There is no shortage of options when it comes to HEPA filters, and that is also true of HEPA filter housing options. Depending on the style and type of seal the filter you choose it will determine what kind of housing you use. Here, we'll focus on side access housings, for built-up frame options, please download our free eBook: "HEPA Frames & Housings" When it comes to side-access housings you have to know if the filter is a gasket seal or gel seal, then you will have the following options:
Gasket Seal Options:
Gasket Seal HEPA Housings are common in most hospitals and general ventilation applications where the added expense and seal integrity of a gel seal isn't necessary. For smaller applications where the housing is only 1 or 2 filters wide, then an inexpensive bolt-style housing is a good choice. This is exxentially a pressure-tested filter box with a built-up style frame system welded to the interior and will sometimes come with a prefilter track. Common options are high-pressure, insulated walls, and are most commonly made out of Galvanived or 304 Stainless Steel. Sometimes Aluminum or 316 Stainless is used as the housing material.
Crank style housings are slightly more expensive than the basic bolt style, but offer a better seal integrity as the pressure from the clamping mechanism is more evenly applied to the filter itself, and for larger applications where the filter bank is 3+ filters wide it makes filter replacement much easier as the installer doesn't need to get inside the unit to loosen bolts on each filter. Operationally the filters slide in from the side and then a crank operated spring mechanism pushes against the filters, which are guided into the sealing face by guides that are welded into the housing. This style of housing offers maximum seal integrity for a gasket style filter.
Gel Seal Options:
Gel Seal HEPA Housings are common in Bio-Safety Labs (BSL-3 and BSL-4), and other high purity areas where the slight chance of bypass that gasket seal filters have needs to be eliminated. Because of their use in high purity applications the housings for gel seal filters are tyically start at a higher standard than gasket seal options - not to say you can't find some cheapo manufacturer looking to sell whatever they can and cut corners to deliver the "low-bid" but those companies are usually not considered by end users due to the critical nature of these spaces.
First, 304 Stainless Steel is the standard option for most gel seal housings, and some companies do not even offer a galvanized option. Where gasket seal housings are typically rated at ±8.0" w.c. the gel seal housings typically start at ±15" w.c.. The Door seal is also different, with a high integrity compression seal and attached with bolts instead of neoprese gasketing and light duty clasps or nuts. Lastly of rthe major differences is that there are no prefilter tracks in a gel seal housing - they provide too much opportunity for leakage and are offered as a different section.
What one is right for you and your application? What options would be worthwhile? The only way to know is to ask one of our application specialists where we will provide a free review and recommendation.