FUGITIVE EMISSIONS
At last, a global standard: ISO 12101 and the revolution in stem seal testing, Part 1
Fugitive emissions from valves, pumps and flanges account for over 1 million metric tons of losses annually. Tackling these invisible leaks could save the industry billions while preserving valuable resources. A major lever in reducing fugitive emissions lies in the sealing system, specifically stem seals.
By Colin Zegers, ITIS BV
F
ugitive emissions are unintended releases of gases or vapours from equipment due to leaks, evaporation, flaring or unplanned losses. Though often undetected during routine operations, they can accumulate to significant environmental and financial consequences. Volatile Organic Compounds( VOCs)— a major category of fugitive emissions— are particularly harmful. Many are toxic, carcinogenic or ozonedepleting, and contribute to smog and climate change. In densely populated or industrial areas, their odour alone can trigger complaints from nearby communities. Regulating VOCs is not just an environmental necessity, but an economic one. Each kilogramme of lost product represents inefficiency and cost. Still, the true price is often underestimated, hidden behind maintenance downtime, product loss, or regulatory fines. While the scale of fugitive emissions varies by chemical, plant design, and operational practices, one truth holds: prevention starts with design, detection and documentation. This is where ISO 12101 steps in.
When a seal fails, everything fails
Stem seals are often overlooked until they fail. Then, the consequences can be catastrophic. Two of the worst technological disasters in modern history— the Challenger shuttle explosion and the Deepwater Horizon oil spill— had one crucial commonality: both began with seal failure.
Not due to faulty materials, but due to human misjudgment in application and assessment. Despite their unassuming appearance, seals are precision components designed to perform under intense pressure, temperature and chemical stress. In critical systems, their performance envelope must not only be understood, it must be respected. In Challenger’ s case, an O-ring failed because of low temperatures outside its design range. The seal wasn’ t defective— the decision to launch in freezing conditions was. On Deepwater Horizon, a cement plug was signed off on prematurely. When it failed, full pressure surged up the drill pipe. A rubber annular preventer— the final line of defence— couldn’ t stop the leak, likely due to erosion and damage from earlier use. The lesson? Seals are frontline safety components. When underestimated, the cost is measured in lives, environmental disasters and billions in damages. Seals often operate at the edge of a system’ s limits— extreme temperatures, pressures and velocities. That makes rigorous testing, specification, and quality control not optional, but essential.
From field to standard: the road to ISO 12101
Over the past 20 years, I’ ve tested hundreds of valves, including stem seals under fugitive emission conditions. In earlier days, end users
About the author Colin Zegers is the founder and managing director of ITIS BV, an ISO 17025-accredited test laboratory and Conformity Assessment Body( CAB) based in the Netherlands. With 27 years of experience in leak testing, valve and product testing, and industrial inspections, he has built a reputation for combining technical depth with practical implementation.
Leaking stem seal during a fugitive emissions test.
30 Valve World August 2025 www. valve-world. net