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Specifications for the Construction and Acceptance of Degreasing Projects – Document No. (82) Hua Ji Zi No. 901 issued by the Ministry of Chemical Industry, announcing the issuance of the \"Specifications for the Construction and Acceptance of Degreasing Projects\". The specifications for the construction and acceptance of degreasing projects, revised by the Construction Company of Lanzhou Chemical Industry Company, have been finalized and are now approved; they shall come into effect as of January 1, 1983 (with the code HGJ202‑82). During the implementation process, it is important to accumulate relevant data; should any issues arise, please inform the Department of Infrastructure at any time so that they can be compiled and used for further revisions. This specification is managed and interpreted by the Department’s Infrastructure Bureau. August 4, 1982 Table of Contents Chapter 1 General Provisions Chapter 2 General Rules Chapter 3 Degreasing of Equipment Chapter 4 Degreasing of Pipes, Fittings, and Valves Chapter 5 Inspection Chapter 6 Safety Techniques Appendix 1 Some characteristic data of commonly used degreasers Appendix 2 Formulas and usage conditions for alkaline degreasing solutions Appendix 3 Formula and usage conditions for the non-ionic metal cleaner “664” Appendix 4 Uses of W41 and W25 vapor-phase rust preventive papers Appendix 5 Uses of BF-7 and CF-4 vapor-phase rust preventive plastic films Chapter 1 General Provisions Article 1.0.1 These specifications apply to the degreasing of oil-repellent equipment, pipes, fittings, valves, etc., in chemical engineering construction. Article 1.0.2 Equipment, pipes, pipe fittings, valves, etc., must be degreased in accordance with these specifications, based on the design documents or the following provisions: 1. When the materials being transported or stored are susceptible to combustion or explosion in the presence of organic substances such as oils ； II. Organic substances such as oils that can mix with the materials being transported or stored and alter the properties of those materials ； III. Organic substances such as oils that have an impact on the catalyst’s activity ； IV. Organic substances such as oils that can affect product purity ； V. Due to pickling ； Those that require degreasing treatment. Article 1.0.3: Where the design specifies additional requirements for degreasing, those specifications shall be followed as stated in the design documents. Article 1.0.4 The storage and transportation facilities for degreasing agents shall comply with the \"Fire Protection Regulations for the Design of Refining and Petrochemical Enterprises\". Chapter 2 General Provisions Article 2.0.1 The degreasing of equipment, pipes, fittings, valves, etc. shall be completed prior to the system airtightness test. Article 2.0.2 Before carrying out the degreasing process, the construction department must prepare specific operating procedures for degreasing. Personnel involved in the degreasing process must carry out their work in accordance with these specifications and the specific operating procedures established for this purpose. Article 2.0.3: For components with obvious oil stains and dirt, these can be removed using solvents such as kerosene or other methods before degreasing, and then degreased with a degreasing agent. Appropriate safety measures must be taken throughout the entire process. Article 2.0.4: Degreasing agents shall be selected in accordance with the design requirements. If the design does not specify otherwise, the construction department shall select the appropriate degreasing agent and degreasing method based on the material, structure, degree of contamination of the parts to be degreased, site conditions, the production medium, and the level of risk or hazard posed by oil contamination. Article 2.0.5: Degreasing agents can be selected according to Table 2.0.5 (some characteristic data of commonly used degreasing agents are shown in Appendix 1). Table 2.0.5 Common degreasing agents Table 2.0.5 Article 2.0.6 Degreasing agents or chemical substances used in preparing degreasing agents must have certificates of conformity. Before use, the degreaser should be rechecked according to the technical specifications regarding its appearance, non-volatile substances, moisture content, reaction medium, and oil content; periodic inspections should also be carried out during its use. Article 2.0.7 The oil content of organic solvents used for degreasing shall not exceed 50 milligrams per liter. Solvents with a high oil content can be used for initial degreasing, followed by further degreasing using a cleaner solvent. Solvents with an oil content of more than 500 milligrams per liter must be regenerated and pass inspection before they can be used as degreasers. Article 2.0.8: Dichloroethane, carbon tetrachloride, and trichloroethylene can all undergo hydrolysis under certain conditions to produce hydrochloric acid, which corrodes