《BS-7812-1995 ISO-4266-1994.pdf》由会员分享,可在线阅读,更多相关《BS-7812-1995 ISO-4266-1994.pdf(26页珍藏版)》请在三一文库上搜索。
1、BRITISH STANDARD BS 7812:1995 ISO 4266:1994 Guide for Selection, specification, installation, operation and maintenance of automatic liquid level and temperature measuring instruments on petroleum storage tanks Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:
2、55:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7812:1995 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 June 1995 BSI 08-1999 The following BSI
3、references relate to the work on this standard: Committee reference PTI/12 Draft for comment 89/52511 DC ISBN 0 580 24138 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee PTI/12, Petroleum measurement and sampling, upon
4、which the following bodies were represented: Department of Trade and Industry (National Engineering Laboratory) Department of Trade and Industry (Oil and Gas Office) Institute of Petroleum Salvage Association The following body was also represented in the drafting of the standard, through subcommitt
5、ees and panels: GAMBICA (BEAMA Ltd) Amendments issued since publication Amd. No.DateComments Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:55:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7812:1995 BSI 08-1999i Contents Page Committees responsibleInside
6、front cover National forewordii 1Scope1 2Normative reference1 3Definitions1 4Precautions for installation and operation4 5Selection, accuracy and installation of automatic level gauges5 6Calibration, operation and maintenance of automatic level gauges14 7Automatic temperature measurement15 8Transmis
7、sion of data18 Annex A (informative) Bibliography20 Figure 1 Installation of automatic level gauge on a fixed-roof tank8 Figure 2 Installation of automatic level gauge on a floating-roof tank9 Figure 3 Installation of automatic level gauge mounted on a tank fitted with floating cover11 Figure 4 Inst
8、allation of automatic level gauge on a high-pressure tank12 Figure 5 Installation of automatic level gauge in marine service13 Figure 6 Installation of averaging resistance thermometer19 List of referencesInside back cover Licensed Copy: London South Bank University, London South Bank University, Fr
9、i Dec 08 13:55:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7812:1995 ii BSI 08-1999 National foreword This British Standard has been prepared by Technical Committee PRI/12. It is identical with ISO 4266:1994 Petroleum and liquid petroleum products Direct measurement of temperature and level in
10、storage tanks Automatic methods, published by the International Organization for Standardization (ISO). ISO 4266 was prepared by Subcommittee 3, Static petroleum measurement, of Technical Committee 28, Petroleum products and lubricants, in which the United Kingdom participated. A previous British St
11、andard, BS 3792:1964 was withdrawn in 1989 because it was obsolete. The Technical Committee has reviewed the provisions of IEC 79-0:1983 (with Amendment No. 1:1987) to which normative reference is made in the text, and has decided that it is acceptable for use in conjunction with this standard. The
12、reference to ISO 8309:1991 is for information only, and does not affect the validity of this standard. CAUTION. Attention is drawn to the Health and Safety at Work etc. Act 1974, and the need for ensuring that the guidance given in this British Standard is used with suitable precautions. The guidanc
13、e given in this British Standard is intended to be used by appropriately qualified and experienced persons or other suitable trained and/or supervised personnel. Normal safety precautions should be observed in the use of the guidance. With respect to the various safety codes and regulations referred
14、 to in 4.2 the user should be familiar with the relevant UK regulations, which should be observed. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard d
15、oes not of itself confer immunity from legal obligations. Cross-references International standardCorresponding British Standard ISO 3838:1983BS 4699:1985 Methods for the determination of density or relative density of petroleum and petroleum products (pyknometer methods) (Identical) BS 7723 Methods
16、for calibration of vertical cylindrical tanks for petroleum and liquid petroleum products ISO 7507-1:1993Part 1:1994 Strapping method (Identical) ISO 8310:1991BS 7575:1992 Specification for resistance thermometers and thermocouples for the measurement of temperature in tanks containing refrigerated
17、light hydrocarbon fluids (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 20, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicat
