I want to ask about which sensor is better for Fire detection alarm, and is the humidity parameter necessary for Fire detection system?
Those are temperature sensors. To detect a fire you are better to use a smoke detecting sensor.
Google fire sensor, or smoke detector.
I'm sorry i didn't give the full context
my system is a fire detection alarm using KY-026 flame sensor, MQ5 smoke sensor and DHT22 Temperature sensor, it's just I want to know is humidity a necessary parameter to include in my system, or should I use LM35 instead of DHT22 in my system.
Personally I can't see why, if you are measuring everything else why humidity is required. When things are burning they may or may not create humidity... I'm not sure how you would use the extra information.
Hi,
Sprinkler systems us heat detection.
Fire detection systems to protect humans us a smoke detector because smoke will kill before flames ever reach the subject.
What sort of environment do you want to protect?
Thanks.. Tom... 
I planned to use my system in a warehouse, but I'm not implementing this system for real-world use its just for a final project.
(My final project is fire detection system but my main case study is about comparing ESP-NOW and UDP protocol QoS, so the fire detection system is just an application of my case study)
So I haven't really thought about using LM35 in my project.
that's what I was wondering, I was asked about this by my lecturer, I don't know if humidity is really a necessary parameter. But I was wondering if high humidity could mess the MQ sensor readings, so the humidity parameter could help with that.