The term 'HEPA', for example, has a history of being misused in terms of consumer marketing having been used when referring to vacuum cleaner filters, water filters and even residential boiler filter.
These products don’t meet the industry definitions, nor do they have the required minimum efficiency of 99.97% at 0.3 micron. The clue is in the name – HEPA stands for high-efficiency particulate air.
That makes these filters perfect for critical applications such as semiconductor, pharmaceutical, and food or beverage manufacture and especially medical facilities. HEPA filter is a type of mechanical air filter; it works by forcing air through a fine mesh that traps harmful particles. HEPA filters are not a recent innovation. Developed for the Federal Government in the early 1950's their original design intent was to capture contaminants associated with the manufacture of the atomic bomb.
They were called Absolute filters at that time as the goal was to have absolute efficiency, capturing any and all particles from the air. After World War II, the rights to the Absolute filter became the property of a company that is now known as Camfil.
For some time, into the 1960s the HEPA filter had no commercial viability. Then came transistors and semiconductor industry.
The filters are typically installed in a ceiling of a room that is commonly referred to as a clean room. Some rooms have cleanliness levels that only allow less than 1 particle per cubic foot of air. The common atmospheric air sample has tens of thousands of particles. Pharmaceuticals commonly use HEPA filters in the 99.97% at 0.3 micron to 99.99% efficiency. Their demands are not as stringent as the semiconductor industry, but they still employ clean room technology to protect the integrity of their products.
As filter manufacturing technology has improved, and the cleanliness requirements of product manufacturers has also increased, filter manufacturers have developed HEPA filters that have extraordinary efficiencies even to the level of 99.99995 at 0.12 micron. Imagine this level of efficiency, yet air can move through the filter.
Another critical application of HEPA filters includes hospitals and medical facilities.
Typically used in the ceiling or HVAC systems serving the operating suites they protect the patient from infection and employees and visitors from airborne organisms. As of recent, they are now being installed in critical care patient rooms to protect the compromised patient.
As per scientific studies, fine particulate matter (PM 2.5) air pollution is a leading global public health risk factor and high efficiency particulate air (HEPA) filter air cleaners are a promising level intervention to reduce these concentrations.
HEPA filters now come in many different configurations, yet all still have the requirement of efficiency testing and certification to meet the definition. They are even manufactured for high temperature applications, up to 2000 degrees Fahrenheit or 1093 degrees Celsius.
For more information about our HEPA filters for clean rooms, click here.