SY/T 10044-2002 Recommended practice for sizing, selection and installation of pressure relief devices for refineries
Some standard content:
ICS 75.020
Registration number: 10487-2002
Petroleum and natural gas industry standard of the People's Republic of China SY/T10044—2002
Recommended practices for sizing, selection and installation of pressure - rclieving devices in refineries
Sizing, selection and installation of pressure - rclieving devices inrefineries
2002-05-28 Issued
National Economic and Trade Commission
2002-08-01 Implementation
API Pre-
Policy Clarifications
Chapter 1 Introduction
1.1 Scope
1.2 Definition of Terms
1.2.1 Pressure Relief Devices
1.2.2 Dimensional Characteristics of Pressure Relief Devices
1.2.3 Operating Characteristics of Pressure Relief Devices
Chapter 2 Pressure Relief Devices
2.1 Overview
2.2 Spring-Loaded Pressure Relief Valve
2.2.1 Safety Valve.
Relief Valve
Safety Relief Valve
Pressure Relief Devices Relief valve
Dimensioning and selection
Part 1
Pressure relief valve controlled by pilot valve…
2.4 Bursting disc device·
2.5 Bursting disc
Overview·
Types of bursting discs
Application of bursting discs
Special term for bursting disc devices·
2.6 Combination of bursting disc and pressure relief valve, 2.6.1 Overview
Bursting disc device installed at the inlet of pressure relief valve·2.6.2
2.6.3 Bursting disc device installed at the outlet of pressure relief valve, 2.7 Other types of pressure relief devices
Chapter 3 Causes of overpressure
Overview·
3.2 Process accidents (excluding fire accidents) 3.3 Fire accidents·…．
Overview,
Effect of fire on wetted surfaces of vessels
Effect of fire on non-wetted surfaces of vessels·
Chapter 4 Sizing Procedures
SY/T 10044—2002
SY/T 10044-2002
Determination of Relief Requirements
4.2 Relief Pressure
Overview·
Operational Failures
4.2.3 Fire Accidents·
4.2.4 Water Vapor Relief
4.3 Sizing of Gas or Steam Reliefs
4.3.1 Critical Flow Characteristics
4.3.2 Sizing of Critical Flow Reliefs
4.3.3 Sizing of Gas or Steam (Non-Steam) Subcritical Flows 4.3.4 Subcritical Flow Reliefs Another sizing method for critical flow conditions 4.4 Sizing of gas releases from a water swallow
4.4.1 Overview.
4.4.2 Examples
4.5 Sizing of liquid releases: it is necessary to confirm the liquid release capacity of the release valve 4.5.1 Overview.
4.5.2 Examples
4.6 Sizing of liquid releases: it is not necessary to confirm the liquid release capacity of the release valve 4.7 Sizing of gas/liquid two-phase releases
4.8 Sizing of bursting disc devices.
4.8 .1 Bursting disc devices for use alone
4.8.2 Bursting disc devices for use in combination with pressure relief valves Appendix A (Normative Appendix)
Specifications for bursting disc devices
Appendix B (Normative Appendix)
Issues to be considered in the design of special systems
Appendix C (Normative Appendix)
Main causes of overpressure
Appendix D (Normative Appendix) Determination of fire relief requirements Appendix F (Normative Appendix)
Evolution of flow equations for determining the size of pressure relief valves Appendix F (Normative Appendix)
Design of the discharge manifold
Appendix (Standard Appendix)
Specifications for pressure relief measurement
Part 2 Installation
Chapter 1 Overview
1.2 Definition of terms
Chapter 2 Inlet piping of pressure relief devices
General requirements
2.1.1 Fluid flow and stress issues
2.1.2 Vibration issues
2.2 Limits of pressure drop and piping principles
2.2.1 Pressure relief devices
2.2.2.3 Pressure relief devices
2.2.4 Pressure relief devices
2.2.5 Pressure relief devices
2.2.6 Pressure relief devices
2.2.7 Pressure relief devices
2.2.8 Pressure relief devices
2.2.9 Pressure relief devices
3.10 Pressure relief devices
3.110 Pressure relief devices
3.120 Pressure relief devices
3.13 Pressure relief devices
3.14 Pressure relief devices
3.15 Pressure relief devices
3.16 Pressure relief devices
3.17 Pressure relief devices
3.18 Pressure relief devices
3.19 Pressure relief devices
4.10 Pressure relief devices
4.11 2.2.2.1 Pressure drop at the inlet of the pressure relief valve
2.2.2.2.2.3.3.4.2.2.2.3 ... 2.6 Combination of bursting disc device and pressure relief valve 2.7 Process branch pipeline connected to the inlet pipeline of pressure relief valve 2.8 Flow in the inlet pipeline of pressure relief valve, discharge pipeline of pressure relief device Chapter 3 General requirements Safe discharge of discharged fluids Back pressure limitation and determination of pipeline size About pilot-controlled pressure oil relief valve Stress in discharge pipeline Block valve on vent line
