1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULOctober 18, 20061SUBJECT 971AOUTLINE OF INVESTIGATIONFORMETALLIC UNDERGROUND FUEL PIPEIssue Number: 1OCTOBER 18, 2006Summary of TopicsThis is the First Issue of Subject 971A, Outline of Investiga
2、tion for MetallicUnderground Fuel Pipe, covering metallic and composite primary carrier,secondary containment, and integral primary/secondary pipe systems(pipe and fittings) intended for underground use in distribution andventing applications of petroleum-base flammable and combustibleliquids, alcoh
3、ols, and alcohol-blended fuels.The UL Foreword is no longer located within the UL Standard. For informationconcerning the use and application of the requirements contained in thisStandard, the current version of the UL Foreword is located onULStandardsInfoNet at: http:/ 2006 UNDERWRITERS LABORATORIE
4、S INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULOCTOBER 18, 2006SUBJECT 971A2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .52 Uni
5、ts of Measurement .53 Undated References 54 Glossary .5CONSTRUCTION5 General 7PERFORMANCE6 General 87 Short Term Pressure Tests .117.1 General 117.2 Leakage test 127.3 Hydrostatic test .127.4 Breakdown test .128 Long Term Pressure Tests 128.1 General 128.2 Sustained pressure test 138.3 Cyclic pressu
6、re test 139 Vacuum Tests .139.1 General 139.2 Static vacuum test .149.3 Cyclic vacuum test 1410 Fitting Torque Test 1411 Fitting Bending Test .1512 Pipe Bending Test 1513 Drop Test .1614 Drop Test After Conditioning 1615 Ball Impact Test .1716 Ball Impact Test After Conditioning .1717 Pipe Burial Te
7、sts .1817.1 General .1817.2 Pull strength test .1817.3 Puncture resistance test 1917.4 Crush resistance test .1918 Long Term Compatibility Test 1919 Interstitial Communication Test .2520 UV Compatibility Test .2521 Nonmetallic Fitting Stress Crack Test .2622 Metallic Fitting Stress Crack Test .2623
8、Permeation Test 26MANUFACTURING AND PRODUCTION TESTS24 General 2825 Leakage Test 28OCTOBER 18, 2006 SUBJECT 971A 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMARKING26 General .28INSTRUCTIONS27 General .30OCTOBER 18, 2006SUBJECT 971A4UL CO
9、PYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover metallic and composite primary carrier, secondary containment, andintegral primary/secondary pipe systems (pipe and fittings) intended for underground u
10、se in distributionand venting applications of petroleum-base flammable and combustible liquids, alcohols, andalcohol-blended fuels as identified in this outline.1.2 The piping covered by these requirements is intended to be installed and used in accordance with theFlammable and Combustible Liquids C
11、ode, NFPA 30, Code for Motor Fuel Dispensing Facilities andRepair Garages, NFPA 30A, and applicable Federal and State regulations for underground piping.1.3 These requirements cover completely metallic and composite metallic/nonmetallic pipe constructionswith manufacturer-supplied fittings for under
12、ground use only. The products covered by this outline havebeen evaluated for assembly in normal soil applications by qualified persons in accordance with themanufacturers instructions.1.4 The products covered by this outline have not been evaluated for applications in sumps (more than12 inches (30.5
13、 cm) from sump walls), as connector pipe (between underground pipe and dispensingdevice), aboveground or marine use, or other applications exceeding ambient temperatures of 75F(23C).2 Units of Measurement2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory
14、 orapproximate information.3 Undated References3.1 Any undated reference to a code or standard appearing in the requirements of this outline shall beinterpreted as referring to the latest edition of that code or standard.4 Glossary4.1 For the purposes of this outline the following definitions apply.
