NEN EN 50216-8 : 2005 AMD 1 2006

1 Scope
2 Normative references
3 Requirements and characteristics
  3.1 Description
  3.2 Operating characteristics
  3.3 Components characteristics
4 Assembly arrangements and dimensions
  4.1 Types of assembly
  4.2 Overall dimensions
5 Dimensions and types of gaskets, dimensions of gasket
  seats
  5.1 General
  5.2 Gaskets and gasket material
  5.3 Admissible operating conditions
  5.4 Design criteria for gasket seats - Choice of flange
      gaskets
6 Performances
  6.1 Tightness of the mounted valve
  6.2 Tightness of the butterfly blade
  6.3 Operating torque
  6.4 Maximum working overpressure with the butterfly valve
      in open and closed position
7 Tests
  7.1 Tightness of the mounted valve
  7.2 Tightness of the butterfly blade
  7.3 Operating torque
  7.4 Maximum working overpressure with the butterfly valve
      in open and closed position
8 Supply conditions

Define valves used on the pipelines, in which the insulating liquid of power transformers or reactors flows, in order to allow the replacement of components, without removing the whole or a large amount of the insulating liquid from the conservator and the tank.