BS 5481 1977
BS 5481 1977
BS 5481 1977
Reprinted,
incorporating
Amendments Nos. 1
and 2
Specification for
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UDC 628.24:621.643:678.743.22
BS 5481:1977
Cooperating organizations
The organizations marked with an asterisk in the above list, together with the
following, were directly represented on the committee entrusted with the
preparation of this British Standard:
Contents
Page
Cooperating organizations Inside front cover
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Foreword ii
1 Scope 1
2 References 1
3 Material 1
4 Colour 1
5 Dimensions and construction 1
6 Fittings 2
7 Marking 3
8 Testing 3
9 Sealing components 4
Appendix A Heat reversion test for pipe 9
Appendix B Stress relief test for injection mouldings 9
Appendix C Stress rupture test for pipe 10
Appendix D Drop test for fabricated fittings 10
Appendix E Negative pressure test for ring seal joints 10
Appendix F Hydrostatic pressure test for solvent cement joints 11
Appendix G Test for impact resistance at 20 °C 11
Appendix H Explanation of symbols used in tables and figures 12
Figure 1 — Effective length of pipe 5
Figure 2 — Socket dimensions 6
Figure 2a — Positions for measurement of snap cap wall thicknesses 5
Figure 3 — Schematic illustrations of typical fittings (including saddles) 7
Figure 4 — Spigot length of fitting 8
Figure 5 — Essential features of apparatus for diameter distortion test
with negative pressure 11
Figure 6 — Suitable type of impact testing machine 14
Figure 7 — Chart for true impact rate (TIR) for test at 20 °C 15
Table 1 — Dimensions of pipe and fittings 1
Table 2 — Dimensions of spigot ends and sockets with sealing rings 2
Table 3 — Dimensions of solvent cement sockets 2
Table 4 — Minimum radius (R) for long bends made from
extruded pipe 2
Table 5 — Type tests 3
Table 6 — Test parameters for impact resistance requirements 3
Table 7 — Test parameters for stress rupture requirement for pipe 4
Table 8 — Quality control tests 5
Table 9 — Number of equally spaced lines to be drawn on test
specimens 12
Publications referred to Inside back cover
© BSI 02-1999 i
BS 5481:1977
Foreword
This British Standard has been prepared under the authority of the Plastics
Standards Committee. Requirements are specified for unplasticized PVC pipe
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and fittings for underground sewers of either the combined or separate pipe
systems intended for the disposal of surface water, domestic effluent and such
effluent as is permitted by the statutory drainage authorities to be discharged
into public sewers by the Public Health Act 1936, and of surface water and sewage
as is permitted and defined by the Sewerage (Scotland) Act 1968. This standard
covers pipe and fittings with nominal diameters in the range 200 mm to 630 mm
inclusive. For sizes below 200 mm, see BS 4660.
Outside diameters included in this standard are in accordance with Table 2 of
BS 3867:1969 and are in technical agreement with ISO 161-1. In the preparation
of this standard attention has been given to the work of ISO/TC 138, Plastics
pipes and fittings for the transport of fluids. In particular, the symbols used in
tables and figures (see Appendix H) are in accordance with the ISO standards
prepared by this committee.
The preliminary document of similar scope under international study includes
pipe with four different values of the standard dimension ratio (SDR), which is
the ratio of the outside diameter of the pipe to its minimum wall thickness. In this
standard only pipe with an SDR of 41 is specified; the thinner walled pipe of
SDR 65 and SDR 51 is intended for specialized application, e.g. the relining of
existing sewers whilst the thicker walled pipe of SDR 34 is intended for the
particularly onerous duty found in some countries.
Pipe and fittings complying with the requirements of this standard and made in
accordance with good commercial practice are clean, smooth and reasonably free
from grooving and other defects likely to impair their performance. Furthermore,
the ends of pipes and fittings made in accordance with good commercial practice
are cleanly cut and square with the axis of the component and the pipes are
reasonably straight.
Certification. It is strongly recommended that in view of the nature of this
specification manufacturers and purchasers should make use of the certification
facilities described on the inside back cover of this standard.
A British Standard does not purport to include all the necessary provisions of a
contract. Users of British Standards are responsible for their correct application.