18、ed in the amendment table on the inside front cover. Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:55:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7812:1995 BSI 08-19991 1 Scope 1.1 This International Standard gives guidance on the selection, specificat
19、ion, installation, operation and maintenance of mechanical and servo-operated automatic tank gauging systems measuring level and temperature in petroleum storage tanks which are at or near atmospheric temperature and pressure, or used under pressure, or for the storage of heated liquid petroleum pro
20、ducts. This International Standard does not apply to tank gauging systems using other sensing principles, such as radar and optical methods. NOTE 1Automatic level gauges may be used with either manual or automatic temperature measurement and automatic temperature measurement may be used with either
21、manual or automatic level gauging. The provisions of this International Standard are intended to ensure a sufficiently high degree of accuracy to meet the requirements of normal commercial operation. This International Standard does not apply to level and temperature measurement systems for refriger
22、ated hydrocarbon liquids, for which reference should be made to ISO 8309 and ISO 8310. 1.2 The provisions of this International Standard are intended to meet the requirements of accuracy necessary for custody transfer purposes. However, automatic level gauges are widely used for monitoring the movem
23、ents of oil to and from storage tanks for stock control, for which a lower standard of accuracy may be acceptable. 1.3 The user of automatic tank gauging systems should consult the system manufacturer for details of any specific requirements not covered in this International Standard. 2 Normative re
24、ference The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International St
25、andard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 79-0:1983, Electrical apparatus for explosive gas atmospheres Part 0: General requiremen
26、ts, (with Amendment No. 1:1987). 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 accuracy degree of closeness with which the indication of gauging equipment approaches the true value of the quantity measured 3.2 analog signal representation of the
27、proportional value of a variable in the form of a physically measurable quantity 3.3 anchor weight weight to which the detecting element guide wires are attached to hold them taut and plumb 3.4 bottom guide-wire anchor bar, welded to the tank bottom, to which the detecting element guide wires are at
28、tached 3.5 automatic level gauge instrument that continuously measures liquid depths or ullages in storage tanks 3.6 automatic temperature-measuring system System that continuously measures the temperature of the contents of a storage tank. 3.6.1 electrical resistance spot thermometer thermometer th
29、at measures the temperature of a liquid at a particular point in a tank by electrical resistance 3.6.2 electrical resistance averaging thermometer thermometer that measures the average temperature of a liquid over the whole or a large part of its depth or at discrete intervals throughout its depth 3
30、.7 calibration process or procedures of setting gauges or instruments so as to bring their reading into agreement with the true value of measurement 3.8 condensate reservoir device situated at the base of a gauge to collect and drain off condensate formed within the tape conduit Licensed Copy: Londo
31、n South Bank University, London South Bank University, Fri Dec 08 13:55:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7812:1995 2 BSI 08-1999 3.9 density mass of a substance divided by its volume (see ISO 3838) 3.10 detecting element that part of the measuring equipment which responds to a specif
32、ic property (e.g. liquid surface encounter or temperature) of the substance presented to it 3.11 digital signal representation of the value of a variable in the form of a series of individually distinct pulses or states 3.12 dip Depth of a liquid in a tank. NOTE 2The term “innage” is synonymous (see
33、 ISO 7507-1). 3.12.1 dip-hatch opening in the top of a tank through which dipping and sampling operations are carried out (see ISO 7507-1) 3.12.2 dip-tape graduated steel tape used for measuring the depth of oil or water in a tank, either directly by dipping or indirectly by ullaging (see ISO 7507-1
34、) 3.12.3 dip-tube vertical pipe built into a tank for manual gauging 3.13 displacer surface-detecting element which is suspended from a level gauge and moves in a vertical direction to follow the change in liquid level. The displacer has a higher mass than the liquid it displaces 3.14 error differen
