Ventilation ducts are ancillary to buildings, and few have studied it. With the increase in duct function, ventilation pipes have not only ventilation requirements, but also with fire, energy saving, environmental protection, easy to clean and other functions. Ventilation ducts in China began in the 40s of last century. In the textile industry, in order to improve the quality of spinning and weaving, to make the workshop to maintain the set temperature and humidity, the specific temperature and humidity of the air pipe was called duct. The first time with the production of wood duct, then switch to metal.
80s of last century, there have been glass fiber reinforced polyester duct (commonly known as FRP duct). Glass fiber polyester air duct for organic materials, water vapor corrosion resistance does not rust, to solve the galvanized iron pipe rust, the shortcomings of life is not long, widely used in textile factories.
However, due to the glass fiber polyester air duct is organic combustible material, once the short-circuit fire or accidental fire, the polyester duct will be ignited, will soon spread to the various workshops, causing a fire. In this way, the combustible polyester air tube caused the fire department's attention. G B 50045-1989 "high-rise building fire design code" stipulates: "ventilation ducts to use non-combustion materials." Since then, ventilation pipes in addition to strength requirements, an increase of fire safety requirements.
With the construction of energy-saving needs, GB 50189-2005 "public building energy efficiency design standards" began to implement, of which the ventilation pipe energy-saving design requirements: the general ventilation pipe thermal resistance ≥ 0.74m2? K / w, low temperature duct Thermal resistance ≥ 1.08m2? K / w, an increase of energy-saving requirements of the wind pipe.
In addition to building energy-saving requirements put forward, the building's air quality began to be more people's attention. Especially after the ***, the ventilation ducts are considered to breed bacteria, the path of disease transmission. G B 19210-2003 "Air conditioning and ventilation system cleaning norms" has been on the public places of the ventilation pipe has made provisions to increase the cleaning, clean, anti-bacterial breeding of health requirements.
Galvanized iron duct defects As we all know, galvanized iron pipe there is easy to rust, life is not long, ventilation noise, air leakage large, due to external thermal damage easy to produce thermal bridge (cold bridge) and other major shortcomings.