1、GEOP Gas Engineering and Operating Practices A Series by the Operating Section The American Gas Association DISTRIBUTION Book D-2 Mains and Services- Operating Considerations Revised iiii Mains and Services Legal Notice The Gas Engineering and Operating Practices Series (GEOP Series or materials) wa
2、s prepared by the American Gas Association (AGA), its member companies and other individuals and groups with an interest in the natural gas industry. The AGA disclaims liability for any personal injury, property or other damages of any nature whatsoever, whether special, indirect, consequential or c
3、ompensatory, directly or indirectly resulting from the publication, use of, or reliance on the GEOP Series; for any violation of any federal, state or municipal regulation with which these materials may conflict; or for the infringement of any intellectual property rights from the use of these mater
4、ials. The AGA does not take position with respect to the validity of any patent rights asserted in connection with any items which are mentioned in or are the subject of the materials, and the AGA disclaims liability for the infringement of any patent resulting from the use of or reliance on the mat
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6、 however, the materials are provided “as is” and neither AGA nor its employees or agents make any representations, warranties or guarantees of any kind, either express or implied, including, but not limited to, any warranty that the materials will fulfill any particular purpose or needs and the impl
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8、rofessional or other services for or on behalf of any person or entity. Nor is the AGA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own independent judgment or, as appropriate, seek the advice of a competent profes
9、sional in determining the exercise of reasonable care in any given circumstances. Information on the topics covered by the materials may be available from other sources, which the user may wish to consult for additional views or information not covered by the materials. The AGA has no power, nor doe
10、s it undertake, to police or enforce compliance with the contents of the materials. Nor does the AGA list, certify, test, or inspect products, designs, or installations for compliance with the materials. Any certification or other statement of compliance with the materials shall not be attributable
11、to the AGA and is solely the responsibility of the certifier or maker of the statement. It may become necessary to make revisions to this document in the future. Whenever any revisions are advisable, recommendations should be forwarded to the American Gas Association, 400 N. Capitol Street, NW, 4thF
12、loor, Washington, DC 20001, USA. Copyrights 1986 and 2004 by the American Gas Association, AGA All rights reserved. Library of Congress Catalog Card Number: 85-70460 ISBN 0-87257-012-6 AGA Catalog Number XY0402 Printed in the United States of AmericaCONTENTS iiiMAINS AND SERVICES -OPERATING CONSIDER
13、ATIONS-REVISED CONTENTS CONTENTS. . iii PREFACE .x ACKNOWLEDGMENTS xi CHAPTER 1- INTRODUCTION 1 SCOPE.1 GENERAL 3 Types of Mains 3 Types of Services.3 TRAINING AIDS .4 Operator Qualification4 In-House .4 American Gas Association 5 Industry .6 CHAPTER 2- GENERAL INFORMATION . 7 PERMITS .7 EASEMENTS8
14、NOTIFICATION OF OTHER UTILITIES AND AGENCIES8 ESTIMATING 10 Selecting the Right Method 11 Labor-hour estimates .11 Dollar Cost Calculations 11 Actual Cost Comparisons.12 WHO SHOULD PERFORM THE WORK?13 TYPES OF CONTRACTS.13 Unit Bid13 Labor and Equipment (L permits should come as soon as possible aft
15、er this. Permits may be difficult to obtain for larger projects or projects in sensitive areas such as navigable waterways, marshlands, state or national forests Public hearings and/or environmental impact statements may be necessary. Obtaining permits or licenses from railroads is often time-consum
16、ing. Permits for longitudinal occupancy (parallel to railroad tracks) are costly and can be more difficult to obtain than a regular crossing permit (perpendicular angle to tracks). A permit or license may not be required when crossing a railroad or providing service in an adjacent public right of wa
17、y, however, notification of all work is required. In recent years, permits for excavating in a Right of Way have increased significantly and local authorities are requiring more extensive restoration of the roadway. In some areas, utility coordination committees or their equivalents have been establ
18、ished. Such committees usually provide the liaison between governmental agencies, private utilities and other interested parties. CHAPTER 2 GENERAL INFORMATION 8Membership on such committees can improve the necessary flow of information for advance planning as well as provide contacts for expediting
