Development of odour irritant combustible gas detectors and discussion on measurement methods

Traditional combustible gas detectors primarily rely on audible and visual stimuli for alerts, yet their effectiveness is limited for individuals with hearing impairments. To address this shortcoming, this paper presents a novel alarm system integrating odour-based stimulation with conventional auditory and visual cues, thereby establishing a multimodal alert mechanism. This approach enhances detection efficacy and better accommodates the needs of hearing-impaired users. Experimental results indicate that in a 30 dB background noise environment, the alarm achieves over 85% effectiveness for hearing-impaired individuals. Even at 50 dB background noise, effectiveness remains at 80%, with an average wake-up time reduced by approximately 30-40 seconds compared to traditional audible-visual alarm. Furthermore, this research established a set of measurement calibration methods covering key parameters of multimodal alarm involving sound, light, and odour. These include sound source sound pressure level, sound field uniformity, light intensity, light intensity uniformity, gas concentration indication error, and gas diffusion uniformity. The scientific validity of these measurement methods was verified through experiments.