Page 158 - GRINNELL Mechanical Products Catalogue

pRESSuRE & DESiGN DATA
Thermal Movement
Directions to calculate the number of couplings required to compensate for the thermal expansion and contraction of pipe (by example):
(1) Thermal Contraction
Utilise the Thermal Expansion Table . Allowance for the minimum installation temperature, in this case 26 .6°C to 4 .4°C (80°F to 40°F), is calculated as:
26 .6°C = 15 .5mm per 30 .5m
4 .4°C = 7 .6mm per 30 .5m
Difference = 7 .9mm per 30 .5m
For 45 .7m of pipe = 7 .9mm x 1 .5 = 11 .9mm per 45 .7m
(80°F = 0.61" per 100'
40°F = 0.30" per 100'
Difference = 0.31" per 100'
For 150' of pipe = 0.31" x 1.5 = 0.47" per 150')
(2) Thermal Expansion
Utilise the Thermal Expansion Table . Allowance for the minimum installation temperature, in this case 26 .6°C to 93 .3°C (80°F to 200°F), is calculated as:
93 .3°C = 38 .6mm per 30 .5m
26 .6°C = 15 .5mm per 30 .5m
Difference = 23 .1mm per 30 .5m
For 45 .7m of pipe = 23 .1mm x 1 .5 = 34 .5mm per 45 .7m
(200°F = 1.52" per 100'
80°F = 0.61" per 100'
Difference = 0.91" per 100'
For 150' of pipe = 0.91 x 1.5 = 1.36" per 150')
(3) Couplings Required
Available linear movement for a 150mm (6") Figure 707 Flexible Coupling on roll grooved pipe = 2 .4mm (0.094") per coupling .
Fully butted together for contraction only . Therefore the number of Figure 707 Flexible Couplings required:
• 11.9mm / 2.4mm per coupling = 4.96
(0.47" / 0.094" per coupling = 5.0)
• Use 5 Figure 707 couplings for pipe contraction
(b) Fully gapped apart for expansion only . Therefore the number of Figure 707 Flexible Couplings required:
• 34.5mm / 2.4mm per coupling = 14.38
(1.36" / 0.094" per coupling = 14.47)
• Use 15 Figure 707 Flexible Couplings for pipe expansion
Thermal Expansion of Carbon Steel in milliMetres/30 .5 Metres (Inches/100 Feet)
Between -18°C (0°F) & Indicated Temperature
-40 -0.30 -30 -0.23 -20 -0.15 -10 -0.08
0 0.00 10 0.08 20 0.15 30 0.23 40 0.30 50 0.38 60 0.46 70 0.53 80 0.61 90 0.68
100 0.76
110 0.84
120 0.91
130 0.99
140 1.06
150 1.14
160 1.22
170 1.29
180 1.37
190 1.44
200 1.52
210 1.60
220 1.67
230 1.75
Mean Coef. of thermal expansion = 0.00000633 in/in/°F Source: ASME B31.9
Temperature C°
F°
Thermal Expansion mm/30.5M Inches/100 Feet
-40
-7.62
-34.4
-5.84
-28.9
-3.81
-23.3
-2.03
-17.8
0.00
-12.2
2.03
-6.7
3.81
-1.1
5.84
4.4
7.62
10.0
9.65
15.6
11.68
21.1
13.46
26.7
15.50
32.2
17.27
37.8
19.30
43.3
21.34
48.9
23.11
54.4
25.15
60.0
26.92
65.6
28.96
71.1
30.99
76.7
32.77
82.2
34.80
87.8
36.58
93.3
38.61
98.9
40.64
104.4
42.42
110.0
44.45
158
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Design Data