PDFWAC 51-50-0506

Section 506—Building area.

Table 506.2
Allowable Area Factor (At = NS, S1, S13R, S13D or SM, as applicable) In Square Feeta,b
Occupancy Classification
See
Footnotes
Type of Construction
Type I
Type II
Type III
Type IV
Type V
A
B
A
B
A
B
A
B
C
HT
A
B
A-1
NS
UL
UL
15,500
8,500
14,000
8,500
45,000
30,000
18,750
15,000
11,500
5,500
S1
UL
UL
62,000
34,000
56,000
34,000
180,000
120,000
75,000
60,000
46,000
22,000
SM
UL
UL
46,500
25,500
42,000
25,500
135,000
90,000
56,250
45,000
34,500
16,500
A-2
NS
UL
UL
15,500
9,500
14,000
9,500
45,000
30,000
18,750
15,000
11,500
6,000
S1
UL
UL
62,000
38,000
56,000
38,000
180,000
120,000
75,000
60,000
46,000
24,000
SM
UL
UL
46,500
28,500
42,000
28,500
135,000
90,000
56,250
45,000
34,500
18,000
A-3
NS
UL
UL
15,500
9,500
14,000
9,500
45,000
30,000
18,750
15,000
11,500
6,000
S1
UL
UL
62,000
38,000
56,000
38,000
180,000
120,000
75,000
60,000
46,000
24,000
SM
UL
UL
46,500
28,500
42,000
28,500
135,000
90,000
56,250
45,000
34,500
18,000
A-4
NS
UL
UL
15,500
9,500
14,000
9,500
45,000
30,000
18,750
15,000
11,500
6,000
S1
UL
UL
62,000
38,000
56,000
38,000
180,000
120,000
75,000
60,000
46,000
24,000
SM
UL
UL
46,500
28,500
42,000
28,500
135,000
90,000
56,250
45,000
34,500
18,000
A-5
NS
UL
UL
UL
UL
UL
UL
UL
UL
UL
UL
UL
UL
S1
 
 
 
 
 
 
 
 
 
 
 
 
SM
 
 
 
 
 
 
 
 
 
 
 
 
B
NS
UL
UL
37,500
23,000
28,500
19,000
108,000
72,000
45,000
36,000
18,000
9,000
S1
UL
UL
150,000
92,000
114,000
76,000
432,000
288,000
180,000
144,000
72,000
36,000
SM
UL
UL
112,500
69,000
85,500
57,000
324,000
216,000
135,000
108,000
54,000
27,000
E
NS
UL
UL
26,500
14,500
23,500
14,500
76,500
51,000
31,875
25,500
18,500
9,500
S1
UL
UL
106,000
58,000
94,000
58,000
306,000
204,000
127,500
102,000
74,000
38,000
SM
UL
UL
79,500
43,500
70,500
43,500
229,500
153,000
95,625
76,500
55,500
28,500
F-1
NS
UL
UL
25,000
15,500
19,000
12,000
100,500
67,000
41,875
33,500
14,000
8,500
S1
UL
UL
100,000
62,000
76,000
48,000
402,000
268,000
167,500
134,000
56,000
34,000
SM
UL
UL
75,000
46,500
57,000
36,000
301,500
201,000
125,625
100,500
42,000
25,500
F-2
NS
UL
UL
37,500
23,000
28,500
18,000
151,500
101,000
63,125
50,500
21,000
13,000
S1
UL
UL
150,000
92,000
114,000
72,000
606,000
404,000
252,500
202,000
84,000
52,000
SM
UL
UL
112,500
69,000
85,500
54,000
454,500
303,000
189,375
151,500
63,000
39,000
H-1
NSc
21,000
16,500
11,000
7,000
9.500
7,000
10,500
10,500
10,000
10,500
7,500
NP
S1
 
 
 
 
 
 
 
 
 
 
 
 
H-2
NSc
21,000
16,500
11,000
7,000
9.500
7,000
10,500
10,500
10,000
10,500
7,500
3,000
S1
 
 
 
 
 
 
 
 
 
