1、BRITISH STANDARD BS 7550-1: 1992 ISO 9091-1: 1991 Calibration of spherical tanks for refrigerated light-hydrocarbon fluids in ships Part 1: Method of stereo-photogrammetryBS7550-1:1992 This British Standard, having been prepared under the directionof the Petroleum Standards Policy Committee, waspubl
2、ished under the authorityof the Standards Boardand comes intoeffecton 31January1992 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference PTC/12 Draft for comment 88/51723 DC ISBN 0 580 20499 5 Committees responsible for this British Standard The preparati
3、on of this British Standard was entrusted by the Petroleum Standards Policy Committee(PTC/-) to Technical CommitteePTC/12, upon which the following bodies were represented: Department of Energy (Gas and Oil Measurement Branch) Department of Trade and Industry (National Engineering Laboratory) Depart
4、ment of Transport (Marine Directorate) GAMBICA (BEAMA Ltd.) Institute of Petroleum Royal Institution of Naval Architects Salvage Association Amendments issued since publication Amd. No. Date CommentsBS7550-1:1992 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword
5、 ii Introduction 1 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Precautions 2 5 Equipment 3 6 Preparation 3 7 Photographing 4 8 Additional measurements 4 9 Processing of photographs 4 10 Determination of coordinates 4 11 Data processing 5 12 Calculation procedure 5 13 Calibration tables 5 An
6、nex A (informative) Safety precautions 7 Annex B (informative) Calibration accuracy 7 Annex C (informative) Example of main gauge table at 160 C 8 Annex D (informative) Example of trim correction table 9 Annex E (informative) Example of list correction table 10 Annex F (informative) Example of corre
7、ction table for tank shellexpansionorcontraction 11 Publication(s) referred to Inside back coverBS7550-1:1992 ii BSI 08-1999 National foreword This Part of BS7550has been prepared under the direction of the Petroleum Standards Policy Committee. It is identical withISO9091-1:1991 “Refrigerated light-
8、hydrocarbon fluids Calibration of spherical tanks in ships Part1: Stereo-photogrammetry”, published by the International Organization for Standardization (ISO). ISO9091-1 was prepared by Subcommittee5, Measurement of light hydrocarbon fluids of Technical Committee28, Petroleum products and lubricant
9、s, in which the United Kingdom participated. It is intended that BS7550will consist of the following Parts. Part 1: Method of stereo-photogrammetry; Part 2: Triangulation method. Part 2 will be identical with ISO9091-2which is in preparation. The Technical Committee has reviewed the provisions ofISO
10、8311:1989, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. CAUTION. Attention is drown to the Health and Safety at work etc.Act1974, and the need for ensuring that the method specified in this Part ofBS7550 is carried out wi
11、th suitable precautions. The procedure described in this Part of BS7550 is intended to be carried out by appropriate qualified and experienced persons or other suitably trained and/or supervised personnel. Normal safety precautions should be observed throughout the use of the method. Attention is dr
12、awn to the precautions given inAnnex A. 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 does not of itself confer immunity from legal obligations. C
13、ross-references International Standard Corresponding British Standard ISO 7078:1985 BS 6953:1988 Glossary of terms for procedures for setting out, measurement and surveying in building construction (including guidance notes) (Identical) Summary of pages This document comprises a front cover, an insi
14、de front cover, pages i and ii, pages1 to 12, 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 indicated in the amendment table on the inside front cover.BS7550-1:1992 BSI 08-1999 1 Introduction Large qu
15、antities of light hydrocarbons consisting of compounds having1 to4 carbon atoms are stored and transported by sea as refrigerated liquids at pressures close to atmospheric. The liquids can be divided into two main groups: liquefied natural gas(LNG) and liquefied petroleum gas(LPG). Bulk transportati
16、on of these liquids requires a special technology in ship design and construction to enable shipborne transportation to be safe and economical. Measurement of cargo quantities in ships tanks for custody transfer purposes has to be of a high order of accuracy. The two parts of this International Stan
17、dard, together with other standards in the series, specify methods of internal measurement of ships tanks from which tank calibration tables can be derived. For internal measurement, liquid calibration, physical measurement, optical measurement and stereo-photogrammetry are in general use. Liquid ca
