ISO/PAS 19891:2016 provides specifications in 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 on board ships prior to entry into those spaces.

ISO/PAS 19891:2016 specifies suitable portable gas detectors for compliance with SOLAS regulation XI-1/7 "Atmosphere testing instrument for enclosed spaces", and can 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 on board ships by 1 July 2016. The SOLAS regulation states that, as a minimum, the appropriate portable atmosphere testing instrument or instruments 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 part of ISO/PAS 19891 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. For an optimal use of ISO/PAS 19891, it should be noted that flammable vapours/gases which are not marked, cannot be measured, or detected by the portable gas detector.

NOTE 2 Iso-butane can be used as calibration gas of portable gas detectors measuring propane and butane.

ISO/PAS 19891:2016 does not give any indication of the toxicity of the flammable gases.