School mechanical basement - what occupancy?

[Tim Mailloux]

Working on a new (2) story elementary school (2018 IBC) with a 2000sf partial basement used only for mechanical, electrical & IT. Is this basement part of the E occupancy? Or can it be classified as a separate occupancy? If it can be a separate occupancy which one would you use?

 

[classicT]

I'd imagine that the area is likely an incidental use under Section 509.

 

[classicT]

What is the total building area? Accessory occupancy per 508.2?

 

[steveray]

What is the total building area? Accessory occupancy per 508.2?

Aggregate accessory occupancies shall not occupy more than 10 percent of the floor area of the story in which they are located

 

[Tim Mailloux]

What is the total building area? Accessory occupancy per 508.2?

total building area is approximate 50k sf, each floor about 25k sf

 

[Tim Mailloux]

I'd imagine that the area is likely an incidental use under Section 509.

Per 509.2 incidental uses shall be included in the building occupancy within which they are located. In this case the basement would be an E occupancy?

 

[Tim Mailloux]

This project is located in Rhode Island, and I have clear direction from the state level to review both the IBC and NFPA 101 and apply the more strict requirement of the two for everything……it’s a royal pain in the ass! If the basement is part of the E occupancy the IBC allows me (1) means of egress due to the size and occupant load. NFPA 101 does not give me that out and I am required to provide (2) means of egress. I am looking for a logical way to classify this basement as an occupancy other than E that will allow for (1) means of egress in both the IBC and NFPA 101.

 

[mtlogcabin]

What is the size of the fuel fired equipment? if any

1006.2.2 Egress based on use.
The numbers of exits or access to exits shall be provided in the uses described in Sections 1006.2.2.1 through 1006.2.2.6.

1006.2.2.1 Boiler, incinerator and furnace rooms.
Two exit access doorways are required in boiler, incinerator and furnace rooms where the area is over 500 square feet (46 m2) and any fuel-fired equipment exceeds 400,000 British thermal units (Btu) (422 000 KJ) input capacity. Where two exit access doorways are required, one is permitted to be a fixed ladder or an alternating tread device. Exit access doorways shall be separated by a horizontal distance equal to one-half the length of the maximum overall diagonal dimension of the room.

 

[classicT]

1006.2.2.1 Boiler, incinerator and furnace rooms.
Two exit access doorways are required in boiler, incinerator and furnace rooms where the area is over 500 square feet (46 m2) and any fuel-fired equipment exceeds 400,000 British thermal units (Btu) (422 000 KJ) input capacity. Where two exit access doorways are required, one is permitted to be a fixed ladder or an alternating tread device. Exit access doorways shall be separated by a horizontal distance equal to one-half the length of the maximum overall diagonal dimension of the room.

Note that this only requires two exit access out of the room that contains the equipment, not necessarily from the story where the equipment is located.

 

[JPohling]

I am with 509.2 incidental use within an E occupancy

 

[Joe.B]

I am looking for a logical way to classify this basement as an occupancy other than E

I think you can do just that.

302.1 Occupancy Classification
Occupancy classification is the formal designation of the primary purpose of the building, structure or portion thereof. Structures shall be classified into one or more of the occupancy groups specified in this section based on the nature of the hazards and risks to building occupants generally associated with the intended purpose of the building or structure. An area, room or space that is intended to be occupied at different times for different purposes shall comply with all applicable requirements associated with such potential multipurpose. Structures containing multiple occupancy groups shall comply with Section 508. Where a structure is proposed for a purpose that is not specified in this section, such structure shall be classified in the occupancy it most nearly resembles based on the fire safety and relative hazard. Occupied roofs shall be classified in the group that the occupancy most nearly resembles, according to the fire safety and relative hazard, and shall comply with Section 503.1.4.

508.1 General
Each portion of a building shall be individually classified in accordance with Section 302.1. Where a building contains more than one occupancy group, the building or portion thereof shall comply with the applicable provisions of Section 508.2, 508.3, 508.4 or 508.5, or a combination of these sections.

