When you are outfitting a clean room one of the most important parts of the process is going to be filtering the air. Depending on the size of the clean room, this may be a relatively small matter or it could be a herculean effort, but you can’t have particulates from the air contaminating your work, can you? In today’s article we are going to talk about the function and general usage of a HEPA Fan Filter Unit as well as advise you on how they may be accessorized to make your clean room the cleanest that it can be!
What does HEPA mean?
HEPA is an acronym that is short for ‘High-Efficiency Particulate Air’ (aka High Efficiency Particulate Arrestance/Absorbing). So, what does this mean in a fan filter?
Quite a lot, actually.
HEPA is a standard that is utilized all over the world and to be a HEPA compliant filter the filtration must be at 99.95% or 99.97% (European and U.S. standards, respectively). The HEPA term itself was first registered in the 1950’s and later became the standard to that extent that even generic filters of high efficiency were often referred to as ‘HEPA filters’.
What does the HEPA Fan Filter do?
An actual HEPA filter has a very big job. Employing a mass of randomly arranged fibers of varying micrometer thickness a HEPA filter is designed to trap contaminants in one of three ways:
- Diffusion method – The first line of defense for the smallest particles is actually coincidental collision with gasses, which slows down the trajectory of the particulates so that they are either impacted or intercepted.
- Impaction stoppage – Larger particles become trapped easily in the fibers although the efficiency of this can diminish as impacted particles begin to separate the fiber openings or with an increase in the air flow.
- Fiber Interception – Following the flow of the passing air, interception is when particles come within 1 degree of radius from a fiber and end up sticking to it.
Think of HEPA as a particle-net that ensures high-efficiency filtration. We should also note that odors and gasses are not filtered through this method but it is efficient for other particulates that might otherwise invade a clean room area.
How are they generally used?
HEPA Fan Filters are generally employed in clean rooms, Medical environs, Laboratories, and Micro environments. Typically installed in grid arrangements in ceilings and sometimes in floors, HEPA fan filters are often employed these days in lieu of the standard duct or plenum systems. This has financial advantages, as an array of less than 20 HEPA fan filters is less expensive than a ducted system. This medium is also easier to implement when there are height restrictions or smaller areas of floor space to work with in a clean room environment.
What does a HEPA fan consist of?
A HEPA fan is typically made of galvanized steel construction which incorporates a fiberglass fiber matrix for catching contaminants. In a pre-filter stage before they reach the actual HEPA filter. They generally employ a 185W 60Hz motor as a standard but this may vary depending on the manufacturer. These generally incorporate a backward curved direct drive assembly and in some models they are both
“99.9% filtration rating for particles of .3 microns or larger”
energy efficient as well as self-powered. Customized HEPA filters are available as well. All of this easy-to-install self-contained technology means that you can get a 99.9% filtration rating for particles of .3 microns or larger in a good fan filter unit. Also available if your needs are more extreme are the optional ULPA filters , which can provide a 99.999% efficiency for removing particles of .12 microns or larger. That is some serious clean air.
Fan Filter Accessories
Aside from the standard HEPA fan filter configuration you can obtain a number of accessories in order to upgrade and improve the efficiency of your fan filter. Some examples of popular upgrades include the following:
- Framing – You can purchase stainless steel framing panels to use for your Hepa fan filter array. They easily mount to drywall and other hard materials to facilitate installation.
- Fan Filter Unit control system – These units are capable of monitoring your Smart WhisperFlow units to not only gauge particulate accumulations but also to regular airflow pressure to ensure proper compliance.
- Wash down filter cover panels – Clean rooms need to be washed, of course, and often. These panels provide protection for your fan filter units so that you can clean the ceiling without worry about damaging your fan filters.
- Power distribution modules – These are good for fan filter and light combinations. With one of these units you can ensure proper power distribution as well as make things easier for yourself for when you want to add or rearrange current fan filter unit configurations.
- Filter replacement alarm – As filters accumulate particles then a natural buildup of backpressure begins, decreasing the efficiency of the filter and requiring a higher concentration of airflow. Rather than relying on a pre-set amount of days for replacing your filters it is better to employ one of these alarms, as this way you can ensure that your filters are performing always at peak efficiency.
- Night service switch – You can extend the life of your filters and also save about 25% on your operating costs with the installation of a Night service switch. These switches put your fan filters into a reduced energy mode during the hours when the clean room will not be in use.
Today we have discussed the ins and outs of HEPA filters so that you can make an informed decision when you are outfitting your clean rooms. As you can see, there are a number of ways to boost efficiency and with accessories and proper planning you can ensure that your clean room, lab, or medical room filtration requirements can be upgraded without hassle as needed. Until next time, keep on keeping those clean rooms clean!