Dear all,
I am consulting on a big project which has small electrical rooms (~30 sq.ft) in the mechanically ventilated parking basement. The Engineers are claiming that it's not practical to provide a fresh air duct to these rooms (too much ductwork that has to pass from one size of the parking all the way to the other side, just for several small rooms like this).
The Engineers are proposing having an exhaust fan in each of these small rooms, along with a Fresh Air Transfer Grill in the room, which will ensure that sufficient amount of fresh air enters the room. The parking is mechanically ventilated with 100% fresh air & exhaust fans.
Would this be acceptable for the prerequisite? Do we need additional calculations from the engineers regarding the amount of fresh air entering these small rooms?
Thanks!
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
May 23, 2014 - 8:32 am
Omar, since these are not considered to be occupiable spaces, they do not need ventilation. You can simply provide cooling as necessary for the equipment inside.
Maya Karkour
EcoConsulting872 thumbs up
May 23, 2014 - 8:38 am
Thanks Andrew,
However ASHRAE 62,1-2007 Table 6-1 has an area outdoor air rate of 0.06 cfm/ft2
The way I understood this is that even if an electrical room isn't occupied (which is true in almost all cases), you still need to provide fresh air.
Isn't this the case?
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
May 23, 2014 - 8:41 am
No, this is not the case. See the definition of Occupiable Space in ASHRAE 62.1.
Maya Karkour
EcoConsulting872 thumbs up
May 23, 2014 - 8:44 am
Andrew, I know that these electrical rooms do not qualify as occupiable space, but still, why does Table 6-1 include ventilation requirements for electrical rooms?
Andrew Mitchell, P.E.
PrincipalMitchell Gulledge Engineering, Inc.
LEEDuser Expert
126 thumbs up
May 23, 2014 - 8:53 am
You have to understand that the 62.1 Standard is meant to be applied to your building according to actual occupancy and use. There are some electrical rooms in the world that are occupied. Your electrical rooms (according to your description) are not. Therefore, you should utilize the exception found in the definition of an Occupiable Space. I hope that helps.
Maya Karkour
EcoConsulting872 thumbs up
May 23, 2014 - 9:02 am
Okay now it's clear, thanks Andrew :)
Richard Mathews
Mechanical Engineer2 thumbs up
June 6, 2014 - 9:57 am
To clarify things, the ventilation requirements for "Electrical equipment rooms" and "Elevator machine rooms" were stricken from ASHRAE 62.1-2007 with Addendum d. At the same time they modified the language for 'storage rooms' to list "Occupiable storage rooms for liquids or gels", along with a separate listing for "Occupiable storage rooms for dry materials", which have both been significantly helpful.
Maya Karkour
EcoConsulting872 thumbs up
June 6, 2014 - 10:10 am
Good to know, thanks Richard!