Compliance with a British Standard does not of itself confer immunity
from legal obligations.
Summary of pages
This document comprises a front cover, an inside front cover, pages i and ii,
pages 1 to 16, an inside back cover and a back cover.
This standard has been updated (see copyright date) and may have had
amendments incorporated. This will be indicated in the amendment table on the
inside front cover.
ii © BSI 02-1999
BS 5481:1977
3.1 Except as provided for in clause 9, the material (450) 450.0 451.0 441.5 459.5 11.0
from which the pipe and fittings are produced shall 500 500.0 501.0 490.5 510.5 12.2
consist substantially of polyvinyl chloride. Only (560) 560.0 561.0 549.3 571.7 13.7
those additives may be used that are needed for the
manufacture of the polymer and for its subsequent 630 630.0 631.0 617.9 643.1 15.4
conversion into sound, durable extrusions or a Non-preferred sizes are indicated in parentheses
mouldings of good surface finish and mechanical b Mean outside diameter is defined as the arithmetic mean of
strength, together with such pigments as are any two diameters at right angles to each other.
c
necessary to meet the requirements of clause 4. These values of wall thickness are for a standard dimension
ratio (SDR) of 41 (see foreword).
3.2 The use of the manufacturer’s own clean rework
material, complying with the requirements of this 5.2 Fittings
standard, is permissible. No other rework material
5.2.1 Injection moulded fittings
shall be used.
5.2.1.1 Fittings having sockets with sealing rings
4 Colour shall conform to the relevant dimensions given in
Table 1 and Table 2 and Figure 2, except that
Pipe and fittings made from unplasticized PVC shall
fittings or those parts of fittings not intended to
be golden brown approximating to colour 414 of
come into contact with the fluid being transported
BS 381C:1980 or colour 06 D 45 of BS 4901:1976.
are not required to comply with the wall thicknesses
The colour known as RAL 8023 is also acceptable.
given in Table 2. Typical fittings are schematically
The requirements of this clause need not apply to illustrated in Figure 3.
snap caps (see clause 9) which may be supplied
The positions for measuring the wall thickness
alternatively in black or grey as agreed between the
dimensions of a typical snap cap shall be as
purchaser and the supplier.
illustrated in Figure 2a.
5 Dimensions and construction 5.2.1.2 Fittings having solvent cement sockets shall
be in accordance with Table 1 and Table 3 and
5.1 Pipe Figure 2. Typical fittings are schematically
5.1.1 Pipe dimensions shall be in accordance with illustrated in Figure 3.
Table 1. 5.2.2 Fabricated fittings manufactured from pipe
5.1.2 Pipe shall normally be delivered in effective complying with this standard. Sockets and spigot
lengths (see Figure 1) of 3 m, 6 m and 9 m. Other ends shall meet the requirements laid down for
lengths may be supplied as agreed between the injection moulded fittings. In the case of long bends,
purchaser and the vendor. fabricated by drawing pipe, minimum radii shall be
5.1.3 The basic dimensions of integral sockets with in accordance with Table 4 (see also Figure 3). The
sealing rings shall be in accordance with Table 2 wall thickness of such bends may be reduced to the
and Figure 2. values given for e2 in Table 2.
© BSI 02-1999 1
BS 5481:1977
Table 2 — Dimensions of spigot ends and sockets with sealing rings (see Figure 2)
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5.3 Chamfer. Spigot ends of pipes and fittings shall Table 4 — Minimum radius (R) for long bends
be chamfered. made from extruded pipe
All dimensions are in millimetres
6 Fittings
Nominal size Minimum radius (R)
6.1 Range of fittings. Fittings covered by this (see note) (measured to the centre line)
standard include bends, sockets, reducers and 200 905
branches. They shall comply with the relevant 250 1 130
requirements given in clause 5 and Table 1, Table 2,
315 1 425
Table 3 and Table 4. Examples of fittings are
illustrated in Figure 3. Other fittings complying (355) 1 605
with the relevant requirements of this standard are 400 1 805
permitted, whether they are illustrated or not. (450) 2 030
500 2 255
(560) 2 525
630 2 840
NOTE Non-preferred sizes are indicated in parentheses.