metals. Therefore, when using such solvents, the degreased parts must be free of moisture. Article 2.0.9 Tools, measuring instruments, meters, etc., used for degreasing, inspection, and installation must be pre-degreased in accordance with the requirements of the parts to be degreased. It must not be used if it has not been degreased. Degreased tools, measuring instruments, meters, etc. should be stored in dedicated cabinets and kept under the care of designated personnel. Protective equipment such as work clothes, shoes, and gloves must be clean and oil-free. Article 2.0.10: Degreasing shall be carried out outdoors or in a well-ventilated indoor area or container. The degreasing area must have good ventilation and be protected from rain, dust, and other contaminants. The degreaser should not be exposed to direct sunlight. Article 2.0.ll: After degreasing, the liquid degreasing agent inside the parts must be drained promptly; it is strictly prohibited to use evaporation drying to remove the remaining liquid. Article 2.0.12: Remove the solvent from the surface of the degreased parts until no residue or odor remains. The method: First, it can be cleaned by blowing with clean, oil-free, dry air or nitrogen ； II. When degreasing with flammable solvents such as dichloroethane or alcohol, it is only permitted to use nitrogen with a purity of 95% or higher (by volume) for purging, or to dry the area in a well-ventilated space ； III. For degreased parts with a simple structure and small size, they can be left to air-dry in the atmosphere for more than 24 hours ； IV. To reduce the purging time, air or nitrogen preheated to 50–60°C can be used for purging ； . V. Clean, degreased cotton can be used to cover the fabric attached to a long rod, forming a pack that helps remove debris and residual liquids from the bottom of the cleaner. Article 2.0.13 To accelerate the removal of residual flux, clean, oil-free steam can be used for blowing, provided it is permissible for the degreased parts. Article 2.0.14: When using the wiping method for degreasing, cotton yarn should not be used; instead, fabrics whose fibers do not easily fall off, such as silk or glass fiber fabrics, should be employed. After degreasing, the surface of the parts to be degreased must be carefully inspected to ensure that no fibers from organic fabrics fall onto or adhere to their surface. Article 2.0.15 After degreasing, equipment, pipes, fittings, valves, etc. must be inspected by designated inspectors and approved by relevant personnel before proceeding to the next processing step. Article 2.0.16 Once the degreased parts have passed inspection, they must be sealed by a designated person and marked accordingly. The parts should be wrapped in clean white cloth and stored properly to prevent dirt and debris from contaminating or getting inside them. Components that have passed the degreasing process and those that have failed or have not been degreased must be stored separately; mixing them is strictly prohibited. Article 2.0.17 Requires that degreased parts requiring rust prevention, after undergoing degreasing and rust-preventing treatment, be protected by measures such as nitrogen flushing or sealing with vapor-phase rust-proof paper or vapor-phase rust-proof plastic film. The nitrogen used for sealing must be oil-free, with a purity of 95% or higher on a volume basis, and its dew point should be below –40°C. The grades and applications of some vapor-phase rust-proof papers and vapor-phase rust-proof plastic films are listed in Appendix 4 and Appendix 5. Article 2.0.18 Equipment and pipelines after dewaxing shall not be subjected to pressure testing or purging using oily media. Article 2.0.19 During the degreasing process, the personnel responsible for degreasing must strictly adhere to the procedures for task handover, shift changes, and maintenance of original records. Chapter 3 Equipment Degreasing Section 3.0.1 Static equipment shall be allowed to undergo degreasing only after passing the strength test. Article 3.0.2 Equipment for which degreasing is specified in the design documents by the manufacturer must be equipped with a certificate from the manufacturer confirming that the degreasing has been performed properly. Equipment that comes with a manufacturer’s degreasing certificate and is sealed and properly stored may not require degreasing during installation. However, it should be carefully inspected and verified by relevant personnel before installation. If dirt or oil contamination is detected, degreasing must be carried out again. For equipment that requires re-degreasing, a degreasing plan must be prepared and approved by the competent technical department. Article 3.0.3 For components or equipment with complex structures and dead corners, necessary measures must be taken to ensure that the degreasing agent can be evenly distributed over all surfaces, and that it can be completely removed after degreasing. Article 3.0.4 The surface of the degreased parts must pass a degreasing