The document applies to heating appliances only in so far as the pipes of the heater contain the heat transfer fluids. The document does not apply to refrigerating plants, heat pumps and cooling appliances, portable room radiators as individual heating and solar heating plants with solar collectors if the heating in the relevant circuit is operated by solar energy only. This standard has the purpose of satisfying protection targets for the production and supply, in particular those specified in the Pressure Equipment Directive (DGRL). It also serves as an aid in the compliance with the specifications of the Industrial Safety Regulation (BetrSichV).