ACR Journal

CMYK / .ai CMYK / .ai CMYK / .ai acrjournal.uk 23 LEAK DETECTION both onshore and o shore. This include power stations, hospitals, oil rigs, retail, supermarkets, food distribution centres, ice rinks, ships, breweries, meat processing plants, schools’ hotels, car parks and recycling facilities. Choosing a system Consider which gases must be measured and in what quantities, as well as the specific requirements on site. Also, what would be the most appropriate sensor technology to use i.e. infra-red, semi- conductor, pellistor or an aspirated system. How many sensors are required and where should they be positioned to ensure maximum coverage? When ammonia detection is required, for example, it is common practice to have a hard-wired fixed leak detection system installed. This would consist of a central main control panel which gives alarm levels in its display and locations of individual hard-wired sensors. thus, giving you continuous detection coverage. Also, via an output from the main control panel a building management system or fire alarm system can be connected to the leak detection system. This system would require simple calibration at least once a year. An aspirated / sampling system which has an infra-red sensor located in its control panel is another type of a leak detection system which is in the marketplace today, using infra-red technology this aspirated system can sample di erent detection points at timed intervals. Benefits of this system are its multi-port sampling capability, the opportunity to monitor several gases, programmable zone locations, it is an attractive solution where the infra- red sensor has long life expectancy. Again, this system requires simple calibration once a year. Residential, hotels and oƒce locations may also be required to have a fixed leak detection system. This would depend on the categorisation of a room where an air conditioning system has been installed and what access is permitted to that room, this is explained in more detail in BS EN378. In hotel rooms if leak detection is required, you would have an individual hardwired room sensor which will alert the occupant in the room, if there was a refrigerant leak detected, this would consist of an alarm buzzer being activated in the sensor. The sensor can also be connected to the fan coil in the room which will notify the air conditioning system that a leak has occurred. Alternatively, you can also have a standalone leak detection system, which will run independent to the hotels air conditioning system, this would consist of a hardwired room sensor which is connected to an area alarm panel which would cover each hotel floor (usually situated in dry riser). This in turn would be connected a main panel situated in the reception area. This panel would give reception information as to which room sensor is in alarm allowing the hotel sta to contact the occupant in the room and make sure that they are safe and well. This system would also require a function test each year to make sure that each sensor would be in working order. www.tqplc.com Gas monitoring solutions – manufactured in the UK