WAC 51-11-0541   Table 5-12.  

TABLE 5-12

MINIMUM PIPE INSULATION REQUIREMENTS
Fluid Design

Operating

Temp. Range,

°F		 Insulation Conductivity Normal Pipe Diameter (in.)
Conductivity Range

Btu•in./(h•ft2•

°F)		 Mean

Rating

Temp. °F		 Runouts2 up to 2 1

and

less		 > 1

to 2		 > 2

to 4		 > 4

to 6		 > 6
Heating systems (Steam, Steam

Condensate and Hot water)		 Nominal Insulation Thickness
Above 350

251-350

201-250

141-200

105-140		 0.32.0.34

0.29.0.31

0.27.0.30

0.25.0.29

0.24.0.28		 250

200

150

125

100		 1.5

1.5

1.0

0.5

0.5		 2.5

2.0

1.5

1.5

1.0		 2.5

2.5

1.5

1.5

1.0		 3.0

2.5

2.0

1.5

1.0		 3.5

3.5

2.0

1.5

1.5		 3.5

3.5

3.5

1.5

1.5
Domestic and Service Hot Water Systems
105 and Greater 0.24.0.28 100 0.5 1.0 1.0 1.5 1.5 1.5
Cooling Systems (Chilled Water, Brine and Refrigerant)
40-55

Below 40		 0.23.0.27

0.23.0.27		 75

75		 0.5

1.0		 0.5

1.0		 0.75

1.5		 1.0

1.5		 1.0

1.5		 1.0

1.5

1. Alternative Insulation Types. Insulation thicknesses in Table 5-12 are based on insulation with thermal conductivities within the range listed in Table 5-12 for each fluid operating temperature range, rated in accordance with ASTM C 335-84 at the mean temperature listed in the table. For insulation that has a conductivity outside the range shown in Table 5-12 for the applicable fluid operating temperature range at the mean rating temperature shown (when rounded to the nearest 0.01 Btu•in./(h•ft2•°F)), the minimum thickness shall be determined in accordance with the following equation:
  T = PR[(1+ t/PR)K/k - 1]
Where  
T = Minimum insulation thickness for material with conductivity K, inches.
PR = Pipe actual outside radius, inches
t = Insulation thickness from Table 5-12, inches
K = Conductivity of alternate material at the mean rating temperature indicated in Table 5-12 for the applicable fluid temperature range, Btu•in/(h•ft2•°F)
k = The lower value of the conductivity range listed in Table 5-12 for the applicable fluid temperature range, Btu•in/(h•ft2•°F)

2. Runouts to individual terminal units not exceeding 12 ft. in length.




[Statutory Authority: RCW 19.27A.025 and 19.27A.045. 98-03-003, § 51-11-0541, filed 1/8/98, effective 7/1/98. Statutory Authority: Chapter 19.27A RCW. 92-01-140, § 51-11-0541, filed 12/19/91, effective 7/1/92.]


NOTES:

     Reviser's note:  The brackets and enclosed material in the text of the above section occurred in the copy filed by the agency.