2 © BSI 02-1999
BS 5481:1977
6.2 Swept fittings. Fittings such as bends, Table 5 — Type tests (clause references)
branches or saddles for angles greater than 45° may
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1)
See foreword for explanation of SDR.
© BSI 02-1999 3
BS 5481:1977
8.1.5 Stress relief requirement for injection moulded 8.1.8 Negative pressure requirement for ring seal
fittings. When tested at 150 °C as described in joints only. When tested by the method described in
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Appendix B, a sample of each combination of fitting Appendix E, a joint, whilst deformed, shall
and material formulation shall not show excessive withstand a pressure of 25 ± 3 kN/m2 below
blisters, excessive delaminations, cracking or weld atmospheric pressure for 1 h without leakage. This
splitting. Weld lines may become more pronounced, test shall be applied to one joint for each size of pipe.
e.g. through localized sinking, during the test but 8.2 Quality control tests
this in itself shall not constitute a failure. For
fittings moulded by conventional techniques special 8.2.1 General. Quality control tests shall be carried
care shall be taken in examining the area around out during manufacture to prove the quality of a
the point of injection where no cracks or production run of pipe or fitting as appropriate. A
delaminations shall penetrate to a depth greater summary of the quality control tests is given in
than 50 % of the wall thickness at that point. Table 8.
For fittings moulded by end-gating techniques, 8.2.2 Impact resistance requirement at 20 °C for
e.g. ring or diaphragm moulds, cracks or pipe. A programme of testing shall demonstrate that
delaminations in the wall of the fittings adjacent to the pipe continues to comply with the requirements
the injection area shall not penetrate to a depth of 8.1.3.
equivalent to more than 25 % of the socket depth. 8.2.3 Reversion requirement for pipe. At least one
The assessment of the depth of penetration shall be sample shall be taken from each machine during
carried out by sectioning the specimen at the point every 8 h production run. When tested by the
of injection and measuring the depth to which these method described in Appendix A, at no point around
defects penetrate the thickness of the fitting. a specimen shall the length change by more
than 5 %; after test, specimens shall show no faults,
8.1.6 Stress rupture requirement for pipe. When e.g. cracks, cavities or blisters.
subjected to an internal hydrostatic pressure
calculated from the hoop stress given in Table 7, 8.2.4 Stress relief requirement for injection moulded
using the equation given in Appendix C, samples of fittings. At least one sample fitting shall be taken at
pipe shall sustain the appropriate pressure for the random from each machine during every 8 h
appropriate time, given in Table 7, without failure. production run and each sample shall comply with
Three specimens of pipe of each combination of pipe the requirements of 8.1.5.
size and material formulation shall be tested 8.2.5 Hydrostatic pressure requirement for solvent
at 20 °C and a further three specimens at 60 °C. cement joint assemblies. Three samples of solvent
Because of the practical difficulties in achieving the cement joint assemblies shall be taken from each
exact stress in the pipe in the test at a temperature machine at least once in every 8 h production run.
of 60 °C, it is permissible for the stress to differ from When tested by the method described in
that specified by ± 1 %. The corresponding minimum Appendix F, each sample shall withstand a
time to failure for the actual test stress shall be pressure of 70 kN/m2 for 60 s without failure.
obtained from the regression curve corresponding to 8.2.6 Stress rupture requirement for pipe. At least
the equation: one sample shall be taken from each machine at
log(stress) = 1.2304 – 0.0768 log(time). least once during each 8 h production run. Each
specimen shall comply with the requirements
Table 7 — Test parameters for stress
of 8.1.6 for the test at 20 °C.
rupture requirement for pipe
Test Minimum time Hoop stress, 9 Sealing components
temperature to failure
MN/m 2
bar a
9.1 Elastomeric sealing rings Sealing rings
°C h
supplied with pipe or fittings shall comply with the
requirements of BS 2494.
