Whether for mains or distribution lines, service connections, fire fighting systems, irrigation or industrial applications, all pipes, fittings and valves must be safely and reliably joined together even when from different materials. Solvent cement jointing is mainly used for water treatment installations. George Fischer offers comprehensive systems comprising fittings, pipes and valves as well as all appropriate metering and control equipment.
There are many ways to weld and join plastics, some more effective than others.
Tangit cement and cleaner systems, which are manufactured by Henkel, are suitable for use with UPVC, CPVC and ABS. CPVC and ABS also have individual cements to join them together.
A more chemical resistant joining method, which is suitable for both UPVC and CPVC materials, is Dytex cement and cleaner. Dytex cement is ideal if the pipe is to be used with chemicals such as Sodium Hypochlorite (over 6%) and Sulphuric acid (over 70%).
UPVC and CPVC can be glued together but the success of the connection is dependent on the application of the pipe. That is, the type of chemicals passing through the pipe and the pressure under which it will be placed.
If you need to connect two very different materials, for example steel and UPVC, then you may wish to consider using mechanical couplings, adaptor fittings, or flanges.
For PVC-U, PVC-C or in ABS.
Jointing technology is used in areas like mains or distribution lines, service connections, fire fighting systems, irrigation or industrial applications.
Plastic pipe dimensions are, by convention, specified by the outside diameter, usually denoted by e. This may be supplemented by stating the nominal inside diameter or DN. Sometimes the pipe wall thickness is specified by the SDR or Standard Dimension Ratio.
SDR = d divided by e.
Where d = the outside diameter (mm)
Where e = the pipe wall thickness (mm)
The pipe size can be calculated as follows:
di = 18.8 √Q1 ÷ v
di = Inside pipe diameter (mm)
Q1 = Flowrate in m3/h
v = Flow velocity, usually 0.5 to 1.0 m/s for suction lines
1.0 to 3.0 m/s for discharge lines.
Material α = mm/mK ABS 0.10 PE 0.15-0.20 PP 0.16-0.18 PVC-U 0.07-0.08 PVC-C 0.06-0.07 PVDF 0.12-0.18
A rough calculation of pressure loss in straight length plastic pipe can be done using,
Δ Pr = λ × (L ÷ di) × (ρ ÷ 2.102) × v2
Δ Pr = Pressure loss (bar)
λ = Pipe friction factor
L = Length of straight pipe (m)
di = Inside pipe diameter
ρ = Liquid density (kg/m3)
v = Flow velocity (m/s)
For smooth bore plastic pipe: λ = 0.02