles down to 0.12 microns.