19、 and securing permits and licenses. The physical requirements during construction must be considered when obtaining permits. Storage of material, movement of equipment, construction of boring pits, directional drilling, and other similar activities require greater area than routine operations and ma
20、intenance. It is important that the crews performing work have a valid permit with them on the jobsite. All special instructions included with the permit must be followed, such as time restrictions, lane closures, maintaining vehicular traffic flow and access to pedestrian walkways. Permits may also
21、 include environmental requirements to address issues such as soil erosion, wetlands, muddying waterways and final job clean-up. EASEMENTS Easements (rights or privileges on anothers land), will be required when installing facilities on private property or on public property that is not part of a de
22、dicated right-of-way. Service lines may be exempt from this requirement. It is advisable to have a signed easement in the local land records and standard easement agreements should be developed to facilitate this operation. Often a “blanket easement” can be obtained from a land developer or builder
23、to cover the installation of all facilities within a sub-division. All easements and permits, should consider future maintenance, ingress and egress of equipment, and possible damages to the surrounding area. NOTIFICATION OF OTHER UTILITIES AND AGENCIES Pre-construction and pre-design meetings are a
24、 common practice on larger projects. Designers, construction contractors, utility representatives and other interested parties meet to discuss the scope and timing of intended work, type of equipment involved, proximity of excavation to underground facilities, potential for accidents and special pro
25、visions or requirements to convey information Prior to the start of construction, other utilities and agencies within the work area must be notified. CHAPTER 2 GENERAL INFORMATION 9“ONE-CALL” SYSTEMS “One-call” systems have been developed throughout the U.S to facilitate locating and marking of unde
26、rground facilities before excavation activity. “One-call” centers process locate requests from utilities, contractors, government agencies, and/or property owners who are intending to excavate in the immediate future. Information concerning the project is obtained from the excavator by the “one-call
27、” center, such as the location, start date, specific type of excavation work, excavators name and contact information. Participation in an ongoing “one-call” program is a valuable method to prevent damage to underground facilities from the excavation activities of others. 4After the “One- Call” orga
28、nization is notified of a forthcoming project, a locate request is sent to participating members. Members must respond within the time frame allowed by the “One- Call” program so that locating and marking are completed before excavation begins. In some cases, a facility owner may not be on the “one-
29、call” system. If known, calls must be placed directly to those involved. In addition, most railroads are not on a “one-call” system but require notification in advance of any work. Excavators should make efforts to confirm that all underground structures are marked by observing valve boxes, sewer ma
30、nhole covers, etc. in the field. Regulations, responsibilities and penalties regarding “one-call” systems vary from state to state. Each operator must follow the notification and marking requirements for the area and type of work involved. Additional precautions may also be specified to prevent dama
31、ge. The American Public Works Association (APWA) publishes an annual Directory of One-Call Systems. This information may be obtained from the APWA, or downloaded from . CHAPTER 2 GENERAL INFORMATION 10APWA directory of One-Call systems. A national damage prevention initiative resulted in the formati
32、on of the Common Ground Alliance (). One Call International and numerous other agencies interested in the prevention of third party damage have now allied themselves with this organization. CFR 192.614 requires that all operators pipelines systems must be covered by a qualified one-call system where
33、 there is one in place. ESTIMATING Estimating costs of building and maintaining gas distribution facilities may be accomplished by several basic methods: Specialized estimatingindividual job costs developed by highly experienced cost estimators Unit cost estimatingunit costs developed by centralized
34、 group of cost technicians and applied to individual jobs by clerks, technicians or designers as a minor part of their total responsibility. Unit costs are based on labor-hours/unit. CHAPTER 2 GENERAL INFORMATION 11 Automated estimatingcomputerized system applies unit cost and adjustment factors to
