Superior wall thermal/ignition barrier

[Sifu]

Got a drive under basement garage constructed out of Superior Walls. They are non-combustible so the supporting walls would probably not be required to be seperated by 1/2" drywall (2006 IRC) but the closed cell foam used as the cavity insulation does require a thermal barrier/ignition barrier. The owner wants to install plywood. Did someone on this forum once write that plywood of a given thickness could provide an equivalent barrier?????

 

[JBI]

Maybe FRT plywood...

 

[rshuey]

3. The foam plastic insulation is protected against ignition

using one of the following ignition barrier materials:

3.1. 11/ z-inch-thick (38 mm) mineral fiber insulation;

3.2. 1/4-inch-thick (6.4 mm) wood structural panels;

3.3. 3/s-inch (9.5 mm) particleboard;

3.4. 1/4-inch (6.4 mm) hardboard;

3.5. 3/s-inch (9.5 mm) gypsum board; or

3.6. Corrosion-resistant steel having a base metal

thickness of 0.016 inch (0.406 mm).

The above ignition barrier is not required where the foam

plastic insulation has been tested in accordance with Section

R316.6.

 

[mtlogcabin]

Did someone on this forum once write that plywood of a given thickness could provide an equivalent barrier?????

Might have referred to

TABLE 721.6.2(1)

TIME ASSIGNED TO WALLBOARD MEMBRANESa, b, c, d

The values are only applicable when attached to studs ar 16" OC.

 

[Francis Vineyard]

Equivalent thermal barriers: Materials equivalent to ½-inch gypsum wall board can be used as thermal barriers provided they have been tested in accordance with the IBC or IRC to limit temperature rise and remain in place for 15 minutes as described above in the “What is a Thermal Barrier” section. Typical equivalent thermal barriers include:

a. Spray-applied cementitious materials

b. Spray-applied cellulose materials

c. Portland cement plaster

d. Other various proprietary materials.

Source: http://www.icc-es.org/News/Articles/AY126ThermalBarriersSPF2011-51811.pdf

Francis

 

[Sifu]

I do remember now it was the table in 721.6.2(1). I'll do a little more research but for now the way I read it a minimum of 19/32 exterior glued plywood with panel edges blocked the 15 min. would be met.