Home>BS standards>BS EN 331:2015 pdf free

BS EN 331:2015 pdf free

BS EN 331:2015 pdf free.Manually operated ball valves and closed bottom taper plug valves for gas installations for buildings.
4 Product characteristics
4.1 Reaction to fire
Manually operated ball valves and closed bottom taper plug valves in compliance with this standard are classified as belonging to Class Al “No contribution to fire”.
4.2 Dimensions and tolerance
4.2.1 Materials The shell, obturator and stern shall be made in one of the following materials:
a) copper alloy excluding aluminium-bronze in accordance with Table 1;
b) ductile cast iron excluding laminar cast iron in accordance with EN 1503-3;
c) forged steel and cast steel in accordance with EN 1503-1.
Any part in contact with the gas or the surrounding atmosphere, shall be manufactured from corrosionresistant materials or shall comply with salt spray test (see 5.6.3). See Table 1 for a list of suitable copper-alloy materials.
The corrosion protection for springs and other moving parts shall not be impaired by any movement. Material indicated in b] and c), excluding a), shall be tested in accordance with 5.6.3 (salt spray resistance).
Once the test has been run, no corrosion which could impair the device’s operation shall be revealed by visual examination (disregarding possible salt deposits), and the external tightness of the device (connected and disconnected) remains in conformity with the requirement defined in 4.4 (leak- tightness). Springs and other moving parts manufactured from non-corrosion-resistant materials shall be protected against corrosion and shall retain their protective coating despite any movement resulting from the operation of the valve. After the test of 5.6.1 these parts shall withstand the test of 5.6.3. Elastomeric sealing materials shall comply with EN 549 or EN 682. Additionally the temperature range of the materials specified in technical data sheet shall cover the valve temperature classes of Table 3 of this standard. Lubricants shall comply with EN 377. Additionally the temperature range of the lubricant specified in technical data sheet shall cover the valve temperature classes of Table 3 of this standard. Anaerobic jointing compounds shall comply with EN 751-1.
4.2.2 Construction
Valves shall be designed such that, once installed, it is impossible to remove the obturator or a seal without damaging the valve or leaving clear signs of tampering on it.
4.2.3 Product appearance
All valve components, when viewed with the naked eye corrected for normal vision, shall be free from sharp edges and corners which could cause damage, injury or incorrect operation.
4.2.4 Valve maintenance
All valves shall be designed to be maintenance free.
4.2.5 Springs
If a spring is used, the two end-faces of the spring shall be parallel and perpendicular to the axis of the spring. The end coils of a spring shall not damage their mating faces.
4.2.6 Wall thickness
The wall thickness from any gas way to atmosphere or to holes connected to the atmosphere, shall not be less than 1 mm. Holes for screws, pins, etc., which are used for the assembly of parts and for mounting, shall not provide any leak path between gas ways and the atmosphere.
4.2.7 Plug valves The plug shall be designed and mounted in the housing in such a way that the top edge of the sealing surface protrudes into the corresponding sealing surface of the housing taper.BS EN 331 pdf download.

Related PowerPoint Templates

Template Categories