Pressure Piping Code - Industrial Piping - Part 6: Safeguarding
压力管道规则 工业管道 第6部分：安全防护
1 Scope
This Part specifies the basic requirements for the safety protection devices (safety relief device and flame arrester) and safety protection of the pressure piping within the range of GB/T 20801.1.Other requirements on safety protection not specified in this Part shall comply with the requirements of the other parts of GB/T 20801-2006 and the current relevant standards and codes of the state.
2 Normative References
The following documents contain provisions which, through reference in this Part of GB/T 20801, constitute provisions of this Part. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties whose enter into agreement according to this Part are encouraged to research whether the latest editions of these references are applied or not. For undated references, the latest edition of the normative document is applicable to this standard.
GB 150 "Steel Pressure Vessels"
GB 567-1999 "Bursting Discs and Bursting Disc Devices"
GB 3836.12-1991 "Electrical Apparatus for Explosive Atmospheres-Classification of Gases or Vapors with Air According to Their Maximum Experimental Safe Gaps and Minimum Igniting Currents" (eqv IEC 60079-12: 1978)
GB/T 3840 "Technical Methods for Making Local Emission Standards of Air Pollutants"
GB 5908 "Flame Arresters for Petroleum Tanks"
GB 12158 "General Guideline for Preventing Electrostatic Accidents"
GB/T 12241-2005 "Safety Valves--General Requirements" (ISO 4126-1: 1991, MOD)
GB/T 12242-2005 "Performance Test Code--Pressure Relief Devices"
GB/T 12243-200 5 "Spring Loaded Safety Valves"
GB 13347-1992 "The Quenching Ability of Flame Arrester and Its Test Method for Petroleum Gas Piping Systems"
GB/T 20801.1-2006 "Pressure Piping Code-Industrial Piping-Part 1: General"
GB/T 20801.3-2006 "Pressure Piping Code-Industrial Piping-Part 3: Design and Calculation"
GB 50016-2006 "Code for Design of Building Fire Protection"
GB 50160 "Fire Prevention Code of Petrochemical Enterprise Design"
GB 50187 "Code for Design of General Plan of Industrial Enterprises"
HG/T 20570.2-1995 "Installation and Selection of Safety Valves"
SH/T 3413-1999 "Specification for Selection Inspection and Acceptance of Pipeline Flame Arresters for Petroleum Gas in Petrochemical Industry"
SY/T 10043-2002 "Guide for Pressure-relieving and Depressuring Systems"
SY/T 10044-2002 "Sizing Selection and Installation of Pressure-relieving Devices in Refineries"
3 Terms and Definitions
3.1
Safety relief device
On occasions with or without fire accidents, the safety relief device is opened to relieve liquid under the action of inlet static pressure so as to prevent the pressure in the system from exceeding the preset safe value. The safety relief device includes safety valve and rupture disk device.
3.2
Safety valve
The spring acted or pilot operated valves. It is a kind of safety relief device of which the valve clack will rise to relieve the liquid so as to prevent the pressure in system from exceeding the preset safe value when the static pressure at the inlet exceeds the set pressure and that can close automatically when the pressure falls to the re-seating pressure.
3.3
Rupture disk device
A kind of non-reclosed safety relief device composed of rupture disk and gripper, in which, the rupture disk will rupture or shed when the pressure difference between both sides of the rupture disk is as high as the preset value at preset temperature.
3.4
Set pressure of the safety valve
It is the inlet static pressure for the safety valve clack starting rising under the operating condition, also named as opening pressure or set pressure. Under this pressure, the measurable opening height starts to exist, the liquid is at the continuous discharge condition that can be sensed visually or aurally.
3.5
Maximum marked burst pressure
One same batch of qualified rupture disks are done with burst test at a certain temperature, and the maximum burst pressure obtained through the tests is the maximum marked burst pressure of this batch of rupture disks.
