GB/T 40815.6-2026Mechanical structures for electrical and electronic equipment - Thermal management for cabinets in accordance with inch and metric system - Part 6: Air recirculation and bypass of indoor cabinets (English PDF)
电气和电子设备机械结构 符合英制系列和公制系列机柜的热管理 第6部分:户内机柜的空气再循环和旁路
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Issued by
State Administration for Market Regulation
Level / Type
National · Recommended
Issue date
February 27, 2026
Implementation date
September 1, 2026
Scope
GB/T 40815.6-2026 is the English-translated version of 电气和电子设备机械结构 符合英制系列和公制系列机柜的热管理 第6部分:户内机柜的空气再循环和旁路.
GB/T 40815.6-2026 — This document pertains to thermal management of cabinets compliant with IEC 60297 and IEC 60917 series standards, providing compatibility measurements for recirculation rate and bypass rate.
These measurement methods define the quality of airflow in forced air cooling and are generally applicable to rack-mounted and/or chassis-based equipment. Indoor server racks.
Note 1.Both recirculation and bypass represent leaky airflow, which is a detrimental phenomenon in terms of cooling efficiency; their measurement is obviously intended to mitigate this situation.
This document contains the following. a) Definitions of recirculation and bypass flow rates in cabinet cooling; b) The level of recirculation rate (RC); c) The definition formula for the recycle rate RCs of forced air-cooled enclosures and/or enclosure-based equipment installed in the rack; d) The definition formulas for the recirculation rate RCr and bypass rate BPR of the entire cabinet; e) Requirements for each temperature measurement method needed to calculate the recirculation rates RCs, RCr, and bypass rate BPR.
Note 2.This document includes provisions for measuring bypass ratio, but does not include provisions for bypass ratio level. The diagrams used are not intended to guide product design; they are only used for illustrative purposes when defining forced airflow.
The recirculation and bypass measurement methods described in this document assume applicability to indoor-installed cabinets. The cooling air inlet is located at the front of the cabinet.
The heated air is exhausted to the rear or top surface, either on the front or bottom. These methods are also suitable for outdoor installations with heat exchangers at the front or back.
Cabinets for cooling devices such as air conditioners or cooling units (see Appendix C). The recycle rate of a cabinet or rack is defined for each individual cabinet or rack-based device installed in the rack, or for the entire rack. The bypass rate of a cabinet is defined for the entire cabinet.
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Document preview — GB/T 40815.6-2026
National Standard of the People's Republic of China
- ICS
- 31.240
- Classification
- K 05
Issued by: State Administration for Market Regulation
Contents
- Preface
- Introduction
- 1 Scope
- 2 Normative References
- 3 Terms and Definitions
- 4 Recycling Level
- 5 Determination of recirculation rate and bypass rate
- 5.1 Cooling airflow in the cabinet
- 5.2 Recycling rate of the interlocking box
- 5.3 Rack Recycling Rate
- 5.4 Cabinet Bypass Rate
- 6 Measurement of recirculation and bypass
- 6.1 Measurement of the recirculation of the test chamber
- 6.2 Rack Recirculation Measurement
- 6.3 Rack Bypass Measurement
- 6.4 Temperature Measurement Methods
- 6.4.1 Inlet air temperature of the casing
- 6.4.2 Inlet air temperature of the junction box assembly
- 6.4.3 Exhaust air temperature of the casing
- 6.4.4 Exhaust air temperature of the injection unit
- 6.4.5 Rack intake air temperature
- 6.4.6 Rack exhaust temperature
- 6.5 Measurement method for empty rack recirculation
- Appendix A (Normative) Recirculation Measurement Method Using Simulated Heat Load
- A.1 Purpose
- A.2 Technical Requirements
- A.2.1 DTL
- A.2.2 Rack Technical Requirements
- A.2.3 Measurement Configuration
- A.3 Environmental Conditions
- A.4 Measurement Point
- A.4.1 DTL Inlet Air Temperature
- A.4.2 DTL exhaust temperature
- A.4.3 Cabinet Inlet Air Temperature
- A.4.4 Rack exhaust temperature
- A.4.5 Evaluation of the interlocking box recycle rate
- A.4.6 Evaluation of rack recirculation rate and bypass rate
- A.5 Case Study
- A.6 Relationship between recirculation rate and inlet air temperature rise
- Appendix B (Normative) Derivation of Recirculation and Bypass in Cabinets
- B.1 General Provisions
- B.2 Derivation of Recirculation and Bypass
- Appendix C (Informative) Application of Recirculation and Bypass in Outdoor Cabinets
- C.1 General Provisions
- C.2 Application Example
- Reference
Foreword
This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents".
