There is a red flashlight on the roof of the hotel. What is this?

Smoke detector (English: Smoke detector).

This is a device that senses smoke and triggers an alarm. It can be used to prevent fires or detect smoke in non-smoking areas to prevent people nearby from smoking. Smoke detectors are usually installed in plastic housings, which detect smoke by photoelectric or ionization.

Smoke detectors are usually installed in a plastic casing, usually shaped like a disk, with a diameter of about 150 mm (6 inches) and a thickness of 25 mm (1 inch), but with different shapes and sizes.

Smoke can be detected by optical (photoelectric) or physical process (ionization). The detector can use one or two sensing methods. Sensitive alarms can be used to detect and prevent smoking in prohibited areas.

Smoke detectors in large commercial and industrial buildings are usually connected to the central fire alarm system. Household smoke detectors range from a single battery-powered unit to multiple interconnected units with spare batteries. With the interconnection unit, if any one of them detects smoke, all alarms will be triggered. This will happen even if the power is cut off at home.

In a house equipped with smoke detectors, the death risk of residential fire is reduced by half. The National Fire Protection Association reported that 0.53 people died in every 65,438+000 fires in households with smoke detectors, while 65,438+0.18 people died in households without smoke detectors (2009-2065,438+03). Some families don't have any smoke alarms, and some families don't have any working batteries in their smoke alarms.

reliability

A NIST report NIST 2004 concluded that "ionization or photoelectric smoke alarms always provide residents with time to escape from most residential fires" and "consistent with previous research results, ionization alarms respond better to burning fires"?

Regular cleaning can prevent false alarms caused by dust and insect accumulation, especially optical alarms, because they are more susceptible to these factors. Vacuum cleaner can be used to clean household smoke detectors and remove harmful dust. Optical detectors are not easy to be affected by false alarms in kitchen and other places where oil smoke is produced.