Office HVAC requirements

[radaes]

Hi,

I'm trying to find the appropriate standard that specifies requirements for office HVAC capacities. Our contractor tried to tell me that our system is "compliant per ANSI 2000" and that strikes me as suspect, since I don't think I've ever seen an ANSI standard in that format. Plus, shouldn't it be an ASHRAE standard? I'd prefer getting the standard, but I'd welcome any answers along the lines of "you need x capacity for y area/space" too. thanks

cheers,
rad
"According to my calculations the problem doesn't exist."

 

[Jabba007]

There are rules of thumb... but as far as capacity is concerned, the only ones I know about are for ventilation, and for occupancy per sqft.

Does the system not work well?

What are the symptoms?

Jabba

 

[radaes]

The system works fine - I just got curious as to what the actual standards are, since anything the contractor tells me to be "compliant per ANSI 2000" is suspect.

cheers,
rad
"According to my calculations the problem doesn't exist."

 

[GMcD]

Depends where you are. ASHRAE specifies the indoor comfort and ventilation standards for North America, and whoever else chooses to use them. In Europe, there are many local (by country) standards (German DIN Standards) and REHVA (the European ASHRAE) standards.

 

[KiwiMace]

I don't think there is a standard for system capacity, as no one number can apply to all spaces.

But there are certainly standards concerned with the components of how the system capacity is derived; in terms of calculation method, allowances for ventilation, room temperatures... the list goes on.

Your contractor should be able to define these individual standards if you care to ask. He may have been talking about a standard for project management for all you really know.

 

[radaes]

@GMcD - we're located in the US, so ASHRAE standards would apply. (Is there anyone else that would apply in the US? OSHA or something along those lines?)

@CinciMace - I wasn't saying, "There must be a standard that says 'all HVAC systems in offices must have a capacity of <specific number>'" - but i am fairly sure that there is a standard that either specifies minimum capacities for a system air conditioning an office space given area/volume, humidity requirements, temperature ranges, etc OR specifies a method of calculation to derive those numbers.... and if there isn't, there should be

cheers,
rad
"According to my calculations the problem doesn't exist."

 

[DUMechEng]

radaes,

there is no standard that specifies minimum capacities for a system. the industry standard for calculating the required capacity of equipment is outlined in the ASHRAE Handbook of Fundamentals. If your town or state has adopted the International Mechanical Code then the designer is required to perform these calculations by Section 312. Most energy codes require the calculations to be peformed as well.

 

[insult2injury]

Consult the building code that is applicable....easy as that.

I believe that I've seen it quoted by number of air changes per hour. This number also changes by how the area is classified. You should be able to find a table with the relevant values fairly easily. I believe that for general office spaces, ASHRAE requires 4-10 air changes per hour.

 

[Engineer6512]

There is a required capacity for ventilation air. It is covered under ASHRAE Standard 62.1 and specifies the amount of outdoor air required based on both the square footage of the space and the occupancy. There is an alternate method called the Indoor air quality procedure that is based on contaminants and their concentrations. Shouldn't your system have been designed and stamped by an engineer?

 

[radaes]

Thanks to everyone who has responded.

@engineer6512: the issue was that we expanded our office and our contractor was saying that the existing system was not sufficient to condition the new spaces, citing some random standard (turns out that he was just trying to get the job of replacing the ac system). I just got curious what the correct standard would have been (you actually answered my question: he should have cited ASHRAE 62.1 and related, rather than ANSI 2000). I don't actually care if the current system is sufficient, since it's slated to be upgraded soon anyway.

anyway, thanks again



cheers,
rad
"According to my calculations the problem doesn't exist."