GB/T 21714.3-2026Protection against lightning - Part 3: Physical damage to structures and life hazard (English PDF)

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 3 of GB/T 21714 "Lightning Protection". GB/T 21714 has the following parts published.

---Part 1: General Provisions;

---Part 2: Risk Management;

---Part 3: Physical Damage to Buildings and Life Hazards;

---Part 4: Electrical and Electronic Systems within Buildings.

This document replaces GB/T 21714.3-2015 "Lightning Protection Part 3: Physical Damage to Buildings and Hazards to Life", and is consistent with...

Compared with GB/T 21714.3-2015, apart from structural adjustments and editorial changes, the main technical changes are as follows.

a) Some terms and definitions have been changed (see Chapter 3, Chapter 3 of the 2015 edition);

b) The parameters that determine the LPS feature classification have been changed (see 4.1, 2015 version 4.1);

c) The continuity of steel structures in reinforced concrete buildings has been removed (see 4.3 in the 2015 edition);

d) The relevant provisions for the application of isolated or electrically isolated LPS have been changed (see 5.1.2, 2015 version of 5.1.2);

e) The relevant regulations for lightning protection systems have been amended (see 5.2, 2015 version 5.2);

f) The relevant provisions of the referencing system have been changed (see 5.3, 2015 version 5.3);

g) The relevant provisions for the grounding terminal system have been amended (see 5.4, 2015 version 5.4);

i) The regulations for lightning protection equipotential bonding of internal systems and lightning protection equipotential bonding of lines connected to the protected building have been changed (see...).

6.2.4~6.2.5 (2015 version of 6.2.4~6.2.5)

j) The relevant regulations regarding spacing have been changed (see 6.3, 2015 version 6.3);

k) The maintenance and inspection procedures for LPS have been changed (see Chapter 7, Chapter 7 of the 2015 edition);

l) The location of the lightning arrester has been removed (see Appendix A of the 2015 edition);

m) The additional requirements for LPS for buildings with explosion risks have been changed (see Appendix C, Appendix D of the 2015 edition).

This document is equivalent to IEC 62305-3:2024 "Lightning protection - Part 3: Physical damage to buildings and danger to life".

The following minimal editorial changes have been made to this document.

---Note 5 has been added to the "Scope" chapter, and additional notes have been added to pages 3.22, 3.29, 3.35, and 3.40 to facilitate understanding of the document;

---Change the informative content in the definition to the example (see 3.7, 3.21);

---Delete content that is irrelevant to my country.

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 Lightning Protection Standardization (SAC/TC258).

Introduction

GB/T 21714 "Lightning Protection" aims to propose lightning protection (LP) measures to effectively reduce lightning risks, and is proposed to consist of four parts.

---Part 1: General Provisions. The purpose is to stipulate the general principles to be followed for lightning protection of buildings and their facilities, internal objects, and personnel.

in principle.

---Part 2: Risk Management. The purpose is to define the process for managing lightning risk in buildings, including calculating the building's lightning strike risk.

Value. After selecting the upper limit of risk tolerance, this process allows for the selection of appropriate protective measures to reduce the risk to the tolerance limit or above.

The following also includes assessing the frequency of damage to internal systems caused by lightning surges. After selecting an upper limit for the allowable frequency of damage, this process is followed.

Choose appropriate protective measures to reduce the frequency of damage to or below the permissible limit.

---Part 3: Physical Damage to Buildings and Life Hazards. The purpose is to specify lightning protection measures for physical damage to buildings.

Requirements for protection systems (LPS) and requirements for preventing personal injury from contact voltage and step voltage near the LPS.

---Part 4: Electrical and Electronic Systems within Buildings. The purpose is to specify surge protection measures for electrical and electronic systems within buildings.

The design, installation, inspection, maintenance, and testing requirements for (SPM) are designed to reduce permanent failures caused by lightning electromagnetic pulses (LEMP).

risk.

This document outlines protections against physical damage to the interior and surrounding areas of buildings, as well as personal dangers caused by contact voltage and step voltage.

measure.

It consists of LPS and internal LPS.

External LPS aims to.

a) Intercepting ground flashes that directly strike buildings (using a lightning interception system);

b) Safely guide the lightning current into the ground (using a down conductor system);

c) Allow the lightning current to drain into the ground (using the grounding terminal system).

Internal LPS is achieved through equipotential bonding, or by maintaining a certain distance between external LPS (defined in 3.2) and other conductive components within the building.

Maintain distance (isolate) to prevent dangerous sparks from escalating inside the building.

