FLOW AND HEAT CAPACITY @ 6' OF HEAD LOSS PER 100' OF PIPE LENGTH
SIZE
INSIDE DIA.
FLOW, gpm
BTU/HR 20°F Δ T
BTU/HR 30°F Δ T
Oxygen Barriered PEX Tubing
5/8” 3/4"
0.574” 0.678" 0 .875” 1.280" 1.600" 2.030"
3
30,000 45,000 65,000 190,000 340,000 640,000
45,000 67,500 97,500 285,000 510,000 960,000
4.5 6.5
1"
1 1/4" 1 1/2"
19 34 64
2"
Type L Rigid Copper Tube - max. vel = 6'/sec for noise; max. vel = 10'/sec for erosion
3/4"
0.785" 1.025" 1.265" 1.505" 1.985"
4.2 8.5
42,000 85,000 120,000 230,000 480,000
63,000 127,000 180,000 345,000 720,000
1"
1 1/4" 1 1/2"
15 23 48
2"
Schedule 40 Black Steel Pipe
3/4"
0.824" 1.049" 1.380" 1.610" 2.067"
5.5 9.5
55,000 95,000 190,000 300,000 600,000
82,000 142,000 285,000 450,000 900,000
1"
1 1/4" 1 1/2"
19 30 60
2"
NOTE: Head loss for different GPMs than those listed in the flow and heat capacity tables can be ESTIMATED with the following formula:
̇
(
)
̇
For Example, let’s say we want to know the head loss of 3 gpm through ¾” Type L copper. Using the 6’ per 100’ table, the flow rate is 4.2 gpm:
(
) (
)
The above calculations could be approximated as 0.5’ per 100’ or 1’ per 100’ depending on the experience/discretion of the designer. The above formula is accurate for flow rates +/-20% of those listed.
For more information on PEX-a pressure drop data visit: ComfortPro Systems Document Center
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Hydronic System Design Manual ©DECTRA CORPORATION - March 2013
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