Briefly introduce: What is the acceptance standard for installation and construction of stainless steel welded ventilation pipes?

The acceptance criteria for installation and construction of stainless steel welded ventilation pipes mainly include the following aspects:

Material and specification of air duct: stainless steel shall meet the design requirements and have corresponding quality certification documents. The thickness, size and other specifications of the air duct should meet the design and relevant specifications to ensure the strength and stability of the air duct.

Duct connection: Duct connection usually includes flange connection and welding connection. Flange connection, the flange should be flat, bolt hole spacing should be uniform, nuts should be on the same side, flange gasket thickness should not be less than 3mm, and should not protrude into the duct or protrude outside the flange. When welding connection, the weld seam should be full and uniform, without cracks, pores, slag inclusion and other defects, and the welding quality should meet the relevant welding standards.

Duct installation: Duct installation should be firm, and the spacing between supports and hangers should meet the specification requirements. Generally speaking, the distance between supports and hangers for air ducts less than or equal to 400mm is not more than 4 m; For ducts greater than 400mm, the spacing between supports and hangers should not be greater than 3 m; The distance between supports and hangers of thin steel flange air ducts should not be greater than 3m. When the air duct passes through a fire-proof and explosion-proof wall or floor, it should be embedded with a pipe or protective sleeve, and the thickness of its steel plate should not be less than 1.6 mm. The flexible material which is incombustible and harmless to human body should be used to block between the air duct and the protective sleeve.

Duct system tightness: After the ventilation duct system is installed, a tightness test should be conducted to check the air leakage of the duct system. The test pressure should meet the design requirements. When there is no design requirement, the leak test pressure of low-pressure system air duct should be 500Pa, that of medium-pressure system air duct should be 1000Pa, and that of high-pressure system air duct should be 1500Pa.

Installation of air duct components: tuyere, air valve and other components should be installed firmly, correctly and flexibly. The connection between tuyere and air duct should be tight and firm, the surface of tuyere should be smooth, the distribution of blades or diffusion rings should be uniform, the color should be consistent, and there should be no obvious scratches and indentations. The installation positions of fire valves, smoke exhaust valves and other valves should meet the design requirements and be easy to operate and maintain.

Anti-corrosion and heat insulation: the anti-corrosion treatment of air duct should meet the design requirements, and the surface should be free of corrosion and peeling. The material, density, specification and thickness of thermal insulation materials shall meet the design requirements, and shall be incombustible or nonflammable. Non-combustible materials must be used in the air ducts and insulation layers of 800mm before and after the electric heater, and in the air ducts, pipes and insulation layers of 2m across the fire partition wall.