Ventilation air code

[aphou]

I am working on a renovation project, the building is built in 1984, I assume 1981 BOCA mechanical code is used at that time. Does anyone know what is the outside air and ventilation requirements for office and conference rooms in 1981 BOCA Mechanical code?

 

[MarauderX]

I would imagine that you won't be able to design to the '81 code for current permits.

http://www.vanderweil.com

 

[aphou]

The outside air requirements for building built in 1984 is 5 cfm/person and 8.33 cfm/person in conference room. It is almost impossible to upgrade the outside air to the current code requirements.

The local building code authority agree us to follow the ventilation code based on the year the building was built. It make sense, because if one floor is being renovated in a high rise building, it is unfair to ask the tenant or owner to upgrade the oa requirements for the entire building.

 

[MarauderX]

It may make sense, but it doesn't make for a good building. I wouldn't want to live or work in the jurisdiction you are under, as every building would comply only with the year it was built.

Almost impossible means that it can be done. I should hope that you make the best engineering decision when designing those office and conference spaces.

http://www.vanderweil.com

 

[TADiep]

"It may make sense, but it doesn't make for a good building. I wouldn't want to live or work in the jurisdiction you are under, as every building would comply only with the year it was built.

Almost impossible means that it can be done. I should hope that you make the best engineering decision when designing those office and conference spaces. "


The best engineeing decision is to bring the building up to code. That is a no-brainer. However, both you and I know that doings thing the proper engineering way equals money. In this case, alot of money. The house system is not set-up for the additional outside air needed to bring the space up to code. Also, since this is located in a high rise...the units are most likely central units that serve multiple floors.

As engineers, we should inform the building owner of the situation and that we recommend they upgrade the units to allow for the current OSA requirement. If they say, "we do not have the money and the local jurisdiction approves of gradfathering in the previous code." At least you performed your due diligence. And thats all we can do.



----
A green thought..."We don't inherit the earth from our ancestors, we borrow it from our children." (unknown)

 

[willard3]

If the Owner doesn't want to spend any money on the new space, he surely doesn't need an Engineer.

Engineers are responsible for best practice and 5 cfm/person in a conference room is not best practice.

 

[mike7941]

What about xtra filtration of the return air and UV or BiPolar Ionization treatment of the supply airstream?
According to their salesmen it can bring the outside air requirements back down to the 5 cfm level. They wouldn't lie to us, would they?

Honestly I haven't tried it. But Its something I'd think about, if forced into a corner.

Mike

 

[NCDesign]

mike7641 & the OP ASHRAE 62.1-2004 section 6.3 allows for an Indoor Air Quality approach, so there is validity to what the salesmen is trying to sell. But, there are several issues.

One is if your jurisdiction will go for it. A lot of codes don't reference 62.1 as a viable way to provide outside air per code. In the case of the International Mechanical Code and several state's derivatives, they have taken Section 6.2, Ventilation Rate Procedure, from 62.1-1999 (I think thats the right year) and made it part of the code. Not by reference but by directly placing that section in the code. This stinks because in my opinion they are requiring way to much outside air and don't give you very much flexibility.

The second is actually being able to meet that approach if the jurisdiction allows it. It takes a lot more work to approach it from that direction. You have to identify and quantify contaminants and then prove that the system you are providing will take care of all those. Even after you have dotted all your i's and crossed all your t's you are still left hanging by section 6.3.1.3 which says:

The criteria to achieve the design level of acceptability shall be specified in terms of the percentage of building occupants and/or visitors expressing satisfaction with perceived indoor air quality

That perception part is enough to scare most people away even if they can get it through the AHJ. Nothing like having to go back and redo your design because the client and/or AHJ just doesn't think the air is clean enough. In my opinion your safety net just isn't there like it is if you follow the ventilation rate procedure.

 

[atlas06]

Dynamic Air filters claims the same air quality approach to reduce outside air quatities.
The latest IMC 2006 403.2 Exception allows an "engineered ventilation system" outside of rates stated in section 403.3. I believe this revision to the code is there to allow the engineer to follow ASHRAE 62.1 instead of the more stringent IMC rates.

 

[AbbyNormal]

A climate where you can run a constant positive or negative it is no problem. You can neglect infiltration load and just worry about ventilation.

NASA can recycle urine into potable water, I would rather drink the fresh stuff myself.

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

 

[RossABQ]

There is likely to be an initial problem with that low of a ventilation rate, if the project includes re-painting and new carpets (seems likely). It will take weeks to get rid of the off-gassing products. An approach may be to specify that only carpet and paints with low volatiles be used, and have the contractor develop and use an IAQ plan (similar to those in Green Building guidelines). Once the renovated areas have "aged", the occupants will just have their own BO and farts to deal with...