ISO 6993-3:2006

Buried, high-impact poly(vinyl chloride) (PVC-HI) piping systems for the supply of gaseous fuels — Part 3: Fittings and saddles for a maximum operating pressure of 1 bar (100 kPa)

ISO 6993-3:2006 gives the requirements for full-end load-resistant fittings and saddles made of high-impact poly(vinyl chloride) (PVC-HI) intended to be used for the supply of gaseous fuels through buried pipelines having an operating temperature range of 0 degrees Celsius up to and including +30 degrees Celsius and a maximum operating pressure of 1 bar (100 kPa). It is applicable only to fittings and saddles manufactured from the high-impact PVC materials PVC-A, PVC-CPE and PVC-EPR. It is applicable to joints with elastomeric sealing elements and of the solvent cement type. The fittings and saddles are suitable for those gases not containing potentially damaging components in such concentrations as to impair the properties of the fitting/saddle material.

Systèmes de canalisations enterrées en poly(chlorure de vinyle) à résistance au choc améliorée (PVC-HI) pour réseaux de combustibles gazeux — Partie 3: Raccords et colliers pour une pression maximale de service de 1 bar (100 kPa)

General Information

• Status: Published
• Publication Date: 13-Jun-2006
• ICS: 75.200 - Petroleum products and natural gas handling equipment
• ICS: 83.140.30 - Plastics pipes and fittings for non fluid use
• Technical Committee: ISO/TC 138/SC 4 - Plastics pipes and fittings for the supply of gaseous fuels
• Drafting Committee: ISO/TC 138/SC 4 - Plastics pipes and fittings for the supply of gaseous fuels
• Current Stage: 9093 - International Standard confirmed
• Completion Date: 14-Nov-2020

Relations

• Revises: ISO 6993:2001 - Buried, high-impact poly(vinyl chloride) (PVC-HI) pipes for the supply of gaseous fuels — Specifications
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 6993-3
First edition
2006-06-01

Buried, high-impact poly(vinyl chloride)
(PVC-HI) piping systems for the supply of
gaseous fuels —
Part 3:
Fittings and saddles for a maximum
operating pressure of 1 bar (100 kPa)
Systèmes de canalisations enterrées en poly(chlorure de vinyle) à
résistance au choc améliorée (PVC-HI) pour réseaux de combustibles
gazeux —
Partie 3: Raccords et colliers pour une pression maximale de service de
1 bar (100 kPa)




Reference number
ISO 6993-3:2006(E)
©
ISO 2006

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ISO 6993-3:2006(E)
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ISO 6993-3:2006(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms. 2
4 Material . 5
5 General characteristics of fittings/saddles . 6
6 Geometrical characteristics. 6
7 Physical characteristics. 7
8 Mechanical characteristics . 8
9 Saddle design and construction . 9
10 Performance requirements . 10
11 Test methods. 11
12 Marking . 11
Annex A (normative) Determination of resistance to external blows at 0 °C for fittings. 13
Annex B (normative) Determination of resistance to external blows at 0 °C for saddles . 15
Annex C (normative) Determination of tensile resistance of in-line fitting assemblies . 18
Annex D (normative) Determination of leaktightness of saddle joints by internal air pressure,
with and without mechanical loading. 19
Annex E (normative) Determination of leaktightness of saddle joints under negative pressure and
mechanical loading. 21
Annex F (normative) Determination of leaktightness under constant load and by tensile testing at
constant speed of lateral connections (end-load resistant joints of tapping saddles with
PE service pipe lines). 23
Bibliography . 25

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ISO 6993-3:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 6993-3 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 4, Plastics pipes and fittings for the supply of gaseous fuels.
This first edition of ISO 6993-3, together with ISO 6993-1, ISO 6993-2 and ISO 6993-4, cancels and replaces
ISO 6993:2001, of which it constitutes a technical revision.
ISO 6993 consists of the following parts, under the general title Buried, high-impact poly(vinyl chloride)
(PVC-HI) piping systems for the supply of gaseous fuels:
⎯ Part 1: Pipes for a maximum operating pressure of 1 bar (100 kPa)
⎯ Part 2: Fittings for a maximum operating pressure of 200 mbar (20 kPa)
⎯ Part 3: Fittings and saddles for a maximum operating pressure of 1 bar (100 kPa)
⎯ Part 4: Code of practice for design, handling and installation

