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Recirculation Of Air

RJJ

RJJ

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Oct 17, 2009
Messages
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Location
about 1' east of the white water
Small 3 bay repair garage/ existing oil fired heater! During renovation they have placed a return grill in the ceiling of the repair bays. The air will be recirculated into bath room,office area and waiting area.

It appears that 403.2.1 prohibits this set up? Yes or NO?
 
Re: Recirculation Of Air

This is prohibited, but 403.2.1 is only part of the citation. 403.2.1 only prohibits the "required amount" of outside air from being recirculated, any air in addition to that is allowed to be recirculated. 403.2.1.1 or.2 do not apply because a dwelling unit or a pool deck is not involved. 403.2.1.3 or .4 do not apply because Table 403 has no footnote B or H for Repair Garages.

However, you can prohibit the recirculation of garage air via the oil fired heater by several other sections - 401.6, 502.1, or 918.6 are good places to start
 
Re: Recirculation Of Air

Thanks Dr.J I have those section referenced in my letter. Funny when I went back to the approved plan all references and a correct installation was on the plan. In the field it is a different story. Some corrections will need to be made.
 
Re: Recirculation Of Air

It's not exactly prohibited. As Dr. J points out, if the amount of air initially introduced into the space is sufficient for the combined requirements for all rooms, it is permissible to introduce the air into one room and then move it from that room to another, and another (as long as the air is not being moved through a means of egress corridor). That's how 403.2 works - by allowing transfer air to meet the needs of the second room as long as it is accommodated in the initial supply design.
 
Re: Recirculation Of Air

Gene: I understand your though on this subject, but I feel that the return air is prohibited under 918.6. I don't see that contaminated air would be allowed to be introduced into office,waiting and bath room areas. I tend to agree with Dr.J unless a reasonable explanation could be provided. This is not just an office set up.

Further, the installation did not follow the approved plan,which is a different issue. A few things exist such as the furnace does not have proper make up air for a confined space, the Shop are does not have the proper induction of fresh air and I don't see a place in the code that would allow for the return system to be able to pick up contaminated air and distributed it through out the building.
 
Re: Recirculation Of Air

Well, if they screwed up the installation that's a whole different story. By all means, make it right!

Regarding the transfer air issue, you might try calling ICC on this. As former staff fro one of the legacy code organizations, this is the interpretation that we gave people on this subject. Granted, it's not the best solution but is adequate. Its the same manner in which natural ventilation is allowed into inner rooms from the room where the window is located - same concept. The issue of recirculation has to do with moving are through a space, and then back through a space without filtering or the introduction of fresh air.
 
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