ISO 15848 fugitive-emission requirements for industrial valves
Fugitive-emission requirements target leakage from the stem seal and body joints rather than leakage through the closed seat. Buyers need to specify the applicable test route, tightness class, temperature range and endurance level so suppliers can offer a qualified sealing system.
TAZ Engineering & Export Team · · 12 min
Separate fugitive emissions from seat leakage
Seat or closure testing measures flow through the closed obturator. Fugitive-emission testing addresses external leakage from stem packing and body seals during pressure, temperature and mechanical cycling. One result cannot substitute for the other.
The datasheet should state both requirements independently. Use a named test standard and class instead of phrases such as “zero leakage” or “low emission,” which have no measurable acceptance value by themselves.
Define the qualification envelope
A type-test certificate applies to a defined valve design, stem-seal arrangement, size or size range, pressure class, material, temperature class, test fluid and endurance class. Procurement must verify that the offered valve sits within that qualified envelope.
Changes to packing material, stem finish, gland geometry, bolting or manufacturing route may affect qualification. Ask the supplier to identify the exact certificate and explain the permitted design-family coverage.
Select tightness and endurance for the service
The required leakage class should reflect fluid hazard, environmental target and plant specification. Mechanical cycles represent operating endurance, while thermal cycles challenge packing behaviour across the stated temperature range.
Do not automatically demand the most severe class for every utility valve. Excess requirements can limit designs and increase cost without corresponding project benefit. The end user should establish the target through process risk and emissions policy.
Control stem and packing manufacture
Repeatable performance depends on stem diameter and surface condition, packing material and ring preparation, gland alignment, fastener control and assembly procedure. The quality plan should identify the characteristics that preserve the qualified design.
Record packing lot, installation method and gland adjustment where required by the project. Repair after failed testing should follow an approved process with defined retest scope.
Specify production acceptance separately
Type qualification demonstrates the capability of a design family under the selected test program. Production acceptance addresses delivered valves and may use a different standard part, sampling plan or screening method.
The RFQ should state whether production fugitive-emission testing is required, the sample size, test medium, pressure, measurement method and documentation. Avoid assuming that a type-test certificate means every shipped valve received the full qualification test.
Review the certificate against the offered configuration
Check certificate holder, manufacturer, valve type, size range, pressure class, temperature, materials, stem seal, test fluid, classes achieved and report validity. Link the certificate review to the approved datasheet.
Include any required production report in the manufacturing record book. The final release note should identify both fugitive-emission evidence and conventional shell and seat pressure-test records.
Checklist
- external-leakage requirement
- ISO 15848 test part and edition
- tightness class
- temperature class
- endurance class
- test fluid
- qualified size and Class range
- packing and stem configuration
- production acceptance plan
- certificate-to-datasheet review