Aerogel coating is a composite material composed of aerogel powder and other binders, which has good high temperature resistance and heat insulation properties, mainly due to the nanopore structure of aerogel. Heat transfer is mainly carried out in three ways, namely, heat conduction, heat radiation and heat convection. The nanopore structure realizes the infinite length of the pore wall link, resulting in long enough heat conduction path and narrow enough conduction path, so that the heat conduction path is not passed, and air convection cannot effectively occur, so that aerogel can be applied in the field of thermal insulation.
According to the Technical Standard for Building Smoke Control and Exhaust System, the fire resistance requirements of smoke control and exhaust pipes are clearly specified. The fire resistance limits of smoke control and exhaust pipes set at different locations are also different, and the fire resistance limit requirements are generally 0.5 to 1.5 hours.

Aerogel coating belongs to class A non-combustible material, with good fire-retardant properties, it can be painted on the smoke exhaust duct to achieve the fire-resistant limit requirements, but in actual cases, few people use this program, which is mainly caused by the price of aerogel insulation coating is relatively expensive and the cost is high.
At present, in order to make the smoke exhaust duct (metal materials such as galvanized steel plate) meet the prescribed fire resistance limit requirements, the traditional mainstream practice is to use class A non-combustible materials such as glass wool, rock wool, fire board to cover the smoke exhaust duct. Glass wool and rock wool have good properties such as fire insulation, heat insulation, sound absorption, moisture resistance and water resistance. These fireproof wrapping materials are also very simple to use and can be cut at will, which can be easily solved for different pipe sizes and elbows. Fireproof coating is easy to construct and relatively inexpensive, because glass wool and rock wool are much cheaper than aerogel coatings.

There is also a way to achieve the specified fire resistance limit requirements of smoke exhaust duct is prefabricated fire resistance duct, which is different from galvanized steel duct, these prefabricated air duct has been made fire resistance treatment when leaving the factory to meet the fire resistance limit requirements. Prefabricated refractory ducts are generally made of A-class non-combustible materials for refractory treatment, and need to be customized, so the time is relatively long, but the construction is simple and the direct installation can be done.
The smoke exhaust duct can use aerogel coating to meet the fire resistance limit requirements, but the use cost is relatively high, and few people use it. The common methods are fireproof coating or prefabricated fire resistance duct to make the smoke exhaust duct reach the fire resistance limit requirements.