GB/T 45846-2025 English PDF
Basic dataStandard ID: GB/T 45846-2025 (GB/T45846-2025)Description (Translated English): Standard atmosphere Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: V04 Classification of International Standard: 49.020 Word Count Estimation: 498,414 Date of Issue: 2025-06-30 Date of Implementation: 2025-10-01 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 45846-2025: Standard atmosphere---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT45846-2025ICS 49.020 CCSV04 National Standard of the People's Republic of China Standard atmosphere (ISO 2533.1975, MOD) Released on June 30, 2025 Implementation on October 1, 2025 State Administration for Market Regulation The National Standardization Administration issued Table of ContentsPreface III 1 Scope 1 2 Normative references 1 3 Terms and Definitions 1 4 Basic principles and calculation formulas 1 4.1 Main constants and symbols 1 4.2 Statics equations and ideal gas state equations 2 4.3 Potential height and geometric height, free fall acceleration 2 4.4 Atmospheric composition and air molar mass 3 4.5 Physical properties of the atmosphere at mean sea level 4 4.6 Temperature and vertical temperature gradient 5 4.7 Atmospheric pressure 5 4.8 Density and specific gravity 5 4.9 Barometric pressure elevation 6 4.10 Number density of air 6 4.11 Average velocity of air particles 6 4.12 Mean free path of air particles 6 4.13 Air particle collision frequency 6 4.14 Speed of sound 6 4.15 Dynamic viscosity 7 4.16 Kinematic viscosity 7 4.17 Thermal conductivity 7 5 Standard Atmosphere Table 7 Appendix A (informative) Structural changes between this document and ISO 2533.1975 8 Appendix B (Informative) Standard Atmosphere Table 10 Preface This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1.Structure and drafting rules for standardization documents" Drafting. This document is modified to adopt ISO 2533.1975 "Standard Atmospheres". Compared with ISO 2533.1975, this document has many structural adjustments. The comparison table of the structural number changes of the two documents is shown in Appendix A. The technical differences between this document and ISO 2533.1975 and their reasons are as follows. --- Added the term and definition of "barometric altitude" (see Chapter 3) to enhance readability; --- Adjust the content of Chapter 3 of ISO 2533.1975 to an informative appendix (see Appendix B), and improve the scientific notation of the standard atmospheric table Some parameter values expressed in this way are added to enhance the completeness and facilitate the application of this document. The following editorial changes have been made to this document. --- Incorporated the contents of ISO 2533.1975/Add1.1985/Add2.1997, in the outer margin of the relevant clauses The positions are marked with vertical double lines (‖); ---Change the table that changes alternately with geometric height and geopotential height to a table that changes with geometric height and a table that changes with geopotential height respectively. table. --- Changed the description of the standard atmospheric parameters table (see Chapter 5) to increase coordination and facilitate the application of this document. Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents. This document was proposed and coordinated by the National Technical Committee for Standardization of Aircraft (SAC/TC435). This document was drafted by. Taiyuan Aviation Instrument Co., Ltd., China Aviation Technology Research Institute, and China Aviation Industry Corporation Chengdu Aircraft Design and Research Institute, Shenyang Aircraft Design and Research Institute of AVIC, Xi'an Aircraft Design and Research Institute of AVIC Institute, National Meteorological Information Center, China Academy of Launch Vehicle Technology, Nanjing University of Aeronautics and Astronautics, Chinese Academy of Sciences Aerospace Information Innovation Research Institute Institute of Engineering Thermophysics, Chinese Academy of Sciences, Shanghai Aircraft Design and Research Institute of Commercial Aircraft Corporation of China, Ltd., and Xi'an Jiaotong University. The main drafters of this document are. Chang Yue, Xuan Xiaogang, Du Wenjie, Ren Haitao, Chen Wenyun, Pu Saihu, Wang Yu, Li Shaoxiong, Guan Yujie, Du Zhenyu, Chen Weisheng, Ren Zhihua, Zhang Mang, Li Rongbing, Lin Zhifeng, Zhang Guoxin, Zhang Hui, Zhang Chao, Qiu Wenbin, Zhang Jianyun, Zhou Zhiguo, Yang Shuangshuang, and Zhang Juan. Standard atmosphere 1 Scope This document gives the basic principles, calculation formulas and standard atmosphere tables for the standard atmosphere between -5km and 80km altitude. This document applies to the design and testing of aircraft, the design and calibration of aircraft instruments, and the processing of geophysical and meteorological observation data. For reference only. 2 Normative references This document has no normative references. 3 Terms and Definitions The following terms and definitions apply to this document. 3.1 pressure scale height At a specific temperature, the atmospheric pressure changes exponentially with altitude, and the value decreases to 1/e (e=2.718) of the initial value. The corresponding height change. Note. Atmospheric pressure is also commonly referred to as atmospheric pressure in some industries. 4 Basic principles and calculation formulas 4.1 Main constants and symbols This document is based on the assumption that the air is an ideal gas without water vapor and dust, and is based on the standard thermodynamic atmospheric temperature at mean sea level, Standard atmosphere calculated using mean sea level standard atmospheric pressure, mean sea level standard atmospheric density and the constants in the table below. Standard atmosphere calculation The main constants used in the calculation are shown in Table 1. Table 1 Main constants used in standard atmosphere calculations Symbol Name Value Unit gn Standard acceleration of free fall a 9.80665 m·s-2 M Molar mass of air at sea level b 28.964420 kg·kmol-1 NA Avogadro constant c 602.257×1024 kmol-1 pn standard atmospheric pressure at mean sea level 101.325×103 Pa 1.01325×103 hPa 760 mmHg R* Universal gas constant 8314.32 J·K-1·kmol-1 or kg·m2·s-2·K-1·kmol-1 ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 45846-2025_English be delivered?Answer: Upon your order, we will start to translate GB/T 45846-2025_English as soon as possible, and keep you informed of the progress. The lead time is typically 1 ~ 3 working days. The lengthier the document the longer the lead time.Question 2: Can I share the purchased PDF of GB/T 45846-2025_English with my colleagues?Answer: Yes. 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