Share thisThe importance of limiting contamination first became evident during the Civil War. During that time, it was realized that when operations were performed in dirty environments, the patients developed infections and died. Operating rooms became the first clean environments. Since then, advances in most areas of industry and science have created a growing need for controlled environments. Industry and science have also answered the need by discovering methods to control contamination. These advances resulted in better air handling technologies to minimize cross-stream contamination; better methods to control the pressure, temperature, and humidity; and the discovery of floor and wall materials that are less likely to generate particulate matter. The air shower, which attempts to control the amount of contamination brought into a workplace by the operating personnel, provides another dimension in the effort to continually improve contamination control.
Contamination is any unwanted transmittable substance that can have a detrimental effect on a desired end result. As technology has advanced, the ability to control contamination has gotten more sophisticated in controlling smaller and smaller particles. The contaminants under scrutiny today are measured in microns. For laboratory animal facilities, the value of avoiding microbial and allergenic contamination can be measured in terms of dollars and research performance. An air shower can literally be the first line of defense in eliminating microbial and allergenic contamination.
Pedal to the Metal: The Acceleration of Air Shower Development
The first air showers were the result of less than scientific beginnings. The air shower story goes something like this: In the early 1950's two men were driving along in a car. As the driver of the car accelerated slowly, the man seated next to him held his arm straight out the side window. The passenger took careful notice of the mounting turbulence around his arm until the cigarette ashes he flicked onto his shirt sleeve had been blown off completely. It was the moment industry had been waiting for.
In laboratory animal facilities that use an air shower, normal gowning procedures are typically followed. Personnel enter the air shower, follow the air shower protocol, and exit into the clean area. The air shower protocol takes about one minute. Forty-five seconds must be spent with the air jets on while making several complete 360 degree turns with hands positioned over the head. Personnel must remain in the shower for several seconds after it has stopped to allow time for particles to enter the return air plenum so that they aren’t ejected into the clean area when the exit door is opened. Air showers should not be confused with air locks. A typical air lock is a room, corridor, or other space that separates the clean area from a less than clean area. It has two doors at opposite ends and is frequently designed with an electrical or mechanical interlock so that one door cannot be opened unless the other one is closed. An airlock is used to prevent the loss of valuable clean air whenever a person leaves or enters the room. An air shower can function as an airlock but also has the additional advantage of being able to clean contamination off personnel and equipment with jets of air.