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PEMB Construction Type

D

duckbill

Bronze Member
Joined
Dec 8, 2009
Messages
51
Location
PA
2018 ICC Code is enforced.
Can a pre-engineered metal building be classified as a 3B construction type?
The building would not have load-bearing exterior walls - no 2-hour rating required per Table 601.
The primary structural frame does not require a rating per Table 601.
Does Section 704.10 influence the column ratings?
 
duckbill said:
2018 ICC Code is enforced.
Can a pre-engineered metal building be classified as a 3B construction type?
The building would not have load-bearing exterior walls - no 2-hour rating required per Table 601.
The primary structural frame does not require a rating per Table 601.
Does Section 704.10 influence the column ratings?
Click to expand...
Although 704.10 isn't worded as well as you might like, that is what I have applied in this situation. I do not think the code intent is to allow a IIB building to be called IIIB just because they design the load-bearing elements to be just inside the exterior walls. Note that if you apply 704.10 in this case, 704.11 might be applicable to load-bearing beams. Given that the heights and areas for IIB and IIIB are usually the same, I assume someone wants to use wood for interior construction (mezzanine?) as allowed for IIIB.
 
tod13511 said:
Although 704.10 isn't worded as well as you might like, that is what I have applied in this situation. I do not think the code intent is to allow a IIB building to be called IIIB just because they design the load-bearing elements to be just inside the exterior walls. Note that if you apply 704.10 in this case, 704.11 might be applicable to load-bearing beams. Given that the heights and areas for IIB and IIIB are usually the same, I assume someone wants to use wood for interior construction (mezzanine?) as allowed for IIIB.
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Thanks for the reply. You are correct. The owner wants to finish the building and only knows how to work with wood for the interior fit-out.
 
IMHO, I have applied 704.10 to require protection of the primary structural frame columns in a PEMB where using Type III-B construction.
 
Type 3B is intended to be the traditional old load bearing masonry wall buildings like you have in large areas of old downtowns. Frequently used wood floor and roof joists. Typical PEMBs don't meet the fire protection requirements.
 
classicT said:
IMHO, I have applied 704.10 to require protection of the primary structural frame columns in a PEMB where using Type III-B construction.
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1641590608400.png
I've often described type III fire resistance as being like an egg: hard on the outside, soft on the inside.
It seems to me that the intent is for the load-bearing frame to have 2 hour fire protection. If a steel column is located 2" inside a corrugated metal panel skin+channel curtain, it seems to me that column is acting as part of the exterior bearing wall.

Can the owner paint the metal columns with 2-hour intumescent paint?


1641590478945.png
 
Yikes said:
View attachment 8486
I've often described type III fire resistance as being like an egg: hard on the outside, soft on the inside.
It seems to me that the intent is for the load-bearing frame to have 2 hour fire protection. If a steel column is located 2" inside a corrugated metal panel skin+channel curtain, it seems to me that column is acting as part of the exterior bearing wall.

Can the owner paint the metal columns with 2-hour intumescent paint?


View attachment 8485
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I tried this argument once and was told in no uncertain terms that 3B didn't apply because the walls weren't load bearing.
 
chrisrog said:
I tried this argument once and was told in no uncertain terms that 3B didn't apply because the walls weren't load bearing.
Click to expand...
If possible, the owner could de-rate this building to Type V-B.
However, if it needs to stay type 3B, that because the code is looking for some kind of extra protection afforded by 2 hour walls in exchange for allowing greater building area, height, or # of stories for a particular use.
 
I wouldn't buy it, but I've seen the argument that columns which are inside the girts are not part of the bearing wall thus don't have to be protected.

Could they use fire-retardant treated wood for partitions and call it II-B?
 
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