HEPA Filter Types

Industrial Filter

• The industrial filters have a performance efficiency of almost 100 percent and follow the military standard MIL STD 282 test method. These filters are similar to the clean room HEPA filters, and thus factors such as purpose of the clean room, equipment and room layout, temperature and humidity, maintenance and filter access and ceiling system design are analyzed before installation. Some of the applications of industrial filters include semiconductor manufacturing, pharmaceutical manufacturing, medical device manufacturing and dental device manufacturing.

Nuclear Containment Filter

• These filters also have performance efficiency close to 100 percent. They use glass as the filter medium and are generally built to have a higher capacity. Nuclear containment type filters also feature a waterproofing binder to resist wet and dry conditions. These filters are tested for overall penetration at 20 percent of rated flow in accordance with MIL STD 282. This particular test is known as the two-flow test. While conducting this test, aerosol is used to create nearly mono-disperse aerosol of approximately 0.3 micrometer diameter droplets. A measuring instrument known as the Q-107 penetrometer is used for the process.

Laminar Flow Filter

• Laminar flow filters have the highest efficiency among all the three filters, missing 100 percent by a mere 0.01. These filters use a photometer method and polydisperse DOP aerosol for the scan test. They are generally used in hospital operating room suites, emergency room trauma centers, pathology and hematology laboratories and intensive care units. The Laminar flow HEPA filters consist of 140 to 190 pleats, which assist in directing the gas as it flows through them. Use of the medical space in consideration, the level of air, cleanliness required and the amount of air needed to appropriately ventilate the space are some of the factors to consider before using this type of filter.

  With higher usage, the efficiency of all types of filters increases. The best part of these filters is that they demand no cleaning, thus providing a maintenance-free safety system to users. However, immediately replace filters exposed to water spray, moisture, hot air, fire and shock pressures.