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INTERNATIONAL STANDARD ISO 6993-3:2006(E)

Buried, high-impact poly(vinyl chloride) (PVC-HI) piping
systems for the supply of gaseous fuels —
Part 3:
Fittings and saddles for a maximum operating pressure of 1 bar
(100 kPa)
1 Scope
This part of ISO 6993 gives the requirements for full-end load-resistant fittings and saddles made of
high-impact poly(vinyl chloride) (PVC-HI) intended to be used for the supply of gaseous fuels through buried
pipelines having an operating temperature range of 0 °C up to and including +30 °C and a maximum operating
1)
pressure of 1 bar (100 kPa) .
It is applicable only to fittings and saddles manufactured from the high-impact PVC materials PVC-A,
PVC-CPE and PVC-EPR. It is applicable to joints with elastomeric sealing elements and of the solvent cement
type. The fittings and saddles are suitable for those gases not containing potentially damaging components in
such concentrations as to impair the properties of the fitting/saddle material.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 580:2005, Plastics piping and ducting systems — Injection-moulded thermoplastics fittings — Methods for
visually assessing the effects of heating
ISO 2507-1, Thermoplastics pipes and fittings — Vicat softening temperature — Part 1: General test method
ISO 2507-2, Thermoplastics pipes and fittings — Vicat softening temperature — Part 2: Test conditions for
unplasticized poly(vinyl chloride) (PVC-U) or chlorinated poly(vinyl chloride) (PVC-C) pipes and fittings and for
high impact resistance poly(vinyl chloride) (PVC-HI) pipes
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
ISO 3127, Thermoplastics pipes — Determination of resistance to external blows — Round-the-clock method
ISO 4422-3:1996, Pipes and fittings made of unplasticized poly(vinyl chloride) (PVC-U) for water supply —
Specifications — Part 3: Fittings and joints
ISO 6993-1:2006, Buried, high-impact poly(vinyl chloride) (PVC-HI) piping systems for the supply of gaseous
fuels — Part 1: Pipes for a maximum operating pressure of 1 bar (100 kPa)

5 2
1) 1 bar = 0,1 MPa = 10 Pa; 1 MPa = 1 N/mm
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ISO 6993-3:2006(E)
ISO 9080, Plastics piping and ducting systems — Determination of the long-term hydrostatic strength of
thermoplastics materials in pipe form by extrapolation
EN 682:2002, Elastomeric seals — Material requirements for seals used in pipes and fittings carrying gas and
hydrocarbon fluids
EN 922:1994, Plastics piping and ducting systems — Pipes and fittings of unplasticized poly(vinyl chloride)
(PVC-U) — Specimen preparation for determination of the viscosity number and calculation of the K-value
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms, definitions, symbols and abbreviated terms given in ISO 6993-1
and the following terms, definitions and symbols apply.
3.1 Terms and definitions
3.1.1
fitting
component, other than a pipe, used in a pipeline
EXAMPLE Bend, tee, coupler, end cap.
3.1.2
joint
connection between the ends of two components (with smooth spigot-ends and/or sockets)
NOTE In this part of ISO 6993, only solvent weld joints are considered.
3.1.3
socket
end of the fitting into which a smooth spigot-end can be inserted and joined by the solvent weld process
3.1.4
tapping saddle
component, including the necessary parts such as wedges and connector, used to make branches from a
main pipeline to a service pipeline of polyethylene (PE) with a maximum d of 63
n
See Figure 1.
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ISO 6993-3:2006(E)