inspection before the specified lubricants, corrosion inhibitors, and sealants can be applied. Article 3.0.5 All operations related to the disassembly, lifting, and blowing of equipment during the degreasing process must comply with the relevant regulations for the installation and disassembly of such equipment. Article 3.0.6: The degreasing of stationary equipment can be carried out using the following methods, depending on the medium in contact, the structure of the equipment, and the degree of oil contamination: 1. Immersion method. For devices with a small volume, degreasing can be achieved by immersing them in a solvent; in this case, the device should be rotated or tilted repeatedly to ensure that all surfaces that need to be degreased come into even contact with the solvent. The soaking time depends on the degree of contamination, usually 1 hour ； II. Wiping method. For larger metal containers, when the oil contamination is mild, a cleaning cloth dipped in degreaser can be used for scrubbing ； III. Spraying method. To degrease the inner surface of large containers, a method involving spraying a degreasing agent using a nozzle can be employed. The nozzle should be able to move up and down, allowing the solvent to be evenly sprayed over all the surfaces of the container that need to be degreased ； IV. Iterative method. The degreasing of tubular heat exchangers can be carried out using a circulating solvent method. But the solvent must be able to circulate to all surfaces that need degreasing. The cycle time should generally be no less than 30 minutes ； V. Slot dipping method. Components that can be removed can be directly immersed in the solvent tank. The soaking time depends on the degree of contamination, usually being 1 hour. Article 3.0.7: For transmission equipment, all components that come into contact with or may come into contact with oil-repellent media (such as lubrication and sealing parts) must be degreased before operation. However, the installation of the equipment, alignment, and adjustment of various clearances must be carried out in accordance with relevant procedures before degreasing. Article 3.0.8: The detachable components of the transmission equipment, such as the cylinder heads of compressors or pumps, piston assemblies, valves, seals, rotors, partitions, volutes, bolts, gaskets, etc., can first be cleaned with kerosene and then immersed in a solvent tank until they meet the required standards. Article 3.0.9 For large components of transmission equipment that cannot be disassembled or for which it is difficult to submerge in a solvent tank, such as the cylinders and housings of compressors and pumps, degreasing can be carried out by wiping. Article 3.0.10: Transmission equipment components that have passed the degreasing process must be kept clean and assembled as soon as possible. After the equipment is assembled, if it cannot be put into use promptly, the pipes should be separated and sealed using degreased blind flanges, and anti-rust protection measures should be taken to prevent contamination and rusting. Chapter 4: Degreasing of Pipes, Fittings, and Valves 4.0:1 Degreasing of installed pipes can be carried out by disassembling them into sections or by using a circulating degreasing method. Pipes that cannot be disassembled or for which it is difficult to perform cyclic degreasing should be degreased before installation, but must remain free from contamination. Article 4.0.2 Pipes with obvious rust should have the rust removed by sandblasting or other methods, followed by degreasing with a degreaser. Article 4.0.3: To degrease the inner surface of the tube, a solvent can be injected into it, with the tube ends sealed using wooden plugs or other methods. Place the tube flat and soak it for 1 to 1.5 hours, turning it every 15 minutes so that it gradually faces the area where it should be soaked. With each rotation, the tube must roll several full circles, so that the entire inner surface of the tube can be evenly soaked in the solvent and washed multiple times. The amount of solvent required to degrease the inner surface of a pipe per 1 meter of length can generally be determined according to Table 4.0.3. Table 4.0.3 Amount of degreasing agent required for the inner surface of pipes. Article 4.0.4: Large-diameter pipes can be cleaned by wiping, while small-diameter pipes can be immersed in a solvent for 1–1.5 hours. Article 4.0.5 Pre-fabricated pipe sections can also be degreased after connection using a circulating solvent method. However, the solvent must be able to circulate to all the internal surfaces that need degreasing; the sealing surfaces must be degreased separately, and the solvent circulation time should generally be no less than 30 minutes. Article 4.0.6: Degreasing of the outer surface of pipes can be done by wiping. Article 4.0.7 Before degreasing the valve, it must first pass the pressure testing after being ground; thereafter, it is disassembled into its components to remove rust and other