 
 
 
SM
 
 
 
 
 
 
 
 
 
 
 
 
H-3
NSc
UL
60,000
26,500
14,000
17,500
13,000
25,500
25,500
25,500
25,500
10,000
5,000
S1
 
 
 
 
 
 
 
 
 
 
 
 
SM
 
 
 
 
 
 
 
 
 
 
 
 
H-4
NSc,d
UL
UL
37,500
17,500
28,500
17,500
72,000
54,000
40,500
36,000
18,000
6,500
S1
UL
UL
150,000
70,000
114,000
70,000
288,000
216,000
162,000
144,000
72,000
26,000
SM
UL
UL
112,500
52,500
85,500
52,500
216,000
162,000
121,500
108,000
54,000
19,500
H-5
NSc,d
UL
UL
37,500
23,000
28,500
19,000
72,000
54,000
40,500
36,000
18,000
9,000
S1
UL
UL
150,000
92,000
114,000
76,000
288,000
216,000
162,000
144,000
72,000
36,000
SM
UL
UL
112,500
69,000
85,500
57,000
216,000
162,000
121,500
108,000
54,000
27,000
Occupancy Classification
See
Footnotes
Type of Construction
Type I
Type II
Type III
Type IV
Type V
A
B
A
B
A
B
A
B
C
HT
A
B
I-1
NSd, e
UL
55,000
19,000
10,000
16,500
10,000
54,000
36,000
18,000
18,000
10,500
4,500
S1
UL
220,000
76,000
40,000
66,000
40,000
216,000
144,000
72,000
72,000
42,000
18,000
SM
UL
165,000
57,000
30,000
49,500
30,000
162,000
108,000
54,000
54,000
31,500
13,500
I-2
NSd, f
UL
UL
15,000
11,000
12,000
NP
36,000
24,000
12,000
12,000
9,500
NP
S1
UL
UL
60,000
44,000
48,000
NP
144,000
96,000
48,000
48,000
38,000
NP
SM
UL
UL
45,000
33,000
36,000
NP
108,000
72,000
36,000
36,000
28,500
NP
I-3
NSd, e
UL
UL
15,000
10,000
10,500
7,500
36,000
24,000
12,000
12,000
7,500
5,000
S1
UL
UL
45,000
40,000
42,000
30,000
144,000
96,000
48,000
48,000
30,000
20,000
SM
UL
UL
45,000
30,000
31,500
22,500
108,000
72,000
36,000
36,000
22,500
15,000
I-4
NSd, g
UL
60.500
26,500
13,000
23,500
13,000
76,500
51,000
25,500
25,500
18,500
9,000
S1
UL
121,000
106,000
52,000
94,000
52,000
306,000
204,000
102,000
102,000
74,000
36,000
SM
UL
181,500
79,500
39,000
70,500
39,000
229,500
153,000
76,500
76,500
55,500
27,000
M
NS
UL
UL
21,500
12,500
18,500
12,500
61,500
41,000
25,625
20,500
14,000
9,000
S1
UL
UL
86,000
50,000
74,000
50,000
246,000
164,000
102,500
82,000
56,000
36,000
SM
UL
UL
64,500
37,500
55,500
37,500
184,500
123,000
76,875
61,500
42,000
27,000
R-1h
NSd
UL
UL
24,000
16,000
24,000
16,000
61,500
41,000
25,625
20,500
12,000
7,000
S13R
 
 
 
 
 
 
 
 
 
 
 
 
S1
UL
UL
96,000
64,000
96,000
64,000
246,000
164,000
102,500
82,000
48,000
28,000
SM
UL
UL
72,000
48,000
72,000
48,000
184,500
123,000
76,875
61,500
36,000
21,000
R-2h
NSd
UL
UL
24,000
16,000
24,000
16,000
61,500
41,000
25.625
20,500
12,000
7,000
S13R
S1
UL
UL
96,000
64,000
96,000
64,000
246,000
164,000
102,500
82,000
48,000
28,000
SM
UL
UL
72,000
48,000
72,000
48,000
184,500
123,000
76,875
61,500
36,000
21,000
R-3h
NSd
UL
UL
UL
UL
UL
UL
UL
UL
UL
UL
UL
UL
S13D
 
