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BOCA Fire Grading

Francis Vineyard

Francis Vineyard

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Joined
Jan 1, 2010
Messages
3,105
Location
Charlottesville, VA
Hi all,

Do you know of the general rule for converting BOCA Fire Grading – Use Group to ICC construction type?



Was told as an example 4 hrs. is type I; 3 hrs. – type II; etc. 2c is 2B . . .



Need an idea for when a set of plans come in for new tenants renovations.

As always; thanks in advance for your help.
 
IS THIS WHAT YOU ARE LOOKING FOR?

Construction Types

BOCA IBC

1A ----- 4 HOUR

1B IA 3 HOUR

2A IB 2 HOUR

2B IIA 1 HOUR

2C IIB UNPROTECTED

3A IIIA PROTECTED

3B IIIB UNPROTECTED

4 I VHT HEV TIMBER

5A VA PROTECTED

5B VB UNPROTECTED
 
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As usual I didn't give enough info. in my OP; the construction type is not listed. Any ideas if the CO provides only the following as an example;

Fire Grading: 3 hrs., Use Group: M, in basement

Fire Grading: 2 hrs., Use Group: B, 1st & 2nd floors.

Hint; most buildings are 3B and some are type 4.

Thanks Mr. Handler; edited his answer I was looking for before my second post.
 
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Mark H I wish they did!

From 1984 BOCA 119.6 The certificate of use and occupancy shall specify the use group, in accordance with the provisions of Article 3; the type of construction as defined in Article 4; and any special stipulations and conditions of the building permit. This is similar to 1970 BOCA 120.6

The example CO only provides the minimum info. as required: Use Group; Fire Grading; Live Loads on Floors; Occupancy Load; Number of Stories and Special Stipulations or Conditions. None of these CO's list if it's sprinklered or other information that the ICC requires today.
 
From 1975 BOCA, the definition of fire grading: The fire hazard classification of a building or structure in hours or fractions of an hour established for its use group and occupancy in Table 902.

Article 9 was titled Fireresistive Construction Requirements. Table 902 specified "...the requirements for fire walls, fire separation walls and the segregation of mixed uses as prescribed in Section 213.0 and all structural members supporting such elements...".

The numbers you provided in Post #3 match the values in Table 902. In reading thru the 75 BOCA this table is mostly for separated mixed use conditions, as there weren't all the sprinkler trade-offs as in the IBC.

I don't have 1984, but the 1987 BOCA is very similar, except mixed uses is in Section 313. Table 902 is also similar with the same hourly grading as in 1975.
 
As luck would have it, I have three renovation projects to review for a client and the original construction of all three were based on the BOCA codes. The two classifications given are 2C and 2B (two projects are 2C and the third is 2B).

One of the projects classifiec as 2C is unprotected, which is okay; the problem I'm having difficulty understanding is whether or not 2C is to be all noncombustible construction. The drawing clearly show glue-laminated beams in some areas, woods roof joists in limited areas, and T&G decking for portions of the roof deck. Is 2C supposed to be noncombustible, or were there exceptions?

The project classified as 2B (which is 1-hour construction) shows steel joists that are unprotected. Was there an exception?

The third project, a 2C, is definitely a IIB, so there's no problem there.

Thanks for any assistance!
 
Ron, hope this will save you some time: Wood Use Provisions in the 1999 BOCA NBC and 2000 IBC

http://www.awc.org/codes/ccwdindex.html

ConstructionType2.jpg


Francis
 
What is the answer to RLGA question? Does the BOCA construction type have any quirks like the old SBCCI concerning the use of wood in a 2C building. For the old SBCCI users, this would have been a type IV unprotected building. This would have allowed wood(not fire treated) to be used in non-rated or non-load bearing partitions within a single story building as long as they were covered by gypsum board.
 
Francis: I found that document, too. Actually, the table on the following page of that document gives some insight to my question, but doesn't answer it completely. Like the IBC, FRTW is permitted; however, it doesn't address HT construction. The glue-laminated beams with T&G decking would be classified as HT construction and I don't know if the BOCA codes allowed HT construction in Types 1 and 2 construction--the IBC doesn't even address HT construction in Types I and II construction, except for the reference to FRTW.
 
Ron, the IBC (2009) Table 601 Roof construction and secondary members footnote c. "In all occupancies, heavy timber shall be allowed where a 1-hour or less fire-resistance rating is required".

Boca section 715 (1996) is the identical; 714 (1993) allows HT in roof construction base building height of the construction type (1A & B, 2A, 2B, 2C one story, etc.).

The other 2B with steel joist is zero rating for roof members.

PM me if you need certain BOCA code sections.

Francis
 
Francis, you know I've looked at that so many times these past copule of days that I never picked up on that. Thanks.
 
Francis, what edition(s) are you dealing with? The 3 model codes were just beginning to get coordinated during the 1980s, and chapter numbers were bouncing all over the place.

If I remember correctly (which is a big assumption) fire grading was related to fire limits, which banned wood frame constriction and requires certain construction types in densely built-up parts of cities. All of that went away sometime in the 1980s when the code was changed to require minimum exterior wall ratings & opening protection based on distance to property lines (or the infamous imaginary line between buildings.)
 
BOCA also had a provision allowing the deletion of rating for roofs more than 20 ft from the floor all use groups
 
1978 BOCA Interpretations

Question: Under Table 214, Type 2-C construction, is Fire treated wood classified as non-combustible material for use on exterior walls bearing or non-bearing as long as the hourly fire-resistance rating is maintained?

Answer: No

Comment: The use limitations for fire-retardant treated wood is specifically limited as a substitute for non-combustible materials by Section 903.6.2 and Note H to Tale 214.

As indicated in these provisions, fire-retardant of Types 1, 2 or 3 construction.

Table 214 FRTW is permitted in Type 2 and 3;

Roof construction including beams, trusses and framing arches and roof deck:

a) 15’ or less in height to lowest member

b) More than 15’ but less than 20’ in height to lowest member

c) 20’ or more in height to lowest member

1975 edition includes the Type 1 and note i. Where the omission of fire protection from roof trusses, roof framing and decking is permitted, the horizontal or sloping roofs in Type 1 and Type 2 buildings, immediately above such members, shall be constructed of noncombustible materials of the required strength without a specified fire-resistance rating, or of mill type construction in buildings not over five (5) stories or sixty-five (65) feet in height (see Section 913.3)

1970 Table identical except without b) above and has note f. In all buildings in which the roof framing may be unprotected, roof slabs and decking may be noncombustible without fire resistance rating except that in buildings not more than five (5) stories in height, roof decking may be of mill type construction or of any other materials providing equivalent fire-resistant and structural properties.

Francis
 
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