Spring loaded safety valves
1 Scope
This document specifies the design, performance, tests and inspections, appearance, marking and lead sealing, and protection, storage and transportation of spring loaded safety valves (hereinafter referred to as “safety valves”).
This document is applicable to steam, gas and liquid safety valves with set pressure of 0.1 MPa ~ 42.0 MPa, of which the flow diameter shall be ≥ 15mm for steam safety valves and shall be ≥ 7 mm for gas and liquid safety valves.
This document is applicable to safety valves with medium temperature not lower than -29℃ during discharge.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 9440 Malleable iron castings
GB/T 12224 General requirements for industrial steel valves
GB/T 12225 General purpose industrial valves - Specification of copper alloy castings
GB/T 12227 General purpose industrial valve - Specification of spheroidal graphite iron castings
GB/T 12228 General purpose industrial valves - Specification of carbon steel forgings
GB/T 12229 General purpose industrial valves - Specification of carbon steel castings
GB/T 12230 General purpose industrial valves - Specification of stainless steel castings
GB/T 12241 Safety valves - General requirements
GB/T 12242 Performance test code - Pressure relief devices
GB/T 23935 Design of cylindrical helical springs
JB/T 2203 Center-to-face dimensions of spring loaded safety valves
JB/T 5263 Specification for steel casting for power station valves
JB/T 6439 Methods of magnetic examination for valves
JB/T 6440-2008 Methods of radiographic examination for steel castings valves
JB/T 6902 Methods for liquid penetrant examination of valves
JB/T 7367 Magnetic particle inspection for helical compression springs
NB/T 47013.2-2015 Nondestructive testing of pressure equipments - Part 2: Radiographic testing
NB/T 47013.3-2015 Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing
NB/T 47013.5-2015 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 12241 and the following apply.
3.1
full-lift safety valve
safety valve with actual discharge area as flow area
3.2
low-lift safety valve
safety valve with actual discharge area as curtain area
3.3
discharge area
minimum sectional area of fluid flow path during valve discharge
Note: The minimum sectional area determines the flow through the valve.
3.4
flow-rating pressure
static pressure at valve inlet when measuring the discharge capacity of the safety valve
Note: Static pressure is the absolute pressure of the sum of the set pressure and the overpressure of the safety valve.
4 Design
4.1 General
4.1.1 The safety valves shall be designed in accordance with GB/T 12241.
4.1.2 The applicable temperature range of safety valves shall be determined according to their construction (such as heat insulation and cold insulation of springs), materials, operating characteristics of medium, and the limit of temperature change during discharge. Safety valves shall operate normally within their temperature range indicated.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Design
4.1 General
4.2 End connection
4.3 Limit deviations of face-to-face dimensions and perpendicularity
4.4 Valve body
4.5 Seat and disc
4.6 Spring
4.7 Materials
4.8 Non-destructive testing
5 Performance
5.1 Deviation of set pressure
5.2 Overpressure
5.3 Blowdown
5.4 Lift
5.5 Mechanical properties
5.6 Tightness
5.7 Discharge capacity
6 Tests and inspections
6.1 Test and inspection items
6.2 General requirements
6.3 Test media
6.4 Test methods
7 Appearance
8 Marking and lead sealing
9 Protection, storage and transportation
Annex A (Normative) Non-destructive testing
Annex B (Informative) An alternative method for calculating the certified capacity of safety valves
Spring loaded safety valves
1 Scope
This document specifies the design, performance, tests and inspections, appearance, marking and lead sealing, and protection, storage and transportation of spring loaded safety valves (hereinafter referred to as “safety valves”).
This document is applicable to steam, gas and liquid safety valves with set pressure of 0.1 MPa ~ 42.0 MPa, of which the flow diameter shall be ≥ 15mm for steam safety valves and shall be ≥ 7 mm for gas and liquid safety valves.
This document is applicable to safety valves with medium temperature not lower than -29℃ during discharge.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 9440 Malleable iron castings
GB/T 12224 General requirements for industrial steel valves
GB/T 12225 General purpose industrial valves - Specification of copper alloy castings
GB/T 12227 General purpose industrial valve - Specification of spheroidal graphite iron castings
GB/T 12228 General purpose industrial valves - Specification of carbon steel forgings
GB/T 12229 General purpose industrial valves - Specification of carbon steel castings
GB/T 12230 General purpose industrial valves - Specification of stainless steel castings
GB/T 12241 Safety valves - General requirements
GB/T 12242 Performance test code - Pressure relief devices
GB/T 23935 Design of cylindrical helical springs
JB/T 2203 Center-to-face dimensions of spring loaded safety valves
JB/T 5263 Specification for steel casting for power station valves
JB/T 6439 Methods of magnetic examination for valves
JB/T 6440-2008 Methods of radiographic examination for steel castings valves
JB/T 6902 Methods for liquid penetrant examination of valves
JB/T 7367 Magnetic particle inspection for helical compression springs
NB/T 47013.2-2015 Nondestructive testing of pressure equipments - Part 2: Radiographic testing
NB/T 47013.3-2015 Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing
NB/T 47013.5-2015 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 12241 and the following apply.
3.1
full-lift safety valve
safety valve with actual discharge area as flow area
3.2
low-lift safety valve
safety valve with actual discharge area as curtain area
3.3
discharge area
minimum sectional area of fluid flow path during valve discharge
Note: The minimum sectional area determines the flow through the valve.
3.4
flow-rating pressure
static pressure at valve inlet when measuring the discharge capacity of the safety valve
Note: Static pressure is the absolute pressure of the sum of the set pressure and the overpressure of the safety valve.
4 Design
4.1 General
4.1.1 The safety valves shall be designed in accordance with GB/T 12241.
4.1.2 The applicable temperature range of safety valves shall be determined according to their construction (such as heat insulation and cold insulation of springs), materials, operating characteristics of medium, and the limit of temperature change during discharge. Safety valves shall operate normally within their temperature range indicated.
Contents of GB/T 12243-2021
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Design
4.1 General
4.2 End connection
4.3 Limit deviations of face-to-face dimensions and perpendicularity
4.4 Valve body
4.5 Seat and disc
4.6 Spring
4.7 Materials
4.8 Non-destructive testing
5 Performance
5.1 Deviation of set pressure
5.2 Overpressure
5.3 Blowdown
5.4 Lift
5.5 Mechanical properties
5.6 Tightness
5.7 Discharge capacity
6 Tests and inspections
6.1 Test and inspection items
6.2 General requirements
6.3 Test media
6.4 Test methods
7 Appearance
8 Marking and lead sealing
9 Protection, storage and transportation
Annex A (Normative) Non-destructive testing
Annex B (Informative) An alternative method for calculating the certified capacity of safety valves
