Development of Gas alarmTokyo Gas has been developing an alarm and improving its reliability to keep customers’ safe in the event of a gas leak, incomplete combustion by gas appliances or fire.
[Approach 1]: Development of a residential alarm
Together with the increased popularity of residential fire alarms has come a decrease in the number of fatalities from residential fires. Nevertheless, of these remaining fatalities, more than 60% of the deaths are still attributed to delays in escape. The most frequent cause of death is considered to be that of the delay in detecting the fire. By the time these victims had noticed the occurrence of fire, their escape routes had already been filled with smoke. Additionally, approximately 60% of the victims were elderly, over 65 years of ages.
Accordingly, in considering the possibility of fire, the most important factors are determined to be early detection and immediate escape. In response, Tokyo Gas is currently developing residential alarm for fire,citygas and CO, which detect smoke and heat, and immediately alert residents with warning sounds and voices. Tokyo Gas is also developing a sensor system that detects carbon monoxide due to a gas leakage and incomplete combustion.
〔Combined alarm for fire and gas leaks〕
Battery-powered gas leak alarms
In order to detect methane, which is the primary component of city gas, gas sensors need to reach a temperature of around 400℃, which requires a conventional gas leak alarm to have an AC100V power source. Due to a variety of reasons, including the hassle and unsightliness of power cords and the lack of power outlets near where the alarms would be installed, gas leak alarms are sometimes not installed at all.
To address this problem, Tokyo Gas began researching and developing power-saving gas leak sensors, and thanks to the adoption of MEMS technology* which has enabled sensors to be miniaturized, the world's first residential, battery-powered gas leak alarms capable of running on a charge thousands of times smaller than a conventional device has been developed. These alarms require no power cord, making them easy to install and visually unobtrusive.
*: Micro-electromechanical systems and the related manufacturing technology, (used, for example, in semiconductor manufacturing).
〔MEMS gas leak sensor〕 〔Battery-powered gas leak alarm〕
[Approach 2]: Development of a commercial alarm
Since November 2006, Tokyo Gas has installed commercial ventilation alarms free of charge in approximately 150,000 restaurants and other venues that use commercial kitchen appliances for the prevention of accidental CO poisoning.
The commercial ventilation alarms employ newly developed electrochemical sensors, highly accurate in the detection of CO, from low to high concentrations. Furthermore, the sensor issues an alarm in response to fluctuations in CO concentration by sequentially calculating the estimated concentration of carbon monoxide hemoglobin (COHb) in the human body that shows the degree of influence of CO on the human body.
With this system, disregard to fluctuations in CO concentration, the sensor issues a timely alarm to prevent any negative effects from CO on the human body, thus avoiding the issuance of false alarms due to minor transient CO concentrations resulting from the starting of commercial kitchen appliances, and reducing the amount of interference to restaurant businesses etc. Additionally, the system issues a more timely alarm than conventional alarms in response to high CO concentrations.
〔Commercial ventilation alarm〕