15、4.2 BARRIER LINER The thin inner or outer layer of a composite pipe that contains internal fuels,provides permeation resistance, and protects the outer structural pipe wall from exposure to fuels orexternal fluids.4.3 CHASE PIPE An underground pipe that is used to route primary carrier, secondary co
16、ntainment,or integral primary/secondary pipe between storage tanks and containment sumps. Typically used toextract pipe without excavation and is not considered secondary containment.4.4 CLOSED SECONDARY CONTAINMENT PIPING SYSTEM A secondary piping system with endsnormally closed at the tank and sum
17、p with a minimum rated pressure of 50 psig (350 kPa).4.5 COMPOSITE PIPE SYSTEM An underground piping system in which the pipe design containsboth metallic and nonmetallic major, critical components.OCTOBER 18, 2006 SUBJECT 971A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTR
18、IBUTION WITHOUT PERMISSION FROM UL4.6 FITTING A manufacturer-supplied component designed to connect, branch, or terminate pipesections and contain liquids. Connections may be threaded, welded, crimped, clamped, compressed,thermo fused, solvent welded, or adhesive joined. Sump boots are not considere
19、d fittings.4.7 FLEXIBLE PIPING Pipe with a manufacturers recommended minimum bend radius less than orequal to 6 feet (1.8 m). Typically constructed from thermoplastic materials.4.8 INTEGRAL Two or more separate components physically joined together or combined to form asingle part at the manufacture
20、r. Primary and secondary pipe joined in the field with a common fitting isnot considered integral.4.9 INTEGRAL PRIMARY/SECONDARY PIPE A single pipe, constructed at the manufacturer, thatcombines both primary carrier and secondary containment with an interstitial space that can bemonitored for leakag
21、e.4.10 METALLIC Pipe, fittings, or components primarily consisting of metals (typically corrosion-resistant malleable types such as steel, aluminum, copper, and brass) with or without minor nonmetalliccomponents (such as gaskets, seals, sleeves or bushings).4.11 METALLIC PIPE SYSTEM An underground p
22、iping system in which the pipe design containsmajor critical components that are formed from metals.4.12 NON-INTEGRAL PRIMARY/SECONDARY PIPE A pipe system with independent primary carrierand secondary containment connected in the field with an interstitial space that can be monitored forleakage.4.13
23、 NONMETALLIC Pipe, fittings, or components primarily consisting of nonmetals (typicallypolymeric thermoplastics, thermosets or composites) with or without minor metallic components (suchas foils, braids, tapes, sleeves, or bushings).4.14 NONMETALLIC PIPE SYSTEM An underground piping system in which
24、the pipe designcontains major critical components that are not formed from metals.4.15 NORMAL VENT PIPE A pipe system intended to transfer displaced gases (air and fluid vapors)from the top of an underground tank to grade during filling and provide atmospheric pressureequalization.4.16 OPEN SECONDAR
25、Y CONTAINMENT PIPING SYSTEM A secondary piping system with endsnormally open at the sump and a minimum rated pressure of 5.0 psig (35 kPa).4.17 PIPE A long cylindrical thin-walled structure designed for the intended use of underground burialand conveying or containing liquids. The pipe structure may
26、 be formed from homogenous (singlematerial), composite (multiple materials mixed together) or integral (individual materials joined as onecomponent) elements.4.18 PIPE OR FITTING SIZE Nominal or trade size (inches or mm) based on inside diameters ofpipe and fittings.Note Nominal or trade sizes may n
27、ot be equivalent to the actual measurements.OCTOBER 18, 2006SUBJECT 971A6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4.19 PIPING SYSTEM A combination of pipes and fittings joined to contain liquids transferredbetween a storage tank and sum
28、ps or dispensers (primary, secondary, or integral primary/secondarytypes) and vapor or air transfer between dispenser or tank to atmosphere (normal vent and vaporrecovery types). The system may be primary, secondary, or an integral primary/secondary type. Alsoknown as system.4.20 PRIMARY CARRIER PIP
29、E Pipe intended to be in continuous contact with the liquid flowing in apiping system under normal use. Also known as carrier pipe, primary pipe, or product pipe.4.21 QUALIFIED PERSON A worker specifically trained by the manufacturer to perform properinstallations of its piping systems in the field
30、in accordance with the specified instructions. The qualifiedperson is not required to be an employee of the manufacturer.4.22 RIGID PIPING Pipe with a manufacturers recommended minimum bend radius greater than 6feet (1.8 m). Typically constructed from thermoset materials.4.23 SECONDARY CONTAINMENT P
31、IPE Pipe intended to contain the liquid of a piping systemduring abnormal use (for example, primary carrier pipe leaks and sump or dispenser spills).4.24 SUMP Accessible atmospheric enclosure located underground, typically below a dispenser orabove a tank, and designed to monitor leaks, contain spil
32、ls and house connector pipe and controlvalves.4.25 UNDERGROUND Physically located below the surface layer of the earth in contact with soil(direct burial) or routed in a secondary or chase pipe (indirect burial). Underground does not includesump use more than 12 inches (30.5 cm) from the sump wall.4
