The hand wheel or spanner of single leaf or multi leaf manual regulating damper shall be closed by clockwise rotation, and the indication of adjustment range and opening angle shall be consistent with the opening angle of blade. Automobile factory household appliances, pneumatic valve transmission device, reliable action, can work normally under working pressure. The fire valve and smoke exhaust valve (smoke outlet) must comply with the relevant provisions of the fire product standard, and the excavator muffler should have the corresponding product qualification certificate. Inspect and check product qualification certificate and performance test report. The moving parts, fixing parts and fasteners of air valves for air conditioning system purification shall be galvanized or other anti-corrosion treatment (such as spraying plastic or baking paint); the gap between the valve body and the outside shall be provided with reliable sealing measures. For the regulating damper with working pressure over 1000Pa, the manufacturer shall provide the certificate of passing strength test (or test report) with working pressure of 1.5 times. The material of flexible short pipe in anti exhaust system must be non combustible material. When the plane edge of muffler grows to 800mm, sound absorption guide vane shall be installed; protective measures shall be taken for the cloth covering layer on the direct windward side of muffler; materials that are not easy to generate dust shall be used for cloth coating in muffler of purification air conditioning system. When the muffler is installed in the air duct passing through the fire-proof wall or floor that needs to be closed, the embedded protective sleeve or protective sleeve shall be adopted, and the thickness of steel plate shall not be less than 1.6 mm. The air duct and the protective sleeve are sealed with non combustible and harmless flexible materials. The installation of air duct shall meet the following requirements: there shall be no other pipeline passing through the air duct; when the air duct system is installed in the inflammable and explosive environment or in the flammable and explosive environment, it shall be kept tight when passing through the living area or other auxiliary production rooms, and there shall be no interface; the fixed cable of outdoor riser shall not be pulled into the lightning rod or lightning net. The air duct with transportation temperature above 80 ℃ shall be protected according to the design requirements.