SY/T 7803-2024 Guideline for explosion safety assessment of buildings inliquefied natural gas station English, Anglais, Englisch, Inglés, えいご
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ICS
E
Professional standard of the People's Republic of China
SY/T 7803-2024
Guideline for explosion safety assessment of buildings in liquefied natural gas station
液化天然气站场建筑物爆炸安全性评估导则
(English Translation)
Issue date: 2024-09-24 Implementation date: 2025-03-24
Issued by National Development and Reform Commission, P.R.C
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Abbreviations
5 General Provisions
6 Vapor Cloud Explosion Assessment Process
7 Assessment Preparation
7.1 Determining Accident Scenarios
7.2 Identifying Buildings Requiring Assessment
7.3 Determining Confined Areas
8 Assessment Methods
8.1 Selection of Vapor Cloud Explosion Models
8.2 Consequence-Based Assessment
8.3 Risk-Based Assessment
9 Conclusions and Recommendations for Explosion Safety Assessment of Blast-Resistant Buildings
Appendix A (Informative) Typical Classification of Buildings Involved in Explosion Safety Assessment
Appendix B (Informative) TNO Model
Appendix C (Informative) Cumulative Frequency Method
Bibliography
Guideline for Explosion Safety Assessment of Buildings in Liquefied Natural Gas Stations
1 Scope
This document provides guidance for conducting explosion safety assessments for buildings in liquefied natural gas stations and specifies the relevant content of the assessment process, assessment methods, assessment conclusions, and recommendations.
This document applies to the safety assessment of buildings with a specified design service life in new, modified, and expanded liquefied natural gas stations against external vapor cloud explosions.
Note: The buildings covered in this document are rigid structures in fixed locations.
2 Normative References
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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 20368-2021 Liquefied natural gas (LNG) — Production, storage and handling
GB/T 37243-2019 Determination method of external safety distance for hazardous chemicals production units and storage installations
3 Terms and Definitions
The following terms and definitions apply to this document.
3.1
liquefied natural gas station
A station with functions for natural gas purification and liquefaction, liquefied natural gas storage and handling, and liquefied natural gas receiving, reloading, and regasification.
Note: Includes baseload natural gas liquefaction plants, peak-shaving liquefaction plants, liquefied natural gas receiving terminals, liquefied natural gas satellite stations, etc.
3.2
vapor cloud explosion
Energy release resulting from the ignition of a flammable cloud formed by the mixture of flammable gas and air, causing the flame speed to accelerate to a velocity sufficient to generate overpressure.
3.3
confinement
The degree of restriction, in at least one direction, that inhibits the expansion of combustion at the flame front of a vapor cloud.
3.4
congestion
The density of obstacles in the path of the flame front, which can potentially increase the flame speed to a level capable of generating damaging shock waves.
3.5
confined area
A space characterized by confinement and congestion where a vapor cloud explosion can occur.
3.6
explosion overpressure
Pressure exceeding atmospheric pressure resulting from an explosion.
3.7
occupied building
A building where the cumulative person-hours of personnel in fixed operating positions are greater than 40 person-hours per day, or where the number of personnel working inside the building for 1 hour or more during peak periods is not less than 10 people (with a frequency of not less than once per month).
3.8
explosion source
A confined area within a congested or enclosed space where flammable gas may accumulate.
4 Abbreviations
The following abbreviations apply to this document.
BST: Baker-Strehlow-Tan Method
TNO: The Netherlands Organization of Applied Scientific Research
TNT: Trinitrotoluene
5 General Provisions
5.1 The leak sources for the explosion safety assessment of liquefied natural gas stations shall be production units and storage/transportation facilities handling Class A and Class B flammable media.
5.2 The damage to blast-resistant buildings from explosion loads shall be limited to an acceptable level. The accident consequences corresponding to typical explosion overpressure values shall be implemented according to Table G.3 in GB/T 37243-2019.
5.3 Consequence-based or risk-based assessment methods may be selected for building explosion safety assessment.
5.4 Liquefied natural gas stations with buildings at risk of vapor cloud explosions shall implement safety improvement measures in accordance with Chapter 9.
6 Vapor Cloud Explosion Assessment Process
The process for the vapor cloud explosion safety assessment of buildings is shown in Figure 1.
7 Assessment Preparation
7.1 Determining Accident Scenarios
7.1.1 The volume of flammable gas involved in the vapor cloud explosion shall be determined through dispersion simulation. When the vapor cloud volume is greater than the confined area volume, the volume of flammable gas involved in the vapor cloud explosion is equal to the confined area volume.
7.1.2 The simulation of the flammable vapor cloud dispersion range shall include the maximum dispersion range resulting from combinations of meteorological conditions (e.g., wind speed, ambient temperature, relative humidity) occurring in the station area with a frequency greater than or equal to 5%. When regional meteorological data are unavailable, conditions of 2 m/s wind speed, F atmospheric stability, local average ambient temperature, and 50% relative humidity may be selected for determination.
7.1.3 The flammable vapor cloud dispersion range shall be the concentration range at 50% of the lower explosive limit of the flammable gas.
7.1.4 For vapor cloud explosion simulation, when the flammable gas disperses into the confined area, it shall be assumed that ignition occurs when the concentrations of flammable gas and oxygen reach stoichiometric proportions, resulting in an explosion.
