Where is the detector head located?

• A. Engine Room
• B. Control Room
• C. CHT Pump Room
• D. Hull No

Answer: (C)

Gas detectors are placed where hazardous gases are likely to originate or accumulate, so the sensing element should be in the space most connected to the gas source. In a ship, hydrogen sulfide can form in the CHT (central hull/holding tank) system and pockets of it can build up in the CHT pump room where the pumps and piping for sewage handling are located. Putting the detector head there ensures early detection and quick ventilation action before the gas reaches other areas or personnel, which is why this location is chosen. The engine room is a different hazard zone with its own typical gases, control rooms are occupied spaces not specifically tied to this gas source, and a hull number isn’t a space for equipment placement. So, the detector head is located in the CHT pump room.