This can be done but with a lot of changes, Arduino uno by it self wont wont, for this project to work we need to connect the arduino to a network so by using either Ethernet or by using a wifi based micro controller such as the esp 8266 to the temperature sensor, and as you are trying to find if there is a fire or not a temp sensor wont work either, suppose a fire breaks out it will not always heat up exactly where the temp sensor is located. you will have to use some kind of smoke detector instead of a temperature sensor or use a temp sensor and a smoke sensor along with it. Triangulation using wifi router is a polluted process and inorder to triangulate a person in room can be done but when there are multiple people in the vicinity the reliability will decrease. Message me and we could discuss further