18、libration cannot be used for large spherical tanks designed to operate at near atmospheric pressure with refrigerated light hydrocarbons because the hydrostatic pressure exerted by the calibrating liquid may exceed the design pressure when filled higher than a certain level. In view of its accuracy,
19、 the last-mentioned should be adopted as the referee method if calibration by another method is in doubt. Stereo-photogrammetry consists mainly of photographing targets on the tank wall and the analytical processing of the photographs in the laboratory. This part of ISO9091specifically describes the
20、 method using a universal metric camera for the photographing and analytical stereoplotter for the analysis. 1 Scope 1.1 This part of ISO9091describes a stereo-photogrammetric procedure for the internal measurement of spherical tanks in liquefied-gas carriers. 1.2 In addition to the actual process o
21、f measurement, this part ofISO9091 also sets out the calculation procedures for compiling the calibration tables. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part ofISO9091. At the time of publication, the edi
22、tions indicated were valid. All standards are subject to revision, and parties to agreements based on this part ofISO9091 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid
23、International Standards. ISO 7078:1985, Building construction Procedures for setting out, measurement and surveying Vocabulary end guidance notes. ISO 8311:1989, Refrigerated light hydrocarbon fluids Calibration of membrane tanks and independent prismatic tanks in ships Physical measurement. 3 Defin
24、itions For the purposes of this part of ISO 9091, the following definitions apply. 3.1 absolute orientation the procedure of final correction of the stereoscopic models formed by inner and relative orientations, in which the scale in the stereoscopic model is converted to the actual length and the i
25、nclination of the model is adjusted to the actual condition of the tank 3.2 calibration the process of determining the total capacity or partial capacities of a tank corresponding to different levels 3.3 calibration table (main gauge table) a table, of ten referred to as a tank table or a tank capac
26、ity table, showing the capacities of or volumes in a tank corresponding to various liquid levels measured from the gauge reference point, with the ship on an even keel and upright 3.4 datum point the south pole to which the tank table is referred 3.5 deadwood any tank fitting which affects the capac
27、ity of a tank. Deadwood is referred to as “positive deadwood” when the capacity of the fitting adds to the effective capacity of the tank, or “negative deadwood” when the volume of the fitting displaces liquid and reduces the effective capacityBS7550-1:1992 2 BSI 08-1999 3.6 equator the largest hori
28、zontal circumference of a spherical shell 3.7 floating mark a mark seemingly occupying a position in the three-dimensional space formed by stereoscopic fusion of a pair of photographs and used as a reference mark in examining or measuring the stereoscopic model 3.8 gauge reference point the point fr
29、om which the liquid depths are measured NOTE 1In spherical tanks, this point may be either the zero of the level gauge or the south pole of the tank. 3.9 inner orientation the process of determining, mathematically, the interior perspective of the photographs at the time of exposure in an analytical
30、 stereoplotter. The calibrated focal length, the location of the calibrated principal point and the calibrated lens distortion are the principal factors used in the calculation 3.10 list transverse inclination of a ship 3.11 north pole the zenith, or highest point, of a spherical tank shell (an imag
31、inary point in most spherical tanks due to the pipe tower or other appurtenances) 3.12 pipe tower a large-diameter pipe coaxial with the tanks north-south axis, containing pipes for loading and discharging, measuring instrumentation, the ladder, wiring and other in-tank facilities designed to protec
32、t them from the effect or sloshing of the tank contents 3.13 port the left-hand side of a ship facing forward 3.14 relative orientation the process of determining the relative position and attitude of a pair of overlapping photographs by mathematical analysis to create a stereoscopic model 3.15 sout
33、h pole the nadir, or lowest point, of a spherical shell 3.16 starboard the right-hand side of a ship facing forward 3.17 stereoscopic model three-dimensional model formed by intersecting homologous rays of a pair of overlapping photographs 3.18 stereoscopic photograph a set of photographs of an obje
34、ct taken from two different positions so that they may form a stereoscopic model of the object depicting it as if it were in three-dimensional space 3.19 targets predetermined positions distinctively marked on the inside surface of the tank for the stereo-photogrammetry 3.20 trim longitudinal inclin
