The May-June 1998 Southern Building Magazine contained an article by the Portland Cement Association dealing with reconciling the allowable area differences of the three model codes. The article states that the allowable areas proposed for the new International Building Code are excessive and should not be adopted. The article also indicated that the new increased areas could be made even larger using the street frontage and sprinkler options. PCA suggests that a maximum increase of 300% be included to prevent excessive non-fire rated buildings from being constructed. It should be noted that both open space and sprinkler increases are currently permitted by the model code. It claims that the new areas will result in larger buildings of non-fire rated construction and will result in larger fires and higher fire losses.

Are Proposed Increases Excessive?
Is this prediction true? Are the proposed height and areas excessive? To find out, NFSA prepared the following tables from the three model codes and the proposed IBC. The tables not only compare the basic allowable areas they also illustrate the differences in the types of construction and occupancy classifications for the various codes. Comparing the footages, you will note that not all the areas are substantively larger. Some are about the same as the NBC, which traditionally permitted greater areas. Any space that is empty indicates that there is no comparable classification for that code. The table legend is: NBC-National Building Code, IBC-International Building Code, SBC-Standard Building Code, UBC-Uniform Building Code and IBCST-International Building Code Sprinkler Threshold. The tables do not include the exceptions and special uses of certain occupancy classifications.
 
 

Increased Areas Encourage Sprinkler Installations
Lets look at the facts. For every occupancy classification except B Business, F-2 Factory and U Utility there is a sprinkler threshold. Most buildings will have sprinklers whenever the floor area exceeds their specified threshold. Also, under the new Fire Area Concept, the sprinkler threshold is based on total area, not on a single floor area. Therefore, even though the basic allowable areas have increased, only a few small buildings will be constructed without sprinklers. The increased areas actually encourage sprinklers by allowing the use of lower types of construction to offset the sprinkler cost.

The new increased allowable areas will actually increase fire safety rather than increase fire losses. Even though the fire resistive ratings may be lower, sprinklers will be installed. Active fire suppression is an excellent alternative to passive fire resistance ratings. If maximum increase limitations are required they should only apply to non-sprinklered buildings.

NFSA Will Submit Proposed Code Changes to IBC
NFSA will be submitting code change proposals to establish a sprinkler threshold for the B and the F-2 occupancies. These proposals will be based on fire loading and life safety. Hopefully the code membership will approve the proposals and add them to the code. Other adjustments may also be needed to ensure building safety.
 

	Code	Type of Construction				t
	NBC	1-A	1-B		2-A		2-B		2-C	3-A			3-B		4		5-A		5-B
	IBC		I-A		I-B		II-A		II-B	III-A			III-B		IV-HT		V-A		V-B
	LSC	I-443	I-332		II-222		II-111		II-000	III-211			IV-III		V-111		V-111		V-000
	SBC		I		II		IV-1Hr		IV-Up	V-1Hr			V-Up		III		VI-1Hr		VI-Up
Use	UBC		I-FR		II-FR		II-1Hr		II-NR	III-1Hr			III-NR		IV		V-1Hr		V-NR
	NBC	NL	NL		19,950		13,125		8,400	11,550			8,400		12,600		8,925		4,200
	IBC		NL		NL		15,500		8,500	14,000			8,500		15,000		11,500		5,500
A-1	SBC		NL		NL
	UBC		NL		29,900
	IBCST		12,000		12,000		12,000		12,000	12,000			12,000		12,000		12,000		12,000
	NBC	NL	7,200		5,700		3,750		2,400	3,300			2,400		3,600		2,550		1,200
	IBC		NL		NL		15,500		9,500	14,000			9,500		15,000		11,500		6,000
A-2	SBC		NL		NL		12,000		12,000	8,000			12,000		8,000
	UBC		NL		29,900		13,500		NP	13,500			NP		13,500		10,500		NP
	IBCST		5,000		5,000		5,000		5,000	5,000			5,000		5,000		5,000		5,000
	NBC	NL	NL		19,950		13125		8,400	11,550			8,400		12,600		8,925		4,200
	IBC		NL		NL		15,500		9,500	14,000			9,500		15,000		11,500		6,000
A-3	SBC		NL		NL		10,000		10,000	6,000			10,000		6,000		4,500		3,000
	UBC		NL		29,900		13,500		NP	13,500			NP		13,500		10,500		6,000
	IBCST		12,000		12,000		12,000		12,000	12,000			12,000		12,000		12,000		12,000
	NBC	NL	NL		34,200		22,500		14,400	19,800			14,400		21,600		15,300		7,200
	IBC		NL		NL		15,500		9,500	14,000			9,500		15,000		11,500		6,000
A-4	SBC		NL		NL		12,000		12,000	8,000			12,000		8,000		7,500		5,000
	UBC		NL		29,900		13,500		NP	13,500			NP		13,500		10,500		6,000
	IBCST		12,000		12,000		12,000		12,000	12,000			12,000		12,000		12,000		12,000
	NBC
	IBC		NL		NL		NL		NL	NL			NL		NL		NL		NL
A-5	SBC
	UBC
	IBCST		1,000		1,000		1,000		1,000	1,000			1,000		1,000		1,000		1,000
	NBC	NL	NL		34,200		22,500		14,400	19,800			14,400		21,600		15,300		7,200
	IBC		NL		NL		37,500		23,000	28,500			19,000		36,000		18,000		9,000
B	SBC		NL		NL		25,500		25,500	17,000			21,000		14,000		13,500		9,000
	UBC		NL		39,900		18,000		12,000	18,000			12,000		18,000		14,000		8,000
	IBCST
	NBC	NL	NL		34,200		22,500		14,400	19,800			14,400		21,600		15,300		7,200
	IBC		NL		NL		26,500		14,500	23,500			14,500		25,500		18,500		9,500
E	SBC		NL		NL		18,000		18,000	12,000			18,000		12,000		12,000		8,000
	UBC		NL		45,200		20,200		13,500	20,200			13,500		20,200		15,700		9,100
	IBCST		20,000		20,000		20,000		20,000	20,000			20,000		20,000		20,000		20,000
	NBC	NL	NL		22,800		15,000		9,600	13,200			9,600		14,400		10,200		4,800
	IBC		NL		NL		25,000		15,500	19,000			12,000		33,500		14,000		8,500
F-1	SBC		NL		NL		31,500		31,500	21,000			22,500		15,000		15,000		10,000
	UBC		NL		39,900		18,000		12,000	18,000			12,000		18,000		14,000		8,000
	IBCST		12,000		12,000		12,000		12,000	12,000			12,000		12,000		12,000		12,000
	NBC	NL	NL		34,200		22,500		14,400	19,800			14,400		21,600		15,300		7,200
	IBC		NL		NL		37,500		23,000	28,500			18,000		50,500		21,000		13,000
F-2	SBC
	UBC		NL		59,900		27,000		18,000	27,000			18,000		27,000		21,000		12,000
	IBCST