Chapter 4
Block valves on pressure relief lines
Overview·
Requirements for block valves·
Examples of installing block valves
4.5 Management procedures for block valves.
Chapter 5 Bonnet or pilot valve vent pipe
5.1 Conventional pressure relief valve
5.2 Balanced bellows pressure relief valve
5.3 Balanced active pressure relief valve
5.4 Pilot valve controlled pressure relief valve·
Chapter 6 Drain pipe|| tt||6.1 Installation conditions requiring a drain pipe
6.2 Safe practices for installing a drain pipe
Chapter 7 Installation location and orientation of pressure relief devices 7.1 Inspection and maintenance
7.2 Proximity to pressure sources
7.3 Proximity to other devices
7.3.1 Pressure reducing station
7.3.2 Orifice plate and flow valve nozzle
7.3.3 Other valves and accessories
7.4 Installation orientation
7.5 Test or lifting rod
7.6. Heating and insulation
Chapter 8 Bolts and gaskets
8.1 Installation precautions -
SY/T 10044--2002
SY/T10044—2002
8.2 Select appropriate gaskets and bolts according to work requirements Chapter 9 Multiple pressure relief valves with graded set pressures Chapter 10 Treatment and inspection before installation
10.1 Storage and treatment of pressure relief devices 10.2 Inspection and testing of pressure relief valves
10.3 Inspection of bursting disc devices
Inspection and cleaning before system installation
SY/T10H44—2002
In order to meet the needs of my country's development of offshore oil and gas resources, China National Offshore Oil Corporation has adopted the American Petroleum Institute's "Recommended Practice for Sizing, Selection and Installation of Pressure Relief Devices in Refineries" Part 1 (1993 Edition) and Part 2 (1994 Edition), namely API RP 520 "Sizing, Selection and Irrstallation of Pressure--Relicving Devices in Refineries" Refincrics》 Part I —Sizing and Selecliun (1993), Part Ⅱ-Install (1994), and at the same time revised Q/HS 7015-93 "Refining" \ Recommended Practice for Sizing, Selection and Installation of Pressure Relief Devices" as the standard of the petroleum and natural gas industry of the People's Republic of China.
In the 1993 edition of APIRP520, the following parts have been modified on the basis of the previous edition of 1990, and many contents have been added, most of which are substantial, especially the additions and modifications of Part 2 exceed 60%, and the contents of Part 1 have not changed much, as follows: a) In 2.6.2.1, the value of K. is changed from 0.8 to 1.9. b) The original 2.8 is deleted,
c) The second paragraph of 4.1 is changed.
d) The third to last paragraph of Appendix E is completely changed. Part II is increased from 9 chapters to 10 chapters, and the contents of each chapter are basically rewritten, which will not be described here one by one. In the process of formulating this standard, some modifications have been made to the terms, symbols, words and grammar to make the use of terms and symbols more standard and the expression of the content more clear and easy to understand. The style is kept consistent with the previous version Q/IS7015-93 as much as possible to maintain the continuity of the standard.
In the design, construction and use of offshore oil and gas development projects involving the laws, regulations and provisions of the government or other competent authorities of the country where the original standard is located, the data or quantitative calculation methods of environmental conditions such as wind, waves, currents, ice, temperature, earthquakes, etc. in the original standard shall be implemented in accordance with the corresponding laws, regulations and provisions promulgated by the government of the People's Republic of China or the competent government departments. All those that are in line with my country's actual situation can be used as a reference; otherwise, data and quantitative calculation methods that meet my country's actual environmental conditions should be used. Regarding the units of measurement, the legal measurement units are mainly used, that is, the legal measurement unit values are in front: the corresponding values of the imperial units are marked in brackets afterwards.
