1、 Reference number ISO 6993-4:2006(E) ISO 2006INTERNATIONAL STANDARD ISO 6993-4 First edition 2006-06-01 Buried, high-impact poly(vinyl chloride) (PVC-HI) piping systems for the supply of gaseous fuels Part 4: Code of practice for design, handling and installation Systmes de canalisations enterres en
2、 poly(chlorure de vinyle) rsistance au choc amliore (PVC-HI) pour rseaux de combustibles gazeux Partie 4: Code de pratique pour la conception, la manutention et linstallation ISO 6993-4:2006(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, t
3、his file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobes licensing policy. The ISO Central Secre
4、tariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ens
5、ure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2006 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utili
6、zed in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax +
7、 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2006 All rights reservedISO 6993-4:2006(E) ISO 2006 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 2 4 Design 4 5 Installation .
8、7 6 Storage, handling and transportation. 14 7 Quality control. 15 Bibliography . 17 ISO 6993-4:2006(E) iv ISO 2006 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing I
9、nternational 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
10、 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 tech
11、nical 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 draw
12、n 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 6993-4 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fl
13、uids, Subcommittee SC 4, Plastics pipes and fittings for the supply of gaseous fuels. This first edition of ISO 6993-4, together with ISO 6993-1, ISO 6993-2 and ISO 6993-3, cancels and replaces ISO 6993:2001, of which it constitutes a technical revision. ISO 6993 consists of the following parts, und
14、er 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 o
15、perating pressure of 1 bar (100 kPa) Part 4: Code of practice for design, handling and installation ISO 6993-4:2006(E) ISO 2006 All rights reserved v Introduction This part of ISO 6993 addresses the common basic principles for gas supply systems. Its users need to be aware that more detailed nationa
16、l standards and/or codes of practice might exist in the ISO member countries and that these will take precedence over this part of ISO 6993, which is intended to be applied in association with those national standards and/or codes of practice related to the above-mentioned basic principles. INTERNAT
17、IONAL STANDARD ISO 6993-4:2006(E) ISO 2006 All rights reserved 1 Buried, high-impact poly(vinyl chloride) (PVC-HI) piping systems for the supply of gaseous fuels Part 4: Code of practice for design, handling and installation 1 Scope This part of ISO 6993 specifies a code of practice for the design,
18、handling and installation of high-impact poly(vinyl chloride) (PVC-HI) pipes and fittings 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 pressure of 1 bar (100 kPa) 1) . The c
19、ode of practice covers mains and service lines, and gives provisions for the design, installation, storage, handling, transportation and quality control of PVC-HI pipes and fittings up to and including an outside diameter of 400 mm, as well as backfilling, pipe system testing and commissioning. The
20、pipes and fittings are suitable for those gases which do not contain potentially damaging components in such concentrations as to impair the properties of the pipe/fitting material. 2 Normative references The following referenced documents are indispensable for the application of this document. For
21、dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4437:1997, Buried polyethylene (PE) pipes for the supply of gaseous fuels Metric series Specifications ISO 6993-1, Buried, high-impact poly(
22、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) ISO 6993-3, 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
23、pressure of 1 bar (100 kPa) ISO 7005 (all parts), Metallic flanges ISO 7387-1:1983; Adhesives with solvents for assembly of PVC-U pipe elements Characterization Part 1: Basic test methods ISO 8085 (all parts), Polyethylene fittings for use with polyethylene pipes for the supply of gaseous fuels Metr
24、ic series Specifications EN 682:2002, Elastomeric seals Material requirements for seals used in pipes and fittings carrying gas and hydrocarbon fluids EN 12327:2000, Gas supply systems Pressure testing, commissioning and decommissioning procedures Functional requirements 1) 1 bar = 0,1 MPa = 10 5 Pa
25、; 1 MPa = 1 N/mm 2ISO 6993-4:2006(E) 2 ISO 2006 All rights reserved3 Terms and definitions For the purposes of this document, the following terms and definitions and symbols apply. 3.1 clearance shortest distance between the outer limits of two objects 3.2 design pressure pressure on which design ca
26、lculations are based 3.3 gas supply system pipeline systems, including pipe work and their associated stations or plants, for the transmission and distribution of gas 3.4 nominal outside diameter d nnumerical designation of size which is common to all components in a thermoplastics piping system oth
27、er than flanges and components designated by thread size NOTE It is a convenient round number for reference purposes. NOTE For metric pipes conforming to ISO 161-1, the nominal outside diameter, expressed in millimetres, is the minimum mean outside diameter d em,min . 3.5 nominal wall thickness e nn
28、umerical designation of the wall thickness of a component, approximately equal to the manufacturing dimension NOTE 1 It is a convenient round number for reference purposes. NOTE 2 It is expressed in millimetres (mm). 3.6 main pipework in a gas supply system to which a number of gas consumers are con
29、nected via service lines 3.7 out-of-roundness difference between the measured maximum outside diameter and the measured minimum outside diameter in the same cross-sectional plane of the pipe 3.8 maximum operating pressure MOP maximum effective pressure of the gas in a piping system, expressed in bar
