7 Gas Detection

  7.1 Suitable means for detecting the leakage of gas should be provided in any compartment containing a gas-consuming appliance, or in any adjoining space of a compartment into which the gas (more dense than air) may seep.

  7.2 Gas detectors heads should be securely fixed in the lower part of the compartment in the vicinity of the gas-consuming appliance and in other space(s) into which gas may seep. In areas where the detector head is susceptible to damage in the lowest part of the compartment (e.g. engine space bilge) the detector head should at least be fitted below the lowest point of ignition.

  7.3 Any gas detector should preferably, be of a type which will be actuated promptly and automatically by the presence of a gas concentration in air of not greater than 0.5% (representing approximately 25% of the lower explosive limit). The detection system should incorporate a visible alarm and an audible alarm which can be heard in the space concerned and the control position with the vessel in operation.

  7.4 Where electrical detection equipment is fitted, it should be certified as being flame-proof or intrinsically safe for the gas being used.

  7.5 In all cases, the arrangements should be such that the detection system can be tested frequently whilst the vessel is in service, which should include a test of the detector head operation as well as the alarm circuit, in accordance with the manufacturer's instructions.

  7.6 All detection equipment should be maintained in accordance with the manufacturer's requirements.