Incite Fire ASD 532, Operating Manual

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Mounting
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5.5.4 Mounting with metal pipes and fittings
Metal tubes (copper, stainless steel) are connected using press fittings according to the manufacturer’s instructions. For this
purpose a special press tool can be obtained from the manufacturer on loan.
5.5.5 Linear expansion
Plastics have sizeable linear temperature expansion coefficient, which is why special attention should be given to the linear
expansion (extension and contraction) of the sampling tube. An increase in temperature causes the tube to expand; a de-
crease in temperature causes it to contract. The importance of taking linear expansion into account increases as the tempera-
ture at the time of installation deviates from the usual operating temperature.
Linear expansion can be calculated as follows:
Calculation:
∆
L = L x
∆ T x α ∆
L = Linear expansion in mm
L = Length in metres of the sampling pipe between two fixed points
∆
T = Temperature change in °C
α = Linear expansion coefficient in mm/m°C
for PVC = 0.08
for ABS = 0.10
Example: sampling pipe length 20 m, anticipated temperature change 10°C, material PVC:
Calculation:
∆
L = 20 x 10 x 0.08 =
16 mm
Notice
For straight layout the linear expansion can be up to 160 mm over the total sampling pipe length (80 m) within the
permitted temperature fluctuation range (20°C). It is therefore essential to ensure that the sampling pipe is able to
“move” (slide) inside the clips/pipe clamps. A distance of 200 mm (0.2 m) must therefore be maintained between
the last clip or fastening clamp and the end cap.
ASD532 Operating Manual