1、Bulk Liquid Stock Control at Retail OutletsAPI RECOMMENDED PRACTICE 1621FIFTH EDITION, MAY 1993REAFFIRMED, MAY 2012Bulk Liquid Stock Controlat Retail OutletsDownstream SegmentAPI RECOMMENDED PRACTICE 1621FIFTH EDITION, MAY 1993REAFFIRMED, MAY 2012SPECIAL NOTES1. API PUBLICATIONS NECESSARILY ADDRESS
2、PROBLEMS OF A GENERALNATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE,AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED.2. API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANU-FACTURERS, OR SUPPLIERS TO WARN AND PROPERLY TRAIN AND EQUIPTHEIR EMPLOYEES, AND OTHERS EXPOSED, CON
3、CERNING HEALTH ANDSAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKING THEIR OBLIGATIONSUNDER LOCAL, STATE, OR FEDERAL LAWS.3. INFORMATION CONCERNING SAFETY AND HEALTH RISKS AND PROPERPRECAUTIONS WITH RESPECT TO PARTICULAR MATERIALS AND CONDI-TIONS SHOULD BE OBTAINED FROM THE EMPLOYER, THE MANUFACTUREROR S
4、UPPLIER OF THAT MATERIAL, OR THE MATERIAL SAFETY DATA SHEET.4. NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED ASGRANTING ANY RIGHT, BY IMPLICATION OR OTHERWISE, FOR THE MANU-FACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COV-ERED BY LETTERS PATENT. NEITHER SHOULD ANYTHING CO
5、NTAINED INTHE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL-ITY FOR INFRINGEMENT OF LETTERS PATENT.5. GENERALLY, API STANDARDS ARE REVIEWED AND REVISED, REAF-FIRMED, OR WITHDRAWN AT LEAST EVERY FIVE YEARS. SOMETIMES A ONE-TIME EXTENSION OF UP TO TWO YEARS WILL BE ADDED TO THIS REVIEWCYC
6、LE. THIS PUBLICATION WILL NO LONGER BE IN EFFECT FIVE YEARS AF-TER ITS PUBLICATION DATE AS AN OPERATIVE API STANDARD OR, WHEREAN EXTENSION HAS BEEN GRANTED, UPON REPUBLICATION. STATUS OF THEPUBLICATION CAN BE ASCERTAINED FROM THE API AUTHORING DEPART-MENT TELEPHONE (202) 682-8000. A CATALOG OF API P
7、UBLICATIONS ANDMATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API,1220 L STREET, N.W., WASHINGTON, D.C. 20005.Copyright 1993 American Petroleum InstituteFOREWORDThis recommended practice contains procedures and methods designed to control andidentify product losses through use of a suitabl
8、e inventory control accounting system. Em-ployees should be trained in the procedures in this recommended practice and be requiredto follow them. Use of these procedures will enable the operator to identify trends and sig-nificant changes in inventory variations that may indicate the presence of con
9、trollablelosses. Suitable corrective actions may then be taken to reduce product losses.On September 23, 1988, the U.S. Environmental Protection Agency (EPA) issued itsTechnical Standards and Corrective Action Requirements for Owners and Operators of Un-derground Storage Tanks (UST). These standards
10、, which will be found in 40 Code of Fed-eral Regulations Part 280, were published in Volume 53 of the Federal Register at pages3719437212. Furthermore, legislation and regulations on all aspects of UST managementare under active development at state and local levels. These levels may have requiremen
11、tsother than those specified in the EPA Technical Standards, and the appropriate governmentagencies should be consulted about regulations that apply in the geographic area of interestbefore any action suggested by this recommended practice is taken. When used in this doc-ument, the term implementing
12、 agency means EPA or the designated state or local agency re-sponsible for carrying out an approved UST program.This recommended practice is based upon the experience of knowledgeable members ofthe petroleum industry. In some respects it may be more stringent than the requirements im-posed by the EP
13、A Technical Standards. However, the recommended practice does not at-tempt to cover all of the subjects covered by the EPA Technical Standards. Furthermore,while substantial effort has been made to ensure that none of the recommendations contra-vene the requirements of the EPA Technical Standards, A
14、PI is not undertaking to interpretthe EPA Technical Standards and cannot guarantee that its recommendations are com-pletely in accord with them, nor is any representation made that these recommendationsconform with any requirements imposed by state and local agencies.This recommended practice supers
15、edes and replaces API Recommended Practice 1621,fourth edition, December 1987. The EPA Technical Standards provide that RecommendedPractice 1621 can be used as a guide to comply with EPAs standards for inventory control.According to EPA, an owner or operator conforms with this provision of the EPA T
16、echnicalStandards if he or she uses the 1987 edition, which was in force when the EPA TechnicalStandards became final. However, an owner or operator who uses this new edition will alsobe meeting the requirements of the 1987 edition and EPA encourages the use of the mostrecent version.API publication
17、s may be used by anyone desiring to do so. Every effort has been madeby the Institute to assure the accuracy and reliability of the data contained in them; however,the Institute makes no representation, warranty, or guarantee in connection with this pub-lication and hereby expressly disclaims any li
18、ability or responsibility for loss or damage re-sulting from its use or for the violation of any federal, state, or municipal regulation withwhich this publication may conflict.Suggested revisions are invited and should be submitted to the director of the Manufac-turing, Distribution and Marketing D
19、epartment, American Petroleum Institute, 1220 LStreet, N.W., Washington, D.C. 20005.iiivCONTENTSPageSECTION 1GENERAL 11.1 Introduction . 11.2 Purpose 11.3 Federal Requirements 11.4 Referenced Publications 1SECTION 2ACCOUNTING SYSTEMS 22.1 Requirements. 22.2 Implementation 2SECTION 3PRODUCT LOSSES .