35、material and non-material labor operations as specified by the job designer. All of the above may be assisted by estimating software. Selecting the Right Method Any one or all of these basic methods, or variations of these methods, may be employed within a given company depending on desired accuracy
36、, volume of estimates, regulatory agency requirements, and economic considerations. Regardless of method selected, any estimate must include all costs involved so that the estimate is comparable to the actual cost recorded in the company accounting system upon completion of the job. Were it not for
37、constantly changing equipment, construction techniques, productivity and the effect of inflation on costs, it would be a relatively simple task to develop estimated average costs based solely on historic costs as recorded in the accounting system. To allow for these continuing changes, an estimating
38、 algorithm must be reasonably simple to update and adjust. Labor-hour Estimates One versatile way to accommodate changes is to establish productive labor-hour unit times for all normal operations, which may be analyzed and adjusted independently from costs in dollars. Work measurement studies, accou
39、nting data, time studies, estimates from construction personnel, and experience may all be used to establish and/or periodically adjust labor-hour unit times. Cost in dollars per labor-hour unit, developed separately, can then be applied to each labor-hour unit and easily adjusted as required for ch
40、anges in the unit time. Dollar Cost Calculations The other part of the algorithm, the cost in dollars, is obtained by extracting current data from the company accounting system using the fewest factors necessary to capture all costs. For example: Labor labor-hour ratetotal dollars paid to constructi
41、on personnel divided by actual work hours. (Total paid dollars should include CHAPTER 2 GENERAL INFORMATION 12 time paid for work hours plus vacations, holidays, sickness and any other paid time-off.) Transportationcost to operate vehicles that transport crews to and from jobs and, in most cases tha
42、t are used on the job. Machine equipmentall equipment, other than crew vehicles, used on job such as digging and boring machines, air compressors, and welding machines. An allowance for tool expense may also be included in this factor or accommodated in a separate factor. Materialcost of material, i
43、f involved, per estimating unit including storeroom operations and any job site delivery charges. Overheadsany indirect costs associated with construction not captured in other factors such as allowance for funds used during construction, pension plan, payroll taxes, unemployment compensation, medic
44、al plans, insurance plans and other fringe benefits. Unless charged directly to each job, cost of engineering, supervision and billing for customer charge work may also be handled as overhead costs. Paving/site restorationoften, particularly in urban areas, repaving costs have a major impact on the
45、cost of a project. Any other known miscellaneous costs such as rights-of-way purchases, inspection charges, permit fees or charges for misc. labor, if required, would be added to produce the total job cost. It is common practice on larger projects to add an “errors and omissions“ factor to cover ove
46、rsights. Actual Cost Comparisons The final stage in devising an estimate system is to provide procedures and reports to compare estimated versus actual job costs. This comparison should be made as soon as is practical upon completion of the job so that any required adjustment to labor-hour unit time
47、s or cost in dollars may be made to maintain current values in the system. To assure accurate cost accounting, it is important that unused materials be returned to storage and that their cost be credited to the job. CHAPTER 2 GENERAL INFORMATION 13WHO SHOULD PERFORM WORK? One question that must be a
48、nswered during the preliminary planning for any construction project is who will do the work. Company personnel, contractors, or both working together may complete construction, as long as operator requirements from CFR part 192.805 are being met. Utilities may have contracts with specific paving an
49、d landscape contractors to perform all or part of the restoration work. In some cases, municipalities perform their own paving work, and then bill the utility. Otherwise, the use of company and contractor personnel is dependent upon the project size and scope availability of company manpower and equipment, completion date estimated cost, union constraints and code requirements.5TYPES OF CONTRACTS 6Contracts are normally solicited as unit-bid, firm-bid or labor and equipment. Unit and firm-bid contracts can mo