Key
1 cap 5 wedge
2 end trust joint 6 lower saddle half
3 upper saddle half 7 tapping tee
4 clamp
Figure 1 — Tapping saddle
3.1.5
bag stopper saddle
component, including the necessary parts such as wedges and balloon entry equipment, used to introduce a
balloon into a pipeline in order to temporarily interrupt the gas flow
See Figure 2.
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ISO 6993-3:2006(E)

Figure 2 — Bag stopper saddle
3.2 Symbols
d depth/total depth of cracks, delaminations, blisters, or open yield seam, as applicable
L crack/blister length
l key-way length
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ISO 6993-3:2006(E)
4 Material
4.1 Material for fittings/saddles
4.1.1 Composition
The fittings and saddles shall be made of high-impact PVC, to which only such additives are added that are
necessary to facilitate conformity of the components to this part of ISO 6993.
The impact-resistant modified PVC shall be one of the following compositions:
a) a mixture based on PVC;
b) a blend based on PVC;
c) a copolymer based on PVC;
d) a combination of these types.
The proportion of the impact modifier in the composition shall be at least 7 % by mass.
4.1.2 Long-term strength
The MRS value of the injection-moulding material shall be at least 14 MPa. Conformity to this requirement
shall be proven using a long-term evaluation in accordance with ISO 9080. Testing is to be carried out at
20 °C, 40 °C and 60 °C, for periods up to 10 000 h. At 60 °C no knee shall occur before 5 000 h.
For injection-moulding compounds, this test shall be carried out on test pieces in the form of an injection
moulded or extruded sample in solid wall pipe form made from the relevant injection-moulding material.
NOTE The MRS evaluation is used for a material qualification and is not intended to be used for a pressure rating.
4.1.3 Vicat softening temperature
The Vicat softening temperature of the injection-moulding material shall be not less than 74 °C when
determined in accordance with ISO 2507-1 and ISO 2507-2.
4.1.4 K-value
The K-value of the unplasticized polyvinyl chloride (PVC-U) resin in the injection-moulding material shall
exceed 57, when measured in accordance with EN 922.
4.2 Material for elastomeric sealing elements
The material of the elastomeric sealing elements shall conform to EN 682:2002, type G.
The elastomeric sealing element shall have no detrimental effects on the properties of the components.
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ISO 6993-3:2006(E)
5 General characteristics of fittings/saddles
5.1 Contaminants
The material of the fitting or saddle shall not be shown to contain any contaminants, such as inorganic
particles or agglomerations thereof, exceeding 50 µm in size, when measured in accordance with 11.1
and 11.2.
5.2 Appearance and finish
The appearance and finish of the fitting/saddle shall be examined visually without magnification.
Internal and external surfaces shall be free from grooves, pits, blisters, indications of burning, an unacceptable
form of cold-flow and other irregularities that could have a detrimental effect on the mechanical properties of
the material and/or on the functional quality of the component.
Transitions in the form shall be smooth, in order to avoid notch influence. The corners in the grooves, in
particular for the fixing of the elastomeric sealing elements, shall be rounded.
6 Geometrical characteristics
6.1 Measurements
All dimensions shall be measured in accordance with ISO 3126.
6.2 Fittings
6.2.1 Spigot ends on moulded fittings
The dimensions of spigot ends on moulded fittings shall meet the outside diameter requirements of
ISO 6993-1:2006, Table 1.
6.2.2 Sockets on moulded fittings
The geometrical characteristics of fittings for solvent cementing shall be in accordance with
ISO 4422-3:1996, 6.1.
6.3 Saddles
6.3.1 General
The dimensions and the admissible tolerances of the saddles shall be in accordance with the values declared
by the manufacturer.
6.3.2 Wall thickness and cross-section area
The wall thickness and the cross-section area of those parts of the saddles subject to tangential stresses due
to the clamp force of the pipe shall be in accordance with Table 1, for every cross section perpendicular to the
direction of the stress.
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ISO 6993-3:2006(E)
Table 1 — Wall thickness and cross-section area of saddles
Saddle
Nominal outside diameter
of main pipe
Minimum wall thickness Minimum cross-section area
d
n
2
mm mm
50 4,3 300
63 4,3 325
75 4,3 325
90 4,8 360
110 5,1 450
125 5,5 450
140 5,7 500
160 6,0 560
180 6,4 600
200 6,8 650
225 7,4 800
250 8,1 950
280 8,7 1 025
315 9,4 1 100
355 10,1 1 200
400 11,0 1 300

