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HEATING VENTILATING AIR CONDITIONING GUIDE 1942
Table 4. Comparative Capacity of Steam Lines at Various Pitches for Steam and Condensate Flowing in Opposite Directions3
Pitch of Pipe in Inches per 10 Ft
Pitch or Pips
H IN.
Pipe Sice
Inches
Sq Ft
Rad. Based on 240
Btu
3
H 25.0 12
1 45.8 12 IK 204.9 18 iK 142.6 18 2 236.0 19
K HI.
Sq Ft Rad.
Based on 240
Bta
*>5 1
30.3
52.6 117.2
159.0 263.5
14 15 20
21
20
1 IN.
Sq Ft Rad. Based on 240 Btu
J
37.3
63.0 133.0
181.0 299.5
18
17 23
23 23
IK IN.
Sq Ft Rad. Baaed on 240
Btu
M(9 a
40.4 70.0 244.5 196.5
325.5
19
20 25 25 25
2 IN.
Sq Ft Rad.
Based on 240 Bta
-j 1
42.5 75.2 154.0
209.3 346.5
20 22 27 27
27
3 IN.
Sq Ft
Rad. 2
Based
on 240 Bta .
.i
2
46.1 83.0
165.0 224.0
371.5
21
23 28
28 28
4 IN.
Sq Ft
Rad. Based on 240
Bta
>
1
2
47.5 87.9
172.6
234.8 388.4
22 25
29
30 29
5 m.
Sq Ft
Rad. Baaed oq 240 Btu
w4
1
49.3 90.2
178.2
242.6 401.1
23 26 31 31
30
Data from American Society of Heating and Ventilating Engineers Research Laboratory.
waver in certain parts of the system until the steam flow is reduced sufficiently to permit the water to pass. The velocity at which such disturbances take place is a function of (1) the pipe size, whether the pipe runs horizontally or vertically, (2) the pitch of the pipe if it runs hori-
Table 5. LEnoT,N^NT^Ei7T OF PlFE T<1 88 Added to Actual Length of Run-
Owing to Fittings--to Obtain Equivalent Length
Size of Pipe Inches
Length in Feet to be Added to Run
Standard Elbow Side Outlet Tee Gate Valve
Globe Valve Angle Valve
H 1H
m
ii^
2
2'A 3
3H 4 5 6 8 10 12 14
1.3 1.8 2.2
3.0 3.5 4.3 5.0
6.5 8 9 11
13
17 21
27 30
"Value in full open position.
Example of length in feet of pipe to be added to actual length of run.
3
0.3 14
7
4
5 6 7
0.4 18 0.5 23 0.6 29 0.8 34
10 12
15 18
8
ir 13
15 18 22 27
35 45 53 63
1.0 46 22
1.1 54 27
1.4 66 34
1.6 80 40
1 9 92' 45
2.2 112
56
2.8 136
67
37 180
92
4 6 230 112
5.5 270 - 132
64 310
152
h *
Measured Length *= 132.0 ft 4 in. Gate Valve . *= 1.9 ft . , 4--*4 in. Elbows ** 36.0 ft --------v Equivalent Length 169.9 ft
1.............. H
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CHAPTER 15. PIPING FOR STEAM HEATING SYSTEMS
Table 6. Steam Pipe Capacities
Capacity Expressed in Square Feet of Equivalent Direct Radiation
(Reference to this table will be by column letter A through L) This table is based on pipe size data developed through the research investiga tions of the American Society of Heating and Ventilating Engineers.
CAPACITIES OF STEAM MAINS AND RISERS
Direction or Condensation Flow in Pipe Line
PlPB With the Steam in One-Pipe and Tiro-Pipe Syetema
8tuIn.
l/z2 lb */* lb Vie lb j or or. or
141b
Xlb or
Klb
. 2 O* 4 0i 8 0*Oi 1 Os
Drop Drop Drop
Drop
Drop
Drop
Against the Steam Two-Pipe Only
Verticall
nCD
1H
VA
m
2
2A
3
'3'A 4
5
6 8
10
12
16
30
39 46 56
79
87 100 122
173
134 155 190
269
273 315 386
546
449 518 635
898
822 948 1,163 . 1,645
1,228 1,419 1,737 2,457
1,738 2,011 2,457 3,475
3,214 3,712 4,546 6,429
5,276 6,094 7,462 10,553
10,983 12,682 15,533 21,967
20,042 23,144 28,345 40,085
32,168 37,145 45,492 64,336
60,506 69,671 84,849 121,012
30
111 157 56 245 346 122
380
538 190
771 1,091 386
1,270 1,797 635
2,326 3,289 129
3,474 4,913 111,548
4,914 6,950 2,042
9,092 12,858
14,924 21,105
31,066 43,934
.56,689 80,171
90,985 128,672
169,698 ,242,024
26 58 95 195 395 700 1.150 1,700 13.150
Special Capacities roa One-Pifs Systems Onlt
Supply Risen
UpFeed
Radiator
Valves and
Vertical Con
nections
tadiator
and Riser Run outs
Jb K Lc
25 45' 98 152 288 464 799 1,144 1,520
_______
*:-----
-- --------
20 55 81 165
--
20
55 81 165 260 475 745 1,110 2,180
z: ______
--
--
All Horizontal Mains and Down-Feed Riaera
_________
Up* Feed
Risers
Mains - - UpFeed
Run Risen outs
Radiator Run-
Connections Dripped
No/*.---All drops shown are in pounds per 100 ft of equivalent run--based on pipe properly reamed,
aDo not use Column H for drops of 1/24 or 1/32 lb; substitute Column C or Column B as required.
f>Do not use Column J lot dropof 1/32 )b except on sizes 3 in. and over; below 3 in. substitute Column 3.
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zontally, (3) the quantity of condensate flowing against the steam, and (4) freedom of the piping from water pockets which under certain con
ditions act as a restriction in pipe size.
Three factors of uncertainty always exist in determining the capacity of any steam pipe. The first is variation in manufacture, which appar ently cannot be avoided. The second is the care used in rearning the ends of the pipe after cutting. The effect of both of these factors increases as the pipe size decreases. According to A.S.H.V.E. Research Laboratory tests, either of these factors may affect the capacity of a 1-in. pipe as much as 20 per cent. The third factor is the uniformity in grading the pipe line. All of the capacity tables given in this chapter include a factor of safety. However, the factor of safety referred to does not cover abnormal defects
or constrictions nor does it cover pipe not properly reamed.
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