NS EN 12953-6 : 2011

Foreword
1 Scope
2 Normative references
3 Definitions
4 General requirements for steam and hot water generators
  4.1 Safeguards against excessive pressure
  4.2 Materials for valves, fittings, flanges and bolting
  4.3 Limiting devices and safety circuits
  4.4 Temperature measurement of the furnace wall
  4.5 Boiler heat supply
  4.6 Flue-gas heated economizers
5 Special requirements for steam boilers
  5.1 Water level indication
  5.2 Steam pressure and temperature indication
  5.3 Drain and blowdown devices
  5.4 Valves for connections
  5.5 Feed water supply
  5.6 Feed water control
  5.7 Limiting devices
  5.8 Heat supply
  5.9 Electrically-heated boilers
6 Special requirements for hot water generators
  6.1 Hot water generating systems (for example see annex A)
  6.2 Expansion and feed lines for open vented systems
  6.3 Water supply
  6.4 Circulating pumps
  6.5 Drain devices
  6.6 Water level indication
  6.7 Water supply control
  6.8 Limiting devices
  6.9 Vent valves
  6.10 Steam pressure and temperature indication
  6.11 Pressure controller
  6.12 Discharge from safety valves
  6.13 Heat supply
  6.14 Electrically heated hot water generators
  6.15 Parallel mode of operation of hot water generators
  6.16 Safety equipment for hot water generators
7 Small shell boilers
  7.1 Steam boilers
  7.2 Hot water generators
Annex A (informative) Design examples for hot water
         generating systems
Annex B (normative) Dimensioning of Expansion Space
Annex C (informative) Operational aspects
Annex ZA (informative) Clauses of this European Standard
         addressing essential requirements or other provisions
         of EU Directives

Describes the minimum requirements for safety related equipment for shell boilers as defined in EN 12953-1, to ensure the boiler operates within the allowable limits (pressure, temperature, etc.) and if the limits are exceeded the energy supply shall be interrupted and locked out without manual (human) intervention at the boiler.