Abstract
Hydrogen is considered a promising energy carrier to achieve the ambitious target of a zero-emission society
in the forthcoming years. Despite its environmental advantages, hydrogen-induced material damages represent
a serious safety concern. Hence, inspection and maintenance activities must be performed to guarantee the
equipment's integrity. The risk-based inspection (RBI) is the most beneficial methodology for inspection planning
but has never been adopted for components operating in hydrogen environments. The probability of failure of
each piece of equipment is quantified through the definition of the damage factor, a parameter that accounts for
the damage mechanism likely to occur. Hydrogen embrittlement (HE) is the main active degrading mechanism
in equipment exposed to hydrogenated environments; if not appropriately accounted for, it can cause failures at
unexpectedly low stress levels. This study aims to bridge a gap in knowledge by proposing a qualitative
methodology to assess the degradation of equipment operating in hydrogenated environments and potentially
subjected to HE. The environmental severity is estimated based on the operating conditions, while the material’s
susceptibility depends on microstructure, strength, and adoption of post-weld heat treatments. This study could
set the basis for the application of the RBI methodology to industrial equipment for producing, handling, and
storing hydrogen. Hence, it will facilitate the inspection and maintenance of emerging hydrogen technologies
in the forthcoming years. Despite its environmental advantages, hydrogen-induced material damages represent
a serious safety concern. Hence, inspection and maintenance activities must be performed to guarantee the
equipment's integrity. The risk-based inspection (RBI) is the most beneficial methodology for inspection planning
but has never been adopted for components operating in hydrogen environments. The probability of failure of
each piece of equipment is quantified through the definition of the damage factor, a parameter that accounts for
the damage mechanism likely to occur. Hydrogen embrittlement (HE) is the main active degrading mechanism
in equipment exposed to hydrogenated environments; if not appropriately accounted for, it can cause failures at
unexpectedly low stress levels. This study aims to bridge a gap in knowledge by proposing a qualitative
methodology to assess the degradation of equipment operating in hydrogenated environments and potentially
subjected to HE. The environmental severity is estimated based on the operating conditions, while the material’s
susceptibility depends on microstructure, strength, and adoption of post-weld heat treatments. This study could
set the basis for the application of the RBI methodology to industrial equipment for producing, handling, and
storing hydrogen. Hence, it will facilitate the inspection and maintenance of emerging hydrogen technologies