The main measures taken to prevent personal injury caused by contact voltage and step voltage are.

a) Reduce dangerous currents flowing through the human body by insulating exposed conductors and/or increasing the soil surface resistivity;

b) Reduce the occurrence of dangerous contact voltage and step voltage through physical limits and/or warning signs.

During the initial design phase of a new building, the type and installation location of the LPS (Limited Power Supply System) must be considered to maximize the utilization of the building's electrical system.

Conductive components. This facilitates integrated installation design and construction, improves the building's aesthetics, and achieves the lowest possible cost and efficiency.

Invest in improving the effectiveness of LPS.

Once construction begins, it becomes difficult to get close to the ground and effectively utilize the foundation steel structure to form an effective grounding terminal. Therefore, soil resistivity and Soil characteristics should be considered in the initial stages of engineering. This information is crucial for the design of the grounding terminal system and may affect the building's...

Basic design work.

To achieve the best results at the lowest cost, LPS emphasizes regular communication between designers and installers, and between architects and construction workers.

It is very important.

If new LPS are added to an existing building, the new LPS must comply with this document. Furthermore, the type and installation location of the new LPS should be carefully considered.

When safety issues are involved and there are significant changes to the structure and use of a building, it is recommended to update the lightning protection system in accordance with this document.

National or local laws and regulations provide guidance or stipulate minimum requirements for the application of this document, including. in the absence of a risk assessment.

Specific applications specify the required LPS class, isolation from other grounding terminal systems, and equipotential bonding conditions, as specified in Appendix C, which has explosion-proof features.

Additional information on LPS for buildings at risk of explosion, and maintenance and inspection requirements for LPS as specified in Chapter 7.

Lightning Protection Part 3.

Physical damage to buildings and life-threatening situations

1 Scope

This document specifies the requirements for lightning protection systems (LPS) used to protect buildings from physical damage, and the prevention of lightning strikes near LPS.

Requirements for personal injury caused by voltage shock and step voltage (see GB/T 21714.1-2026).

This document applies to.

a) Design, installation, inspection, and maintenance of building LPS;

b) Develop protective measures to prevent personnel from being injured by contact voltage and step voltage.

Note 1.For buildings that pose a danger to the surrounding environment due to the risk of explosion, the specific requirements for LPS are given in Appendix C.

Note 2.This document does not specify protective measures for electrical and electronic systems that fail due to overvoltage. For specific requirements in such cases, please refer to GB/T 21714.4-2026.

Note 3.Specific requirements for lightning protection of wind turbine generators are given in IEC 61400-24.

Note 4.Specific requirements for overvoltage protection of photovoltaic systems are given in Appendix F of IEC 61643-32 and GB/T 21714.4-2026.

Note 5.In this document, "buildings" refers to any structure or building.

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.

This document.

GB/T 21714.1-2026 Lightning protection – Part 1: General principles (IEC 62305-1:2024, IDT) GB/T 21714.2-2026 Lightning protection – Part 2: Risk management (IEC 62305-2:2024, IDT) GB/T 21714.4-2026 Lightning protection – Part 4: Electrical and electronic systems in buildings (IEC 62305-4:2024, IDT) GB/T 33588.1-2025 Lightning Protection System Components (LPSC) Part 1: Requirements for Connectors (IEC 62561-1) 2023, IDT) Note. There are no technical differences between the content referenced in GB/T 33588.1-2025 and the content referenced in IEC 62561-1:2017.

GB/Z 33588.8-2022 Lightning Protection System Components (LPSC) Part 8: Requirements for Isolation Components of Lightning Protection Systems (IEC TS62561-8:2018, IDT) ISO 3864-1 Graphical symbols, safety colors and safety signs – Part 1: Design principles for safety signs and markings (safetymarkings) Note. GB/T 2893.1-2013 Graphical symbols, safety colors, and safety signs—Part 1: Design principles for safety signs and markings (ISO 3864-1.

2011, MOD)

IEC 60079-10-1 Explosive Atmospheres – Part 10-1.Classification of Locations – Explosive Gas Atmospheres Note. GB 3836.14-2014 Explosive Atmospheres - Part 14: Classification of Locations - Explosive Gas Atmospheres (IEC 60079-10-1:2008, IDT) IEC 60079-10-2 Explosive Atmospheres – Part 10-2.Classification of Locations – Explosive Dust Atmospheres Note. GB/T 3836.35-2021 Explosive Atmospheres - Part 35: Classification of Explosive Dust Atmospheres (IEC 60079-10-2:2015, MOD)