In order not to change the formulas, curve shape characteristics, constants and coefficients in the original standard, all the imperial units are still used.
Appendix A, Appendix B, Appendix C, Appendix D, Appendix E, Appendix F, and Appendix G of this standard are normative appendices. This standard is proposed and managed by China National Offshore Oil Corporation: The drafting unit of this standard is the Development and Design Institute of the Offshore Oil Research Center of China National Offshore Oil Corporation. The main drafter of this standard is Gao Peng.
The chief examiner of this standard is Xu Liying.
SY/T 10044—2002
API Foreword
APIRP520 "Recommended Practice for Sizing, Selection and Installation of Refinery Pressure Relief Devices" is the result of many years of work by petroleum engineers.
The information in this publication is intended to supplement the recommendations in Chapter 1, Pressure Vessels, of the American Society of Mechanical Engineers' Boiler and Pressure Vessel Code. It does not replace applicable codes and regulations. Users of this recommended practice are cautioned that publications of this type are neither complete nor is any written document a substitute for competent engineering analysis.
This recommended practice is a two-part publication. It revise the generally accepted methods of all equipment installations in previous editions and contains supplementary information based on revisions requested by many individuals and organizations. The first edition of this recommended practice was issued in 1955. The second edition was published in two parts: Part T "Design" was issued in 1960, Part II "Installation" was issued in 1963, and the third edition of Part I was issued in November 1967 and reprinted in 1973. API publications are available for use by anyone who needs to do so. The Institute makes every effort to ensure the accuracy and reliability of the data in the publications; however, the Institute makes no representation, warranty or guarantee with respect to the publications, and the Institute expressly disclaims any responsibility or liability for loss or damage caused by the use of the publications or for violation of any federal or state regulations that may be inconsistent with this publication. Comments for revisions are welcome and should be sent to the Director, Production, Distribution and Sales Division, American Petroleum Institute, 1220 I. Strect, NW, Washington, DC 20005.
Policy Statement
SY/T 100442002
1. API publications are necessarily specific to a particular problem. When it comes to specific situations, local, state, and federal laws and regulations should be consulted.
2. API does not assume any obligation for employers, manufacturers, or suppliers to warn, train, or equip their employees with regard to health, safety risks, and preventive measures, nor does it assume any responsibility for their compliance with local, state, or federal laws. 3. Information about the safety and health risks and corresponding preventive measures involved in individual materials and processes should be obtained from the employer, the manufacturer or supplier of their materials, or from the safety data sheet of their materials. 4. The content of any API publication cannot be interpreted, by implication or otherwise, as granting any right to manufacture, sell, or involve the use of any patented method, device, or product. Nor can anything in this publication be interpreted as excusing any Liability for patent infringement:
5. Generally, API standards are reviewed at least once every five years and are revised, re-certified or revoked. Sometimes, this review cycle can be extended by one time, up to two years. As the current API standard, this publication shall be valid for no more than five years from the date of publication, unless it is authorized to be reprinted and its validity period is extended. The status of publications can be obtained from the API Editorial Office [Tel: (202) 682-8000. API (1220L Street, NW, Washington, DC, 20005) publishes a publications and patent information catalog once a year and updates it quarterly.
1.1 Scope
Recommended Practice for Sizing, Selection and Installation of Refinery Pressure Relief Devices
Part 1 Sizing and Selection
Chapter 1 Introduction
SY/T 10044—2002
This standard applies to the sizing and selection of pressure relief devices on refineries and related industrial equipment with the maximum allowable operating pressure equal to or higher than 103.4kPa (gauge pressure) (15msig). The pressure relief devices involved in this standard are used to protect non-fired pressure vessels and mechanical equipment from overpressure during operation and fire accidents. This standard includes basic definitions and the operating characteristics and application scope of various pressure relief devices, including the procedures and methods for sizing based on steady flow and Newtonian flow.
Pressure relief devices only prevent overpressure of containers, but cannot prevent the destruction of container structures during fire accidents. See SY/T10043-2002 "Guidelines for Pressure Relief Systems" for applicable methods to reduce pressure and limit heat input. Atmospheric and low-pressure storage tanks and pressure vessels used for bulk or packaged transportation of petroleum products included in APIStd2000 are not included in this standard.
The fire-carrying devices referred to in Chapter 1 of the ASM Code for Boilers and Pressure Vessels and in ASME I3I.1 are also not included in this standard.
