ISO 15848 Part 1 & 2

Measurement, test and qualification procedures for fugitive emissions

ISO 15848 Part 1 & 2 Standard

ISO 15848 standard was first published in 2006 after more than 10-years of work the third edition was released in 2017.

This standard specifies test procedures to measure and specify the external leakage from stem packing for on-off valves, control valves and for body gasket joints intended for use in contact with volatile atmospheric pollutants and dangerous fluids.

ISO 15848 standard is comprised of the following parts:

ISO 15848-1 (Part 1): Classification system and qualification procedures for type testing of valves.
ISO 15848-2 (Part 2): Production acceptance test of valves.

ISO 15848-1 (Part 1)

ISO 15848-1
is an international standard for fugitive emissions issued by the ISO Organization. It contains both dynamic life cycles and thermal cycles and is considered one of the most demanding fugitive emission standards for soft seated valves.

This standard contains different levels of acceptance based on the number of thermal and mechanical cycles, temperature, and number of adjustments. The objective of ISO 15848-1 is to enable classification of performance in different designs and constructions of valves to reduce fugitive emissions.

ISO 15848-1 (Part 1)

Sealing class

This section of the standard specifies method of leakage measurement on packing. It must be measured either by the ‘global method’ (vacuum or bagging) or by gas sweeping (flushing).
Measurement using a helium mass spectrometer is precise, reliable, and independent of operator and environment.
This method allows measurement of the total gas escaping the valve stem packing.

The Sniffing method is used to measure emissions on the body-joint.

The standard defines 3 classes of sealing based on stem seals types (i.e. bellows, PTFE, or graphite).

In the standard, the class of sealing is expressed in mg/s per meter of circumference (of the stem).

Endurance Class

The standard defines endurance classes by the number of mechanical and thermal cycles of operation.
On-off valves differ from control valves.

Temperature Class

The standard proposes reference temperatures for testing the valves.
For a valve to be qualified, for example, within the range of -46°C with and 200°C, the valve must be tested separately for each level of temperature.

Adjustment Class

The standard allows different levels of packing adjustment.
The number of adjustments are manually performed on the valve during temperature swings.
SSA0 = No Adjustment,
SSA3 = 3 adjustments during the thermal & mechanical cycles

ISO 15848-2 (Part 2)

ISO 15848-2 (Production acceptance test) is applicable to valve designs that have been successfully type-tested and certified according to ISO 15848-1.

The objective of ISO 15848-2 is to check that a valve was well assembled where a specimen was qualified according to part 1

Overall the test conditions defined by part 2 are less severe than in part 1, in particular:

Pressure test of 6 bar
Test at room temperature
Fewer cycles of operation (only 5 in total)

ISO 15848-2 test is done under sniffing method.