1、 Buried Pressurized Piping Systems Leak Detection GuideRegulatory and Scientific AffairsAPI PUBLICATION 4716APRIL 2002Buried Pressurized Piping Systems Leak Detection GuideRegulatory and Scientific AffairsAPI PUBLICATION 4716APRIL 2002SPECIAL NOTES1. THIS PUBLICATION ADDRESSES ISSUES OF A GENERAL NA
2、TURE. WITH RESPECT TOPARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONSSHOULD BE REVIEWED.2. THROUGH THIS PUBLICATION, NEITHER THE AMERICAN PETROLEUM INSTITUTE (API) NORTHE AIR TRANSPORT ASSOCIATION OF AMERICA (ATA) IS UNDERTAKING TO MEET THE DUTIESOF EMPLOYERS, MANUFACTURERS,
3、OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIPTHEIR EMPLOYEES, OR OTHERS, CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS,NOR UNDERTAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS.3. INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPER PRECAUTIONS WITHRESPECT TO PARTICULAR MAT
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6、LICATIONS AND MATERIALS ISPUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API. APIs ADDRESS IS 1220 L STREET,N.W., WASHINGTON, D.C. 20005.All rights reserved. No part of this work may be reproduced, stored in a retrieval system,or transmitted by any means, electronic, mechanical, photocopying, recording
7、, or otherwise,without prior written permission from the publisher. Contact the Publisher,API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2002 American Petroleum Institute2FOREWORDThis do cum en t is in ten ded to pr o vide th e reader w ith a g en er al back g ro un d
8、 in leak detection tech n olog ies f or th eb ur ied p ress u rized p ip in g in air po rt hy dr an t f uelin g sy s tems an d petro leu m pr od u ct term in al sy stems . T h i s d o c u m e n tw as d ev elo ped b y Ar g us Co ns ultin g an d K en W ilcox As so ciates u nd er th e gu idance o f th
9、e joint Air Trans po r tA ss ociatio n o f Am er ica ( A TA ) an d the Am er ican Petro leum In stitu te ( A PI ) Leak Detectio n Co mm ittee. The d o cu men tincor po r ates in fo rm ation on leak d etectio n techn o lo gies in clu ding r esear ch, lab o rato r y testing , f ield testin g , an aly
10、sis,and exp erien ce. W hile an attemp t h as been m ade to d eter m in e the m os t log ical techn olo gies f o r ap p licatio n in airp or th yd rant fu eling and petr o leum p r od uct ter min al s y stem s, th e r eader s ho uld r ecog n ize that th ere m ay b e o t h e r f o r m s o fleak detec
11、tio n tech n olog ies and co ncepts no t d is cus sed in th is pu blicatio n. The read er is also ad vised that p ip in gs ys tems , f acilities , and site-s p ecif ic diff erences can aff ect techn o lo gy perf or m an ce. Th er efo re, each techn o lo gy b ein gcon sider ed f o r actu al us e s ho
12、 uld b e car ef ully ev alu ated . I nclu sio n in th is p u blication o f a p articular leak detection techn olo gy s h ou ld n o t be co ns tr u ed as an en d or sem en t of th at tech no log y b y eith er AP I o r ATA .This ATA and API publication may be used by anyone desiring to do so. Every ef
13、fort has been made to assurethe accuracy and reliability of the data contained therein. No representation, warranty or guarantee in connectionwith this publication is made by either the ATA or API, and the ATA and API hereby disavow any liability orresponsibility for loss or damage resulting from it
14、s use or the violation of any federal, state, or municipal regulationwith which this publication may conflict.Comments and suggestions are invited and should be submitted to the Air Transport Association of America,1301 Pennsylvania Avenue, N.W. Suite 1100, Washington D.C. 20004 or the American Petr
15、oleum Institute, 1220L Street, N.W., Washington D.C. 20005.TABLE OF CONTENTSSECTION TITLE PAGEI. EXECUTIVE SUMMARY .I-1II. INTRODUCTION.II-1A. Background II-1B. Program StructureII-1C. Applications .II-2D. Testing FacilitiesII-2E. Who Should Read This ReportII-3F. Notes of Caution II-3III. FACILITY/
16、SYSTEM CHARACTERISTICS . III-1A. Airport Hydrant Fueling Systems . III-1B. MCI Operating Characteristics III-2C. Petroleum Product Terminal Systems. III-2IV. LEAK DETECTION TECHNOLOGIES IV-1A. Technology TypesIV-1B. Selection Criteria .IV-2C. Technologies Selected for Evaluation.IV-3V. STATISTICAL N
17、ATURE OF THE TESTING PROCESS. V-1A. Signal and Noise . V-1B. Concept of Performance . V-2C. Declaring a Leak. V-2VI. TECHNOLOGIES TESTED VI-1A. Pressure Decay Dual PressureVI-11. The Nature of the SignalVI-12. Sources of Noise.VI-23. Key Features.VI-24. Test Results VI-3B. Dual Pressure VolumetricVI
18、-41. The Nature of the SignalVI-42. Sources of Noise.VI-53. Key Features.VI-64. Test Results VI-7C. Pressure Decay with Temperature CompensationVI-81. The Nature of the SignalVI-82. Sources of Noise.VI-93. Key Features.VI-94. Test Results VI-10D. Acoustic Emission .VI-101. The Nature of the SignalVI
19、-102. Sources of Noise.VI-113. Key Features.VI-114. Test Results VI-12E. Chemical Marker .VI-121. The Nature of the SignalVI-132. Sources of Noise.VI-133. Key Features.VI-144. Test Results VI-14F. Vapor Monitoring VI-151. The Nature of the SignalVI-162. Sources of Noise.VI-163. Key Features.VI-164.