1.2 Definition of Terms
The terms related to pressure relief devices and their dimensions and operating characteristics in this standard are given in 1.2.1 to 1.2.3. In addition, more precise explanations are given in the corresponding chapter references and appendices. 1.2.1 Pressure Relief Device
Pressure relief device pressure relief device is a static pressure-actuated device that opens in an emergency or abnormal situation to prevent the fluid pressure in the equipment from exceeding the set pressure. The pressure relief device can also be used to prevent excessive negative pressure. The pressure relief device can be a pressure relief valve, a non-reclosing pressure relief device, or a vacuum relief valve.
Spring-loaded pressure relief valve is a pressure relief device that automatically recloses and prevents the fluid from flowing out in one step. 1.2,1,2.1
Relief valve
A spring-loaded pressure relief valve driven by the static pressure in front of the valve. The valve opening is proportional to the pressure increment above the set pressure. Mainly used for incompressible fluids
1.2.1.2.2
Safety valvesafctyvalve
A spring-loaded pressure relief valve driven by the static pressure in front of the valve. It has the characteristics of rapid opening or emergency action and is usually used for compressible fluids
1.2.1.2.3
Safety relief valvesafetyrclicfvalye
A spring-loaded pressure relief valve that can be used as both a safety valve and a relief valve. 1
SY/T 10044—2002
1.2.1.2.4
Conventional pressure relief valve
conventional prcssurc relief valve-A spring-loaded pressure relief valve in which the back pressure change of the valve directly affects the valve characteristics. 1.2.1.2.5
Balanced pressure relief valve balancedpressurereliefvalve A spring-loaded pressure relief valve that can reduce the influence of back pressure on the operating characteristics of the valve: 1.2.1.3
Pilot-operatedpressurereliefvalve A pressure relief valve composed of a main valve and an auxiliary pressure relief valve (pilot valve) that controls the main valve. 1.2.1.4
Rupture disk
is a non-reclosing differential pressure relief device that relies on the static pressure in front of the diaphragm and works by the rupture of the diaphragm. The rupture disk device consists of a rupture disk and a retainer.
1.2.2 Dimensional characteristics of pressure relief devices
actual discharge area
artificial discharge area
The minimum net cross-sectional area of the fluid passing through the valve. 1.2.2.2
curtal area
refers to the area of the cylindrical or conical passage formed between the valve disc when it is lifted on the valve seat. 1.2,2.3
Effective discharge area or equivalent flow area The nominal or calculated area of a pressure relief valve, usually measured in the recognized calculation formula. It is smaller than the actual discharge area.
Nozzle area
The cross-sectional area of the valve orifice at the minimum valve orifice diameter. 1.2.2.5
Huddling chamber
An annular pressure relief valve with a repelling chamber, installed on the upper part of the valve seat, plays a quick opening role. 1.2.2.6
Inlet size
Unless otherwise specified, usually refers to the nominal diameter of the valve inlet pipe connection. 1.2.2.7
Outlet size
Unless otherwise specified, it usually refers to the nominal diameter of the valve outlet pipe connection: 1.2.2.8
Lift
refers to the actual travel of the valve disc away from the closed position when the valve is released. 1.2.3 Operating characteristics of pressure relief devices
1.2.3.1 System pressure
1.2.3.1.1
Maximum operating pressure
refers to the maximum pressure that can be reached during operation. 1.2.3.1.2
Maximum allowable working pressure
refers to the maximum allowable gauge pressure at the top of the container under the operating conditions of the design temperature. This repulsive force is calculated based on the nominal wall thickness of the container, excluding the corrosion allowance of the wall thickness and the non-pressure load allowance. The maximum allowable working pressure is the basis for determining the set pressure of the pressure relief device protecting the container.
1.2.3.1.3
Design pressure [gauge pressure]
design gauge pressure
The pressure under the most severe temperature and pressure conditions in operation. It can be used as a substitute when the maximum allowable working pressure is not determined. It is equal to or less than the maximum allowable working pressure.
