Townhome 2 hr Tenant Separation clearance from combustible framing

[DSinspector]

I was hoping someone could give me a bit of guidance with this one. The townhome in question is using Georgia Pacific Shaftliner for 2hr rated assembly. In the manual it requires 3/4" clearance from combustible materials. Under special circumstances item 7 states that the 3/4" clearance can be omitted if the metal framework of the party wall is covered by one of a variety of materials. This is immediately followed by "attic areas not accessible do not require the 6" wide gypsum strips" This seems to contradict the whole omittance clause or suggest that combustion cannot happen in a non-accessible attic. Can someone shed some light on this for me? The full exception is below:

7. The required 3/4” (19 mm) air space can be eliminated if the metal framing is covered on both faces with 6” (152 mm)
wide, 1/2” (12.7 mm) DensArmor Plus® Fireguard C® or 1/2” (12.7 mm) ToughRock® Fireguard C® or 5/8” (15.9 mm)
ToughRock® Fireguard X® or 5/8” (15.9 mm) DensArmor Plus® Fireguard® gypsum board strips. The gypsum board strips
are attached with 1” (25.4 mm) drywall screws spaced 12” (305 mm) o.c. to the metal framing. This primarily occurs in
accessible attic areas. Attic areas not accessible do not require the 6” (152 mm) wide gypsum board strips.

 

[jar546]

I was hoping someone could give me a bit of guidance with this one. The townhome in question is using Georgia Pacific Shaftliner for 2hr rated assembly. In the manual it requires 3/4" clearance from combustible materials. Under special circumstances item 7 states that the 3/4" clearance can be omitted if the metal framework of the party wall is covered by one of a variety of materials. This is immediately followed by "attic areas not accessible do not require the 6" wide gypsum strips" This seems to contradict the whole omittance clause or suggest that combustion cannot happen in a non-accessible attic. Can someone shed some light on this for me? The full exception is below:

7. The required 3/4” (19 mm) air space can be eliminated if the metal framing is covered on both faces with 6” (152 mm)
wide, 1/2” (12.7 mm) DensArmor Plus® Fireguard C® or 1/2” (12.7 mm) ToughRock® Fireguard C® or 5/8” (15.9 mm)
ToughRock® Fireguard X® or 5/8” (15.9 mm) DensArmor Plus® Fireguard® gypsum board strips. The gypsum board strips
are attached with 1” (25.4 mm) drywall screws spaced 12” (305 mm) o.c. to the metal framing. This primarily occurs in
accessible attic areas. Attic areas not accessible do not require the 6” (152 mm) wide gypsum board strips.

The manual does state that a 3/4" clearance from combustible materials is generally required. However, under special circumstances, this clearance can be omitted if the metal framework of the party wall is covered with specific gypsum board strips. These strips must be 6” wide and attached with 1” drywall screws spaced 12” apart.

The key distinction here is between accessible and non-accessible attic areas. In accessible attic areas, the special provision for omitting the 3/4" clearance applies, and the specified gypsum board strips are required to cover the metal framing. This additional protection is necessary because accessible areas are more likely to have maintenance activities, increasing the risk of fire hazards.

On the other hand, non-accessible attic areas do not require these 6” wide gypsum board strips. This is because these areas are not meant to be accessed, thus significantly reducing the likelihood of fire hazards due to the introduction of combustible materials. The manual assumes a lower risk profile for these areas, hence the omission of the clearance without the need for additional protection.

So, while it might seem contradictory at first glance, the distinction lies in the level of risk associated with accessibility. Accessible areas require extra precautions, whereas non-accessible areas do not, according to the manual's guidelines. Does this make sense?

Any other takers on this one?

 

[DSinspector]

I do understand what you are stating, and it seems to make sense. But let me get a little more specific here and ask your opinion. Would you still require the strips in floor systems or walls that are within the 3/4"? Since the exception only mentions attic space, does it not apply in these circumstances?

 

[Yankee Chronicler]

I do understand what you are stating, and it seems to make sense. But let me get a little more specific here and ask your opinion. Would you still require the strips in floor systems or walls that are within the 3/4"? Since the exception only mentions attic space, does it not apply in these circumstances?

If you have the 3/4-inch clearance, you don't need the gypsum strips anywhere.

If you DON'T have the 3/4-inch clearance, you need the gypsum strips everywhere except in non-accessible attics.

 

[DSinspector]

Yankee,
I'm not sure why it took me so long to wrap my head around this, but after reading your last response my only applicable response is, "DUH" and "Thank you"! Sometimes it just takes someone else to point your way out of the weeds, I guess. Again, thank you and I hope you have a great holiday!