Wood deck for Breezeway in IIIB Construction

[ETThompson]

Hi

I'm working on a mixed-use R-2 4-story apartment building classified as IIIB*. We're under the Ohio Building Code 2017 which is based on the 2015 IBC.

The project has a large breezeway (covered but open air) which functions as the primary circulation. The plans examiner rejected the project's specified composite decking.

Can we use conventional (non-FRT) wood decking as a substitute? Type IIIB requires 0 hrs rating for floors and secondary members. I had been under the impression that you could not use wood in this kind of application in this construction type (I have not used it very often), but I cannot find anything telling me I cannot. The structural framing supporting this decking is wood.


*This project was designed (and permitted) by an earlier design team under an earlier code (2011 OBC/2009 IBC). They needed IIIB to make the project work. We're considering changing to VA (we think we qualify), but the earlier approval appears to be a negotiated solution and we're wary of opening the door for reconsidering that precedent approval.

 

[e hilton]

Did he cite a paragraph for the rejection?

 

[BN4537]

Is the plans examiner considering the breezeway as a combustible projection per 705.2.3? Or, is the problem that the composite decking has a flame spread or smoke developed index that won't work for an interior space? Is breezeway inside or outside the non-combustible exterior wall denoted by being Type IIIB construction? Is the breezeway separating two Type III buildings?

Pictures would help.

 

[ETThompson]

The citation against the composite decking was 2612.5, Composite plastics, basically saying you can only use those products for decking in Type VB.

 

[mtlogcabin]

It is an R-2 occupancy that is already required to be sprinkled. Just sprinkle the balconies also an you are good to go with non fire treated wood. I agree with the plans examiner that the composite (plastic) deck would not be permitted

705.2.3.1 Balconies and similar projections.
Balconies and similar projections of combustible construction other than fire-retardant-treated wood shall be fire-resistance rated where required by Table 601 for floor construction or shall be of heavy timber construction in accordance with Section 2304.11. The aggregate length of the projections shall not exceed 50 percent of the building’s perimeter on each floor.

Exceptions:

1. On buildings of Types I and II construction, three stories or less above grade plane, fire-retardant-treated wood shall be permitted for balconies, porches, decks and exterior stairways not used as required exits.

2. Untreated wood and plastic composites that comply with ASTM D7032 and Section 2612 are permitted for pickets, rails and similar guard components that are limited to 42 inches (1067 mm) in height.

3. Balconies and similar projections on buildings of Types III, IV and V construction shall be permitted to be of Type V construction and shall not be required to have a fire-resistance rating where sprinkler protection is extended to these areas.

4. Where sprinkler protection is extended to the balcony areas, the aggregate length of the balcony on each floor shall not be limited.

 

[ETThompson]

Is the plans examiner considering the breezeway as a combustible projection per 705.2.3? Or, is the problem that the composite decking has a flame spread or smoke developed index that won't work for an interior space? Is breezeway inside or outside the non-combustible exterior wall denoted by being Type IIIB construction? Is the breezeway separating two Type III buildings?

Pictures would help.

See above, I think it's the composite plastics. So far, the examiner hasn't said anything against wood, we're just trying to check before resubmitting. And, by the way, the building is fully suppressed which I think means this breezeway will be too.

See attached rough sketch of the overall context.

 

[ETThompson]

It is an R-2 occupancy that is already required to be sprinkled. Just sprinkle the balconies also an you are good to go with non fire treated wood. I agree with the plans examiner that the composite (plastic) deck would not be permitted

705.2.3.1 Balconies and similar projections.
Balconies and similar projections of combustible construction other than fire-retardant-treated wood shall be fire-resistance rated where required by Table 601 for floor construction or shall be of heavy timber construction in accordance with Section 2304.11. The aggregate length of the projections shall not exceed 50 percent of the building’s perimeter on each floor.

Exceptions:

1. On buildings of Types I and II construction, three stories or less above grade plane, fire-retardant-treated wood shall be permitted for balconies, porches, decks and exterior stairways not used as required exits.

2. Untreated wood and plastic composites that comply with ASTM D7032 and Section 2612 are permitted for pickets, rails and similar guard components that are limited to 42 inches (1067 mm) in height.