3.6
Maximum relieving pressure
The maximum inlet pressure when the safety valve clack reaches the specified opening height under the relieving condition. As for the rupture disk device, the maximum relieving pressure refers to the maximum pressure bear by the pressure system when the rupture disk cracks.
3.7
Required relief capacity
The flow capacity that the safety relief system in order to prevent excessive pressure of the system.
3.8
Relief area
The net flow area when the safety valve discharges or the rupture disk cracks.
3.9
Block valve; stop valve
The valve used for blocking or connecting the fluid in pipe. The common block valves include gate valve, ball valve, plug valve, butterfly valve, diaphragm valve as well as the stop valve with flat seat, large valve opening and small flow resistance.
3.10
Independent pressurize system
A pressure system composed of one or more equipments (containers) by pipe connection without the blocking of any valves at middle, both ends of this system are installed with valves to separate from other systems.
3.11
Flame arrester
A safety protection equipment used for preventing the flame from spreading or extending in the piping.
3.12
Venting flame arrester
It is installed on the vent pipe of storage tank to prevent external flame from entering into the storage tank, and it has the pipe end type and ordinary type.
The pipe-end type venting flame arresters are of the anti-conflagration type, with one end connected to the atmosphere, installed with wind-rain protective hood on the top to prevent the dust and rainwater from entering into the flame arrester.
The ordinary type venting flame arresters are divided into anti-conflagration type and anti-detonation type, with both ends connected with the piping and being connected with the atmosphere through the downstream piping.
3.13
Pipeline flame arrester
The pipeline flame arrester is installed in the closed pipe system to prevent the flame at one end of the piping system from spreading to the other end. It is divided into anti-detonation type and anti-detonation type.
3.14
Maximum experimental safe gap (MESG)
The minimum slit width that the flame can pass through under the standard test conditions (0.1MPa, 20℃) (the slit is 25mm long).
4 Safety Relief Device
4.1 General Requirements
4.1.1 The installed safety relief device shall be able to prevent the system or any one part from having excess pressure accident.
4.1.2 Generally, the automatic control instrument and accident interlocking device shall not replace the safety relief device to act as the protective equipments of the system, however, the cases that the safety relief device can not be installed and the reliability of control instrument or interlocking device is no less than that of the safety relief device are excluded.
4.1.3 When installing the safety relief device, the factors may causing excess pressure shall be considered:
a) The outlet of equipment piping system is closed;
b) The public works (cooling water, electricity, vapor, instrument air, inert gas and fuel oil/gas) are out of order;
c) The equipments and instruments (pump, compressor, fan, heat exchanger, air cooler system, transmitter, controller, control valve and alarm interlocking device, etc) are out of order;
d) Thermal expansion and phase change of liquid;
e) Out-of-control exothermic reaction;
f) Misoperation of operation personnel;
g) Accumulation of non-condensable gas;
h) Volatile substances enter into the system (light hydrocarbon or water enters into the hot oil, etc);
i) External fires, etc;
4.1.4 The safety relief device shall be installed if any one of the following conditions is met:
a) The equipment and piping system of which the design pressure is less than the pressure of external pressure source and the outlet may be closed or blocked;
b) The outlet piping of the positive displacement pump and compressor, of which the outlet may be closed;
c) The gas-phase piping at top of distillation tower which causes excess pressure by the interrupted cooling water or backflow or the excess heat input of reboiler;
d) The equipment and piping system with excess pressure due to the accumulation of non-condensable gas;
e) The upstream pipings of block valve or control valve in the outlet piping of heating furnace;
f) The piping system producing thermal expansion or vaporization due to the closed block valves at both ends under the influence of ambient temperature, sunshine radiation or heat tracing;
g) The upstream piping system of block valve at the outlet of such reactor of which the exothermic reaction may be out of control;
h) The steam outlet piping of condensing steam turbine;
i) The outlet piping of the equipments producing steam, such as steam generator;
j) The outlet piping of the low boiling point liquid (liquefied gas, etc) container;
k) The outlet piping on the on low pressure side of heat exchanger of which the tube pass may crack;
l) Other positions where the designer thinks excess pressure may generate.