	Code	Type of Construction
	NBC	1-A	1-B	2-A	2-B	2-C	3-A	3-B	4	5-A	5-B
	IBC		I-A	I-B	II-A	II-B	III-A	III-B	IV-HT	V-A	V-B
	LSC	I-443	I-332	II-222	II-111	II-000	III-211	IV-III	V-111	V-111	V-000
	SBC	I	II		IV-1Hr	IV-Up	V-1Hr	V-Up	III	VI-1Hr	VI-Up
Use	UBC	I-FR	II-FR		II-1Hr	II-NR	III-1Hr	III-NR	IV	V-1Hr	V-NR
	NBC	16,800	14,400	11,400	7,500	4,800	6,600	4,800	7,200	5,100	NP
	IBC		21,000	16,500	11,000	7,000	9,500	7,000	10,500	7,500	NP
H-1	SBC
	UBC		15,000	12,400	5,600	3,700
	IBCST		0	0	0	0	0	0	0	0	0
	NBC	16,800	14,400	11,400	7,500	4,800	6,600	4,800	7,200	5,100	NP
	IBC		21,000	16,500	11,000	7,000	9,500	7,000	10,500	7,500	3,000
H-2	SBC
	UBC		15,000	12,400	5,600	3,700	5,600	3,700	5,600	4,400	2,500
	IBCST		0	0	0	0	0	0	0	0	0
	NBC	36,300	28,800	22,800	15,000	9,600	13,200	9,600	14,400	10,200	4,800
	IBC		NL	60,000	26,500	14,000	17,500	13,000	25,500	10,000	5,000
H-3	SBC
	UBC		NL	24,800	11,200	7,500	11,200	7,500	11,200	8,800	5,100
	IBCST		0	0	0	0	0	0	0	0	0
	NBC	NL	NL	34,200	22,500	14,400	19,800	14,400	21,600	15,300	7,200
	IBC		NL	NL	37,500	17,500	28,500	17,500	36,000	18,000	6,500
H-4	SBC
	UBC		NL	24,800	11,200	7,500	11,200	7,500	11,200	8,800	5,100
	IBCST		0	0	0	0	0	0	0	0	0
	NBC
	IBC		NL	NL	63,000	42,000	45,000	30,000	63,000	45,000	30,000
H-5	SBC
	UBC		NL	24,800	11,200	7,500	11,200	7,500	11,200	8,800	5,100
	IBCST		0	0	0	0	0	0	0	0	0
	NBC
	IBC
H-6	SBC
	UBC		NL	39,900	18,000	12,000	18,000	12,000	18,000	14,000	8,000
	IBCST		0	0	0	0	0	0	0	0	0
	NBC	NL	NL	19,950	13,125	8,400	11,550	8,400	12,600	8,925	4,200
	IBC		NL	55,000	19,000	10,000	16,500	10,000	18,000	10,500	4,500
I-1	SBC		NL	NL		15,000
	UBC		NL	15,100	6,800	NP	6,800	NP	6,800	5,200	NP
	IBCST
	NBC	NL	NL	17,100	11,250	7,200	9,900	NP	10,800	7,650	NP
	IBC		NL	NL	15,000	11,000	12,000	NP	12,000	9,500	NP
I-2	SBC
	UBC		NL	15,100	6,800	NP	6,800	NP	6,800	5,200	NP
	IBCST