3. Balconies and similar projections on buildings of Types III, IV and V construction shall be permitted to be of Type V construction and shall not be required to have a fire-resistance rating where sprinkler protection is extended to these areas.

4. Where sprinkler protection is extended to the balcony areas, the aggregate length of the balcony on each floor shall not be limited.

Thanks, we saw that, but weren't sure if this really qualified as a balcony (see sketch in previous post, maybe it does).

 

[mtlogcabin]

What you have is not a balcony by older code definitions, they are not defined in todays codes. However every ESR report I have read in the past for plastic composite deck boards limit their use to a V-B construction. Here is the current link with some new manufactures products. Perhaps you will find one that will work for Type III or V-A construction.

Reports Directory - ICC Evaluation Service, LLC (ICC-ES)

icc-es.org

 

[BN4537]

Looked it up, in the 2015 IBC it says that Plastic Composites shall be permitted in VB construction, but in the 2018 IBC it was changed, and now says that Plastic Composites shall be permitted where combustible construction is permitted.

I cannot find any prohibition to use wood in the scenario you propose.

Personally, I would ask the PE if they would accept the composite decking based on the 2018 IBC, as they are allowed to do that based on Chapter 1 of the IBC. Pretty please with a cherry on top, (of course).

 

[ETThompson]

Looked it up, in the 2015 IBC it says that Plastic Composites shall be permitted in VB construction, but in the 2018 IBC it was changed, and now says that Plastic Composites shall be permitted where combustible construction is permitted.

I cannot find any prohibition to use wood in the scenario you propose.

Personally, I would ask the PE if they would accept the composite decking based on the 2018 IBC, as they are allowed to do that based on Chapter 1 of the IBC. Pretty please with a cherry on top, (of course).

Thanks! I think we'll do just that...

 

[mtlogcabin]

Yes the IBC 2018 states that however the ESR report will limit its use to V-B construction or the IRC. Unless you can classify your project as a V-B construction type plastic composite decking is not permitted. A PE is not the AHJ and does not have the authority to accept anything contrary to code or an ESR report. He can give an opinion but in this case it would have no more weight than anyone else's opinion

SECTION 1409
PLASTIC COMPOSITE DECKING

1409.1 Plastic composite decking.
Exterior deck boards, stair treads, handrails and guards constructed of plastic composites, including plastic lumber, shall comply with Section 2612.

2612.5 Construction requirements.
Plastic composites meeting the requirements of Section 2612 shall be permitted to be used as exterior deck boards, stair treads, handrails and guards where combustible construction is permitted.

2612.6 Plastic composite deck boards, stair treads, handrails and guards.
Plastic composite deck boards, stair treads, handrails and guards shall be installed in accordance with this code and the manufacturer’s instructions.

This is just one example where a manufactures installation instructions can be misleading if you do not read the ESR for a specific product.
Code Listings Trex complies with major model building codes and has been evaluated by the International Code Council evaluation service. (ESR Report)

 

[ETThompson]

Yes the IBC 2018 states that however the ESR report will limit its use to V-B construction or the IRC. Unless you can classify your project as a V-B construction type plastic composite decking is not permitted. A PE is not the AHJ and does not have the authority to accept anything contrary to code or an ESR report. He can give an opinion but in this case it would have no more weight than anyone else's opinion

SECTION 1409
PLASTIC COMPOSITE DECKING

1409.1 Plastic composite decking.
Exterior deck boards, stair treads, handrails and guards constructed of plastic composites, including plastic lumber, shall comply with Section 2612.

2612.5 Construction requirements.
Plastic composites meeting the requirements of Section 2612 shall be permitted to be used as exterior deck boards, stair treads, handrails and guards where combustible construction is permitted.

2612.6 Plastic composite deck boards, stair treads, handrails and guards.
Plastic composite deck boards, stair treads, handrails and guards shall be installed in accordance with this code and the manufacturer’s instructions.

This is just one example where a manufactures installation instructions can be misleading if you do not read the ESR for a specific product.
Code Listings Trex complies with major model building codes and has been evaluated by the International Code Council evaluation service. (ESR Report)
View attachment 8372

Ah. well thank you for that clarification. I think we're OK using just wood in that case...

 

[steveray]

It does say "and other construction types, as allowed in the IBC"