20、23.1 Sources of Losses 23.2 Unavoidable Losses. 23.2.1 Description of Normal Losses 23.2.2 Magnitude of Normal Losses . 33.3 Controllable Losses . 33.3.1 Description of Normal Losses 33.3.2 Leakage 33.3.3 Spillage. 43.3.4 Theft . 43.3.5 Product Used on Premises 4SECTION 4PROCEDURES FOR REDUCTION OF
21、CONTROLLABLE LOSSES 54.1 Introduction . 54.2 Daily Procedures . 54.3 Procedure for Receipt of Product 54.4 Special Circumstances. 6SECTION 5MANUAL TANK GAUGING . 65.1 Description 65.2 Federal Requirements 65.3 Conditions for Use. 65.4 Form and Procedure 6APPENDIX ASAMPLE RECONCILIATION FORMS 7APPEND
22、IX BPROCEDURE FOR TESTING ACCURACY OFGASOLINE-DISPENSING METERS . 13APPENDIX CGAUGING PROCEDURE FOR UNDERGROUNDHORIZONTAL TANKS . 15APPENDIX DWATER-GAUGING PROCEDURE 19APPENDIX EMANUAL TANK GAUGING RECORD ANDRECONCILIATION FORM . 23FiguresC-1Balance System Schematic. 17D-1Water Removal Procedure Usi
23、ng an Oil Skimmer 211.1 Introduction1.1.1 The primary application of this recommended prac-tice is in connection with the underground storage of motorfuels and used oil at retail and commercial facilities. Thisrecommended practice does not apply to inground (that is,where a part of the tank is above
24、ground) or abovegroundbulk storage systems. Hereafter, the use of the term tankrefers to an underground petroleum storage tank. Any mer-chandising operation in which a commodity is handled inbulk is susceptible to stock or inventory losses. This problembecomes even more critical at retail outlets se
25、lling motor fu-els since the principal bulk commodity handled is volatile.Thus, special care must be exercised to control productlosses to (a) provide a safe environment for the operator, em-ployees, customers, and neighbors; (b) minimize air and wa-ter pollution; and (c) maximize profits.1.1.2 The
26、negative effect of product losses on profitsneeds no explanation. However, the operator should under-stand that he or she, as well as the owner of the undergroundstorage and dispensing equipment, may be subject to finan-cial penalties imposed by government agencies if productleakage causes contamina
27、tion. He or she may also be liablefor personal injuries and property damage resulting fromhazardous conditions caused by product leakage as a resultof his or her negligence. Most states have regulations thatcontain penalties for noncompliance.1.2 PurposeThe purpose of this recommended practice is to
28、 assist theoperator in controlling bulk stock losses, thereby achievinga high level of safety and pollution control while maximizingprofits. This recommended practice describes and explainspractices and procedures needed to achieve good bulk stockcontrol. This control is achieved through the daily p
29、repara-tion and review of inventory control records. Achievinggood control of bulk stock allows the operator to quantifyproduct losses and quickly recognize the presence of leaks orequipment problems.1.3 Federal RequirementsThe U.S. Environmental Protection Agency (EPA) ac-cepts inventory control in
30、 conjunction with tank tightnesstesting as an approved method of release detection until De-cember 22, 1998, or 10 years after a new tank has been in-stalled or an existing tank has been upgraded, whichevercomes later. The EPA requires that any suspected release bereported within 24 hours to the aut
31、hority having jurisdiction.Authority having jurisdiction refers to one or more federal,state, or local government agencies or individuals responsi-ble for approving equipment, installations, and proceduresassociated with underground storage tank systems. When us-ing inventory control as a method of
32、release detection, vari-ances exceeding 1 percent of product throughput plus 130gallons for two consecutive months must be reported to theauthority having jurisdiction. In addition, the tank tightnesstest must be capable of detecting a 0.1 gallon per hour leakrate with a 95 percent probability of de
33、tection and a 5 per-cent probability of false alarm.An alternate method of release detection accepted by theEPA is the use of an automatic tank gauging (ATG) system.The ATG must be capable of detecting a release equivalentto 0.2 gallons per hour with a 95 percent probability of de-tection and a 5 pe
34、rcent probability of false alarm during amonthly test. In addition to providing a tank testing feature,some ATG systems may be able to perform automatic inven-tory control. The scope of this recommended practice doesnot include additional discussion of ATG systems.The EPA also allows manual tank gau
