# equipment platform w/fire-retardant-treated wood possible?



## sergoodo (Dec 19, 2016)

2015 IBC
Type II construction, sprinklered
Area of platform < 2/3 room
no equipment platform assembly rating required.
platform sprinkled

410.4 -  platforms are not more than 30 inches above the main floor can use fire-retardant-treated plywood.  Yet 805.1 Combustible materials in type I or II ....with an exception for 410.4.

My question is: For an equipment platform above 30"; Is it acceptable not to take the 410.4 exception and use fire-retardant-treated plywood as the subfloor/flooring per 805.1?


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## RLGA (Dec 19, 2016)

Platforms per Section 410.4 are not "equipment platforms" -- there are separate definitions for "platform" and "equipment platform." "Equipment platforms" are required to comply with Section 505.3, which does not address construction. The Exception to 805.1 only applies to a "platform" and not an "equipment platform." Therefore, the only requirements that would allow combustible construction for an "equipment platform" would be found in Section 603, and from what I can see, there are no provisions that would permit the use of combustible construction for an "equipment platform."


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## sergoodo (Dec 19, 2016)

Yes! Thanks RLGA, A specific definition for “Equipment Platform”...now that cleans up some confusion.

I interpret CH 6 can be used.  603.24, for combustible materials allowed:

_*SECTION 603 COMBUSTIBLE MATERIAL IN TYPE I AND II CONSTRUCTION
24.* Materials allowed in the concealed spaces of buildings of Types I and II construction in accordance with Section 718.5._

_*718.5 Combustible materials in concealed spaces in Type I or II construction.*
Combustible materials shall not be permitted in concealed spaces of buildings of Type I or II construction.
Exceptions:
3. Class A interior finish materials classified in accordance with Section 803._

Fire-retardant-treated Plywood, “Class A” (classified in accordance with Section 803) is an acceptable material to use on the equipment platform in a concealed space.

Any agreement with this interpretation? comments?  

There are also allowances for “floors”, the specific definition cleans up the grey area conflict with the 805 exception for “platform” floor.


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## RLGA (Dec 19, 2016)

FRT plywood decking would not be considered a concealed space, especially if exposed. As a floor finish over a metal deck is a possible solution per Section 603.1 application #10, but I doubt it would be permitted as the structural decking for supporting the floor.


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## sergoodo (Dec 19, 2016)

Steel framing over a non storage space with an air handler placed on top of FRT plywood "equipment platform". The exception for "platform" floor is N/A because applies to a "platform" and not an "equipment platform."  805.1 & 2 requires subfloor to be non combustable or fireblocked per 718.  

718 allows 2 layers non FRT 3/4" structural ply as fire blocking. 

so min 2  layers 3/4" ply over the light ga. structural  steel framing,  then a wood finish over the fire block (continuous integrity)....assuming finish is optional?  

2 layers 3/4" non FRT , stagger joints... seems 1 layer 3/4" or 1-1/8" FRT T&G would be acceptable and less confusing direction.


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## RLGA (Dec 20, 2016)

What is the space underneath the platform? If one can move freely under the platform (no special access like an attic) and see the plywood, then it is not concealed. If access underneath is restricted, then the entire space underneath is a concealed space and Section 718.5 applies, which prohibits combustible materials in concealed spaces unless allowed per Section 603, which does not address that particular application. You might get approval (via Section 104.11) by applying Type X gypsum board to the underside of the platform framing in one or two layers as deemed acceptable by the building official.

Another observation: fireblocking is nonstructural--its sole purpose is to prevent the rapid spread of fire through concealed draft openings. Applying plywood over metal framing does not cut off draft openings between a structural floor deck and a floor finish.


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## Paul Sweet (Dec 20, 2016)

*PLATFORM.* A raised area within a building used for worship, the presentation of music, plays or other entertainment; the head table for special guests; the raised area for lecturers and speakers; boxing and wrestling rings; theater-in-the-round _stages_; and similar purposes wherein there are no overhead hanging curtains, drops, scenery or stage effects other than lighting and sound. A temporary platform is one installed for not more than 30 days.

An equipment platform isn't included in this definition.

*410.4 Platform construction.* 
Permanent _platforms_ shall be constructed of materials as required for the type of construction of the building in which the permanent _platform_ is located. Permanent _platforms_ are permitted to be constructed of_ fire-retardant-treated wood _for Types I, II and IV construction where the _platforms_ are not more than 30 inches (762 mm) above the main floor, and not more than one-third of the room floor area and not more than 3,000 square feet (279 m2) in area. Where the space beneath the permanent _platform_ is used for storage or any purpose other than equipment, wiring or plumbing, the floor assembly shall be not less than 1-hour fire-resistance-rated construction. Where the space beneath the permanent _platform_ is used only for equipment, wiring or plumbing, the underside of the permanent _platform_ need not be protected.

The limited exception for FRT wood in 410.4 is because there is very little fire hazard in a 30" high space.  There is a much greater risk of fire starting or spreading under a platform over 30" high where people might walk under it or set up desks, file cabinets, machinery, etc.

805 applies to finishes, not subflooring.  I suppose you could have noncombustible framing, a metal deck with the flutes filled with insulation, and attach a plywood finish floor over that, as RLGA pointed out.


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## sergoodo (Dec 20, 2016)

Paul Sweet said:


> *PLATFORM.....*



Not a "platform" it is an "equipment platform" as RLGA clarified.
Difference is "platforms" have to be non-combustible because there is more opportunity for access by stupid as opposed to an "equipment platform"


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## sergoodo (Dec 20, 2016)

RLGA said:


> What is the space underneath the platform? If one can move freely under the platform (no special access like an attic) and see the plywood, then it is not concealed. If access underneath is restricted, then the entire space underneath is a concealed space and Section 718.5 applies, which prohibits combustible materials in concealed spaces unless allowed per Section 603, which does not address that particular application. You might get approval (via Section 104.11) by applying Type X gypsum board to the underside of the platform framing in one or two layers as deemed acceptable by the building official.
> 
> Another observation: fireblocking is nonstructural--its sole purpose is to prevent the rapid spread of fire through concealed draft openings. Applying plywood over metal framing does not cut off draft openings between a structural floor deck and a floor finish.



It is an air-handler in the attic space, finish clg. & fixtures seen underneath.  Looks like non combustible lightweight concrete panel like "cem deck" is the way to avoid this discussion outside of cyberspace.


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## ADAguy (Dec 29, 2016)

Ah yes, "common "cents" is being considered", better safe than sorry for the few extra pennies.


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