We have installed a number of Broan RDH bathroom exhaust fans in an apartment building. They contain a radiation damper that is activated by a fusible link. (165F I think) They are in no way designed to be tested. The manufacture does not have a written test procedure for doing so. However, NFPA 90a - 7.2 appears to require testing of these dampers after installation, and every four years. I have contacted the manufacture and they have never run into this before. I don't know how that's possible. Has anyone else run into this? Thanks in advance.
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Testing exhaust fan dampers
- Thread starter shockin
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NoVA Comms Power
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- Alexandria, VA
While I've not dealt w/ that particular item, my experience w/ testing fusible-link systems has always been to ensure that all components actuated by the link "parting" (e.g. mechanical linkages, electrical contacts, etc.) actually function as designed.
Can the fusible link be removed? (many can to allow post-actuation replacement)
If so, perhaps you could simulate the link parting by first replacing the link w/ a wire or zip-tie so as to "arm" the system; followed by cutting the tie to simulate actual the link parting.
Can the fusible link be removed? (many can to allow post-actuation replacement)
If so, perhaps you could simulate the link parting by first replacing the link w/ a wire or zip-tie so as to "arm" the system; followed by cutting the tie to simulate actual the link parting.
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The problem is removing the link itself. It is held in place by what I believe are two stainless steel "eye hooks." In order to remove the link you would have to physcially bend open a hook, then bend if closed when finished. It seems to me that by bending the eye hook you are adjusting the amount of tention on the fuselink, which may or may not be a problem. In addtion, by bending and rebending I would think it would damage the integrety of the steel, and risk breaking. I would think if they were designed to be tested - there would be a more logical way to do so.
NoVA Comms Power
Senior Member
- Location
- Alexandria, VA
Given your description of the design I agree 100% that the link is NOT designed to be removed.shockin said:... I would think if they were designed to be tested - there would be a more logical way to do so ...
That would seem to make it effectively a "single-shot" device which would require replacement whenever actuated.
Not sure how this impacts the applicability of any testing requirements ... but clearly single-shot devices can't be "op-tested" by the installer / customer / maintainer.
It sounds more akin to a portable fire extinguisher -- it undoubtedly has characteristics which can be inspected, and which should give a reasonable assurance that the device WILL operate -- but it can't actually be op-tested.
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