GB/T 12250-2023 Automatic steam traps - Marking
1 Scope
This document specifies the general requirements for the marking of automatic steam traps, the mandatory marking, the optional marking, and the additional markings.
It is applicable to automatic steam traps.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 12220 Industrial valves - Marking (GB/T 12220-2015, ISO 5209:1977, MOD)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 maximum allowable pressure
maximum pressure that the automatic steam trap shell can endure at a given temperature
3.2 maximum allowable temperature
maximum temperature that the automatic steam trap shell can endure at a given pressure
4 General requirements
The automatic steam traps may be marked on the valve body or on the nameplate, which shall be firmly fixed to the body or bonnet. Ensure that the markings are not obscured when installing and fixing a steam trap.
5 Mandatory marking
The following markings shall be used on the automatic steam traps:
——manufacturer’s name and/or trademark;
——maximum allowable pressure (MPa);
——maximum allowable temperature (℃);
——indication of the flow direction (arrow);
——body materials;
——nominal diameter (DN or NPS);
——nominal pressure (PN or Class).
The markings used above shall meet the requirements of GB/T 12220. If an automatic steam trap has no defined PN or Class designation, maximum allowable pressure and maximum allowable temperature are mandatory.
For PN or Class designated automatic steam traps, it is permissible to omit the letters “DN” or “NPS” from the nominal diameter designation provided the PN or Class designation follows immediately after the diameter number and is on the same line.
Example: DN50 PN25 may be abbreviated to 50 PN25; NPS2 Class300 may be abbreviated to 2CL300.
Note: For automatic steam traps less than or equal to DN50 or NPS2, the body material marking may be omitted.
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 Mandatory marking
6 Optional markings
7 Additional markings
