Page 60 - HVAC Pump Handbook

Rishel_CH03.qxd 20/4/06 5:35 PM Page 57

Piping System Friction
Piping System Friction 57

TABLE 3.7 K Factors for Inlets from
Open Tanks

Type of inlet K factor
Bell-mouth inlet 0.05
Square-edged inlet 0.50
Inward-projecting pipe 1.0*
*K decreases with increases in wall thick-
ness and rounding of edges.

TABLE 3.8 K Factors for Elbows, 90°
Regular Long-radius Regular Long-radius
Size, in screwed screwed flanged flanged
1
00 ⁄ 2 2.10 — — —
3
00 ⁄ 4 1.70 0.85 — —
01 1.50 0.76 0.43 —
1
01 ⁄ 4 1.30 0.65 0.40 0.37
1
01 ⁄ 2 1.20 0.53 0.39 0.35
02 1.00 0.43 0.37 0.31
1
02 ⁄ 2 0.85 0.36 0.35 0.27
03 0.76 0.29 0.33 0.25
04 0.65 0.23 0.32 0.22
06 — — 0.29 0.18
08 — — 0.27 0.15
10 — — 0.25 0.14
12 — — 0.24 0.13
14 — — 0.23 0.12
16 — — 0.23 0.11
18 — — 0.22 0.10
20 — — 0.22 0.09
24 — — 0.21 —
TABLE 3.9 K Factors for Elbows, 45°
Size, in Regular screwed Long-radius flanged
1
00 ⁄ 2 0.36 —
3
00 ⁄ 4 0.35 —
01 0.33 0.21
1
01 ⁄ 4 0.32 0.20
1
01 ⁄ 2 0.31 0.18
02 0.30 0.17
1
02 ⁄ 2 0.29 0.15
03 0.28 0.14
04 0.27 0.14
06 — 0.13
08 — 0.12
10 — 0.11
12 — 0.10
14 — 0.09
16 — 0.08

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