Application of electric heating technology in antifreeze of fire pipelines of underground parking

Published on:

2022-10-15 09:57

In cold areas, the underground space of some buildings is not fully heated, and internal fire hydrants, sprinklers and other water pipelines are laid in local areas such as very closed entrance groups, open areas with direct lighting, exhaust vents. The specification requires that the indoor temperature is not lower than 4 °C and not higher than 70 °C. A wet system should be used. In order to solve the antifreeze problem of pipelines, when the production insulation cannot meet the demand, it is necessary to design an auxiliary electric heating system; in some large areas of the external pipeline in deep permafrost, to reduce the depth of the pipeline or reduce the roof of the basement, it is necessary to perform auxiliary electric heating and antifreeze treatment of external pipelines. Electric heating is now widely used in the northern regions, and is generally applied in unheated rooms, and open (partial) supply of water and antifreeze for fire protection of pipelines.

Electric heating is an event to provide heat and antifreeze through electric heating belts, accompanying the laying of the pipeline. It is divided into variable power (self-regulation of temperature) and constant power. To calorific value per unit length \ nWhen the temperature changes, it can be folded crosswise and overlapping. It is divided into low temperature type (maximum maintaining temperature 65 °C), medium temperature type (maximum maintaining temperature 90 °C), and high temperature type (maximum operating temperature 125 °C) The product structure is shown in the figure.

Constant-power electric heating is divided into parallel band electric heating and series constant-power strip electric heater. Since the serial type cannot be cut and needs to be customized, it is rarely used. Parallel type does not allow cross-spacing and should be used with Parallel thermostat The figure shows the design of a constant power electric heating belt.

To better demonstrate the anti-freezing electric heating technology scheme in an engineering project, taking the pipe insulation and freezing protection scheme of the underground parking lot of a large commercial office building in Huaiyin District, Jinan, the advantages of electric heating in the insulation of fire extinguishing pipelines.

In this underground parking lot, the ground floor is connected to the exits of the buses and the subway of the western station of the Jinan high-speed railway. There are often many holes. Except for the pipeline after the pre-action sprinkler valve, other water supply. And fire-fighting pipelines must be thermally insulated and non-freezing. The minimum ambient temperature is-10 degrees Celsius, and the maximum ambient temperature is 40 degrees Celsius. The pipeline temperature should be maintained at 5 degrees Celsius, and the insulating material is rubber and plastic.

It uses variable-wattage electric heating, which can automatically control temperature and electric heating, and its electric heating system is shown in the figure.