[ leak detection ] tapes wrapped around joints and fittings change color when in contact with diatomic gaseous hydrogen . This can be especially useful during commissioning or in areas that may experience high levels of vibration increasing the possibility for a leak . Special care should be taken as some detection tapes may show a false positive if they come in contact with hydrogen sulfide .
In the case of a hydrogen fire , a flame camera or sensor with an audiovisual alarm can notify personnel of a problem area and trigger emergency shutdown and / or evacuation procedures . Hydrogen flames are often invisible or difficult to see with the human eye , especially in daylight or artificial light . Flame cameras designed for hydrogen flame detection monitor radiation emitted by the flame in the ultraviolet ( UV ) and infrared ( IR ) spectral bands . These cameras are appropriate for indoor or outdoor use and multiple cameras can be strategically
installed to ensure full visual coverage over the area in which hydrogen is being stored and transported . These cameras usually have a wide field of view (~ 130 °) and a range of less than 20 m ( 65 ft ).
Odorization potential
Because hydrogen is an odorless gas , adding an odorant into a gas stream will make the gas smell and can allow for humans to detect the presence of the gas even at concentrations well below flammability levels in order to ensure their own safety and potentially help identify possible leaks . Odorants allow for the detection of leaks in positions where it may be difficult to place detectors . Commonly used with hydrocarbons for the past century , odorizers allow for an early warning system before flammable levels are reached . 9 Gas odorization is , in most countries , a legal or regulatory requirement that specifies that natural gas in air must be readily detectable by odor at a concentration of 20 – 25 % of
Fig . 2 : Common leak detectors used in hydrogen systems . Catalytic bead point sensor ( top left ) 3 , ultrasonic area leak detector ( top middle ) 4 , handheld electrochemical sensor with pump ( top right ) 5 , handheld ultrasonic leak detector ( bottom left ) 6 , handheld thermal imaging leak detector ( bottom middle ) 7 , UV / IR flame camera ( bottom right ) 8 .
Hydrogen Tech World | Issue 9 | April 2023 39