Emergency generator for Group B occupancy

[Grouch]

Hi All,
I'm trying to determine if a particular building requires an emergency generator. It is group B, less than 75 feet high, so, using the 2008 NYC building code (this is in brooklyn NY), i would follow chapter 27, section 2702.2.20 where it states:

"An emergency power system shall be required in those Group B, E, and R-1 occupancies specified in this section:

1. Group B occupancies with occupied floor less than 75 feet above the lowest fire department vehicle access having a gross floor area over 15,000 square feet per floor or a total gross floor area of 100,000 square feet or more."

The total square footage does not equal 100,000 square feet, so i am now obligated to follow the second condition... 15,000 square feet per floor. Is the code saying that every floor has to be over 15,000 sq. ft. for the building to require a generator, or that only one floor has to be over 15,000 sq ft (and the other floors can be less, like 10,000 sq ft)?

Thanks in advance!

 

[chris kennedy]

This question may be better addressed at The Building Code Forum.
It's free and very informative.

 

[Grouch]

I'll check with that forum... didn't even know that forum existed. thanks!

 

[ron]

The rules are somewhat similar, but I would suggest using the current adopted NYC Building Code http://www.nyc.gov/html/dob/apps/pd...apter_27_Electrical.pdf&section=conscode_2014

Other times that you might need a generator anyway, is if you have some odd requirement for smoke control, like a tall atrium covering several stories.

 

[ron]

This question may be better addressed at The Building Code Forum.
It's free and very informative.

I've found that site to be sparsely attended by electricals, mostly Arch and since this is more electrical in nature, I think this site is probably better.

 

[mgookin]

Hi All,
I'm trying to determine if a particular building requires an emergency generator. It is group B, less than 75 feet high, so, using the 2008 NYC building code (this is in brooklyn NY), i would follow chapter 27, section 2702.2.20 where it states:

"An emergency power system shall be required in those Group B, E, and R-1 occupancies specified in this section:

1. Group B occupancies with occupied floor less than 75 feet above the lowest fire department vehicle access having a gross floor area over 15,000 square feet per floor or a total gross floor area of 100,000 square feet or more."

The total square footage does not equal 100,000 square feet, so i am now obligated to follow the second condition... 15,000 square feet per floor. Is the code saying that every floor has to be over 15,000 sq. ft. for the building to require a generator, or that only one floor has to be over 15,000 sq ft (and the other floors can be less, like 10,000 sq ft)?

Thanks in advance!

Here's how I interpret that:

Group B occupancies with occupied floor less than 75 feet above the lowest fire department vehicle access having a gross floor area over 15,000 square feet per floor or a total gross floor area of 100,000 square feet or more."

means:

Group B occupancies with occupied floor less than 75 feet above the lowest fire department vehicle access having:

a gross floor area over 15,000 square feet per floor,

or,

a total gross floor area of 100,000 square feet or more.

Since in the first part with reference to 15k sf they say "a gross floor area" that to me means any one of the floors having 15k sf gross floor area. To answer your question as asked, yes, you need the "emergency power system".

But I question whether you cited that verbatim. Are you sure you posted it exactly as it reads?

Edit: I just pulled it up using the above link provided.
2702.2.20 Occupancy Groups B, E and R1.
Emergency and standby power shall be required in those Group B, E and R-1 occupancies specified in this section:
1.Group B occupancies with occupied floor less than 75 feet (22 860 mm) above the lowest fire department vehicle access having a gross floor area over 15,000 square feet (1393.6 m2) per floor or a total gross floor area of 100,000 square feet (9290.3 m2) or more.

Same conclusion.
You need it if any one floor is >15,000 sf.

 

[Grouch]

Thanks for that analysis. yeah, i did write it in verbatim, i made sure to capture every word as i was typing it.

Originally i thought it meant all floors had to be over 15,000 sq ft... Now that i read what you wrote, I'm leaning more towards 15,000 sq ft on any floor. Still a bit unsure though. I'll keep rereading it

I wish these parts of the code were crystal clear... needless to say, its effect on the budget $$$$$$$ and building infrastructure are huge!