7 Physical characteristics
When tested in accordance with 11.1 and 11.3 at 150 °C (oven test), injection moulded fittings and saddles
shall meet the following requirements (see Figures 3 and 4).
The depth, d, of all cracks, delaminations or blisters occurring within a distance of 1,5 times the wall thickness
measured at the injection point, with a minimum of 20 mm, shall not be greater then 30 % of the wall thickness
at that point.
For diaphragm-gated injection moulded fittings or saddles, the depth, d, of all cracks, delaminations or blisters
occurring within a distance of 1,0 times the wall thickness of the diaphragm zone shall not be greater than
30 % of the wall thickness at that point.
For ring-injected fittings or saddles, the depth, d, of all cracks, delaminations or blisters occurring within a
distance of 1,0 times the wall thickness at the ring gate zone shall not be greater than 30 % of the wall
thickness at that point.
For fittings or saddles with a yield seam, the total depth, d, of the opened yield seam shall not be greater than
10 % of the wall thickness at that point.
For all other parts of the surface outside the injection zone, the total depth, d, of cracks or delaminations shall
not be greater than 10 % of the wall thickness at that point.
Blisters in the wall shall not be longer than twice the wall thickness at that point, with a maximum length, L, of
20 mm (see Figure 4).
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ISO 6993-3:2006(E)

d shall be a maximum of 30 % of the wall thickness.
Figure 3 — Maximum allowable crack depth

Figure 4 — Maximum allowable crack/blister length
8 Mechanical characteristics
8.1 Fittings
Fittings shall be tested against their resistance to external blows at 0 °C in accordance with 11.1 and Annex A.
They shall have a true impact rate (TIR) of no more than 5 % under the test conditions according to Table 2.
8.2 Saddles
Saddles shall be tested against their resistance to external blows at 0 °C in accordance with 11.1 and
Annex B. No failure in the saddle or leakage in the connection part shall occur.
Failure is considered to have occurred when there is fracture, cracking or leakage.
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ISO 6993-3:2006(E)
Table 2 — Resistance of fittings to external blows — Test conditions
Nominal outside diameter
of pipe Striker mass Drop height
d
n
mm g mm
+5
50 750
−0
+10
63 1 000
−0
+10
75 1 250
−0
+15
90 1 500
−0
+15
110 1 750
−0 +10
2 000
−0
+15
125 2 000
−0
+15
140 2 250
−0
+15
160 2 500
−0
+15
180 2 750
−0
+15
W 200 3 000
−0

9 Saddle design and construction
The design and construction of the saddle shall be such that, when assembled, no inadmissible constriction
and/or deformation occur.
The constriction of the pipe is considered inadmissible when it is greater than the tolerance given for the mean
outside diameter in any point (d ) in accordance with of ISO 6993-1:2006, Table 1.
em
This outside diameter shall be measured directly next to the saddle.
The construction of the saddle shall be such that incorrect assembling is not possible.
Displacement in an axial direction of parts of the saddle in respect to one another shall not occur.
The key ways of the saddle halves and the clamps shall be self-braking.
The angle of the key ways shall not be greater than 7° (see Figure 5).
The deviation over the plane of the key ways shall not be greater than 0,008 × l, where l is the length of the
key way (see Figure 5).
The key ways shall be rounded under a radius of at least 1,5 mm.
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ISO 6993-3:2006(E)

l length of key ways
a
Angle of key ways.
Figure 5 — Example of sealing element — Key ways
10 Performance requirements
10.1 Fittings — Tensile test for in-line fitting assemblies
When tested in accordance with 11.1 and Annex C at a temperature of 23 °C and at a constant pulling r
...