4.1.5 The independent pressurize system shall be installed with one or more parallel safety relief devices (depending on the relieving capacity) at the proper positions (equipments or piping).
4.1.6 The relevant pressure of safety relief device shall be determined in accordance with the following requirements.
4.1.6.1 As for the safety relief devices on the piping in independent pressurize system, the relevant pressure shall be determined based on the design pressure of the system and shall meet the following requirements:
a) Where only one safety relief device is installed, the set pressure of safety valve (or the maximum marked burst pressure of rupture disk device) shall not be larger than the design pressure of the system, and the maximum relieving pressure shall not be larger than shall not be larger than the larger value between 10% of the system design pressure and 20kPa.
b) Where more than one safety relief devices are installed, the set pressure of at least one safety valve (or the maximum marked burst pressure of rupture disk device) shall not be larger than the design pressure of the system, and the set pressure of the rest safety valves (or the maximum marked burst pressure of rupture disk devices) shall not exceed 5% of the system design pressure, and the maximum relieving pressure of all the safety valves shall not be larger than the larger value between 12% of the system design pressure and 30kPa.
c) The maximum relieving pressure of those safety relief devices that are installed for preventing fire accidents shall not be larger than 16% of the system design pressure.
4.1.6.2 As for the safety relief devices installed for preventing the thermal expansion of fluid piping, the set pressure of the safety valves (or the maximum marked burst pressure of rupture disk devices) shall not be larger than the smaller value between 120% of the piping design pressure and the system test pressure, and the maximum relieving pressure shall not exceed 20% of the rating value of pipe pressure at the corresponding temperature or the nominal stress of piping produced by pressure shall not exceed 20% of the allowable stress of materials.
4.1.6.3 Except for the above-mentioned two kinds of cases, with the requirements specified in 4.2.3.1~4.2.3.8 of GB/T 20801.3-2006 being met, the maximum relieving pressure shall not exceed the variation range of allowable pressure as specified in 4.2.3.9 and 4.2.3.10 of GB/T 20801.3-2006.
4.1.6.4 The set pressure of the safety valves of Leve-GC1 piping (or the maximum marked burst pressure of rupture disk devices) shall not be larger than the design pressure of piping, and the maximum relieving pressure of safety valves shall not exceed 10% of the design pressure.
4.1.7 The determination of required relief capacity and minimum relief area shall meet the following requirements.
4.1.7.1 The required relief capacity shall be determined according to the following requirements:
a) The required relief capacity under various excess pressure conditions shall be calculated according to the material balance and energy balance.
b) If one position in the system has several kinds of excess pressure conditions, then the required relief capacity under each kind of excess pressure condition shall be calculated respectively, among which the maximum value shall be taken as the required relief capacity of this position.
c) The calculation of required relief capacity shall comply with those specified in Appendix A; the required relief capacity under the excess pressure conditions not provided in Appendix A may be calculated by making reference to the corresponding provisions in SY/T 10043-2002, SY/T 10044-2002 and HG/T 20570.2-1995.
4.1.7.2 The minimum relief area shall be determined according to the following requirements:
a) The minimum relief area shall be calculated according to the required relief capacity, maximum relieving pressure, temperature of relieved fluid, rated relieving coefficient and physical properties of fluid.
b) The minimum relief area of safety valve and rupture disk device shall be calculated according to those specified in Appendix A of this Part.
c) The actual relief area of the selected safety relief device shall not be less than the minimum relief area.
