Europe aims to be climate‑neutral by 2050. Achieving the climate targets set out in the European Green Deal will require a profound transformation of the current energy system. As the electricity grid alone cannot meet future energy demands, hydrogen is expected to play a pivotal role in the transition to a sustainable and resilient energy landscape. Heavy‑duty (HD) transport represents a pillar of this emerging hydrogen economy, supporting the shift toward zero‑emission mobility by 2050. Hydrogen fuel is particularly suited to HD applications because it enables long driving ranges and rapid refuelling, making it ideal for heavy‑duty trucks and public transit buses, which routinely travel hundreds of kilometres per day. It is estimated that at least 60 000 hydrogen‑powered trucks will be in operation in Europe by 2030. While substantial knowledge has already been gathered regarding the durability of light‑duty (LD) fuel cell electric vehicles, HD applications present additional challenges: heavy‑duty vehicles must operate over longer lifetimes, demonstrate enhanced durability, and maintain reliable performance under more demanding conditions. Hydrogen purity is critical for fuel cell longevity and efficiency. Even trace‑level contaminants—such as carbon monoxide or hydrogen sulphide—can severely degrade the catalyst layers on either side of the membrane, which are among the most expensive components of a fuel cell. Some impurities, such as ammonia, can also damage the polymer electrolyte membrane itself. Ensuring that hydrogen dispensed at refuelling stations meets the required purity levels is therefore essential for both safety and performance. The dispensed hydrogen must comply with the specifications defined in ISO 14687:2025 and EN 17124:2022 . Reliable and traceable purity measurements can be obtained only when the collected sample is representative of the hydrogen delivered at the HRS nozzle. Existing sampling methods described in ISO 19880‑9:2024 were developed for light‑duty hydrogen refuelling stations (HRSs) and must be adapted and validated for heavy‑duty stations. Therefore, MetHyTrucks project studied if the hydrogen refuelling stations parameters could affect the hydrogen fuel composition. Based on the two different sampling systems, the project identified several key recommendations for serial or direct sampling and key recommendations for parallel sampling. The results of the project work were submitted to a peer review journal, and a summary of the recommendations or good practice are presented here.