35、ation of a ship 4 Precautions This clause outlines the precautions to be taken during measurement in order to ensure that the required calibration precision is obtained. 4.1 Utmost care and attention shall be exercised in taking measurements and during photographing, and any unusual occurrence durin
36、g the measurement or photographing which might affect the results obtained shall be recorded. The calibration method described in this part ofISO9091 may be applied to ships whether afloat or in a dry dock. However, its use in a dry dock may be preferable, because trim or list, if any, will remain t
37、he same throughout the measurement. Keep trim and list of the ship unchanged while an optical level or any other levelling device is being used. 4.2 If any unusual distortions are found in the tank shell, additional measurements shall be taken to obtain sufficient data for correct calculation in the
38、 calibration table, and the calibrators notes shall be provided in connection with such extra measurements.BS7550-1:1992 BSI 08-1999 3 4.3 Measurements shall be taken in duplicate without interruption, and if they do not agree within the following tolerances, measurements shall be continued until tw
39、o consecutive readings in duplicate agree within the specified tolerance: 4.4 The reference scale shall have a damping device at its bottom and shall not be touched whilst taking photographs. 4.5 The paint used to mark the targets shall be manufactured from materials which are resistant to liquids a
40、t cryogenic temperatures. 4.6 When measurements are made with a measuring tape, the tension specified in the tape calibration certificate shall be applied. 4.7 Measurements in the analytical instrument shall be independently taken twice to check whether they agree within0,01mm on the scale of a nega
41、tive or positive film and, if they do not agree, measurements shall be continued until two consecutive readings agree within0,01mm. 4.8 The targets shall be photographed when the tank is isothermal, either after dark or after the tank has been insulated. 5 Equipment 5.1 Analytical stereoplotter A co
42、mputerized instrument used to measure the coordinates of the targets in the photographs. It shall be capable of determining or distinguishing the position of each target by means of a three-dimensional coordinate system. 5.2 Camera platform A platform having an area large enough to accommodate the p
43、hotographer and a tripod for the camera and provided with adequate guard rails. It shall be mounted on a support structure of suitable strength and long enough to enable the camera to be installed at each photographing position. It shall be capable of being located at360 around the pipe tower at one
44、 end, and along the tank wall at the other end. 5.3 End-to-end rule A rule, graduated in centimetres and millimetres, to be used to measure deadwood, etc. The rule shall bear the identification of a recognized standardizing authority or a certificate of identification. 5.4 Measuring tape A tape bear
45、ing the identification of a recognized standardizing authority or a certificate of identification. 5.5 Metric camera A camera used for stereo-photogrammetry, calibrated in respect of principal distance, distortion and principal-point location, with clear and distinctive fiducial-mark separation. 5.6
46、 Optical level An optical level having an erect image, a magnification of 20 or greater, capable of being focussed to1,5m or less and with a spirit level sensitivity of40sper2mm or better. 5.7 Reference scale A steel scale with a plumb bob at its bottom and marked at several points to identify speci
47、fied lengths. This is used to denote the reference length by which all photographic dimensions obtainable in the photogrammetric instrument are scaled to the actual lengths. 5.8 Remote thermometer A thermometer used to measure the atmospheric temperature in the vicinity of the reference scale with a
48、n accuracy of 0,5 C in order to correct errors due to expansion or contraction of the scale. 5.9 Steel rule The rule, to be used to measure clearances, etc., shall be graduated in millimetres. The rule shall bear the identification of a recognized standardizing authority or a certificate of identifi
49、cation. 5.10 Surface thermometer A thermometer used to measure the temperature of the surface of the tank with an accuracy of 0,5 C in order to convert the coordinates of the targets at the temperature at the time of measurement to those at the certified reference temperature. 6 Preparation 6.1 Marking of targets 6.1.1 Each target shall consist of a square measuring100mm 120mm, painted black and with a distinguishing number, leaving a circle of20mm diameter with a cross at its centre. The paint used to mark the targets shall be manufactured from mat
