2. Low level alarm set at 10 ppm and high level alarm set not higher than 300 ppm are to be designed. The high level alarm is to activate an evacuation alarm. If the alarm at the main control point is unanswered within 2 minutes, the toxic gas (hydrogen sulphide) alarm and the helideck status light is to be automatically activated.

3. At least two portable hydrogen sulphide gas monitoring devices are to be provided on the unit.

310. Respiratory protection equipment for hydrogen sulphide