1.0.1 In order to ensure the design service life of external corrosion protection of chemical equipment, piping and steel structures, this standard is developed for unifying and regulating the design criteria.
1.0.2 This code applies to the external corrosion protection of chemical equipment, piping and steel structures made of carbon steel, cast iron, low alloy steel and stainless steel.
1.0.3 The environmental conditions to which this code applies include the industrial atmosphere (collectively referred to as the atmosphere), liquid media, soil, etc.
1.0.4 The anti-corrosion methods used in this code include non-metallic coatings, fortified coatings and wrapping films, excluding metal spraying, metal plating and electrochemical protection.
1.0.5 The performance indicators of anti-corrosive materials shall meet the requirements of this code, and shall have a factory certification and inspection documentation. Materials shall be used within the validity period, and expired ones shall not be used.
1.0.6 The external corrosion protection design for chemical equipment, piping and steel structures shall not only meet the requirements of this code, but also comply with relevant current standards of the nation.
2 Terms
2.0.1 coat
a film layer with anti-corrosion, decoration or other special functions formed by coating liquid or solid materials on the surface of a workpiece by a certain process
2.0.2 fortified coat
a reinforced coating composed of a liquid material and a continuous reinforcing material of a certain strength
2.0.3 wrapping film
an anti-corrosion or insulated isolation layer formed on the surface of a workpiece with a solid material covered by sticking and / or winding process
2.0.4 paint film
a continuous film formed by one or more passes of coat on a base material
2.0.5 primer coat
a paint film directly applied to the surface of a base material
2.0.6 wet film thickness (WFT)
the film thickness as uncured or wet
2.0.7 dry film thickness (DFT)
the film thickness as dry or cured
2.0.8 total dry film thickness (TDFT)
the total film thickness of multiple coats as dry or cured
2.0.9 generic soil
soil that is free of or contains a small amount of sulfate or other sulfides, and is uniform in quality
2.0.10 thermal insulation
the coating applied on equipment and piping surfaces to prevent heat radiation, for the purpose of this code
3 Surface preparation
3.1 The method of surface preparation
3.1.1 Surface preparation shall be made before anti-corrosion of chemical equipment, piping and steel structures.
3.1.2 The main methods of surface preparation include blasting, manual with powered tool, chemical, flame, hydro-blasting, etc.
3.1.3 The advantages and disadvantages and applicability of various surface preparation methods may be determined according to the provisions given in Table 3.1.3.
HG/T 20679-2014 The following standards are cited：
