What are the rules for chemical cleaning of low pressure boilers?
Article 1 These rules are formulated to prevent the safe operation of boilers due to improper chemical cleaning, to ensure the safe and reliable chemical cleaning of boilers, and to improve the cleaning effect.
Article 2 This rule uses a chemical cleaning of a fixed steam boiler and a pressurized hot water boiler with a rated outlet steam pressure of less than 2.45MP (25kgf/cm2).
Article 3 The chemical cleaning of boilers includes two types: alkaline cooking and pickling. Cleaning can be combined with soaking, recirculating cleaning, and soaking and reversing cleaning.
Article 4 Boiler water treatment is an important measure to ensure the safe and economic operation of the boiler. It is not allowed to replace or relax the regular and effective water treatment work with chemical cleaning. The pickling time of each boiler should not be less than two years.
Article 5 The professional unit for boiler chemical cleaning must obtain the qualification approval of the safety supervision institution for the boiler and pressure vessel of the labor part above the provincial level (including the provincial level). Professional units for boiler chemical cleaning should have the following prerequisites:
1. Have a sound organization and obtain legal personality.
2. There are professional and technical staff who are suitable for the chemical cleaning work undertaken.
The cleaning unit responsible for cleaning the Class C boiler should have at least one intermediate technical staff member and two junior technical staff. Units that qualify for Class C boiler cleaning can undertake chemical cleaning of boilers below Class C. The cleaning unit responsible for cleaning boilers of Class D and below shall have at least one intermediate technical staff or two junior technical staff.
3. The cleaning and testing staff shall agree to the boiler and pressure vessel safety supervision agency at or above the municipal level (including the city level).
4. Complete and safe cleaning equipment and analytical tools.
5. Have a sound governance system and develop safety control procedures.
Units that meet the above premise can pickle the boiler by themselves after approval by the local labor department. Units that only perform soda cooking do not require qualification.
Article 6 Before the chemical cleaning of the boiler, the chemical cleaning unit must formulate a cleaning plan and, after approval by the technical person in charge, report to the local and municipal labor part boiler pressure vessel safety supervision organization where the boiler is located.
Article 8 can be chemically cleaned if the boiler meets one of the following conditions:
1. The heating surface of the boiler is covered by scale by more than 80% and the uniform scale thickness reaches or exceeds the following values.
For boilers without superheater: 1mm,
For boilers with superheater: 0.5mm,
For hot water boilers: 1mm.
2. The boiler heating surface has significant oil or rust.
Article 9 Before cleaning, specific inspections shall be carried out inside and outside the boiler to determine the cleaning method and safety measures.
