scope:

NEN-EN 331 specifies the characteristics for the construction, performance and safety of ball valves and closed bottom taper plug valves. It also details the test methods and marking provisions. It applies to metallic valves not directly buried for domestic and commercial installations inside or outside of buildings, using gases of the first, second and third family (specified in EN 437) and working up to 0,2 × 105 Pa, 0,5 × 105 Pa, 1 × 105Pa, 5 × 105 Pa and 20 × 105Pa and with temperature limits from - 5 °C or -20 °C to + 60 °C. Valve nominal sizes (DN) covered by this European Standard are as follows: 6, 8, 10, 12, 15, 20, 25, 32, 40, 50, 65, 80, 100.