1.2.3.1.4
Accumulation pressure
The pressure increase exceeding the maximum allowable working pressure of the container during the non-discharge period of the pressure relief device, expressed in pressure units or percentages: The maximum allowable accumulation pressure is determined according to the corresponding specifications for operation and fire accidents. 1.2.3.1.5
Overpressure
Refers to the pressure exceeding the set pressure of the pressure relief device, expressed in pressure units or percentages. When the set pressure of the relief device is set at the maximum allowable working pressure of the container, the overpressure and the accumulated pressure are the same. 1.2.3.1.6
Rated relief capacity Rated relief capacity The measured relief capacity allowed by the applicable specifications or regulations is the basic data for selecting the pressure relief device. 1.2.3.1.7
Nameplate relief capacity Stamped capacity
The rated relief capacity marked on the nameplate. The nameplate relief capacity is the relief capacity determined by the set pressure or burst pressure plus the allowable overpressure for compressible fluids and the allowable pressure difference for incompressible fluids. 1.2.3.2 Device pressure
1.2.3.2.1
Set pressure
setpressure
refers to a specific value of the inlet gauge pressure of the pressure relief device, at which the pressure relief valve is set to open under operating conditions. 1.2.3.2.2
Cold differential test pressure is the pressure at which the pressure relief valve is adjusted to open under test conditions. This cold test differential pressure includes corrections for various operating conditions of temperature or temperature, or both. 1.2.3.2.3
Back pressure
The pressure at the outlet of the pressure relief device is the sum of the superimposed back pressure and the built-up back pressure. 1.2.3.2.4
Built-up back pressure is the pressure increase in the discharge manifold caused by the flow after the pressure relief device is opened. 1.2.3.2.5
Superimposed back pressure is the static pressure at the outlet of the pressure relief device before it is opened. It can be from other pressure sources in the discharge system. The pressure may be stable or variable.
SY/T10044--2002
1.2.3.2.6
Blowdown
refers to the pressure difference between the set pressure and the closing pressure of the pressure relief valve, expressed as a percentage of the set pressure or in pressure units. 1.2.3.2.7
Opening pressure
opening pressure
refers to the pressure value at which the valve disc has a moderate lifting height and the fluid is discharged continuously when the inlet static pressure increases to this pressure value. 1.2.3.2.8
Closing pressure (
closing pressure) pressurc
refers to the pressure value to which the inlet static pressure drops, the valve disc closes and the lifting height is zero. 1.2.3.2.9
slow leakage simmer
refers to the leakage of compressed fluid between the valve seat and the valve disc that cannot be measured and can be heard or seen when the inlet static pressure is lower than the set pressure. 1.2.3.2.10
leakage test pressure leak-test pressure leak-test pressure refers to the specified inlet static pressure when the valve seat leakage test is performed. 1.2.3.2.11
releasing condition
the inlet pressure and temperature of the pressure relief device at a specific overpressure. The relief pressure is equal to the set pressure of the valve (or the bursting pressure of the bursting disc) plus the overpressure value (the temperature of the fluid at the relief condition may be higher or lower than the operating temperature). Note: Figure 1 shows the relationship between various terms for single or multiple pressure relief valve devices41
Maximum operating pressure
The maximum operating pressure
refers to the maximum pressure that can be reached during operation. 1.2.3.1.2
Maximum allowable working pressure
Imaximum allowable wnrking pressnre- MAWPSY/r 10044—2002
refers to the maximum allowable gauge pressure at the top of the vessel under the operating conditions of the design temperature. This repulsion is calculated based on the nominal wall thickness of the vessel part, excluding the corrosion allowance of the wall thickness and the non-pressure load allowance. The maximum allowable working pressure is the basis for determining the set pressure of the pressure relief device protecting the vessel.
1.2.3.1.3
Design pressure [gauge pressure]
design gauge pressure
The pressure under the most severe temperature and pressure conditions in operation. When the maximum allowable working pressure is not determined, it can be used as a substitute, which is equal to or less than the maximum allowable working pressure.
