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Walls required for Separated Construction in similar Occupancy / Hazard groups?

M

Mech

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Joined
Oct 30, 2009
Messages
1,056
Location
Eastern PA
2009 IBC

Type VB construction

Mixed Occupancy S-1, M, B

No sprinklers

Table 503 allows one story for S-1 and M groups and two stories for B groups.

Separated Construction (Section 508.4.3) would allow a second floor, provided it is used for Business use only

508.4.3 Allowable Height. Each separated occupancy shall comply with the building height limitations based on the type of construction of the building in accordance with Section 503.1.

Exception: Special provisions permitted by Section 509.

(see Code Commentary thread here --> http://www.thebuildingcodeforum.com/forum/commercial-building-codes/15709-2009-code-commentary-explanation-request-section-508-4-separated-occupancies.html).

508.4.4 Separation. Individual occupancies shall be separated from adjacent occupancies in accordance with Table 508.4.

Table 508.4 states "No separation requirement" between B, F-1, M, and S-1 occupancies.

Question:

Is a wall even necessary between uses to claim separated occupancies and allow a second story Business use? The proposed floor plan has an unenclosed stair leading from a first story Mercantile area up to a second story Business use. The 110+ sf landing on the second floor presents occupants with a choice of 3 rooms, each with non-fire rated doors, walls, and windows. Alternatively, second floor occupants could walk back alongside the stairs a distance of 7 feet to overlook the Mercantile area. A guardrail prevents occupants from falling off / accessing a 17 inch deep ledge that runs the width of the second floor. The required enclosed stairs is accessed through the conference room for the second floor occupants. In my over-thought assessment, the unenclosed stairs and second story landing are Business use, as they are necessary for the second story, and should need non-fire rated walls to complete the separated construction.

Thanks (especially if you made it all the way through :yawn)
 
Thanks JPohling, but do I need a non-rated separation / barrier / wall or nothing at all?

On the second floor, common path of travel is less than 40 feet. Travel distance from most remote point to enclosed stairs (discharging directly to building exterior) is less than 75 feet. Total travel distance from the most remote point to the exit discharge is less than 100 feet.
 
Lost my hyperlink to the free I-Codes. D'OH! Unless there is an issue with fire areas then I believe you are correct, no physical separation required.
 
Very interesting......But if you are not separating, aren't you by default having an S1 on the second floor?...Can you say loophole boys and girls?
 
Very interesting......But if you are not separating, aren't you by default having an S1 on the second floor?...Can you say loophole boys and girls?
Click to expand...
Yup. That and Mercantile on the second floor.

However, there will not be storage or merchandise on the second floor adding to the fuel load.

how are the occupant areas defined?
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The business is an equipment tool rental company. There's S-1 where the rental equipment is stored / serviced. There's B where the customers will complete their paperwork and also the second floor training and conference rooms. Lastly, there is M area that will have consumable items like gloves, hammers, tape measures, etc.
 
All those uses are permitted on the upper floor as accessory if they do not exceed 10% of the floor area

508.2.1 Area limitations.

Aggregate accessory occupancies shall not occupy more than 10 percent of the building area of the story in which they are located and shall not exceed the tabular values in Table 503, without building area increases in accordance with Section 506 for such accessory occupancies.

The second floor main occupancy is a "B" occupancy so you can have 10% S and 10% M on the second floor.
 
Nope the aggregrate of the nonseperated occupancies cannot exceed 10%, not each occupancy. That is an important point in the code section.
 
pyrguy said:
Nope the aggregrate of the nonseperated occupancies cannot exceed 10%, not each occupancy. That is an important point in the code section.
Click to expand...
Aggregate accessory areas can't exceed 10%

If the second floor primary occupancy is a B then you can have accessory uses not exceeding 10%

S for a file or records room for example

A B for a barber and 10% for sales of shampoos and other hair products
 
Sorry mtlog, 10% for all accessory spaces combined...

Full Definition of AGGREGATE

: formed by the collection of units or particles into a body, mass, or amount : collective: as

a (1) : clustered in a dense mass or "]head (2) : formed from several separate ovaries of a single flower <aggregate fruit>

b : composed of mineral crystals of one or more kinds or of mineral rock fragments

c : taking all units as a whole <aggregate sales>
 
shall not occupy more than 10 percent of the building area of the story in which they are located

Does not state 10% of the total building area
 
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