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planning for passing IEST leak tests

Trying to consistently pass IEST leak tests

The Details Matter

With new regulations making IEST-RP-CC034 HEPA and ULPA Filter Leak Tests required in many more facilities than ever before there are considerations for passing these tests initially and in the future that are easily overlooked.


Keeping out the challenge gas is much more difficult than simply not having a “leaky” ceiling by normal HVAC standards. Being truly sealed from gas penetration is much more difficult than it may first appear. Keeping it that way harder still. You have to assume everything above the ceiling level is contaminated and cannot be allowed to pass through.

Gaskets just aren’t good enough in most cases. All devices must be airtight and leak free in both positive and negative pressure differential conditions. Penetrations need to be kept to a minimum. Every possible leak path must be effectively blocked with a sealant that will stay effective for years to come, with the settling of buildings, the vibrations of construction, and everyday use.

Hard ceilings with good rigid support that will stay in place under changing pressure conditions (like every time someone opens a door). Good caulks that remain flexible, regular inspections and maintenance, as well as ensuring any new work is just as carefully done will help ensure the room will keep passing tests for years to come.

Testing Considerations

Who is doing the testing? What equipment do they have? What are their preferred challenge methods? You can save a lot of time and effort later by doing some footwork ahead of time.

Do they want challenge ports at each unit? At the face or remotely mounted? What size and type of fittings do they need? Are the units ducted or share a plenum? Finding out what your testing company needs at the design phase will prevent you from having costly delays and modifications at the last minute when you are trying to get that new facility online.


AJ Manufacturing has heard these hardships from our customers and created solutions for them. We have reduced ceiling penetrations by offering integrating lighting. We have challenge manifolds that meet the IEST requires with data to back them up. We have optimized our knife edge seals to work under the widest variety of conditions to minimize leakage opportunities. We have knowledgeable staff that can help you from planning through certification to make sure your project is done right the first time.