FUGITIVE EMISSIONS
Stem seal failure after a few operational cycles at room temperature. Stem seal leakage after high-temperature testing.
It establishes a method for classifying and qualifying valve stem seals, enabling manufacturers to select proven sealing systems that meet the requirements of ISO 15848-1. The standard applies to linear and quarterturn valves, and covers:
• Compressible packing( with or without live loading)
• Pressure- and spring-energised seals
• Elastomeric systems
By testing stem seals under pressure, with temperature cycling and tracer gases( such as methane or helium), ISO 12101 assigns leak-tightness and endurance classifications, providing engineers with the data they need to make informed, emission-conscious design decisions. It’ s not a replacement for full valve testing— that’ s still the realm of ISO 15848-1— but it is a critical new tool in the fight against fugitive emissions.
Conclusion
ISO 12101 was released in June 2025 and marks a major leap forward in sealing technology. Its goal is simple but ambitious: to reduce unnecessary emissions from stem seals in industrial valves. By offering clear guidelines and performance benchmarks, the standard empowers valve manufacturers, end users, valve overhaul companies and regulators alike. It brings transparency, comparability, and— above all— trust.
Coming next in Part 2:
How the standard works in detail— how to test, how to certify, and what information is essential for seal suppliers, valve makers and service providers.
References:
FUGITIVE EMISSIONS The term“ fugitive emissions” covers all losses of( usually volatile) materials from a process plant, through evaporation, flaring, spills and unanticipated or spurious leaks. To put the scale of the challenge into perspective, fugitive emissions in the USA have been estimated to be in excess of 300,000 tonnes per year, accounting for about one third of the total organic emissions from chemical plants, and these will inevitably be mirrored in Europe. A typical Oil Refinery will have a minimum of 20,000 flanged joints connected with pumps, compressors, mixers, valves, level gauges, instruments, heat exchangers and vessels, all of which are a potential leak source. Although losses per piece of equipment are usually very small the total loss via fugitive routes may be very significant. For example, fugitive emissions from European refineries range from 600 to 10000 tonnes of VOC’ s per year. In some plants in the Netherlands, 72 % of VOC emissions were attributed to leakage losses from equipment, 18 % from flaring, 5 % from combustion, 1 % from storage and 4 % from other process emissions. In these plants, leakage is the greatest challenge and therefore it is crucial that programmes are established to identify leak sources and to instigate actions to minimise them.
Testing a stem seal with‘ live loading’, using methane as the test medium and an FID leak detector.
Sources of fugitive emissions A significant proportion of fugitive emissions are losses from unsealed sources, including storage tanks, openended( non-blanked) lines, pressure-relief valves, vents, flares, blowdown systems, spills, and evaporation from water treatment facilities. These are part of the industrial process, anticipated( usually) by the process operator, and will not be considered further here. In other cases, these losses may be caused by leaks in the sealing elements of particular items of equipment, such as valves 50 %-70 %, pumps 10 %, flanges 5 %, compressors 3 % and agitators / mixers 2 %. Source: www. esaknowledgebase. com
32 Valve World August 2025 www. valve-world. net