ISO 19891-1:2017 provides specifications on performance, gases to be measured, sensitivities, indications, alarm levels, protection against shock, temperature and water ingress, and testing requirements of portable gas detectors used for atmosphere testing of enclosed spaces onboard ships prior to entry into those spaces.

ISO 19891-1:2017 specifies suitable portable gas detectors for compliance with SOLAS regulation XI-1/7 "Atmosphere testing instrument for enclosed spaces", and may be used for deciding whether portable gas detectors available on the market are suitable for compliance with these SOLAS requirements.

NOTE 1 SOLAS regulation XI-1/7 requires appropriate portable atmosphere testing instrument or instruments to be carried onboard ships, by 1 July 2016. The SOLAS regulation requires, as a minimum, the appropriate portable atmosphere testing instrument or instruments to be capable of measuring concentrations of oxygen, flammable gases or vapours, hydrogen sulphide and carbon monoxide prior to entry into enclosed spaces.

For the purpose of measurement of concentrations of flammable gases or vapours, this document specifies the flammable gas as either "methane" or "propane and butane", and requires clear marking of types of flammable gases which can be measured by the portable gas detectors. Flammable vapours/gases which are not marked cannot be measured or detected by the portable gas detector.

NOTE 2 Iso-butane is an alternative calibration gas of portable gas detectors in measuring propane and butane.

ISO 19891-1:2017 does not give any indication of toxicity of the flammable gases.