4.1.8 The safety relief device shall not be installed with block valves on its inlet or outlet side. The block valves to be installed for the testing, maintenance and replacement of safety relief device shall meet the following requirements:
a) The full bore block valves shall be installed or the pressure fall of block valves shall not affect the normal operations and the required relieving capacity of safety relief device.
b) The block valves at the fully open or close position shall be able to be locked or lead sealed, the block valves at normal operations shall be locked or lead sealed at the fully open position, and they shall be closed under the supervision of authorized personnel.
4.1.9 The inlet piping of safety relief device shall meet the following requirements:
a) The pipe diameter shall be at least equal to the inlet size of safety relief device, and the inlet piping shall be as short as possible.
b) Where safety relief devices are installed on the outlet piping of reciprocating compressor, the ripple damper or orifice plate shall be installed abutting upon the compressor, and the distance between the ripple damper or orifice plate and the straight pipe segment of safety relief device shall be at least 10 times of the pipe diameter.
4.1.10 The outlet piping of safety relief device shall meet the following requirements:
a) The piping outlet relieving into the atmosphere shall face towards safe sites, the relieving piping and the pipe support shall have adequate strength to bear the relieving counterforce.
b) The backpressure of the outlet piping and main relieving pipe connected to the closed system (into the exhaust funnel, flare system, collecting container or other processing systems through the main relieving pipe) shall not exceed the maximum allowable backpressure of safety relief device.
c) The low-temperature brittle failure affect of the shock cooling of low boiling point liquid (liquefied gas, etc) sue to depressurization and flash vaporization on the piping material shall be taken into account.
1 Scope
2 Normative References
3 Terms and Definitions
4 Safety Relief Device
4.1 General Requirements
4.2 Selection of Safety Relief Device
5 Flame Arrester
5.1 Installation of Flame Arrester
5.2 Requirements for Selection of Flame Arrester
6 Safety Protection
6.1 General Requirements
6.2 Safety Protection in Plant Layout
6.3 Safety Protection in Production Management
6.4 Safety Protection Facilities and Measures
Appendix A (Normative) Calculation of Safety Relief Device
Pressure Piping Code - Industrial Piping - Part 6: Safeguarding
压力管道规则 工业管道 第6部分：安全防护
1 Scope
This Part specifies the basic requirements for the safety protection devices (safety relief device and flame arrester) and safety protection of the pressure piping within the range of GB/T 20801.1.Other requirements on safety protection not specified in this Part shall comply with the requirements of the other parts of GB/T 20801-2006 and the current relevant standards and codes of the state.
2 Normative References
The following documents contain provisions which, through reference in this Part of GB/T 20801, constitute provisions of this Part. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties whose enter into agreement according to this Part are encouraged to research whether the latest editions of these references are applied or not. For undated references, the latest edition of the normative document is applicable to this standard.
GB 150 "Steel Pressure Vessels"
GB 567-1999 "Bursting Discs and Bursting Disc Devices"
GB 3836.12-1991 "Electrical Apparatus for Explosive Atmospheres-Classification of Gases or Vapors with Air According to Their Maximum Experimental Safe Gaps and Minimum Igniting Currents" (eqv IEC 60079-12: 1978)
GB/T 3840 "Technical Methods for Making Local Emission Standards of Air Pollutants"
GB 5908 "Flame Arresters for Petroleum Tanks"
GB 12158 "General Guideline for Preventing Electrostatic Accidents"
GB/T 12241-2005 "Safety Valves--General Requirements" (ISO 4126-1: 1991, MOD)
GB/T 12242-2005 "Performance Test Code--Pressure Relief Devices"
GB/T 12243-200 5 "Spring Loaded Safety Valves"
GB 13347-1992 "The Quenching Ability of Flame Arrester and Its Test Method for Petroleum Gas Piping Systems"
GB/T 20801.1-2006 "Pressure Piping Code-Industrial Piping-Part 1: General"
GB/T 20801.3-2006 "Pressure Piping Code-Industrial Piping-Part 3: Design and Calculation"
GB 50016-2006 "Code for Design of Building Fire Protection"
GB 50160 "Fire Prevention Code of Petrochemical Enterprise Design"
GB 50187 "Code for Design of General Plan of Industrial Enterprises"
HG/T 20570.2-1995 "Installation and Selection of Safety Valves"
SH/T 3413-1999 "Specification for Selection Inspection and Acceptance of Pipeline Flame Arresters for Petroleum Gas in Petrochemical Industry"
SY/T 10043-2002 "Guide for Pressure-relieving and Depressuring Systems"
SY/T 10044-2002 "Sizing Selection and Installation of Pressure-relieving Devices in Refineries"
3 Terms and Definitions
3.1
Safety relief device
On occasions with or without fire accidents, the safety relief device is opened to relieve liquid under the action of inlet static pressure so as to prevent the pressure in the system from exceeding the preset safe value. The safety relief device includes safety valve and rupture disk device.
