The International Fire Code (IFC) Section 6004 for highly toxic and toxic gases states the following for exhausted enclosures:
6004.1.3(1) The average ventilation velocity at the face of the enclosure shall not be less than 200 feet per minute with not less than 150 feet per minute. However, in the same section for gas cabinets (Section 6004.1.2(1)), the words "at any point of the access port or window" are added after "150 feet per minute." Doe anyone know if this was an oversight by the authors of this section? Did they miss a few words in the requirement for exhausted enclosures? I don't understand why the 150 feet per minute would be for gas cabinets but not exhausted enclosures (albeit without referencing where the 150 feet per minute measurement is to be taken). This issue is coming up at my work as we have several exhausted enclosures and gas cabinets and some of the exhausted enclosures have ports/windows which are sealed shut. Thanks in advance! Sent in anonymously for discussion. Discuss This | Submit Your Question | Subscribe
3 Comments
Tony
3/17/2021 12:15:36 pm
I see what you are saying. That has to be an typo. It doesn't even make sense without the "at any point of access..." after.
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Vincent
3/18/2021 06:45:37 am
One difference between the gas cabinet and exhausted enclosure is that with a gas cabinet the access port or windows is sometimes opened to access the controls inside the gas cabinet. This is normally not the case with the exhausted enclosure. If I recall correctly, the not less than 150 ft./min addresses when the gas cabinet access port or window is open.
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Ritz
3/19/2021 08:37:19 am
It’s probably due to the configuration of the enclosure opening. If it’s rectangular, floor to ceiling, exhaust duct connected in the top or back, etc. the ft/min will vary at different points along the enclosure opening. If the duct is connected at the top there will be more draw at the upper portion of the enclosure opening vs lets say the opening goes clear to the floor. One may need 250ft/min at the top to get the minimum of 150 at the floor portion of the enclosure opening.
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