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wood mechanical platform in IIB construction

Hyrax4978

Registered User
Joined
Nov 28, 2016
Messages
205
Location
Hartford, CT
I would like to do a small wood platform in IIB construction to hold a mechanical fan unit. the platform will be upon metal joist and metal framed walls. Typically i provide a metal deck and utilize the plywood as just the floor finish if its a large platform or mezz but i would like to avoid the metal decking for this small scope. I have been required to provide rails at the edges of equipment platforms prior for osha reasons so I would also like to put a wood rail around the edge.

Its truly an equipment platform, as it would take a ladder to get onto to pull a filter or maintain the unit. I can't seem to find anywhere that says this would be allowed. Has anyone come across this at all?

Thank you,

Brian
 
I don't believe that you will find an exception in IBC Section 603.... at least not without stretching reality a bit.

Section 603 Combustible Material in Types I and II Construction

603.1 Allowable Materials
Combustible materials shall be permitted in buildings of Type I or II construction in the following applications and in accordance with Sections 603.1.1 through 603.1.3:
  1. Fire-retardant-treated wood shall be permitted in:
    1. Nonbearing partitions where the required fire-resistance-rating is 2 hours or less.
    2. Nonbearing exterior walls where fire-resistance-rated construction is not required.
    3. Roof construction, including girders, trusses, framing and decking.

      Exception: In buildings of Type IA construction exceeding two stories above grade plane, fire-retardant-treated wood is not permitted in roof construction where the vertical distance from the upper floor to the roof is less than 20 feet (6096 mm).
  2. Thermal and acoustical insulation, other than foam plastics, having a flame spread index of not more than 25.

    Exceptions:
    1. Insulation placed between two layers of noncombustible materials without an intervening airspace shall be allowed to have a flame spread index of not more than 100.
    2. Insulation installed between a finished floor and solid decking without intervening airspace shall be allowed to have a flame spread index of not more than 200.
  3. Foam plastics in accordance with Chapter 26.
  4. Roof coverings that have an A, B or C classification.
  5. Interior floor finish and floor covering materials installed in accordance with Section 804.
  6. Millwork such as doors, door frames, window sashes and frames.
  7. Interior wall and ceiling finishes installed in accordance with Sections 801 and 803.
  8. Trim installed in accordance with Section 806.
  9. Where not installed greater than 15 feet (4572 mm) above grade, show windows, nailing or furring strips and wooden bulkheads below show windows, including their frames, aprons and show cases.
  10. Finish flooring installed in accordance with Section 805.
  11. Partitions dividing portions of stores, offices or similar places occupied by one tenant only and that do not establish a corridor serving an occupant load of 30 or more shall be permitted to be constructed of fire-retardant-treated wood, 1-hour fire-resistance-rated construction or of wood panels or similar light construction up to 6 feet (1829 mm) in height.
  12. Stages and platforms constructed in accordance with Sections 410.3 and 410.4, respectively.
  13. Combustible exterior wall coverings, balconies and similar projections and bay or oriel windows in accordance with Chapter 14.
  14. Blocking such as for handrails, millwork, cabinets and window and door frames.
  15. Light-transmitting plastics as permitted by Chapter 26.
  16. Mastics and caulking materials applied to provide flexible seals between components of exterior wall construction.
  17. Exterior plastic veneer installed in accordance with Section 2605.2.
  18. Nailing or furring strips as permitted by Section 803.13.
  19. Heavy timber as permitted by Note c to Table 601 and Sections 602.4.4.9 and 1406.3.
  20. Aggregates, component materials and admixtures as permitted by Section 703.2.2.
  21. Sprayed fire-resistant materials and intumescent and mastic fire-resistant coatings, determined on the basis of fire-resistance tests in accordance with Section 703.2 and installed in accordance with Sections 1705.14 and 1705.15, respectively.
  22. Materials used to protect penetrations in fire-resistance-rated assemblies in accordance with Section 714.
  23. Materials used to protect joints in fire-resistance-rated assemblies in accordance with Section 715.
  24. Materials allowed in the concealed spaces of buildings of Types I and II construction in accordance with Section 718.5.
  25. Materials exposed within plenums complying with Section 602 of the International Mechanical Code.
  26. Wall construction of freezers and coolers of less than 1,000 square feet (92.9 m2), in size, lined on both sides with noncombustible materials and the building is protected throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
 
#12 Platform via 410.4 won't work due to the definition of platform used in the IBC context.