3.2
Safety valve
The spring acted or pilot operated valves. It is a kind of safety relief device of which the valve clack will rise to relieve the liquid so as to prevent the pressure in system from exceeding the preset safe value when the static pressure at the inlet exceeds the set pressure and that can close automatically when the pressure falls to the re-seating pressure.
3.3
Rupture disk device
A kind of non-reclosed safety relief device composed of rupture disk and gripper, in which, the rupture disk will rupture or shed when the pressure difference between both sides of the rupture disk is as high as the preset value at preset temperature.
3.4
Set pressure of the safety valve
It is the inlet static pressure for the safety valve clack starting rising under the operating condition, also named as opening pressure or set pressure. Under this pressure, the measurable opening height starts to exist, the liquid is at the continuous discharge condition that can be sensed visually or aurally.
3.5
Maximum marked burst pressure
One same batch of qualified rupture disks are done with burst test at a certain temperature, and the maximum burst pressure obtained through the tests is the maximum marked burst pressure of this batch of rupture disks.
3.6
Maximum relieving pressure
The maximum inlet pressure when the safety valve clack reaches the specified opening height under the relieving condition. As for the rupture disk device, the maximum relieving pressure refers to the maximum pressure bear by the pressure system when the rupture disk cracks.
3.7
Required relief capacity
The flow capacity that the safety relief system in order to prevent excessive pressure of the system.
3.8
Relief area
The net flow area when the safety valve discharges or the rupture disk cracks.
3.9
Block valve; stop valve
The valve used for blocking or connecting the fluid in pipe. The common block valves include gate valve, ball valve, plug valve, butterfly valve, diaphragm valve as well as the stop valve with flat seat, large valve opening and small flow resistance.
3.10
Independent pressurize system
A pressure system composed of one or more equipments (containers) by pipe connection without the blocking of any valves at middle, both ends of this system are installed with valves to separate from other systems.
3.11
Flame arrester
A safety protection equipment used for preventing the flame from spreading or extending in the piping.
3.12
Venting flame arrester
It is installed on the vent pipe of storage tank to prevent external flame from entering into the storage tank, and it has the pipe end type and ordinary type.
The pipe-end type venting flame arresters are of the anti-conflagration type, with one end connected to the atmosphere, installed with wind-rain protective hood on the top to prevent the dust and rainwater from entering into the flame arrester.
The ordinary type venting flame arresters are divided into anti-conflagration type and anti-detonation type, with both ends connected with the piping and being connected with the atmosphere through the downstream piping.
3.13
Pipeline flame arrester
The pipeline flame arrester is installed in the closed pipe system to prevent the flame at one end of the piping system from spreading to the other end. It is divided into anti-detonation type and anti-detonation type.
3.14
Maximum experimental safe gap (MESG)
The minimum slit width that the flame can pass through under the standard test conditions (0.1MPa, 20℃) (the slit is 25mm long).
4 Safety Relief Device
4.1 General Requirements
4.1.1 The installed safety relief device shall be able to prevent the system or any one part from having excess pressure accident.
