General information Steam traps - International standards
7
Automatic steam traps. Production and performance characteristic tests BS EN ISO 5117:2023
This standard defines the test methods used to validate that steam traps meet established safety and functionality requirements, through shell integrity tests and performance tests respectively. The standardisation of the testing methods ensures clarity and consistency for both manufacturer and customer. For the manufacturer, it provides a standard framework for quality assurance, and for customers it enables informed steam trap selection for their system.
Determination of live steam loss of automatic steam traps Two alternative test methods are specified to determine the steam loss of automatic steam traps. One of these was developed as a result of the work that Spirax Sarco undertook with the National Engineering Laboratory in the UK. Steam trap buyers can now make comparisons of true steam trap losses through various types of steam traps with the assurance that the figures published are accurate and all tests are conducted in accordance with this standard. Spirax Sarco are able to undertake these tests if required. Any manufacturers test figures that are not obtained within the parameters of this standard must be treated with caution. It is important to understand that under normal conditions steam traps do not waste steam. Wastage can only occur if there is no load (not practical even in a superheated system) or if the internals have been damaged. The following table shows the results of extensive testing to determine steam wastage from all trap types at a pressure of 5 bar g. It can be clearly seen that the radiation losses from the trap surface are much greater than losses through the trap orifice! Energy requirements of various steam traps - expressed in kg/h of steam at 5 bar
No-load
Reasonable load
Traps
Through trap
From trap
Total
Through trap
From trap
Total
BPT/SM
0.5
0.50
1.00
0
0.50
0.50
FT
0.0
1.40
1.40
0
1.40
1.40
IB
0.5
1.20
1.70
0
1.20
1.20
TD
0.5
0.25
0.75
0
0.25
0.25
The purpose of the above table is not to establish the fact that one type of trap is marginally more efficient than another. It is simply to show that steam traps require only a minimal amount of energy. Losses only become significant when traps are defective. The important thing therefore is to combine selection, checking and maintenance to achieve reliability. Properly done, costs and steam wastage will be minimised.
7.3 3
Determination of condensate capacity (discharge capacity) of automatic steam traps Manufacturers can choose between one of two alternative test methods to determine discharge capacity for steam traps. A manufacturer’s compliance with this standard will put an end to difficulties experienced in the past over trap selection. The customer will no longer have to ask whether the capacity curves produced for any particular manufacturer of steam trap are based upon cold water or hot water condensate tests. All steam traps manufactured in the UK and France by Spirax Sarco have capacity tests conducted in accordance with this standard. By comparison some manufacturers will include the capacity of internal air vents in the overall capacity of their float traps - the air vent is only open when condensate is subcooled. Production and performance characteristic tests for automatic steam traps This standard specifies tests which are used to ensure that the steam trap functions correctly and that the performance is acceptable for the design. The tests include product inspection, hydrostatic and operational checks. Testing of capacities and the identification of any steam losses are also discussed. Other standards are also used in the design and manufacture of Spirax Sarco steam traps. These include :- TRB 801 and Nr45, ISO 3548-1, DIN EN 1092, DIN EN 12516-2, AD 2000-Merkblatt, EN ISO 9606-1, EN ISO 15607, EN 289, EN 12569, BS 5500, ASME VIII and ASME IX.
TI-F01-27 CMGT Issue 7
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Steam Trap International Standards
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