20、Test Results VI-17G. Facts and Findings VI-17VII. DEVISING THE BEST TESTING STRATEGY FOR APARTICULAR SITE .VII-1A. Site Characteristics .VII-1B. Piping System ConsiderationsVII-1C. Operational Characteristics VII-2D. Cost ConsiderationsVII-2E. Operational Considerations VII-4F. Assessment of Vendors
21、 Claims VII-4G. Combining Technologies Effectively VII-5H. Using Multiple Tests.VII-5I. Testing Strategy . VII-5GLOSSARY .VII-6TABLE1-1 Performance Summary Airport Hydrant Systems .I-41-2 Performance Summary Petroleum ProductTerminal System.I-45-1 Possible Detection Results. V-26-1 General Character
22、istics of Pipeline LeakDetection Technologies.VI-196-2 General Characteristics of Volumetric andPressure Decay Technologies .VI-216-3 General Characteristics of Acoustic and ExternalMonitoring TechnologiesVI-22FIGURE3-1 Typical ATA Aircraft Hydrant Fueling System Schematic III-23-2 Representative Pe
23、troleum Product Terminal System III-35-1 Leak Rate Illustration. V-25-2 Leak Rate Illustration. V-36-1 Pressure Decay Dual Pressure .VI-16-2 Dual Pressure Volumetric .VI-56-3 Pressure Decay with Pressure WaveTemperature Compensation. .VI-86-4 Acoustic Emission.VI-116-5 Chemical Marker Test Pit .VI-1
24、36-6 Vapor Monitoring Test PitVI-15I-1Buried Pressurized Piping SystemsLeak Detection GuideI. EXECUTIVE SUMMARYThis Study Documentation Report (the Study)analyzes of the performance of different types of leakdetection technologies that were applied to buriedpressurized piping systems used in airport
25、 hydrantfueling and petroleum product terminals. The Studywas conducted by Argus Consulting and Ken WilcoxAssociates on behalf of the Air Transport Associationof America (ATA) and the American PetroleumInstitute (API). This report is intended to provide anoverview of the Study methodology and result
26、s.The purpose of the Study, as defined by the jointAPI and ATA Leak Detection Committee, was toidentify and evaluate reliable leak detectiontechnologies that are currently commerciallyavailable and cost-effective for buried pipingassociated with airport hydrant fueling systems andpetroleum product t
27、erminals.The Study was conducted in three phases. InPhase I, the Study consultants collected publisheddata and vendor information regarding the leakdetection technologies reported to be applicable tothe buried, pressurized piping in airport hydrantfueling systems and petroleum product terminals.Duri
28、ng that phase, criteria were identified forevaluating the leak detection technologies in thespecified applications. Through application of thosecriteria, six types of leak detection technologies weredetermined to have the potential to satisfy the Studypurpose. One vendor of each of these technologie
29、swas selected and agreed to participate in Phase II ofthe Study, which consisted of actual testing underconditions intended to represent or approximateconditions at an airport hydrant fueling system orpetroleum product terminal.Testing of the various technologies addressed inPhase II of the Study wa
30、s conducted at either theKansas City International Airport (MCI) or a specialtest facility designed and maintained by Ken WilcoxAssociates. The factors considered in evaluating thepotential of these technologies included, but were notlimited to: applicability to buried piping at airporthydrant fueli
31、ng systems and petroleum productterminals; compatibility with the operatingrequirements for such systems and facilities;performance of the technology; installationprocedures; operational requirements; reliability, andcost.Because the Study is not intended to serve as anevaluation or endorsement of p
32、articular leakdetection technology vendors, rather than identifyingthe technologies tested by vendor name, thetechnologies are identified by descriptive categories.While technology categories are used throughout thereport, the reader is advised that each of thetechnologies actually tested have propr
33、ietary featuresthat may be unique. The features are described to theextent necessary for accurate reporting purposesconsistent with the vendors proprietary protections.The six categories of leak detection technologiestested are identified as follows: Pressure decaydual pressure Volumetricdual pressu
34、re Pressure decay with temperature compensation Acoustic emission Chemical marker Hydrocarbon vapor monitoringThe first three technologies can be classified aspressure-based technologies involving themeasurement of fluid within the pipe. The acoustictechnology analyzes acoustic signals caused by ale
