Minimum Radius Of Bends; Thermal Expansion - emmeti Gerpex Manuel D'utilisation

2. INSTALLATION

2.4 Minimum radius of bends

• The bending of pipes must be carried out in
accordance with the minimum values provided by
the following table.
Pipe
dimension (Ø x S)
14 x 2
16 x 2
18 x 2
20 x 2
26 x 3
32 x 3
40 x 3.5
50 x 4
63 x 4.5
75 x 5
It is preferable to use elbow unions to form curves on
pipes with a diameter greater than 26.
In bending the pipe you must also avoid putting pres-
sure on the unions already installed and the distance
between a union and the beginning of the bend must
be greater than 5xø, where Ø is the external diameter
of the pipe.

2.5 Thermal expansion

• During the installation phase, pay particular atten-
tion to thermal expansion that can particularly
affect multilayer pipes. The elongation a pipe
undergoes as a result of a variation in temperature
can be calculated with the following formula:
ΔL = α x L x ΔT
where:
α is the coefficient of linear expansion, equal to
0.026 mm/m K for insulated pipes;
L is the initial length of the pipe (m);
ΔT is the temperature difference (K).
Example:
Length of pipe: 12 m
Temperature difference: 50 K
ΔL = 0.026 x 12 x 50 = 15.6 mm
Minimum radius
of bend R
5 x Ø
5 x Ø
5 x Ø
5 x Ø
8 x Ø
Minimum radius
of bend R
with spring pipe bender
3 x Ø
3 x Ø
3 x Ø
3 x Ø
4 x Ø
ΔT 10
20
L
0.1 0.026 0.052 0.078 0.104
0.2 0.052 0.104 0.156 0.208
0.3 0.078 0.156 0.234 0.312
0.4 0.104 0.208 0.312 0.416
0.5 0.130 0.260 0.390 0.520
0.6 0.156 0.312 0.468 0.624
0.7 0.182 0.364 0.546 0.728
0.8 0.208 0.416 0.624 0.832
0.9 0.234 0.468 0.702 0.936
1.0 0.260 0.520 0.780 1.040
2.0 0.520 1.040 1.560 2.080
3.0 0.780 1.560 2.340 3.120
4.0 1.040 2.080 3.120 4.160
5.0 1.300 2.600 3.900 5.200
6.0 1.560 3.120 4.680 6.240
7.0 1.820 3.640 5.460 7.280
8.0 2.080 4.160 6.240 8.830
9.0 2.340 4.680 7.020 9.360
10.0 2.600 5.200 7.800 10.400 13.000 15.600 18.200
L = Length (m) ΔT = Temperature difference (K) ΔL = Longitudinal expansion (mm)
Ø
R
x
Minimum radius
of bend R
with hydraulic bender
4 x Ø
4 x Ø
4 x Ø
4 x Ø
4.5 x Ø
5 x Ø
Ø
L = 5 x Ø
30 40 50 60
ΔL
0.130 0.156
0.260 0.312
0.390 0.468
0.520 0.624
0.650 0.780
0.780 0.936
1.910 1.092
1.040 1.248
1.170 1.404
1.300 1.560
2.600 3.120
3.900 4.680
5.200 6.240
6.500 7.800
7.800 9.360
9.100 10.920 12.740
10.400 12.480 14.560
11.700 14.040 16.380
GB
70
0.182
0.364
0.546
0.728
0.910
1.092
1.274
1.456
1.638
1.820
3.640
5.460
7.280
9.100
10.920
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