20 ± 1 1 42 420
9.2 Other components Components, e.g. snap
60 ± 2 1 000 10 ± 0.1 100 ± 1 caps used to retain the sealing rings, may be
a 5 2
1 bar = 10 N/m = 100 kPa.
manufactured from materials other than
unplasticized PVC, e.g. polyethylene or
8.1.7 Drop requirements for fabricated fittings. polypropylene. These components shall comply with
When tested by the method described in the requirements applicable to fittings and
Appendix D, fittings shall neither break nor crack. assemblies i.e. 8.1.3, 8.1.5, 8.1.8, and 8.2.4. For
Three fittings of each type and size shall be tested. polyethylene components the stress relief test shall
be carried out in accordance with Appendix B except
that the temperature of test shall be 110 ± 2 °C.
4 © BSI 02-1999
BS 5481:1977
© BSI 02-1999 5
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6
BS 5481:1977
© BSI 02-1999
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© BSI 02-1999
Figure 3 — Schematic illustrations of typical fittings (including saddles)
7
BS 5481:1977
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BS 5481:1977
© BSI 02-1999
BS 5481:1977
Appendix A Heat reversion test for Appendix B Stress relief test for
pipe injection mouldings
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A.1 Apparatus. The apparatus shall consist of a B.1 General. This test may be carried out either in
thermostatically controlled bath which maintains an air oven or alternatively in a bath of polyethylene
the temperature of the heat transfer medium glycol, glycerol or a mineral oil free from aromatic
at 150 ± 2 °C. The heat transfer medium may be hydrocarbons.
polyethylene glycol or a mineral oil free from B.2 Oven method
aromatic hydrocarbons.
B.2.1 Apparatus. An electrically heated air oven
A.2 Form of test specimen. The test specimen with circulating fan, the whole interior of which is
shall consist of a length of pipe maintained, by thermostatic means, at a
approximately 300 mm long. Two circumferential temperature of 150 ± 2 °C.
marks shall be scribed on the test specimen 100 mm
B.2.2 Procedure. Place the specimen in the oven
apart in such a way that one of these marks is
standing on one socket mouth. The specimen may be
approximately 15 mm from one end of the specimen.
supported if necessary by a simple jig that has been
A.3 Procedure. Suspend the test specimen in the preheated in the oven.
heat transfer medium by the end furthest from the
Measure the time from the moment at which the
scribed marks in such a way that both scribed
oven regains the temperature of 150 ± 2 °C.
marks are completely immersed. Take care that the
specimen does not contact the sides or bottom of the After one hour remove the specimen from the oven
bath. and allow it to cool naturally in air before
examination.
Immerse the test specimen in the bath for a time
determined as follows: B.3 Immersion method
a) for pipe of nominal size 200, 250 B.3.1 Apparatus. A thermostatically-controlled bath
and 315: 15 min, in which the heat transfer medium is polyethylene
glycol, glycerol or mineral oil free from aromatic
b) for pipe of nominal size 355, 400, 450, 500
hydrocarbons. The bath is stirred continuously and
and 560: 30 min,
maintained, by thermostatic means, at a
c) for pipe of nominal size 630: 60 min. temperature of 150 ± 2 °C.
After the specified immersion period, remove the B.3.2 Procedure. Place the specimen in the bath
specimen from the bath, lay it on its side and allow standing on one socket mouth. Measure the time
to cool to room temperature. Measure the distance from the moment at which the bath regains a
between the two scribed marks along the surface of temperature of 150 °C. After 30 min, remove the
the pipe and calculate the percentage change in specimen and allow it to cool naturally in air before
length. Inspect the specimen for any faults, examination.
e.g. cracks, cavities or blisters.
B.4 Examination of specimens. Examine
As an alternative, it is permissible to use an air carefully each specimen after test for excessive
circulating oven in which the test specimen shall be blisters, delamination, cracking or signs of weld line
supported in such a way as to leave it free of splitting. Take special care in examining the areas
external stresses. Increase the three immersion around the point of injection.
times given for the oil bath method detailed above
Assess the depth of penetration of any defects by
to 30 min, 60 min, and 120 min, respectively. In this
sectioning the specimen at the point of injection and
case, measure the immersion times from the time
measuring the depth to which the defects penetrate
the oven regains a temperature of 150 ± 2 °C. Upon
the thickness of the fitting.
removal from the oven, allow the specimens to cool
naturally to room temperature and determine the
change in length.