Drafting.
This document is part of GB/T 40815 "Mechanical Structures of Electrical and Electronic Equipment - Thermal Management of Cabinets in Accord and Metric Series".
GB/T 40815 has been published in 6 parts.
---Part 2: Methods for Determining Forced Air Cooling;
---Part 4: Cooling performance test of water supply heat exchanger in electronic cabinet;
---Part 5: Evaluation of Cooling Performance of Indoor Cabinets;
---Part 6: Air recirculation and bypass for indoor cabinets.
This document is equivalent to IEC 62610-6:2020 "Mechanical construction of electrical and electronic equipment conforming to IEC 60297 and IEC 60917 series".
Thermal Management of Server Racks Part 6: Air Recirculation and Bypass for Indoor Server Racks.
The following minimal editorial changes have been made to this document.
---To harmonize with existing standards, the standard name has been changed to "Mechanical Structures of Electrical and Electronic Equipment in Conformity to Imperial and Metric Series".
Thermal Management of Cabinets Part 6: Air Recirculation and Bypass for Indoor Cabinets.
Please note that some content in this document may involve patents. The issuing organization of this document assumes no responsibility for identifying patents.
This document was proposed and is under the jurisdiction of the National Technical Committee on Comprehensive Standardization of Electrical and Electronic Equipment Structures (SAC/TC34).
Introduction
Imperial and metric series server racks are widely used in data center computer rooms and various communication equipment rooms for installing various information and communication equipment.
Communication equipment. To improve the heat dissipation efficiency of equipment within the cabinet, ensure safe and efficient operation of the equipment, and reduce energy consumption in the computer room, GB/T 40815 "Electrical Equipment" is required.
The document "Thermal Management of Air and Electronic Equipment Mechanical Structures in Imperial and Metric Series Cabinets" elaborates on the requirements for imperial and metric series cabinets.
This paper presents thermal management methods that provide design guidelines for rack thermal management. The main problems it addresses include.
---Specifies the universal installation interface specifications and requirements for the thermoelectric cooling system of indoor electronic cabinets;
---Specifies the design specifications and requirements for optimal airflow in indoor electronic cabinets and their internal enclosures and chassis;
---Specifications for evaluating the cooling performance of indoor electronic cabinets and thermoelectric cooling systems;
---Specifies the performance test specifications and requirements for water supply heat exchangers in indoor electronic cabinets;
---Specifies the test specifications for air recirculation and bypass of indoor electronic cabinets.
GB/T 40815 is proposed to consist of six parts.
---Part 1: Design Guidelines. Interface Dimensions and Specifications for Thermoelectric Cooling Systems (Peltier Effect). This aims to standardize thermoelectric cooling systems.
It has universal installation interface dimensions and requirements.
---Part 2: Methodology for Determining Forced Air Cooling. This section aims to specify the optimal airflow configuration and design for indoor electronic cabinets, enclosures, and chassis.
method.
---Part 3: Design Guidelines. Evaluation Methods for Thermoelectric Cooling Systems (Peltier Effect). Aimed at standardizing the performance of thermoelectric cooling systems.
Evaluation methods and design guidelines are provided.
---Part 4: Cooling Performance Testing of Water Supply Heat Exchangers in Electronic Cabinets. This section aims to specify the performance testing procedures for water supply heat exchangers.
Fan, guiding the experiment.
---Part 5: Evaluation of Cooling Performance of Indoor Cabinets. This section aims to define a methodology for evaluating the air cooling capacity of indoor electronic cabinets.
---Part 6: Air Recirculation and Bypass in Indoor Cabinets. This section aims to specify the testing methods for air recirculation and bypass in indoor electronic cabinets.
specification.