impurities, and then immersed in a solvent for 1–1.5 hours. Bolts and metal gaskets are degreased in the same way. For valve housings that cannot be soaked, the wiping method can be used. Article 4.0.8: For the degreasing of non-metallic gaskets, carbon tetrachloride solvent shall be used. The gaskets are immersed in the solvent for 1.5–2 hours, after which they are removed and hung in a well-ventilated area or a ventilation device, where they are dried one by one until no odor of solvent remains. Article 4.0.9 Degreasing of gaskets with an outer metal coating or gaskets that require coating shall be carried out prior to applying the metal coating and coating them. Article 4.0.10: Asbestos fillers that come into contact with strongly oxidizing media such as oxygen and concentrated nitric acid can be burned at a temperature of around 300°C for 2–3 minutes (a flaming flame must not be used), and then immersed in the specified coating. Finished products with asbestos fillers coated in paint should come with a certificate indicating their applicable range; otherwise, they must pass testing before they can be used. Article 4.0.11 Valves, fittings, ceramic rings, etc., whose working medium is concentrated nitric acid. It can be washed or soaked in 98% concentrated nitric acid, followed by rinsing with clean water, and then blown with steam until the condensate is free of acidity. After washing and soaking aluminum and aluminum alloy parts in concentrated nitric acid, the acid on the degreased parts must be removed promptly to prevent corrosion by dilute acid. Chapter 5 Inspection Article 5.0.1 Equipment, pipes, pipe fittings, and valves shall be inspected and tested after degreasing. The inspection criteria shall be implemented in accordance with Articles 5.0.2 to 5.0.5 of these specifications, based on the different roles of the degreased parts in production and the degree of risk or hazard caused by oil contamination. Article 5.0.2 For equipment, pipes, fittings, valves, etc. that are in direct contact or may come into contact with strongly oxidizing media such as oxygen, oxygen-enriched gases, and concentrated nitric acid, any of the following methods may be used for inspection: 1. Examine the surface of the degreased parts using ultraviolet light with a wavelength of 3200–3800 angstroms; no oil fluorescence indicates compliance ； II. Wipe the surface of the degreased parts with clean, dry white filter paper; it is considered acceptable if no traces of oil remain on the paper ； III. Blow clean the degreased parts with oil-free steam, collect the condensate, add a small particle of pure camphor (with a diameter of less than 1 millimeter), and it is considered satisfactory if the camphor keeps rotating continuously ； IV. For degreased parts that cannot be tested using the above methods, samples can be taken for inspection; a qualified result is achieved when the solvent and oil content after degreasing does not exceed 350 milligrams per liter. Article 5.0.3 Equipment and pipelines cleaned with concentrated nitric acid shall have their total organic content in the acid analyzed, with a limit of 0.03% being considered acceptable. Article 5.0.4: Parts degreased with solvents must have any remaining solvent thoroughly blown away until no odor of solvent is present. Those who use alkaline solutions for degreasing must rinse thoroughly with oil-free water until the pH reaches neutral, and then dry it. For those using steam to blow off contaminants, the degreased parts should be dried promptly. Oil-free water used for rinsing austenitic stainless steel shall have a chloride content of no more than 25 ppm. Article 5.0.5 Where design specifications stipulate inspection standards, inspections shall be carried out in accordance with those standards. Chapter 6: Safety Techniques Article 6.0.1: All flammable, explosive materials and other debris must be removed from the area surrounding the degreasing site; a dedicated degreasing zone should be established, and unauthorized personnel are not allowed to enter it. Fire is strictly prohibited; all sources that could generate sparks must be eliminated, and a sign reading “Fire is strictly prohibited!” must be installed ”“, Toxic substances! ”Wait for the sign. The degreasing area must be equipped with necessary fire and gas prevention facilities, which should be regularly checked to ensure they are in good working condition. Article 6.0.2 Solvents such as dichloroethane, carbon tetrachloride, and trichloroethylene are volatile toxic liquids that can cause poisoning through the respiratory tract and damage internal organs and the nervous system ； Dichloroethane and carbon tetrachloride can also cause poisoning through intact skin. The degreasing process should be carried out outdoors or in a well-ventilated indoor area. When working, it is necessary to strengthen personal protection by wearing work clothes, masks, safety glasses, rubber gloves, aprons, and long boots; a gas mask should be worn if required. Smoking