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IBC 2009 - RE Subfloor in Type II-B Construction

RLM-Architect

RLM-Architect

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Oct 24, 2009
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Florida Panhandle
Sections 804 and 805 leave me guessing a bit.

Question

Can 3/4" plywood be used for sub-flooring directly on metal joists without being required to be FR Treated?

The references in Section 805 only appear to relate to sleepers which will provide a void under any additional flooring.

I am not doing that.

Only plywood decking on steel joists.

Otherwise, all building elements are meeting Type II-B.

Thanks in advance.
 
No

804 and 805 deal with finished flooring, other than the reference to sleepers and those requirements. You need to go back to Section 603.

JMHO
 
RLM-Architect,

Check Section 712.3 - Horizontal assemblies, in the 2009 IBC. Agree with fatboy, not allowed!

.
 
Doesn't it depend on whether there is a required separation? If the whole building is non-separated. . . a rated floor/ceiling assemble is not required (???)
 
Yankee said:
Doesn't it depend on whether there is a required separation? If the whole building is non-separated. . . a rated floor/ceiling assemble is not required (???)
Click to expand...
Nonseparated use is another part of the design, from chapter 5.
 
Here is my solution then:

The project is renovation of an existing building formerly a grocery store (Winn Dixie).

Existing construction type is II-B, 44,000 SF, was Group M, fully sprinkler protected (sprinkler protection to remain and be redone for new configuration)

New facility is to be a large HVAC shop with offices at the front entrance to the building.

New occupancy Group F-2 33,200 shop area. Any individual hazards such as paint spray booth protected as required.

New occupancy Group B Offices 10,800 sf first floor with 3,800 sf second floor above (14,600 Group B total).

If instead of Type II-B, I call the C Type V-B

Group F-2 with 60 foot clearance at all sides (Frontage) allows 61,750 sf

Group B with frontage permission and sprinkler protection 42,750

The sprinkler and fire alarm protection meets or exceeds protection requirements for the two occupancies.

Any problems then calling this Construction Type V-B?
 
I am not sure where the 42,750 SF for a two story B comes from [9K * 2] automatic sprinkler increase for two story + (9K * 0.75) Maximum open area modification = 24,750 (18,000 + 6750 ) . I assume a typo ( It's a way of life)

However, The path you are suggesting works as long as the open area is registered to restrict any development in this area except for flat work
 
Right Bob

Miscalculation. Forgot to plug in 2 story. Should have been 33,750. [9,000 + (9000x0.75=6750 frontage) + (9,000x2 for sprinkler increase)=18000] = 33,750

Any problem you see submitting as non-separated? I will have more than Code protection for both occupancies.
 
fatboy said:
And, you go to 603 for construction type requirements.
Click to expand...
thanks, I knew that but somehow was reading just the floor joists as non-combustible, so I needed to slow down.
 
Decision made!

Going with Type V-B, giving owner choice of wood or steel studs and joists at construction for new offices.

Building is fully sprinkler protected by NFPA 13.

Second floor has occupant load less than 300 so NFPA 101 12.1.6 permits assembly on second floor with load less than 300.

More than 30 feet clearance at all side for FD access.

Thanks all for input.

Now for that dance studio.
 
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