Parts 1 and 3 correspond to international documents that are technical specifications and have not yet been converted into Chinese documents.
This document proposes a method for easily measuring the airflow recirculation rate and bypass rate within a server rack, clarifying the characteristics of cooling airflow in such racks.
The level of effective recyclability is intended to provide a reference for cabinet equipment integrators and developers.
Mechanical structure of electrical and electronic equipment Thermal management compliant with imperial and metric series cabinets Part 6: Air Recirculation and Bypass in Indoor Cabinets
1 Scope
This document pertains to thermal management of cabinets compliant with IEC 60297 and IEC 60917 series standards, providing compatibility measurements for recirculation rate and bypass rate.
These measurement methods define the quality of airflow in forced air cooling and are generally applicable to rack-mounted and/or chassis-based equipment.
Indoor server racks.
Note 1.Both recirculation and bypass represent leaky airflow, which is a detrimental phenomenon in terms of cooling efficiency; their measurement is obviously intended to mitigate this situation.
This document contains the following.
a) Definitions of recirculation and bypass flow rates in cabinet cooling;
b) The level of recirculation rate (RC);
c) The definition formula for the recycle rate RCs of forced air-cooled enclosures and/or enclosure-based equipment installed in the rack;
d) The definition formulas for the recirculation rate RCr and bypass rate BPR of the entire cabinet;
e) Requirements for each temperature measurement method needed to calculate the recirculation rates RCs, RCr, and bypass rate BPR.
Note 2.This document includes provisions for measuring bypass ratio, but does not include provisions for bypass ratio level.
The diagrams used are not intended to guide product design; they are only used for illustrative purposes when defining forced airflow.
The recirculation and bypass measurement methods described in this document assume applicability to indoor-installed cabinets. The cooling air inlet is located at the front of the cabinet.
The heated air is exhausted to the rear or top surface, either on the front or bottom. These methods are also suitable for outdoor installations with heat exchangers at the front or back.
Cabinets for cooling devices such as air conditioners or cooling units (see Appendix C).
The recycle rate of a cabinet or rack is defined for each individual cabinet or rack-based device installed in the rack, or for the entire rack.
The bypass rate of a cabinet is defined for the entire cabinet.
2 Normative references
The contents of the following documents, through normative references within the text, constitute essential provisions of this document. Dated citations are not included.
For references to documents, only the version corresponding to that date applies to this document; for undated references, the latest version (including all amendments) applies.
This document.
IEC 60297-3-100 Mechanical structures of electronic equipment, 482.6 mm (19 in) series, part 3-100.dimensions of mechanical structures.
panels,subracks,chassis,racksandcabinets] Note. GB/T 19520.16-2015 Mechanical Structures of Electronic Equipment 482.6mm (19in) Series Mechanical Structure Dimensions Part 3-100.Panels, Inserts, Basic dimensions of chassis, racks and cabinets (IEC 60297-3-100:2008, IDT) IEC 60917-1 Modular sequence of mechanical structures for developing electrical and electronic equipment - Part 1: General specifications Part 1: Generic standard) Note. GB/T 19290.1-2003 Mechanical Structure Modular Sequence for Developing Electronic Devices - Part 1: General Specification (IEC 60917-1:1998, IDT)
......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 18 pages — is available in the English PDF.
Referenced standards
Normative references
- GB/T 19520.16-2015Mechanical structures for electronic equipment -- Dimension of mechanical structures of the 482.6 mm (19 in) series -- Part 3-100: Basic dimensions of front panels, sub-racks, chassis, racks and cabinets
- GB/T 19290.1-2003Modular order for the development of mechanical structures for electronic equipment practices -- Part 1: Generic standard
IEC 60297 · IEC 60917
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Related Standards
GB/T 19290.1-2003 — Modular order for the development of mechanical structures for electronic equipment practices -- Part 1: Generic standard
GB/T 19520.16-2015 — Mechanical structures for electronic equipment -- Dimension of mechanical structures of the 482.6 mm (19 in) series -- Part 3-100: Basic dimensions of front panels, sub-racks, chassis, racks and cabinets
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