4.1.2 Generally, the automatic control instrument and accident interlocking device shall not replace the safety relief device to act as the protective equipments of the system, however, the cases that the safety relief device can not be installed and the reliability of control instrument or interlocking device is no less than that of the safety relief device are excluded.
4.1.3 When installing the safety relief device, the factors may causing excess pressure shall be considered:
a) The outlet of equipment piping system is closed;
b) The public works (cooling water, electricity, vapor, instrument air, inert gas and fuel oil/gas) are out of order;
c) The equipments and instruments (pump, compressor, fan, heat exchanger, air cooler system, transmitter, controller, control valve and alarm interlocking device, etc) are out of order;
d) Thermal expansion and phase change of liquid;
e) Out-of-control exothermic reaction;
f) Misoperation of operation personnel;
g) Accumulation of non-condensable gas;
h) Volatile substances enter into the system (light hydrocarbon or water enters into the hot oil, etc);
i) External fires, etc;
4.1.4 The safety relief device shall be installed if any one of the following conditions is met:
a) The equipment and piping system of which the design pressure is less than the pressure of external pressure source and the outlet may be closed or blocked;
b) The outlet piping of the positive displacement pump and compressor, of which the outlet may be closed;
c) The gas-phase piping at top of distillation tower which causes excess pressure by the interrupted cooling water or backflow or the excess heat input of reboiler;
d) The equipment and piping system with excess pressure due to the accumulation of non-condensable gas;
e) The upstream pipings of block valve or control valve in the outlet piping of heating furnace;
f) The piping system producing thermal expansion or vaporization due to the closed block valves at both ends under the influence of ambient temperature, sunshine radiation or heat tracing;
g) The upstream piping system of block valve at the outlet of such reactor of which the exothermic reaction may be out of control;
h) The steam outlet piping of condensing steam turbine;
i) The outlet piping of the equipments producing steam, such as steam generator;
j) The outlet piping of the low boiling point liquid (liquefied gas, etc) container;
k) The outlet piping on the on low pressure side of heat exchanger of which the tube pass may crack;
l) Other positions where the designer thinks excess pressure may generate.
4.1.5 The independent pressurize system shall be installed with one or more parallel safety relief devices (depending on the relieving capacity) at the proper positions (equipments or piping).
4.1.6 The relevant pressure of safety relief device shall be determined in accordance with the following requirements.
4.1.6.1 As for the safety relief devices on the piping in independent pressurize system, the relevant pressure shall be determined based on the design pressure of the system and shall meet the following requirements:
a) Where only one safety relief device is installed, the set pressure of safety valve (or the maximum marked burst pressure of rupture disk device) shall not be larger than the design pressure of the system, and the maximum relieving pressure shall not be larger than shall not be larger than the larger value between 10% of the system design pressure and 20kPa.
b) Where more than one safety relief devices are installed, the set pressure of at least one safety valve (or the maximum marked burst pressure of rupture disk device) shall not be larger than the design pressure of the system, and the set pressure of the rest safety valves (or the maximum marked burst pressure of rupture disk devices) shall not exceed 5% of the system design pressure, and the maximum relieving pressure of all the safety valves shall not be larger than the larger value between 12% of the system design pressure and 30kPa.
c) The maximum relieving pressure of those safety relief devices that are installed for preventing fire accidents shall not be larger than 16% of the system design pressure.
4.1.6.2 As for the safety relief devices installed for preventing the thermal expansion of fluid piping, the set pressure of the safety valves (or the maximum marked burst pressure of rupture disk devices) shall not be larger than the smaller value between 120% of the piping design pressure and the system test pressure, and the maximum relieving pressure shall not exceed 20% of the rating value of pipe pressure at the corresponding temperature or the nominal stress of piping produced by pressure shall not exceed 20% of the allowable stress of materials.
