PDFWAC 51-50-0601

Section 601General.

Table 601
Fire-resistance Rating Requirements for Building Elements (hours)
Building Element
Type I
Type II
Type III
Type IV
Type V
A
B
A
B
A
B
A
B
C
HT
A
B
Primary structural framef (see Section 202)
3a
2a
1
0
1b
0
3a
2a
2a
HT
1
0
Bearing walls
 
 
 
 
 
 
 
 
 
 
 
 
Exteriore, f
3
2
1
0
2
2
3
2
2
2
1
0
Interior
3a
2a
1
0
1
0
3
2
2
1/HT
1
0
Nonbearing walls and partitions exterior
See Table 602
Nonbearing walls and partitions interiord
0
0
0
0
0
0
0
0
0
See Section 602.4.4.6
0
0
Floor construction and associated secondary members (see Section 202)
2
2
1
0
1
0
2
2
2
HT
1
0
Roof construction and associated secondary members (see Section 202)
1 1/2b
1b,c
1b,c
0c
1b,c
0
1 1/2
1
1
HT
1b,c
0
For SI: 1 foot = 304.8 mm.
 
a
Roof supports: Fire-resistance ratings of primary structural frame and bearing walls are permitted to be reduced by 1 hour where supporting a roof only.
 
b
Except in Groups F-1, H, M and S-1 occupancies, fire protection of structural members in roof construction shall not be required, including protection of primary structural frame members, roof framing and decking where every part of the roof construction is 20 feet or more above any floor immediately below. Fire-retardant-treated wood members shall be allowed to be used for such unprotected members.
 
c
In all occupancies, heavy timber complying with Section 2304.11 shall be allowed where a 1-hour or less fire-resistance rating is required.
 
d
Not less than the fire-resistance rating required by other sections of this code.
 
e
Not less than the fire-resistance rating based on fire separation distance (see Table 602).
 
f
Not less than the fire-resistance rating as referenced in Section 704.10.
[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 19-02-038, § 51-50-0601, filed 12/26/18, effective 7/1/19.]