35、ak, which are transmitted through the piping andpiping contents. The last two technologies employexternal monitoring methods, monitoring the backfilloutside of the buried piping for evidence of a leak.The following is a summary of the informationgleaned about the six categories of leak detectiontech
36、nologies: Pressure decaydual pressure. This leakdetection technology requires a means toisolate sections of the piping to conduct thetest. This is normally accomplished withdouble block and bleed valves and apressure transmitter installed in each testsection. Application of this technology alsorequi
37、res a means to pressurize anddepressurize the piping section being tested.Each leak detection test takes approximately45 minutes when the piping system isisolated and under static pressure conditions.The technology appears to be capable ofdetecting a leak of about 0.01 percent of the linevolume per
38、hour with 99 percent probabilitywhile operating at a one percent false alarm rate.I-2It appears to be viable on both new and existingpiping systems.Previous applications of the technology haveused a minimum test pressure of 100 psi, whichwould limit its applicability for petroleumproduct terminals.
39、Conversations with thevendor indicate that the technology can be usedon lower pressure lines, but there is littleexperience with that application. The technologyrequires that any trapped air in the lines beeliminated, and surge suppressors be isolatedfrom the lines, during the test. Elevationdiffere
40、nces in the line can affect the results.There is no effect if the leak is at the sameelevation as the pressure measurement. Thereported result will be biased high if the leak isabove the test point, and biased low if the leak isbelow the test point. The effect would be about10 percent for a 50-ft el
41、evation change.Reported rates are standardized to 10 bar (150psi). Since most of the testing is conducted atnight, the effects of exposed pipeline areminimized. Volumetricdual pressure. This technology isdesigned for permanent installation but can alsobe employed as a mobile unit where the vendorcan
42、 conduct a leak detection test on demand.When permanently installed, it is often set up toblock in and test the entire line. Unless there isspecial provision for switching the leak detectionunit to different sections of the line by valves,separate fixed units are required for each section.Alternativ
43、ely, a mobile unit can be utilized to testindividual segments of the piping system on ascheduled basis.This leak detection technology tests the line in astatic condition and controls the pressure to twodifferent levels during the test by adding orremoving a volume of liquid product from theline. The
44、 test can take two to three hours,depending on the size of the line being tested.This technology appears capable of detecting aleak of about 0.006 percent of the capacity of theline with a 99 percent probability of detectionand with a false alarm rate of about one percent.This technology appears to
45、be viable on bothnew and existing airport hydrant fueling systemsand petroleum product terminals.The technology is affected by elevationdifferences, with the measured leak rate biasedlow if the leak is located below the top of theline. The performance estimates are based ontesting a line with a 50-f
46、t elevation differenceand with the measured rates biased low by about40 percent. If the same tests were run on a flatline, the system should be able to detect a leak of0.0037 percent of the line volume based on the175,000 gallon line tests. Pressure decay with temperature compensation.This technolog
47、y monitors the pressure decay in astatic line and sends a pressure pulse through theline at the beginning and end of the test tomeasure any temperature changes. It requiresapproximately a 30-minute test period. Testingof this technology during the Study wasabbreviated because the vendor determined t
48、hatfurther enhancements were needed.This technology showed promise, but it appearsto require further research and developmentbefore being implemented in an operationalsetting. Its application will depend onimprovements by the vendor, but apparently thistechnology could be designed for eitherpermanen
49、t installation or point-in-time testing atboth airport hydrant fueling systems andpetroleum product terminals. Acoustic emission. This technology operatesthrough the placement of microphones (oraccelerometers) with radio transmitters on thepipe at intervals of 300 to 500 feet. The acousticsignal generated by liquid flowing out of a defectin the pipe is recorded and analyzed by acomputer software program.This technology is adversely affected by ambientnoise. Thus, given the noise associated withoperations at airports, this technology appears torequire further de