 
 
 
 
 
 
 
 
 
 
 
S13R
 
 
 
 
 
 
 
 
 
 
 
 
S1
 
 
 
 
 
 
 
 
 
 
 
 
SM
 
 
 
 
 
 
 
 
 
 
 
 
R-4h
NSd
UL
UL
24,000
16,000
24,000
16,000
61,500
41,000
25,625
20,500
12,000
7,000
S13D
 
 
 
 
 
 
 
 
 
 
 
 
S13R
 
 
 
 
 
 
 
 
 
 
 
 
S1
UL
UL
96,000
64,000
96,000
64,000
246,000
164,000
102,500
82,000
48,000
28,000
SM
UL
UL
72,000
48,000
72,000
48,000
184,500
123,000
76,875
61,500
36,000
21,000
S-1
NS
UL
48,000
26,000
17,500
26,000
17,500
76,500
51,000
31,875
25,500
14,000
9,000
S1
UL
192,000
104,000
70,000
104,000
70,000
306,000
204,000
127,500
102,000
56,000
36,000
SM
UL
144,000
78,000
52,500
78,000
52,500
229,500
153,000
95,625
76,500
42,000
27,000
S-2
NS
UL
79,000
39,000
26,000
39,000
26,000
115,500
77,000
48,125
38,500
21,000
13,500
S1
UL
316,000
156,000
104,000
156,000
104,000
462,000
308,000
192,500
154,000
84,000
54,000
SM
UL
237,000
117,000
78,000
117,000
78,000
346,500
231,000
144,375
115,500
63,000
40,500
U
NSi
UL
35,500
19,000
8,500
14,000
8,500
54,000
36,000
22,500
18,000
9,000
5,500
S1
UL
142,000
76,000
34,000
56,000
34,000
216,000
144,000
90,000
72,000
36,000
22,000
SM
UL
106,500
57,000
25,500
42,000
25,500
162,000
108,000
67,500
54,000
27,000
16,500
For SI: 1 square foot = 0.0929 m2.
UL = Unlimited; NP = Not permitted; NS = Buildings not equipped throughout with an automatic sprinkler system; S1 = Buildings a maximum of one story above grade plane equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; SM = Buildings two or more stories above grade plane equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1; S13R = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.2; S13D = Buildings equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.3.
 
a
See Chapters 4 and 5 for specific exceptions to the allowable height in this chapter.
 
b
See Section 903.2 for the minimum thresholds for protection by an automatic sprinkler system for specific occupancies.
 
c
New Group H occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.5.
 
d
The NS value is only for use in evaluation of existing building area in accordance with the International Existing Building Code.
 
e
New Group I-1 and I-3 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6. For new Group I-1 occupancies Condition 1, see Exception 1 of Section 903.2.6.
 
f
New and existing Group I-2 occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.6 and Section 1103.5 of the International Fire Code.
 
g
For new Group I-4 occupancies, see Exceptions 2 and 3 of Section 903.2.6.
 
h
New Group R occupancies are required to be protected by an automatic sprinkler system in accordance with Section 903.2.8.
 
i
The maximum allowable area for a single-story nonsprinklered Group U greenhouse is permitted to be 9,000 square feet, or the allowable area shall be permitted to comply with Table C102.1 of Appendix C.
[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 20-01-090, § 51-50-0506, filed 12/12/19, effective 7/1/20; WSR 19-02-038, § 51-50-0506, filed 12/26/18, effective 7/1/19; WSR 16-03-064, § 51-50-0506, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-067, § 51-50-0506, filed 2/1/13, effective 7/1/13. Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-097, § 51-50-0506, filed 1/20/10, effective 7/1/10. Statutory Authority: RCW 19.27.074, 19.27.020, and chapters 70.92, 19.27, and 34.05 RCW. WSR 07-01-091, § 51-50-0506, filed 12/19/06, effective 7/1/07.]