GT tripped on 2 fire detectors on accessory compartment, but no real fire detected. UV Detector sensor cards, and amplifier cards, PLC input cards checked, no issue. what are the other possibilities to cause this fire detectors to trigger?

 

Sundar2015,

Either there's a wiring error, or the sensors detected smoke, UV and/or temperature sufficient to warrant activation. Are you absolutely certain there are no leaks of lube oil or hydraulic oil or fuel oil in the compartment which may have been exposed to sufficient temperature to warrant vapourization/combustion for a brief period of time?

Also, are you certain of the calibration of the fire detection sensors and/or the PLC input modules? High temperatures can wreak havoc with electronics over time, as can oil vapours, and humidity combined with dust and dirt. Many compartment sensors are not rated for some of the ambient temperatures they are exposed to. Problems with fans and/or air circulation in the compartments can also lead to problems, as can poor housekeeping and maintenance practices. So, frequent "calibration" (which is really done to check to make sure the devices operate properly, because only occasionally do some devices require calibration adjustment (their as-found condition is fine)--but often failed devices are found which can lead to nuisance trips and even lack of detection of critical parameters.

 

Many things can trip UV detectors, sunlight, welding nearby, halogen lamps/torches.

 

Dear CSA,

thanks for your reply.

but no sign of flame or spark, UV detector are working fine, still cause not found. we are doing RCA, any lightening or Xray around the area.

 

Dear,

Thanks for your sincere reply.

we are checking any possibility of X rays near the area.
Did you experience Lightening? could cause this.

 

keep the enclosure lights off during normal operation unless you enter the enclosure for your needs e.g checking; befor entering of coursce you have to switch on the lights of the required compartment, however you have to lock off the fire protection for the area before switching on.

hope it resolve the problem else you have to:

1- replace the lamps with the type that does not trigger the fire detection.

2- the lamps & detector sensing angle might also work.

Khan

 

The UV detectors work fine inside a temperature range and they trip outside this temperature range. Sometimes there is a combustion gas leak that increase the temperature in the compartment and this temperature makes the UV detectors trip. Please check the temperature specs for the UV detectors and measure the temperature into the compartment. Also check if there is a combustion gas leak at the flanges who connect the combustion chambers and probably this is the cause of the UV detectors trip

Regards,
Voyager2-kbc