 

[mtlogcabin]

1006.2.2.4 Electrical rooms.
​

The location and number of exit or exit access doorways shall be provided for electrical rooms in accordance with Section 110.26 of NFPA 70 for electrical equipment rated 1,000 volts or less, and Section 110.33 of NFPA 70 for electrical equipment rated over 1,000 volts. Panic hardware shall be provided where required in accordance with Section 1010.2.9.2.

Note that this only requires two exit access out of the room that contains the equipment, not necessarily from the story where the equipment is located.

Agree, just letting him know some things that might trip him up trying to have one exit out of the basement. As you said create individual rooms for the equipment if needed.

​

 

[steveray]

Note that this only requires two exit access out of the room that contains the equipment, not necessarily from the story where the equipment is located.

Hunh....Wonder if this got screwed up between 1006.2 and .3.....? Almost seems like anything in 1006.2 only requires the EAD, not necessarily the continued path to the separate and distinct exits....

 

[mtlogcabin]

The only thing that got screwed up is the addition of Common Path of Travel requirements from the ICC.


106.2.2 through 106.2.2.4 is basically the same requirements that the legacy codes had 25 years ago for those specific rooms due to the hazards associated with the equipment in those rooms and how difficult it can be to navigate those rooms for service people.

 

[steveray]

The only thing that got screwed up is the addition of Common Path of Travel requirements from the ICC.


106.2.2 through 106.2.2.4 is basically the same requirements that the legacy codes had 25 years ago for those specific rooms due to the hazards associated with the equipment in those rooms and how difficult it can be to navigate those rooms for service people.

Yeah...my "concern" is it says they need two exit access doors, not really access to two exits so in theory these could "re-merge" which might not matter for the specific hazard rooms, but matters a whole lot for the others....


Sorry Tim...I don't want to continue OT....

 

[steveray]

Nope...that doesn't work either:

509.3 Area Limitations​

Incidental uses shall not occupy more than 10 percent of the building area of the story in which they are located.

So I guess we need to pick a use....

 

[mtlogcabin]

How about a U occupancy? Might be a stretch though.

SECTION 312
UTILITY AND MISCELLANEOUS GROUP U

312.1 General.
Buildings and structures of an accessory character and miscellaneous structures not classified in any specific occupancy shall be constructed, equipped and maintained to conform to the requirements of this code commensurate with the fire and life hazard incidental to their occupancy. Group U shall include, but not be limited to, the following:

 

[steveray]

How about a U occupancy? Might be a stretch though.

SECTION 312
UTILITY AND MISCELLANEOUS GROUP U

312.1 General.
Buildings and structures of an accessory character and miscellaneous structures not classified in any specific occupancy shall be constructed, equipped and maintained to conform to the requirements of this code commensurate with the fire and life hazard incidental to their occupancy. Group U shall include, but not be limited to, the following:

Yeah...I keep leaning towards S1..we have already kind of established they are a "higher hazard" per the incidental stuff If you go U, you would still have to separate the U basement or upper story mech room in a NFPA13 building (or go non-sep), with S1 you don't...




I know that is very one dimensional, but it's a start....I think the U is more limiting for stories and area too...

 

[mtlogcabin]

It is a 2 story E occupancy so it will be sprinklered so no separation are required between an E and a U occupancy

 

[steveray]

It is a 2 story E occupancy so it will be sprinklered so no separation are required between an E and a U occupancy

Correct, but the IIB E is allowed to be 43500 Sprinklered Multistory and the U is only 25500......The S1 is 52500.....Don't hold me to any of those numbers....

 

[Tim Mailloux]

Circling back on this. Its looking like we are going to classify the basement as F-2 IBC / Industrial NFPA. Both allow for one exit from the basement and will not have any real impact on allowable building area going non-separated mixed use.


thanks for all the feedback!