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-theround stages; and similar purposes wherein, other than horizontal sliding curtains, 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.
 
you would only stand on it when you need to maintain the equipment. there is no access unless you set up a ladder. its just to keep the equipment off the ground and over acoustical ceiling. But access to change filters etc is required.
 
you would only stand on it when you need to maintain the equipment. there is no access unless you set up a ladder. its just to keep the equipment off the ground and over acoustical ceiling. But access to change filters etc is required.
That would be an equipment platform per IBC Section 505.3.

Walls and floors remain load bearing; therefore, I do not believe you meet an exception from Section 603 (see my prior post).
 
You can use CLT under the 2018 IBC

2018 IBC 603.1
Exception
19. Heavy timber as permitted by Note c to Table 601 and Sections 602.4.3 and 705.2.3.1.
Table 601 Note
c. In all occupancies, heavy timber complying with Section 2304.11 shall be allowed where a 1-hour or less fire-resistance rating is required.

2304.11.3 Floors.
Floors shall be without concealed spaces. Wood floors shall be constructed in accordance with Section 2304.11.3.1 or 2304.11.3.2.
2304.11.3.1 Cross-laminated timber floors.
Cross-laminated timber shall be not less than 4 inches (102 mm) in actual thickness.
 
Can you make it meet #12?
I hav done my handful of stages and platforms in type 2B buildings and they still need to be non combustible construction. I either do a strctural 9/16" metal deck with FT plywood sub floor, or use one of the structural non combustible cementitous sub flooring products.
 
I don't recomend to do the platform from woor, wood is not a very good material in my opinion
Wood, the single most common material from which buildings are made, is not a very good material in your opinion?

Well, glad you cleared it up. No more wood. o_O
 
I hav done my handful of stages and platforms in type 2B buildings and they still need to be non combustible construction. I either do a strctural 9/16" metal deck with FT plywood sub floor, or use one of the structural non combustible cementitous sub flooring products.
I'll second this and agree that this is a proper path forward.
 
I would like to do a small wood platform in IIB construction to hold a mechanical fan unit. the platform will be upon metal joist and metal framed walls. Typically i provide a metal deck and utilize the plywood as just the floor finish if its a large platform or mezz but i would like to avoid the metal decking for this small scope. I have been required to provide rails at the edges of equipment platforms prior for osha reasons so I would also like to put a wood rail around the edge.

Its truly an equipment platform, as it would take a ladder to get onto to pull a filter or maintain the unit. I can't seem to find anywhere that says this would be allowed. Has anyone come across this at all?

Thank you,

Brian
Typically you say? for what types of buildings? Wood will be susceptable to dry rot over time, how do you propose to address that?
 
I hav done my handful of stages and platforms in type 2B buildings and they still need to be non combustible construction. I either do a strctural 9/16" metal deck with FT plywood sub floor, or use one of the structural non combustible cementitous sub flooring products.
Just to clarify, 410.4 allows FRTW for platforms which is not "non-combustible"....And watch for sprinkler requirements in the potential concealed combustible spaces created by these situations...NFPA 13 does have some breaks for "limited combustible"
 
Just to clarify, 410.4 allows FRTW for platforms which is not "non-combustible"....And watch for sprinkler requirements in the potential concealed combustible spaces created by these situations...NFPA 13 does have some breaks for "limited combustible"
maybe using the term sub-floor was wrong. what I was describing was a metal structural deck with FRTW plywood ontop, the plywood acts as blocking to attach a finish floor to and it not structural
 
Sounds OK Tim, but do watch out for the "sleeper" like situation that creates with the metal deck ribs and the subfloor...Not sure if there is actually a code section on that, but.....
 
Sounds OK Tim, but do watch out for the "sleeper" like situation that creates with the metal deck ribs and the subfloor...Not sure if there is actually a code section on that, but.....
I have done it on several state projects reviewed by OSBI and haven't been called out yet (knock on wood)
 
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