35、ce between a computed or measured quantity and its true value 3.15 fixed-roof tank vertical cylindrical storage vessel with a cone- or dome-shaped roof, of either the non-pressure (freely-vented) type or the low-pressure type 3.16 float detecting element floating on the surface of a liquid in a tank
36、 which moves in a vertical direction to follow the change in liquid level 3.17 floating cover (screen) lightweight cover of either metal or plastics material designed to float on the surface of a liquid in a tank NOTE 3The cover rests upon the liquid surface. The device is used to retard evaporation
37、 of volatile products in a tank (see ISO 7507-1). 3.18 floating-roof tank tank in which the roof floats freely on the surface of its contents only in the vertical direction; the roof is restrained from rotation in the horizontal plane 3.19 gauge head housing of the liquid level measuring element, wh
38、ich may include the local indicator, transmitter and associated equipment 3.20 gauge well vertical cylindrical structure built into the roof of a floating-roof tank to contain and guide the detecting element 3.21 guide pole vertical tube used in floating-roof tanks to prevent rotation of the roof th
39、e guide pole may also be used as the still pipe (3.34), the support pipe (3.35) or the dip-tube (3.12.3) 3.22 guide wire spring-tensioned solid wire or flexible cable used to guide the travel of an automatic gauge float 3.23 indicator device which indicates the value of the measurement being made by
40、 the gauging equipment 3.24 non-pressure tank storage tank designed for operation at atmospheric pressure 3.25 operation checker externally operated device sometimes incorporated in a mechanical level gauge by which a sudden movement may be imparted to the tape in order to ensure that it moves freel
41、y Licensed Copy: London South Bank University, London South Bank University, Fri Dec 08 13:55:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 7812:1995 BSI 08-19993 3.26 pressure tank storage tank designed for operation at pressures above atmospheric pressure tanks are divided into two main classes
42、: a) low-pressure tanks, used for volatile products which are liquid at ambient temperatures; b) high-pressure tanks, used for liquids which are normally in the vapour phase at ambient temperature and atmospheric pressure. 3.27 receiver system which receives signals from a transmitter 3.28 remote tr
43、ansmission and telemetering systems separate or integral systems used in conjunction with level or temperature measuring devices to transmit local data readings to some point other than the point of measurement such systems usually comprise a transmitter to convert the readings into a form suitable
44、for transmission to a receiver which presents the readings at a remote location 3.29 resistance thermometer (RTD) temperature-sensing element constructed from material whose electrical resistance changes with temperature in a predictable manner 3.30 sampling hatch any hatch used for sampling; often
45、the dip-hatch 3.31 seal unit device that seals the gauge assembly from tank vapours 3.32 sensitivity minimum change in the measured parameter required to produce a movement of the indicator 3.33 servo-mechanism externally powered mechanism which is controlled by the detecting element 3.34 still pipe
46、; still well vertical pipe built into a tank to contain the liquid level-detecting element in order to reduce measurement errors arising from liquid turbulence, surface flow or agitation of the liquid 3.35 support pipe still pipe used to support an automatic tank gauge near or by the bottom of the t
47、ank or from the lower part of the tank shell 3.36 tank shell cylindrical part of a storage tank 3.37 tape; measuring wire element connecting the liquid level-detecting element of a direct-detecting automatic level gauge with the gauge head mechanism 3.38 thermowell tube installed in a tank to house
48、the resistance thermometer or any other temperature-measuring device if vertical, the thermowell may be a perforated pipe 3.39 ullage 1) Capacity of a tank not occupied by the liquid. 2) Distance between the surface of a liquid in a tank and some fixed reference point on the top of a tank. NOTE 4The
49、 term “outage” is synonymous (see ISO 7507-1). 3.40 ullage lip marine term for the reference point on the dip-hatch from which manual measurements are made 3.41 ullage plug marine term for the manual dip-hatch usually fitted with a heavy-duty cover 3.42 ullage reference point point clearly marked on the dip-hatch, or on a plate suitably located above or below the dip-hatch, and situated above the maximum level in the tank to indicate the point from which measurements of ullage are taken 3.43 upper reference point point clearly defined on the dip-hatch directly abo
链接地址:https://www.31doc.com/p-3736139.html