1、Designation:D277412Standard Practice forUnderground Installation of Thermoplastic Pressure Piping1This standard is issued under the fixed designation D2774;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A n
2、umber in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONIn general,thermoplastics pressure piping materials behave as ductile materials under load,meaningthat they can undergo considerable deform
3、ation without damage.Piping made from such materials hasthe ability to bend under a load without breaking and to deform in other ways,while offering continuedresistance.This flexibility allows ductile thermoplastic pipe to activate through pipe deformationlateral soil forces which create a pipe/soil
4、 system capable of safely supportingeven in pipes subjectto little or no internal pressurethe earth and superimposed loads which are encountered in most pipeinstallations.However,proper installation techniques are required to ensure that the necessary supportat the bottom and passive soil pressures
5、at the sides of the pipe are developed and maintained.Soils in which trenches are dug shall be examined and identified and the trenches prepared andbackfilled in accordance with sound bedding procedures and this practice.1.Scope*1.1 This practice governs procedures and references ASTMspecifications
6、for underground installation of thermoplasticpressure piping,63-in.(1372-mm)nominal size and smaller.Itis beyond the scope of this practice to describe these proce-dures in detail since it is recognized that significant differencesexist in their implementation depending on kind and type ofpipe mater
7、ial,pipe size and wall thickness,soil conditions,andthe specific end use.1.1.1 This practice assumes that over the range of antici-pated operating conditions,including maximum external load-ing and minimum internal pressure,the soil/pipe system willoffer sufficient structural stability to resist pos
8、sible excessivediametrical deformation,or even collapse.In cases,particu-larly with large diameter thinner-walled pipe,for which thevalidity of this assumption may be in question,the selection ofpipe and recommended installation conditions shall be deter-mined by a qualified engineer.1.1.2 Specific
9、pipe characteristics and end-use requirementsshall dictate addition to,or modification of the proceduresstated or referenced herein.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for in
10、formation onlyand are not considered standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulato
11、ry limitations prior to use.Specific precau-tionary statements are given in Sections 10 and 11.2.Referenced Documents2.1 ASTM Standards:2D1600 Terminology forAbbreviated Terms Relating to Plas-ticsD2487 Practice for Classification of Soils for EngineeringPurposes(Unified Soil Classification System)D
12、2488 Practice for Description and Identification of Soils(Visual-Manual Procedure)E11 Specification for Woven Wire Test Sieve Cloth and TestSievesF412 Terminology Relating to Plastic Piping SystemsF1668 Guide for Construction Procedures for Buried PlasticPipe2.2 AWWA Standard:C 651 Standard for Disi
13、nfecting Water Mains33.Terminology3.1 Definitions:1This practice is under the jurisdiction of ASTM Committee F17 on PlasticPiping Systems and is the direct responsibility of Subcommittee F17.61 on Water.Current edition approved Feb.1,2012.Published March 2012.Originallyapproved in 1969.Last previous
14、 edition approved in 2008 as D2774 08.DOI:10.1520/D2774-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Availa
15、ble from American Water Works Association(AWWA),6666 W.QuincyAve.,Denver,CO 80235,http:/www.awwa.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.1 Definitions are in
16、 accordance with Terminology F412,unless otherwise specified.Abbreviated terms are in accor-dance with Terminology D1600.Installation terminology usedin this practice is illustrated in Fig.1.3.1.2 The term pipe refers to both pipe and tubing,unlessspecifically stated otherwise.3.1.3 protective sleeve,na short section of pipe installedover system piping where there is a transition from relativelyrigid piping or structure to relatively flexible piping or structureto protect the transition region f
