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Nominal
Pipe Size
Pressure classes
of AC pipe
mm
Outside Diameter
of AC pipe
Equivalent OD of
PVC/HDPE pipe
mm
mm
50,63
50
F
69
75
D,E,F
96
75
100
C,D,E,F
122
110,125
150
C,D,E,F
177
160
200
B,C,D,E,F
232
200
250
B,C,D,E,F
286
250
300
B,C,D,E,F
345
315
350
B,C,D,E,F
426
355,400
450
B,C,D,E
507
450
500
B,C,D,E
587
500, 560
600
B,C,D
667
630
AC pipes are connected with Triplex push-fit rubber ring couplings,
manufactured from fibre cement. The pipes were supplied with
a machined spigot end to fit the coupling. Repair couplings,
known as “short collars” also use rubber ring seals and are
manufactured from ductile iron. Short-collars are currently still
available, however they only fit the AC pipe diameters, hence the
need for a range of variable sized couplings and adaptors to suit
both the AC and the Standard ISO sizes of modern pipe materials,
such as PVC and HDPE. Plastic pipes are flexible systems, as
opposed to the “rigid” classification of AC pipes. This prevents
the use of short-collars for adaption to flexible pipe systems, in
combination with a PVC/ AC adaptor, due to the inadequate
socket depth presented by the short-collar. It should also be noted
that the nominal wall thickness of PVC pipe systems is far less than
that of AC piping. This should not present any problems from a
hydraulic point of view, however the specifications for trenching,
bedding and backfilling of the two systems should be noted (rigid
vs flexible)
Coupling options
AC pipe failures may be repaired through the use of shortcollars or stainless steel repair clamps, however the availability
of replacement AC piping is a major problem to the Irrigation
Engineer. Therefore the need exists to be able to quickly insert
plastic pipes (PVC or HDPE) into an AC line, given the difference
in the OD (outside diameter) of the two systems.
be noted that these couplings are all designed to be used in
buried or restrained pipe systems where the end thrust has been
contained via thrust blocks or brackets. A range of restrained
couplings is also available. The coupling incorporates a serrated
grip ring that will accommodate the end thrust without the need
for additional thrust restraint mechanisms. For details refer to the
relevant product manual available on-line.
Size Selection Table of Ranger Couplings
Nominal
Bore
Pipe OD
Range
Nominal
Bore
Pipe OD
Range
Nominal
Bore
mm
mm
50
59-72
65
80
100
125
mm
mm
mm
mm
225
242-262
450
454-460
72-85
250
250-267
450
476-493
88-103
250
272-289
450
480-500
109-128
300
315-332
500
500-508
138-153
300
322-340
500
526-546
150
150-170
300
340-360
600
600-630
150
159-182
350
351-378
600
628-650
175
192-210
350
367-391
600
630-650
200
218-235
400
390-410
225
230-247
400
417-437
The size selection process is as follows. The example for size
selection is based on the connection of a 100 NB AC pipe to a
110mm PVC pipe, using both of the above tables.
ff The actual OD (outside diameter) of the 100mm AC
pipe is 122mm
ff The OD of the PVC pipe is 110mm
ff The choice of coupling for this connection will be the
109-128mm
ff The same coupling may be used for AC-AC or PVC-PVC
connections
The stainless steel repair clamp is used for the connection of similar
pipe diameters such as AC-AC, PVC-PVC etc. the following table
is based on the VARIplus-RC clamp sizes. Note that the clamps
are pressure rated at PN 16 bar up to DN 234 [H[