4.1.6.3 Except for the above-mentioned two kinds of cases, with the requirements specified in 4.2.3.1~4.2.3.8 of GB/T 20801.3-2006 being met, the maximum relieving pressure shall not exceed the variation range of allowable pressure as specified in 4.2.3.9 and 4.2.3.10 of GB/T 20801.3-2006.
4.1.6.4 The set pressure of the safety valves of Leve-GC1 piping (or the maximum marked burst pressure of rupture disk devices) shall not be larger than the design pressure of piping, and the maximum relieving pressure of safety valves shall not exceed 10% of the design pressure.
4.1.7 The determination of required relief capacity and minimum relief area shall meet the following requirements.
4.1.7.1 The required relief capacity shall be determined according to the following requirements:
a) The required relief capacity under various excess pressure conditions shall be calculated according to the material balance and energy balance.
b) If one position in the system has several kinds of excess pressure conditions, then the required relief capacity under each kind of excess pressure condition shall be calculated respectively, among which the maximum value shall be taken as the required relief capacity of this position.
c) The calculation of required relief capacity shall comply with those specified in Appendix A; the required relief capacity under the excess pressure conditions not provided in Appendix A may be calculated by making reference to the corresponding provisions in SY/T 10043-2002, SY/T 10044-2002 and HG/T 20570.2-1995.
4.1.7.2 The minimum relief area shall be determined according to the following requirements:
a) The minimum relief area shall be calculated according to the required relief capacity, maximum relieving pressure, temperature of relieved fluid, rated relieving coefficient and physical properties of fluid.
b) The minimum relief area of safety valve and rupture disk device shall be calculated according to those specified in Appendix A of this Part.
c) The actual relief area of the selected safety relief device shall not be less than the minimum relief area.
4.1.8 The safety relief device shall not be installed with block valves on its inlet or outlet side. The block valves to be installed for the testing, maintenance and replacement of safety relief device shall meet the following requirements:
a) The full bore block valves shall be installed or the pressure fall of block valves shall not affect the normal operations and the required relieving capacity of safety relief device.
b) The block valves at the fully open or close position shall be able to be locked or lead sealed, the block valves at normal operations shall be locked or lead sealed at the fully open position, and they shall be closed under the supervision of authorized personnel.
4.1.9 The inlet piping of safety relief device shall meet the following requirements:
a) The pipe diameter shall be at least equal to the inlet size of safety relief device, and the inlet piping shall be as short as possible.
b) Where safety relief devices are installed on the outlet piping of reciprocating compressor, the ripple damper or orifice plate shall be installed abutting upon the compressor, and the distance between the ripple damper or orifice plate and the straight pipe segment of safety relief device shall be at least 10 times of the pipe diameter.
4.1.10 The outlet piping of safety relief device shall meet the following requirements:
a) The piping outlet relieving into the atmosphere shall face towards safe sites, the relieving piping and the pipe support shall have adequate strength to bear the relieving counterforce.
b) The backpressure of the outlet piping and main relieving pipe connected to the closed system (into the exhaust funnel, flare system, collecting container or other processing systems through the main relieving pipe) shall not exceed the maximum allowable backpressure of safety relief device.
c) The low-temperature brittle failure affect of the shock cooling of low boiling point liquid (liquefied gas, etc) sue to depressurization and flash vaporization on the piping material shall be taken into account.
Contents of GB/T 20801.6-2006
1 Scope
2 Normative References
3 Terms and Definitions
4 Safety Relief Device
4.1 General Requirements
4.2 Selection of Safety Relief Device
5 Flame Arrester
5.1 Installation of Flame Arrester
5.2 Requirements for Selection of Flame Arrester
6 Safety Protection
6.1 General Requirements
6.2 Safety Protection in Plant Layout
6.3 Safety Protection in Production Management
6.4 Safety Protection Facilities and Measures
Appendix A (Normative) Calculation of Safety Relief Device