1.2.3.1.4
Accumulation
During the non-discharge period of the pressure relief device, the pressure increase exceeding the maximum allowable working pressure of the container is expressed in pressure units or percentages: the maximum allowable accumulation pressure is determined according to the corresponding specifications for operation and fire accidents. 1.2.3.1.5
Overpressure
refers to the pressure exceeding the set pressure of the pressure relief device, expressed in pressure units or percentages. When the set pressure of the relief device is set at the maximum allowable working pressure of the container, the overpressure and accumulation pressure are the same. 1.2.3.1.6
Rated relief capacity Rated relief capacity The measured relief capacity allowed by the applicable specifications or regulations is the basic data for the selection of pressure relief devices. 1.2.3.1.7
Stamped capacity
The rated relief capacity marked on the nameplate. The nameplate discharge volume is the discharge volume determined by the set pressure or burst pressure plus the allowable excess pressure for compressible fluids and the allowable pressure differential for incompressible fluids. 1.2.3.2 Device pressure
1.2.3.2.1
Set pressure
setpressure
refers to a specific value of the inlet gauge pressure of the pressure relief device, at which the pressure relief valve is set to open under operating conditions. 1.2.3.2.2
Cold test differential pressurecold differential test pressurerefers to the pressure at which the pressure relief valve is adjusted to open under the test state. This cold test differential pressure includes corrections for various operating conditions of temperature or temperature, or both. 1.2.3.2.3
Back pressure
The pressure at the outlet of the pressure relief device is the sum of the superimposed back pressure and the accumulated back pressure. 1.2.3.2.4
Built-up back pressureThe pressure increase in the discharge manifold caused by the flow after the pressure relief device is opened. 1.2.3.2.5
Superimposed back pressureThe static pressure at the outlet of the pressure relief device before it is opened. It can come from other pressure sources in the discharge system. The pressure may be stable or variable.
SY/T10044--2002
1.2.3.2.6
Blowdown
Refers to the pressure difference between the set pressure and the closing pressure of the pressure relief valve, expressed as a percentage of the set pressure or in pressure units. 1.2.3.2.7
Opening pressure
opening pressure
refers to the pressure value at which the valve disc has a moderate lifting height and the fluid is discharged continuously when the static pressure at the inlet increases to this value. 1.2.3.2.8
Closing pressure (
closing pressure) pressurc
refers to the pressure value to which the inlet static pressure drops, the valve disc closes and the lifting height is zero. 1.2.3.2.9
slow leakage simmer
refers to the leakage of compressed fluid between the valve seat and the valve disc that cannot be measured and can be heard or seen when the inlet static pressure is lower than the set pressure. 1.2.3.2.10
leakage test pressure leak-test pressure leak-test pressure refers to the specified inlet static pressure when the valve seat leakage test is performed. 1.2.3.2.11
releasing condition
the inlet pressure and temperature of the pressure relief device at a specific overpressure. The relief pressure is equal to the set pressure of the valve (or the bursting pressure of the bursting disc) plus the overpressure value (the temperature of the fluid at the relief condition may be higher or lower than the operating temperature). Note: Figure 1 shows the relationship between various terms for single or multiple pressure relief valve devices41
Maximum operating pressure
The maximum operating pressure
refers to the maximum pressure that can be reached during operation. 1.2.3.1.2
Maximum allowable working pressure
Imaximum allowable wnrking pressnre- MAWPSY/r 10044—2002
refers to the maximum allowable gauge pressure at the top of the vessel under the operating conditions of the design temperature. This repulsion is calculated based on the nominal wall thickness of the vessel part, excluding the corrosion allowance of the wall thickness and the non-pressure load allowance. The maximum allowable working pressure is the basis for determining the set pressure of the pressure relief device protecting the vessel.
1.2.3.1.3
Design pressure [gauge pressure]bzxZ.net
design gauge pressure
The pressure under the most severe temperature and pressure conditions in operation. When the maximum allowable working pressure is not determined, it can be used as a substitute, which is equal to or less than the maximum allowable working pressure.
1.2.3.1.4
Accumulation
During the non-discharge period of the pressure relief device, the pressure increase exceeding the maximum allowable working pressure of the container is expressed in pressure units or percentages: the maximum allowable accumulation pressure is determined according to the corresponding specifications for operation and fire accidents. 1.2.3.1.5
Overpressure
refers to the pressure exceeding the set pressure of the pressure relief device, expressed in pressure units or percentages. When the set pressure of the relief device is set at the maximum allowable working pressure of the container, the overpressure and accumulation pressure are the same. 1.2.3.1.6
Rated relief capacity Rated relief capacity The measured relief capacity allowed by the applicable specifications or regulations is the basic data for the selection of pressure relief devices. 1.2.3.1.7
Stamped capacity
The rated relief capacity marked on the nameplate. The nameplate discharge volume is the discharge volume determined by the set pressure or burst pressure plus the allowable excess pressure for compressible fluids and the allowable pressure differential for incompressible fluids. 1.2.3.2 Device pressure
1.2.3.2.1
Set pressure
setpressure
refers to a specific value of the inlet gauge pressure of the pressure relief device, at which the pressure relief valve is set to open under operating conditions. 1.2.3.2.2
Cold test differential pressurecold differential test pressurerefers to the pressure at which the pressure relief valve is adjusted to open under the test state. This cold test differential pressure includes corrections for various operating conditions of temperature or temperature, or both. 1.2.3.2.3
Back pressure
The pressure at the outlet of the pressure relief device is the sum of the superimposed back pressure and the accumulated back pressure. 1.2.3.2.4
Built-up back pressureThe pressure increase in the discharge manifold caused by the flow after the pressure relief device is opened. 1.2.3.2.5
Superimposed back pressureThe static pressure at the outlet of the pressure relief device before it is opened. It can come from other pressure sources in the discharge system. The pressure may be stable or variable.