33、.26 VAPOR RECOVERY PIPE A pipe system intended to transfer collected gasses (air and fluidvapors) from a vacuum system to an underground tank during dispensing. Also known as vapor pipe.CONSTRUCTION5 General5.1 System determination shall be made using guidelines specified in 5.2 (metallic), 5.3 (non
34、metallic), or5.4 (composite). All materials used in the construction of pipe, fittings, or systems shall be suitable for theirintended use with respect to normal (expected use within marked ratings) and abnormal (reasonableforeseeable misuse) conditions per the required performance tests described i
35、n Table 6.1.5.2 Metallic pipe (as covered by the requirements in this outline) shall be either completely constructed ofmetals or contain structural or critical metal components such as primary pipe or secondary pipe. Metalliccomponents that are not considered critical, with respect to standard dete
36、rmination, are containmentliners, fittings, wraps, covers, and rings. Metal joining methods, such as welding, shall not significantlychange the metallurgical properties or impede corrosion protection methods.5.3 Nonmetallic pipe (as covered by the requirements in the Standard for Nonmetallic Undergr
37、oundPiping for Flammable Liquids, UL 971) shall be either completely constructed of polymers, or containstructural or critical nonmetallic components such as primary pipe or secondary pipe. Nonmetalliccomponents that are not considered critical, with respect to standard determination, are corrosion
38、liners,fittings, wraps, covers and seals.OCTOBER 18, 2006 SUBJECT 971A 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL5.4 Composite pipe (as covered by the requirements in this outline) shall be constructed from an integralor nonintegral mix
39、ture of metals and polymers such as coaxial pipe with a metal primary and polymersecondary, a polymer primary and metal secondary, or multi-layer pipe with mixtures of metals andpolymers. Polymer pipe with thin metal foils used for liners or covers or metals in fittings are notconsidered critical in
40、 system determination.5.5 Metallics used in the construction of pipe, fittings, or systems shall be stainless steel, aluminum,brass, or other metals with similar corrosion-resistant properties. Other metals may be used if protectedagainst corrosion per 5.6 or 5.7. All metals shall comply with all ap
41、plicable requirements in this outline andshall not promote dielectric corrosion of dissimilar metals.5.6 Galvanized platings shall be (or evaluated as equivalent to) coating Designation G90 (minimum 40percent zinc on all external surfaces) in ASTM A 653/A 653M, Standard Specification for Steel Sheet
42、,Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process.5.7 Equivalent alternate corrosion protection methods shall be determined by an evaluation of:a) Protective platings and coatings in accordance with the Standard for Electrical MetallicTubing Steel, UL 797, and
43、b) A visual corrosion comparison between the benchmark G90 coating and the alternateprotection after exposures to the test fluids specified in Table 18.1.5.8 Protective packaging or other devices that provide short term resistance for protection of pipe orfittings during transport are permitted if w
44、eather resistant, but shall remain in place until installation andshall be evaluated for short term physical damage (as indicated in this outline).PERFORMANCE6 General6.1 Representative sample sizes of each type pipe, component, or system shall be subjected to theappropriate Performance Tests as spe
45、cified in Table 6.1:a) Pipe type rigid (R), flexible (F);b) Component pipe (P), fitting (F);c) System primary carrier (PC), secondary containment (SC), integral primary/secondary(PS), normal vent (NV) or vapor recovery (VR).OCTOBER 18, 2006SUBJECT 971A8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURT
46、HER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULTable 6.1Performance tests for underground metallic pipingClause Test Pipe type Sample Component/System7.2 Leakage R, F ALL PC, SC, PS, NV, VR7.3 Hydrostatic R, F ALL PC, SC, PS, NV, VR7.4 Breakdown R, F ALL PC, SC, PS, NV, VR8.2 Sustained Pr
47、essure F WC PC, PS8.3 Cyclic Pressure R WC PC, PS9.2 Static Vacuum R, F ALL PC, PS, NV9.3 Cyclic Vacuum R, F ALL PC, PS, VR10 Fitting Torque R, F ALL F11 Fitting Bending R, F ALL F12 Pipe Bending R, F ALL P13 Drop R, F ALL F, P14 Drop after Conditioning R, F ALL F, P15 Ball Impact R, F ALL PC, SC, P
48、S, NV, VR16 Ball Impact afterConditioningR, F ALL PC, SC, PS, NV, VR17.2 Pull Strength R, F ALL PC, SC, PS, NV, VR17.3 Puncture Resistance R, F ALL PC, SC, PS, NV, VR17.4 Crush Resistance R, F ALL PC, SC, PS, NV, VR18 Long TermCompatibilityR, F WC PC, SC, PS, NV, VR19 InterstitialCommunicationR, F W
49、C PC, SC, PS, NV, VR20 UV Compatibility R, F WC PC, SC, PS, NV, VR21 Nonmetallic FittingStressR, F WC F22 Metallic Fitting Stress R, F WC F23 Permeation R, F WC PC, SC, PSNOTE WC (worst case) indicates a sample, size, or test condition that is most likely to cause a noncomplying result.Material, thickness, construction, components, and connections are to be considered for the selection of worst case samples ortest conditions.6.2 Critical dimensions of all pipe (as a
