15.1.1 Each unit should carry an appropriate portable
atmosphere testing instrument or instrumentsfootnote. As a minimum, these should be capable of
measuring concentrations of oxygen, flammable gases or vapours, hydrogen sulphide and
carbon monoxide prior to entry into enclosed spacesfootnote. Instruments carried under other requirements
may satisfy this regulation. Suitable means should be provided for the calibration of
all such instruments.
15.1.2 Such instruments should be in addition to those
provided with the unit's firemen's outfits.