or eating is strictly prohibited in the degreasing area, and the concentration of harmful substances in the air at that location should be checked regularly; such concentrations must not exceed the values specified in Table 6.0.2. Table 6.0.2 Maximum allowable concentrations of hazardous substances in the air at degreasing work sites. Article 6.0.3 Nitric acid can damage skin and mucous membranes. Persons degreasing with concentrated nitric acid should wear woolen, silk, or rubber work clothes, acid-resistant rubber gloves, protective goggles, and a double-layer mask containing baking soda; a gas mask should be worn if necessary. Article 6.0.4 Alkalis can corrode skin and mucous membranes. When degreasing with an alkaline solution, operators should wear rubber work clothes, aprons, gloves, long boots, and protective glasses. Article 6.0.5 Temporary flushing water pipes shall be installed at sites where degreasing is carried out using concentrated nitric acid or alkaline solutions. When acid or alkaline liquid touches the skin, it should be immediately rinsed with clean water; rubbing is not allowed. Article 6.0.6 Trichloroethylene, dichloroethane, and alcohol all belong to Class A fire-hazardous substances; they will catch fire and explode upon contact with sparks in air, and can ignite spontaneously when in contact with concentrated nitric acid or oxidizing agents. Fire and sparks must be strictly prohibited during use and storage, and it should be kept separate from strong acids, oxidizing agents, etc. Article 6.0.7 Alcohol shall not be stored together with or used simultaneously with other degreasers listed in this specification, such as dichloroethane. Article 6.0.8 After degreasing with flammable solvents such as dichloroethane or alcohol, it is strictly prohibited to dry the remaining solvent by forced blowing with oxygen or air. Article 6.0.9 Carbon tetrachloride, when in contact with flames or hot light metals such as potassium, magnesium, sodium, aluminum, etc., as well as other chemicals such as calcium carbide, ethylene, carbon disulfide, etc., can undergo intense decomposition and even explode. Therefore, when storing and using carbon tetrachloride, open flames are strictly prohibited, and it must not come into contact with such substances. Article 6.0.10: Trichloroethylene can produce phosgene when in contact with flame; it can react with solid sodium hydroxide or potassium hydroxide, leading to explosions, and it decomposes easily when in contact with water or other impurities. Therefore, when storing and using trichloroethylene, open flames are strictly prohibited, and it must not come into contact with such substances. Article 6.0.11 Concentrated nitric acid is a strong oxidizing agent that can catch fire on contact with organic materials, turpentine, water, and organic fabrics; it produces toxic gases such as nitrogen oxides during combustion. During storage, the containers must be tightly sealed to prevent moisture absorption and leakage; a dedicated warehouse should be used, and they must be kept separate from organic substances, flammable materials, acids, and other oxidizing agents. Article 6.0.12: Degreasing agents shall be stored separately in sealed glass bottles or iron drums, and kept in a well-ventilated, dry, and cool warehouse away from light. The degreaser must not come into contact with strong acids or strong bases. Article 6.0.13: Spills and leaks of degreasers must be prevented from reaching the floor. Spilled solvents should be immediately absorbed with wood chips, sand, etc., and collected together with the fabrics used for degreasing in a dedicated, sealed metal container. However, spilled acids or bases should be immediately rinsed with plenty of water until they reach a neutral pH. Article 6.0.14 When transferring a solvent from one container to another, it must be done in an open area, and protective equipment such as gas masks must be worn before proceeding. Article 6.0.15 It is strictly prohibited to mix different solvents and to use them outside their approved scope of application. Article 6.0.16: The discharge of degreasing residues and wastes must be carried out in accordance with the provisions of the Interim Standards for the Discharge of Industrial ‘Three Wastes’ GBJ4–73. Article 6.0.17: Strict management and security measures must be implemented at the degreasing site to prevent accidents. Appendix 1: Some characteristic data of commonly used degreasers. Appendix 2: Formulas for alkaline degreasing processes and their application conditions. Appendix 3: Formula and application conditions for the non-ionic metal cleaner “664”. Appendix 4: Uses of W41 and W25 vapor-phase rust prevention papers. Note: Parts packaged in W41 and W25 vapor-phase rust prevention papers, after being cleaned and dried, can be sealed in plastic bags, allowing a rust prevention period of over three years. Appendix 5: Uses of BF-17 and CF-4 vapor-resistant plastic films. Last edited by Tjuleo on 2009-3-13 09:14.]