30、s, which is allowed in continuous use NOTE 1 It takes into account the physical and the mechanical characteristics of the components of the piping system. NOTE 2 The MOP is given by the equation: 20 MRS MOP (SDR 1) C = ISO 6993-4:2006(E) ISO 2006 All rights reserved 3 where MRS is the minimum requir
31、ed strength (see ISO 6993-1); SDR is the standard dimension ratio. 3.9 standard dimension ratio SDR numerical designation of a pipe series, which is approximately equal to the ratio of the nominal outside diameter, d n , to the nominal wall thickness, e n : n n SDR d e = NOTE It is a convenient roun
32、d number for reference purposes. 3.10 pipeline components elements from which a pipeline is constructed including, in PVC-HI pipeline systems, the distinct elements of straight pipes, fittings and ancillaries EXAMPLE 1 Fittings: socket joint, saddle, reducer, tee, factory-made bend/elbow, end-cap. E
33、XAMPLE 2 Ancillaries: valve, flange. 3.11 installer trained person authorized by the pipeline operator to assemble PVC-HI systems from pipes and fittings, based on a written procedure agreed by the pipeline operator 3.12 overall service design coefficient C overall coefficient with a value greater t
34、han 1, which takes into consideration service conditions as well as properties of the pipeline components 3.13 pipeline operator private or public organization responsible for the design, construction, operation and maintenance of a gas supply system 3.14 service line pipework in a gas supply system
35、 that connects a gas consumer with a main 3.15 depth of cover vertical distance between the top of a buried pipe and the normal surface after finishing work 3.16 high-impact poly(vinyl chloride) PVC-HI mixture of unplasticized PVC and an impact-resistance modifier ISO 6993-4:2006(E) 4 ISO 2006 All r
36、ights reserved4 Design 4.1 General Written laying procedures, authorized by the pipeline operator, shall be made available prior to the construction of a pipeline. The laying procedure shall include specification of the pipe and fitting materials to be used, the trenching and backfilling requirement
37、s, the pressure testing and commissioning procedures. The selection of materials, SDR series, dimensions and assembly techniques shall be the responsibility of the pipeline operator. It is an established practice in PVC-HI distribution systems to construct service lines in polyethylene in order to t
38、ake advantage of the natural flexibility of this material. 4.2 Materials and components The maximum operating pressure (MOP) for PVC-HI gas supply systems is 1 bar (100 kPa). Pipes shall meet the requirements of ISO 6993-1. The most commonly used SDR values are 41 and 33. For specific applications,
39、other SDR values can be taken from all series stated in ISO 4065 and ISO 161-1. Assembly techniques in systems with a MOP above 200 mbar (20 kPa) and up to and including 1 bar (100 kPa) shall be of the end thrust type in accordance with ISO 6993-3. For systems with a MOP up to and including 200 mbar
40、 (20 kPa) both the end thrust type assembly or the push-in type of fittings in accordance with ISO 6993-2 may be used. Rubber parts for other components shall be in accordance with EN 682:2002, type G. Polyethylene service line materials shall be in accordance with ISO 4437 and the relevant part of
41、ISO 8085. Other components not covered by the above-mentioned International Standards shall conform to the relevant International Standards or national standards, and/or national or international specifications. 4.3 Assembly techniques 4.3.1 Slip-on socket joints (for gas supply systems with MOP u 2
42、0 kPa) Because of the relatively low operating pressure, the joints in PVC-HI gas supply systems with a MOP up to and including 200 mbar (20 kPa) do not normally need to be tensile-resistant. In special situations, provision shall be made to prevent pipes from sliding out of the sockets by using ext
43、ernal clamps or anchors. Socket joints consist of a spigot (end) and a PVC-HI socket, in which gas tightness is achieved by the use of a rubber ring, tightened between the spigot and the socket. Distinction is made between sockets with, and those without, a stop shoulder or dead stop (see Figure 1).
44、 Tees, reducers and elbows also may bear socket joints or have spigot ends. 4.3.2 Solvent-cement socket joints Solvent cement is used to effect a seal between close-fitting spigots and sockets. The resulting joint is end-load bearing. 4.3.3 Tapping saddles Tapping saddles are used for connecting ser
45、vice lines to a main (see Figure 2). ISO 6993-4:2006(E) ISO 2006 All rights reserved 5a) Socket joint b) Sleeve joint Figure 1 Straight socket joints Key 1 sealing cap 5 main 2 upper half of saddle 6 lower half of saddle 3 clamp 7 rubber seal 4 wedge 8 O-ring Figure 2 Tapping saddle with PE service
46、line 4.3.4 Bag stopper saddles Bags stoppers are used for temporarily stopping the gas stream, thereby making it possible to work on the pipe system without gas pressure. A bag is inserted in the pipe via a bag stopper saddle, and then inflated by means of a hand pump (see Figure 3). When the work i
47、s done, the bag stopper is deflated and removed, after which the saddle is sealed with a cap. ISO 6993-4:2006(E) 6 ISO 2006 All rights reservedFigure 3 Insertion of bag stopper via bag stopper saddle 4.3.5 Mechanical joints for ancillaries Joints of this type are assembled in a mechanical way, where
48、by gas tightness is achieved by compression using a rubber ring, see, for example, Figure 4. Other types of mechanical jointing systems exist. The manufacturers instructions shall be followed at all times. Mechanical jointing systems also include metal-to-PVC-HI transition fittings. Figure 4 Mechani
49、cal metal joints 4.3.6 Flange joints for ancillaries Flanged joints shall comply with ISO 7005. ISO 6993-4:2006(E) ISO 2006 All rights reserved 7 5 Installation 5.1 Assembly procedures All joints shall be assembled in accordance with the manufacturers written instructions. 5.2 Training The installer shall be competent in the appropriate laying and jointing of the pipes. He/she shall possess the necessary skill and knowledge to produce good quality work. Installers shall receive f
