Abstract
In order to make clear the causes of false alarms in cases in which the fire detectors were installed inside and/or outside the cultural heritage old buildings, we collected the data of temperature, humidity, atmospheric pressure, wind velocity, temperature measured by the heat detectors, smoke density measured by the smoke detectors and intensity measured by the flame detectors for one year. The sensors and the detectors were installed in four old wooden houses and one old shrine.
The following factors were found to be the causes of false alarms.
Weather conditions ------ passage of an atmospheric depression, strong wind, the sunlight in the early morning, flashes of lightning and flickering of sunlight streaming through the leaves of trees
Artificial conditions ------ the smoking to prevent decay and expel insects, rays from haloid lamps and sparks of welding.
