9.12.1 A fixed automatic gas detection and alarm system
should be provided to the satisfaction of the Administration so arranged as to monitor
continuously all enclosed areas of the unit in which an accumulation of flammable gas
may be expected to occur and capable of indicating at the main control point by aural
and visual means the presence and location of an accumulation.
9.12.2 At least two portable gas monitoring devices should
be provided, each capable of accurately measuring a concentration of flammable gas.