SY/T10044--2002
1.2.3.2.6
Blowdown
Refers to the pressure difference between the set pressure and the closing pressure of the pressure relief valve, expressed as a percentage of the set pressure or in pressure units. 1.2.3.2.7
Opening pressure
opening pressure
refers to the pressure value at which the valve disc has a moderate lifting height and the fluid is discharged continuously when the static pressure at the inlet increases to this value. 1.2.3.2.8
Closing pressure (
closing pressure) pressurc
refers to the pressure value to which the inlet static pressure drops, the valve disc closes and the lifting height is zero. 1.2.3.2.9
slow leakage simmer
refers to the leakage of compressed fluid between the valve seat and the valve disc that cannot be measured and can be heard or seen when the inlet static pressure is lower than the set pressure. 1.2.3.2.10
leakage test pressure leak-test pressure leak-test pressure refers to the specified inlet static pressure when the valve seat leakage test is performed. 1.2.3.2.11
releasing condition
the inlet pressure and temperature of the pressure relief device at a specific overpressure. The relief pressure is equal to the set pressure of the valve (or the bursting pressure of the bursting disc) plus the overpressure value (the temperature of the fluid at the relief condition may be higher or lower than the operating temperature). Note: Figure 1 shows the relationship between various terms for single or multiple pressure relief valve devices47
Opening pressure
refers to the pressure value at which the valve disc has a moderate lifting height and the fluid is discharged continuously when the static pressure at the inlet increases to this value. 1.2.3.2.8
Closing pressure (
closing pressure) pressurc
refers to the pressure value to which the inlet static pressure drops, the valve disc closes and the lifting height is zero. 1.2.3.2.9
slow leakage simmer
refers to the leakage of compressed fluid between the valve seat and the valve disc that cannot be measured and can be heard or seen when the inlet static pressure is lower than the set pressure. 1.2.3.2.10
leakage test pressure leak-test pressure leak-test pressure refers to the specified inlet static pressure when the valve seat leakage test is performed. 1.2.3.2.11
releasing condition
the inlet pressure and temperature of the pressure relief device at a specific overpressure. The relief pressure is equal to the set pressure of the valve (or the bursting pressure of the bursting disc) plus the overpressure value (the temperature of the fluid at the relief condition may be higher or lower than the operating temperature). Note: Figure 1 shows the relationship between various terms for single or multiple pressure relief valve devices47
Opening pressure
refers to the pressure value at which the valve disc has a moderate lifting height and the fluid is discharged continuously when the static pressure at the inlet increases to this value. 1.2.3.2.8
Closing pressure (
closing pressure) pressurc
refers to the pressure value to which the inlet static pressure drops, the valve disc closes and the lifting height is zero. 1.2.3.2.9
slow leakage simmer
refers to the leakage of compressed fluid between the valve seat and the valve disc that cannot be measured and can be heard or seen when the inlet static pressure is lower than the set pressure. 1.2.3.2.10
leakage test pressure leak-test pressure leak-test pressure refers to the specified inlet static pressure when the valve seat leakage test is performed. 1.2.3.2.11
releasing condition
the inlet pressure and temperature of the pressure relief device at a specific overpressure. The relief pressure is equal to the set pressure of the valve (or the bursting pressure of the bursting disc) plus the overpressure value (the temperature of the fluid at the relief condition may be higher or lower than the operating temperature). Note: Figure 1 shows the relationship between various terms for single or multiple pressure relief valve devices4
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