Our common CRAC Units (Cooling, Refrigeration and A/C) for data centers only cool the air directly from the data center and back into the data center.
Do these need to be shutdown with the use of a total-flooding clean agent system? If the CRAC unit is only exchanging air within the same space then I'm not sure what harm it would do if it's running during or after clean agent discharge. I'm curious if I'm off the mark here, thanks! Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
6 Comments
Jocelyn
2/20/2020 10:56:48 am
Per NFPA 2001 5.3.6.1 (2018 ed), if the CRAC is not shut down, the volume of the ventilation system needs to be considered as part of the total hazard volume.
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Jen
2/20/2020 11:26:56 am
I think the unit he is referring to is just an heating/cooling unit and brings in no ventilation air since the air it heats/cools is from the space itself.
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Mike
2/20/2020 11:33:28 am
The CRAC units are typically wired to the fire alarm so upon activation, the CRAC unit is shut down.
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Jen
2/20/2020 11:46:10 am
Hi Mike,
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JOnathan D Griffin
2/20/2020 12:05:49 pm
If the CRAC is serving only the protected space, then it is allowed to continue to run. A Room Integrity Test would test as a "Mixing Volume" for agent concentration purposes, as when the CRAC unit is running, a descending interface is not established.
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Travis De Goei
2/20/2020 02:11:30 pm
I completed our enclosure integrity testing for many years. I agree that the mixing method of testing is an option that considers retention conditions while the fans in are in operation.
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