© BSI 02-1999 9
BS 5481:1977
Appendix C Stress rupture test for Appendix E Negative pressure test for
pipe ring seal joints
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C.1 Form of test specimen. Each piece of pipe E.1 Apparatus. The apparatus shall be as
shall have a free length between end fittings illustrated in Figure 5 and shall be capable of
of 750 ± 10 mm. permitting the application of a constant force and a
C.2 Apparatus. The apparatus consists of a constant hydrostatic test pressure for a period of at
thermostatically controlled bath maintained least 1 h.
at 20 ± 1 °C or at 60 ± 2 °C, as appropriate, and Figure 5 shows the apparatus with the pipe in the
equipment that permits the application to the horizontal position but a disposition with the pipe in
specimens of controlled internal hydrostatic the vertical position is permissible. If the pipe is
pressure accurate to ± 2 %. horizontal it is necessary to ensure that the annular
C.3 Procedure. Measure the minimum wall space between the pipe and the socket is
thickness and the mean outside diameter of each continuously flooded with water, e.g. by use of a
specimen and calculate the internal pressure to be suitable flange.
applied from the formula; The distortion load shall be applied to a rocker on
2 dt the top of a beam which is free to move in the
P = ------------- vertical plane through the axis of the pipe. The
D–t
effective beam length shall be equal to the nominal
where diameter of the pipe under test. The pipe assembly
P is the pressure to be applied (in bar) under test shall be placed so that the face of the
d is the hoop stress (in bar) socket housing the joint under test is 10 mm from
the end of the load-bearing beam.
t is the minimum wall thickness (in mm)
E.2 Procedure. Measure accurately the maximum
D is the mean outside diameter (in mm)
socket inside diameter at the mouth of the joint and
Connect the specimen to the apparatus and apply the minimum spigot outside diameter of the pipe.
the calculated internal hydrostatic pressure at a Take the difference of the two measurements.
rate of increase so that it is reached within 30 s Carefully dry the interior of the test specimen before
to 40 s of first applying pressure. Maintain the assembly. Apply a distorting load to the pipe so that
pressure with an accuracy of ± 2 % throughout the the vertical movement of the load distribution plate
test for the time and at the appropriate temperature is equal to the difference of the two measurements
given in Table 7. taken. Reduce the air pressure in the assembly
to 25 ± 3 kN/m2 below ambient pressure, and, if
Appendix D Drop test for fabricated necessary, readjust the position of the load-bearing
fittings plate so that the distortion of the pipe is maintained
at the level defined before the pressure was reduced.
Drop the fitting freely, in random positions, from a Maintain these conditions for one hour, during
height of 1 ± 0.05 m on to a flat concrete floor which time the annular space between pipe and
within 10 s of having been conditioned for 30 min at socket mouth shall be kept filled with water.
a temperature of 0 ± 1 °C. Examine the fittings for
At the end of this period examine the assembly for
breaks or cracks.
evidence of leakage by either of the following
methods.
a) Remove the assembly from the apparatus, dry
the exterior thoroughly and then examine the
interior for evidence of water penetration.
b) After shutting off the source of negative
pressure, maintain a static negative pressure
(of 25 ± 3 kN/m2) for a further 10 min and, by
means of a pressure gauge, determine if any
leakage into the assembly occurs.
10 © BSI 02-1999
BS 5481:1977
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© BSI 02-1999 11
BS 5481:1977
Table 9 — Number of equally spaced lines Place the first test specimen in the machine with
to be drawn on test specimens one of the marked lines uppermost. Allow the
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12 © BSI 02-1999
BS 5481:1977
Figure 4).
e is the wall thickness of pipe and body of fitting.
Minimum values are given in Table 2.
e2 is the wall thickness of parts of a socket as
indicated in Figure 2. Minimum values are
expressed in terms of e.
e3 is the wall thickness of parts of a socket as
indicated in Figure 2. Minimum values are
expressed in terms of e.
L is the effective length of pipe (see Figure 1).
R is the centre line radius of long bends
(see Figure 3).
© BSI 02-1999 13
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BS 5481:1977
© BSI 02-1999
BS 5481:1977
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© BSI 02-1999 15
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BS 5481:1977
Publications referred to
© BSI 02-1999
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