I'm having a hard time finding any references as to whether Sulfur Hexafluoride, a clear, heavier than air gas used for leak detection in buildings, would set off smoke (either ionizing, photoelectric, or aspirating) detection systems. Does anyone have any background or references on this subject they'd like to share?
Are you leak testing an enclosure or some type of piping??
The leak test is being performed on a Control Room and the associated HVAC.
My advice
Talk to the fire alarm company that handles the building and see what they say.
Posdibly they could take a bowl of this stuff and just put it up to one smoke detector, and see what it does.
My other highly suggestion, depending on the fire alarm system, some can selectively, disable in individual detectors, for your test
Whatever you do I would have a fire alarm rep onsite while you do your test.
The likely concentration of SF6 that you are using for control room envelope testing is well below that which would activate a smoke detector. We have never had an issue with detector activation during similar testing at the nuclear power station I worked at for 34 years. As an additional precaution, just assure injection point is not directly next to a detector. Bigger issue from a fire protection standpoint is the number of fire doors that get blocked open to assure mixing of the SF6 throughout the test area.
Thanks Stanford - very helpful suggestions. We recently switched contractors performing the test, and the previous gas used did set off the detectors - not sure what the gas was. We have a history of extensive fire watches, and management wants to eliminate fire watches where they're not needed, and I'd rather have the system in service from a plant risk standpoint.
Out of friendly curiosity, what plant did you work at? I'm working at Brown's Ferry.
Susquehanna. Current contact for this SF6 test (and a former system engineer for fire protection) is Bill Rigotti. Bill said feel free to give him a call if you would like to discuss further. Bill’s email is William.rigotti@talenenergy.com and his number is 570 542-3779.
Stan Davis
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Well almost anything sets off smoke detectors.
Now it has to get to the level of the detector for it to sense it.
Now if you think that you can isolate the gas say in a few rooms or areas, cover the smoke detectors during the test time.