Ventilation Air Distribution Requirement

[psulee]

I am looking for some guidance on a disagreement that I am having with another engineer regarding the design of a ventilation system for a new residence hall. The residence hall is subject to both the IMC and ASHRAE 62-2004 ventilation requirements. The building is designed with a suite approach (3-4 bedrooms, 1 common space, 1 shared bathroom). The engineer would like to supply all the fresh air into the corridor and let the corridor transport the air to the bedrooms. Without a return or exhaust air path at the bedroom, this was not possible. But my question is: can the engineer use the corridor as the delivery method to the occupied spaces? I have found in the noted compliance documents where it indicates that transfer air may be used in lieu of direct OA supply (bathrooms/kithenettes). But I did not find a statement indicating that the supply air for the occupied spaces must be supplied directly. The engineer is proceeding to design a system that will pull air from the corridor, through the common space, and into the bedrooms. I am uncomfortable with this direction and would like to reference a specific requirement indicating that this solution is not acceptable. I would also be interested to hear those that disagree allowing me to put this to rest. (Note that the design had originally intended to use the windows to comply with the OA requirement, but the window could not accomodate minimum openning). Thank you.

 

[Wareagl487]

psulee -

I am assuming the "corridor[/i]" is the common public corridor leading to each of the dwelling units. I don't know how he can justify this against the 2006 International Mechanical Code section 601.2 which states:

Corridors shall not serve as supply, return, exhaust, relief or ventilation air ducts.

There are exceptions listed, but with information provided, do not appear to apply.

Andy W.

 

[MintJulep]

And it just sounds like a bad idea.

Someone does something smelly in the corridor and the entire floor is affected.

 

[mechanicaldude]

The IMC states under "Mechanical Ventilation" that "Ventilation supply systems shall be designed to deliver the required rate of supply air to the occupied zone WITHIN an occupied space.

Providing your code required ventilation air to another space (ie the corridor) defeats the whole point of providing mechanical ventilation. That would be the same as having natural ventilation in the corridor via windows and saying that it covers you for the adjacent rooms because the air will transfer there under the doors...

 

[AbbyNormal]

used to see a lot of pressurized corridor schemes in apartment complexes, hotels

keeps smells in the apartments, would tend to keep smoke out as well

There is usually a constant exhaust out of each unit or hotel room, works better in the north than the south.

The exhaust fan in the units does not care where it gets air from, it will 'suck' as hard on an exterior wall as it will on a transfer grille from the corridor.

Best to dump the air directly to the units

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[cry22]

I don't have IMC on hand this minute but I do know that IMC prohibits occupied spaces from being used as plenums, i.e. transfer air from one room to another before you return or exhaust it unles it is unoccupied space such as crawl space, mechnaical room, etc.. It is under Air Distribution.

 

[DonPhillips]

IMC 602.1 General. Supply, return, exhaust, relief and ventilation air plenums shall be limited to uninhabited crawl spaces, areas above a ceiling or below the floor, attic spaces and mechanical equipment rooms. Plenums shall be limited to one fire area. Fuel-fired appliances shall not be installed within a plenum.

IBC 1017.4 Air movement in corridors. Corridors shall not serve as supply, return, exhaust, relief or ventilation air ducts.
Exceptions:
1. Use of a corridor as a source of makeup air for exhaust systems in rooms that open directly onto such corridors, including toilet rooms, bathrooms, dressing rooms, smoking lounges and janitor closets, shall be permitted, provided that each such corridor is directly supplied with outdoor air at a rate greater than the rate of makeup air taken from the corridor.
2. Where located within a dwelling unit, the use of corridors for conveying return air shall not be prohibited.
3. Where located within tenant spaces of 1,000 square feet (93 m^2) or less in area, utilization of corridors for conveying return air is permitted.



Don Phillips

http://worthingtonengineering.com

 

[psulee]

Thank you all for your assistance. There seems to be quite a bit of agreement on restricting the use of corridors to supply the OA to the suite.

As a note of clarification, after I read my original post I realized that I did not mention that there are 10 "Suites" per floor that are connected by a public corridor. It is this corridor that they are using to supply air to the rooms.

I will continue my oppose this design and make mention of the information noted above. Thanks again.

 

[Wareagl487]

I will continue my oppose this design and make mention of the information noted above. Thanks again.

You are wise beyond your years......

Andy W.

 

[Jabba007]

I concur with everyone else. It USED to be allowed and no longer is.

Jabba