General information Steam traps - International standards
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Marking of automatic steam traps BS EN ISO 6553:2017 Establishes certain minimum basic requirements for the marking and identification of steam traps. To conform to this standard all traps Maximum allowable pressure (PMA) Maximum allowable temperature (TMA) Indication of the flow direction Shell material designation Nominal size (DN) Nominal pressure (PN) Optional markings to include:- Maximum operating pressure (PMO) or maximum differential pressure ( D PMX) Maximum test pressure (PTMX) If steam traps do not have this information clearly marked on them many insurance companies may not validate or insure the steam system. should be marked with the following :- Manufacturer’s name and / or trade mark Face-to-face dimensions for flanged automatic steam traps ISO 6554:1980 This standard specifies face-to-face dimensions for steam traps in the size range DN15 to DN50, for pressures up to PN40. It is mainly used in European influenced markets. There are 6 series of dimensions with the most commonly used being Series 1. The following face-to-face dimensions are specified for Series 1 steam traps:
Series 1
DN15 150 mm
DN20 150 mm DN25 160 mm DN32 230 mm DN40 230 mm DN50 230 mm
Note: There is currently no ASTM/ASME equivalent for steam traps.
7.3 2
Face-to-face
Classification of automatic steam traps EN 26704:1991 ISO 6704:1982
Specification details the various types of operating principle for steam traps including mechanical, thermostatic and thermodynamic types. Many manufacturers claim that a trap operates in a different manner than it actually does. This is not only confusing but may also lead to operational problems. An example is where a bimetal trap (classed as a thermostatic trap) is incorrectly claimed to be a thermodynamic trap. This implies that it discharges condensate at steam temperature when in fact it may cause subcooling by up to 40 ° C below steam saturation temperature. This type of trap must not be confused with a true thermodynamic steam trap with a disc.
TI-F01-27 CMGT Issue 7
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Steam Trap International Standards
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