BS 8562:2011 pdf download – Gas cylinders – In situ, non‑destructive examination and testing of refllable seamless steel tubes of water capacity between 150 L and 3 000 L, used for compressed gases – Specifcation
4.3.2 Visual examination
All external visual examinations (see Annex A) shall be performed in accordance with the requirements of ISO 6406:2005, Annex B. All internal visual examinations shall be performed in accordance with the requirements of BS EN 1968:2002. All signs of corrosion and any form of mechanical damage shall be carefully investigated. Where necessary, additional equipment (e.g. a video camera or an endoscope) shall be used to help clarify and interpret the initial observations.
4.3.3 Acoustic emission testing Acoustic emission testing (AT) shall be carried out in accordance with the requirements of BS EN ISO 16148 (an examination procedure using AT is described in Annex B).
4.3.4 Hydraulic testing Hydraulic testing shall be carried out in accordance with the requirements of ISO 6406:2005, Clause 11.
4.3.5 Supplementary tests Where there is doubt about the type and/or severity of any imperfection identifed by the tests in 4.3.2 to 4.3.4, additional test(s) shall be conducted to supplement or clarify the results obtained [e.g. ultrasonic examination (UE), magnetic particle inspection, dye penetrant inspection, radiography, eddy current inspection, hardness testing]. Where particular parts of the tube are inspected using UE, the relevant requirements of ISO 6406:2005, 11.4 shall be met. Corrosion mapping or faw detection may be used to further evaluate imperfection distribution.
NOTE 1 Corrosion mapping is a pulse-echo ultrasonic technique that produces a colour graphic image of the area scanned. It involves scanning with one or more straight beam probes using a prescribed, dual axis scan pattern over the tube surface whilst taking thickness measurements.
The measurements are converted into digital values, which are colour-coded to create a topographic map of the tube wall thickness profle. Images (C-scans) from individual scan areas can be assembled together to create a composite image covering large areas of the tube surface. The thickness profle of the corroded area can be evaluated at the time of the test and/or can be stored and used to monitor future surface degradation.
NOTE 2 Eddy current testing may be used as part of the overall programme for tube examination and verifcation. The requirements for the examination, verifcation and equipment used for this technique are specifed in BS EN ISO 15548.
NOTE 3 Magnetic particle inspection (MPI) may be used as part of the overall programme for the evaluation and detection of surface breaking and slightly sub-surface discontinuities within the tube. The general principles for this technique are given in BS EN ISO 9934-1.
5 NDE personnel qualifcation
All personnel performing NDE work shall be certifed in accordance with relevant standards (e.g. BS EN 473).
After satisfactory completion of the periodic inspection and test programme the shoulder of the tube, where accessible, shall be stamp-marked with the test details in accordance with the requirements of BS EN ISO 13769.
The marking shall include the date of the next retest (YYYY). Under no circumstances shall the parallel section of the tube be hard-stamped. Where the tube shoulder cannot be stamped, the nearest position to it where damage is unlikely to occur or the information unlikely to be rendered illegible shall be stamped. Where it is not possible to stamp the tube, other techniques shall be used to mark the information (e.g. installing a data plate or paint stencilling) or the information may be presented on another integral part of the installation, but as close as possible to the tube shoulder.
For every tube examined a test certifcate/report shall be issued and signed by the competent person giving the following information as a minimum:
a) the serial number(s) of the tube(s) examined;
b) a description of the installation (e.g. site details, tube installation and its/their position within the site);