Safety Technical Supervision Regulations for Safety Valves
Article 1 In accordance with the relevant provisions of Regulations on Safety Supervision for Special Equipment (hereinafter referred to as the Regulations), this regulation is formulated to ensure the safe operation of boiler, pressure vessel and pressure pipeline.
Article 2 This regulation is applicable to such safety valves as maximum working pressure is greater than or equal to 0.02MPa and used in boiler, pressure vessel, pressure pipeline and other equipment (hereinafter referred to as the Equipment), which is specified in the Regulations.
Please refer to Annex A for the related terminologies of safety valve.
Article 3 As for the material, design, manufacture, inspection, installation, usage, checking and maintenance of safety valve, it shall be in strict accordance with this regulation.
Please refer to Annex B for the related safety technical requirement of safety valve.
Article 4 The manufacturing unit of safety valve shall acquire License for Manufacturing Special Equipment. The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China (hereinafter referred to as the AQSIQ) is responsible for uniform management on the manufacturing license of domestic and foreign safety valve and issue of license for manufacturing special equipment. The manufacturing license is valid for 4 years. For the manufacturing unit acquiring license for manufacturing special equipment, it shall apply "license mark" and license number to its product as required in Annex B of Pressure Pipe Unit Manufacture Appraisal Regulation (TSG D2001-2006).
The manufacture license of safety valve is classified into A-level and B-level. The AQSIQ is responsible for accepting and approving foreign and domestic A-level license application while the provincial, autonomous-region and municipal quality and technology supervision bureau (hereinafter referred to as the Provincial Quality and Technical Supervision Department) entrusted by the AQSIQ is responsible for accepting and approving B-level license application within its jurisdictions.
The procedures for safety valve manufacturing license include application, acceptance, trial production, type test, review and evaluation, examination and approval as well as license issue. The specific license procedures shall be carried out in accordance with the relevant provisions. The trial product shall represent the highest specification of its application level.
Please refer to Annex C for manufacturing license conditions of safety valve. If there are manufacturing license requirements for components of safety valve, it shall acquire license for manufacturing special equipment in accordance with the corresponding requirement of safety technical specification.
Article 5 If one of the following conditions occurs to safety valve, it shall carry out trial production and pass type test;
(1) Before the new product goes into production or restart production 1 year after production cessation.
(2) Major change takes place to the structure and technique of product, which makes effect on the safety performance;
(3) The requirement of manufacturing license;
(4) There are problems with the safety performance of product and it is required by quality and technical supervision department at provincial level and above.
Please refer to Annex D for the content and requirement of safety-valve type test.
Article 6 After the license application of safety-valve manufacturing unit is accepted, production-type test shall be carried out in accordance with the specification and amount required in review and evaluation as well as type test and in accordance with the requirement of Annex D via safety-valve-type test organization published by the AQSIQ.
The type test procedures of safety valve include invitation and acceptance, design review, sampling, inspection and test as well as submission of type-test report and type-test certificate.
Article 7 As for the organization engaged in checking in-use safety valve, it shall possess checking technical director, technician as well as checking device, instrument and site.
As for safety valve users with available conditions, they may check safety valve by themselves. As for the users without checking capability, they may entrust inspection and test organization with the related qualification for checking of safety valve.
When the users check the in-use safety valve by themselves, they shall submit the checking report to the inspection and test organization responsible for the checking of such equipment.
As for the personnel engaged in the operation and maintenance, dismantlement and overhaul as well as checking of in-use safety valve, they shall acquire Special Equipment Operating Personnel License.
Please refer to Annex E, Annex F and Annex G for the checking methods of safety valve.
Article 8 This regulation shall be explained by the AQSIQ.
Article 9: This regulation shall come into force on January 1, 2007.
Annex A
Terminology
A1 Relief valve
A kind of self-acting valve, which use the force of medium instead of external force to discharge a rated quantity of fluid so as to prevent the pressure from exceeding the rated safety value. When the pressure returns to normal, the valve will close up and prevent the medium from outflow.
A2 Direct loaded safety valve
A kind of safety valve, which depends only on direct machinery loading device (such as weight, lever and weight or spring) to overcome the acting force produced by the medium pressure of disc.
A3 Balanced safety valve
A kind of safety valve, which takes measures to reduce the effect the back pressure has on performance characteristic (set-pressure, reseating pressure and discharge capacity) to the minimum.
A4 Pilot operated safety valve
A kind of safety valve, which depends on the medium discharged from pilot valve for driving or control. Actually, the pilot valve itself shall be a kind of direct loaded safety valve.
A5 Assisted safety valve
By virtue of an auxiliary power devices (such as air pressure, hydraulic pressure and electromagnet), this safety valve may open when the pressure is lower than normal set pressure.
A6 Set pressure
As for the pre-set pressure when the safety valve begins to open under operating condition, it refers to measured gauge pressure at the valve inlet. Under such pressure and normal operating condition, it tends to keep mutual balance between the force to open the valve and the force to keep disc at valve seat, both of which are produced by medium pressure.
A7 Set-pressure deviation
The deviation value of set-pressure when the safety valve opens more than one time
A8 Cold differential test pressure
The inlet static pressure when the safety valve in test bed is adjusted to begin opening. Such pressure includes correction for such operating condition as back pressure and temperature.
A9 Relieving pressure
It refers to set-pressure plus overpressure.
A10 Rated discharge pressure
The upper limit value for discharge pressure specified in related standard or code
A11 Overpressure
The pressure increment over set-pressure of safety valve, which are generally expressed by the percentage of set-pressure
A12 Reseating pressure
The inlet static pressure when disc re-contact with valve seat after the discharge of safety valve, namely when the lift reduces to zero
A13 Blowdown
The difference between set-pressure and reseating pressure, which is usually expressed with the percentage of set-pressure. When the set-pressure is less than 0.3MPa, it shall be expressed by unit MPa.
A14 Back pressure
The pressure at the discharge outlet of safety valve, which refers to the sum of built-up back pressure and adding back pressure.
A15 Built-up back pressure
The pressure formed at the valve outlet when the medium flows across safety valve and discharge system.
A16 Adding back pressure
The static pressure at the outlet of safety valve before it acts and it is caused by other pressure sources in the discharge system.
A17 Seal test pressure
The inlet pressure when seal test is carried out. Under such pressure, the leakage rate between disc and sealing surface of valve seat is measured.
A18 Lift
The actual lift when disc departs from closed position.
A19 Flow area
The minimum cross-section area between valve inlet side and sealing face of closing parts, which is used to calculate theoretical flow when there is no resistance
A20 Flow diameter
The diameter corresponding to flow area
A21 Curtain area
The cylindrical-surface or circular-conical-surface passage area formed between sealing faces when disc rises over valve seat.
A22 Lifting device (spanner)
A device to open safety valve manually. It uses external force to reduce the spring load which keeps safety valve closed.
A23 Theoretical flow capability
The calculated discharge capacity of ideal nozzle when flow cross-section is equal to the flow area of flow area. It is expressed by mass flow or volume flow.
A24 Discharge coefficient
The ratio between actual discharge capacity and theoretical discharge capacity.
A25 Rated relieving capability coefficient
The product of discharge coefficient and reduction coefficient (Taking 0.9).
Contents
Foreword
Safety Technical Supervision Regulations for Safety Valves
Annex A Terminology
Annex B Technical requirement for safety valve
Annex C Conditions of safety valve manufacturing license
Annex D Type test of safety valve
Annex E Checking and repair of safety valve
Annex F Recommended method for seal test with air
Annex G The recommended safety valve checking system (gas)
Annex H The recommended method for safety valve low-temperature test
