The characteristics of cold storage fire
1. Traditional detectors cannot be used
Traditional fire detectors are not suitable for installation inside the cold storage, because the internal temperature of the cold storage is too low, it will cause the detector to frost or malfunction.
2. There are many fire hazards
Air conditioning and refrigeration equipment, cargo transport equipment, lighting equipment and other electrical or mechanical failures, polystyrene foam insulation materials, plastic packaging materials, and wooden pallets are flooded inside the cold storage. The temperature in the cold storage is very low, which will cause the plastic sheath of the cable to become brittle and easily damaged for a long time, which will further cause the line to short-circuit and burn, and the air in the cold storage is abnormally dry, and it burns very quickly after a fire.
3. Difficult to extinguish fire
The internal space of the cold storage is closed and the smoke does not disperse for a long time. The fire spreads and burns along the thermal insulation material. The internal space is large and there are many shelves. It is difficult for the water gun to cool and extinguish the fire.
The solution of cold storage fire
High-sensitivity air-sampling smoke detectors. In cold storage applications, the detection host can be installed outside the cold storage, and the air sampling pipeline can be extended to the inside of the cold storage, so that the high-efficiency exhaust pump inside the detection host can take air sampling The pipeline draws the air sample in the cold storage back to the detection host for smoke detection, solving the problem that the detector cannot be used when the internal temperature of the cold storage is too low. In addition, because AVA air sampling smoke detectors have very high sensitivity (more than 1000 times that of traditional smoke detectors), they can generate early warning signals in the early stages of a fire.
1、Under the ceiling
The spacing of the sampling holes is recommended to be within 6m, which is equivalent to the protection area of the sampling holes within 36m2
In the cold storage with shelves, and the ceiling height is more than 12m, sampling pipelines should be set at different heights. For example, when the ceiling height is 14m, the sampling pipeline should be set along the shelf at a height of about 7m.
Return air sampling can have a very good early smoke detection effect, especially in a low temperature environment such as a cold storage, where high-temperature smoke particles lose their upward thermal buoyancy after being cooled by the ambient temperature, and are easily brought to the return air outlet by the airflow generated by the air conditioner.
2. Installation precautions
Using ABS pipe, UPVC is easy to become brittle at low temperature
The sampling pipe should be as far away as possible from the wall or ceiling by more than 300mm to avoid frost in the pipeline.
The side hole is open, the condensate is easy to be generated on the lower edge of the pipeline, and the side hole can avoid the situation of blocking the sampling hole after the condensate freezes.
The detection host is installed outside the cold storage, and the exhaust must be connected back to the inside of the cold storage
The pipeline must be immediately connected to the heater at the position where it exits from the cold storage to heat the air inside the pipeline, so that the pipeline outside the cold storage will not be affected by the cold air inside the cold storage and freeze. Frozen pipelines may produce a large amount of surface condensation due to high external temperature, and then generate a freeze-thaw cycle (Freeze-Thaw Cycle), leading to possible health and safety risks.
The sampling pipe entering the heater should be kept horizontal or inclined to the heater to avoid the condensate flowing into the sampling pipe and causing freezing and blocking the sampling pipe.
When the heater or detection host is installed outdoors, it must be protected by a corresponding waterproof box.
When installing the sampling pipeline, it is necessary to consider the possible thermal expansion and contraction. In extreme cases, the temperature of the cold storage may be as low as -35C during operation, and the temperature during installation of the sampling pipeline may be normal room temperature.