ISO 14246 pdf download.Transportable gas cylinders — Gas cylinder valves — Manufacturing tests and inspections
1 Scope
This Standard specifies the requirements for tests and inspections of gas cylinder valves at time of manufacture. This Standard is applicable to valves to be fitted to industrial and medical gas cylinders, up to 1 50 l water capacity, intended to convey compressed, liquefied or dissolved gases. This Standard is only applicable to valves operated by a hand wheel or a key. This Standard is not applicable to valves for breathing equipment, fire extinguishers, cryogenic equipment and liquefied petroleum gas (LPG).
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply : 3.1 shift period of continuous work not exceeding one day 3.2 batch a quantity of valves of the same design, comprising either the production of one shift or 1 000 valves, whichever is the smaller 3.3 working pressure (p w ) settled pressure, at a uniform temperature of 1 5 °C, for a full gas cylinder 3.4 valve test pressure (p vt ) for compressed gases:p vt = 1 ,2 p w For liquefied gases and dissolved gases under pressure (for example, acetylene), p vt is at least equal to the minimum test pressure of the cylinder quoted in the relevant transportation regulation for that gas or gas group, taking account of the actual filling ratio to be used. NOTE : Transportation regulations sometimes offer a choice of filling ratio together with appropriate minimum test pressures. Generally, p vt will be the highest of these minimum test pressures for the gas, but in circumstances where a lower filling ratio is to be used, p vt may be an appropriate lower test pressure.
4 Manufacturing tests and inspections
4.1 General Manufacturing tests and inspections shall include : – routine manufacturing checks (to be performed on every valve) ; – batch acceptance tests ; – revalidation tests. 4.2 Routine manufacturing checks The presence of a through passage shall be established. All valves shall be subjected to both internal and external tightness testing prior to dispatch. Testing shall be conducted at p vt or for valves equipped with pressure relief devices at 0,8 times the set pressure. The tightness test shall be performed at ambient temperature. The internal or external leakage rate shall not exceed 6 cm 3 /h measured at 20 °C and 1 013 mbar. For valves for highly toxic or high purity gas service, a lower leakage rate may be specified. Generally, these tests are conducted with oil free dry air or nitrogen but other gases may be used. An example of a test procedure is given in annex A. NOTE : Additional testing may be required for valves with special features, e.g. residual pressure valves, pressure reducing valves.4.3 Batch acceptance tests The valve manufacturer shall subject at least one valve per batch to the following checks and tests : a) tests shall be carried out for internal and external tightness at high and low pressures in accordance with the requirements of EN 849 at ambient temperature ; b) the torque required to seal the valve against an inlet pressure of p vt with the outlet sealed shall not exceed the requirements of EN 849 ; c) the disassembly torques of the valve components shall be checked during disassembly of the valve. The assembly and components shall be checked for suitability, possible damage or contamination ; d) the cleanliness of valves intended for oxygen service shall be checked (less than 1 00 mg/m 2 of hydrocarbons) and the valves shall be free from particles ; NOTE : EN 1 2300 (Cryogenic vessels – Cleanliness for cryogenic service) may be used as a guide.