HEPA filters are specialized filters designed to filter dry air with a rated efficiency of 99.97% or greater. They are not absolute filters, but instead provide a rated reduction in particulate burden.
HEPA filters use media to clean the air and capture airborne particles through several mechanisms including the sieve effect, impaction, interception, and diffusion. Below is a short description of each filtering mechanism used by HEPA filters:
– Sieve effect: This effect occurs for large particles larger than 5 micrometers in diameter. These particles are just too large to fit through the open areas in the filter media. Removal efficiency for large particles due to the sieve effect is typically 99% successful.
– Inertia impaction: Inertial impaction occurs as particles are carried through tile filter media by the airstream. As the airstream shifts to flow around fibers, inertia causes the particles carried by the airstream to impact the fibers. This mechanism typically occurs for particles in the 0.5 micrometer to 5 micrometer range.
– Interception: Smaller particles may be intercepted by the fibers when they come within 1 particle diameter of a fiber when following the gas stream. This mechanism can be effective because of the high fiber density of HEPA media. This mechanism is effective in the 0.1 micrometer to 1 micrometer range.
– Brownian diffusion: Brownian diffusion occurs with very fine particles that are small enough to be affected by collision with the gas molecules in the airstream. Brownian motion causes these particles to move randomly within the airstream, increasing the probability of the particles contacting a fiber.
DC Cheek Heating and Cooling will help you maintain and upgrade your HEPA filters in order to create safe and healthy air quality standards for your home and workplace. Contact us today to schedule an appointment and visit our website for more information. 70-888-8788
One of the most important factors affecting indoor air quality is how a building is heated, ventilated and air conditioned. Well designed and maintained ventilation and air-conditioning systems are crucial to having good air quality, but problems can form quickly when the HVAC system is not functioning correctly.
Lack of HVAC maintenance can quickly lead to problems. Sometimes a home will be having indoor air quality problems because controls in the control system have failed and no one has noticed. Problems such as clogged up filters and unemptied drain pans for air conditioners and dehumidifiers can cut down air circulation while providing a fertile breeding ground for mold and bacteria which have been associated with respiratory allergies and asthma and have been linked to the airborne transmission of various infections.
A microbiological growth may also occur in an HVAC system equipped with low efficiency filters, humidifiers that use water recycling or in areas in which water condensation remains stagnant and large re-circulation of air is present. Microorganisms can thus spread in the indoor air by the HVAC system and be inhaled.
DC Cheek Heating and Cooling will help you maintain and upgrade your HVAC systems to create safe and healthy air quality standards for your home and workplace. Contact us today to schedule an appointment and visit our website for more information. 70-888-8788