35、ging (MTG) as analternate method of leak detection for tanks of 2000 gallonscapacity or less (refer to 5.2). MTG can be used for tankscontaining motor fuels, used oil, and petroleum distillates.However the EPA exempts certain tanks from the UST reg-ulations, including heating oil tanks used for cons
36、umptiveuse on the premises where stored. Some state regulations,however, do not exempt such tanks.State and local agencies may have more stringent stan-dards and should be consulted.1.4 Referenced PublicationsThe most recent editions of the following standards,codes, and specifications are cited in
37、this recommendedpractice.APIRP 1615 Installation of Underground Petroleum Stor-age SystemsRP 1628 A Guide to the Assessment and Remediationof Underground Petroleum ReleasesRP 1631 Interior Lining of Underground Storage TanksRP 1637 Using the API Color-Symbol System to MarkEquipment and Vehicles for
38、Product Identifi-1Bulk Liquid Stock Control At Retail OutletsSECTION 1GENERAL2 API RECOMMENDED PRACTICE 1621cation at Service Stations and DistributionTerminalsEPA1Straight Talk on TanksTechnical Standards and Corrective Action Requirementsfor Owners and Operators of UndergroundStorage Tanks (40 Cod
39、e of Federal Regula-tions Part 280)NFPA277 Static ElectricitySECTION 2ACCOUNTING SYSTEMS2.1 Requirements2.1.1 The necessity of establishing and using an adequateaccounting system, not only for inventory but for the busi-ness in general, cannot be stressed enough. Even a very sim-ple system may be ad
40、equate to control inventory of bulkliquid stock, but it is of the utmost importance that it be usedevery day.2.1.2 As a minimum, the system should clearly show thefollowing information for each grade or type of bulk liquidproduct for each day of operation:a. A record of all bulk liquid receipts (tha
41、t is, delivery in-voices).b. A record of all bulk liquid sales (obtained from the fueldispensers).c. A record of bulk liquid used other than that sold.d. A daily reconciliation between sales, use, receipts, andinventory-on-hand.2.2 Implementation2.2.1 Many different accounting systems are available.
42、Most oil suppliers will advise their operators as to the properaccounting procedures to be used, including sources and useof suitable accounting forms. A sample daily gasoline inven-tory record is contained in Appendix A.2.2.2 Once the operator has adopted a system, he or shemust use it conscientiou
43、sly and according to the instructions.In some cases, the circumstances of an individual operationmay be such that after a reasonable period of use, the systemcan be simplified without impairing its purpose, or aug-mented to provide additional useful information. No matterhow it is modified, the syst
44、em must be used daily to be offull value.SECTION 3PRODUCT LOSSES3.1 Sources of LossesFor the purpose of this discussion, losses are divided intotwo categories: (a) those that are unavoidable because of thenature of the business and the characteristics of the product,and (b) those that can be control
45、led and reduced by follow-ing appropriate stock control procedures.3.2 Unavoidable Losses3.2.1 DESCRIPTION OF NORMAL LOSSES3.2.1.1 Any business involving the handling of bulk mer-chandise is subject to unavoidable stock losses. The operatorof a retail gasoline outlet is even more subject to unavoida
46、blestock loss because of the volatile nature of the liquid producthe or she handles. A portion of the product in the storagetanks will vaporize and occupy the empty portion of the tankas a vapor-air mixture. When the product is received, anequivalent volume of vapor-air mixture is forced out through
47、the vents by the incoming product. Where vapor emissioncontrol equipment is in use, the vapor-air mixture is returnedto the tank truck making the delivery.3.2.1.2 Regardless of whether the storage system is or isnot equipped with vapor emission control equipment, vapor-air mixture is seldom, if ever
48、, expelled from undergroundtanks except during deliveries. The only other times whenthis condition could occur are when the vapor-air mixtureexpands as a result of an increase in temperature or when thebarometric pressure changes.3.2.1.3 The temperature of the ground around under-ground tanks does n
49、ot vary appreciably from day to day.Even if underground product temperatures increase, vapor-air mixture normally will not be expelled from the vent be-cause increased space is created whenever product ispumped from the tank during a sale to a customer. As a re-sult, air is drawn into the tank rather than vapor-air mixturebeing forced out.1Environmental Protection Agency, The Code of Federal Regulations isavailable from the U.S. Government Printing Office, Washington, D.C.20402; Straight Talk on Tanks is available from the National Technical In-formation Services, Departme
