GB/T 20936.2-2024Gas detectors for explosive atmospheres - Part 2: Selection, installation, use and maintenance of detectors for flammable gases and oxygen (English PDF)

Foreword

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 part 2 of GB/T 20936 "Gas detectors for explosive atmospheres". GB/T 20936 has been published for the following part.

--- Part 1: Performance requirements for combustible gas detectors;

--- Part 2: Selection, installation, use and maintenance of combustible gas and oxygen detectors;

--- Part 3: Guidelines for functional safety of fixed gas detection systems;

--- Part 4: Performance requirements for open path combustible gas detectors.

This document replaces GB/T 20936.2-2017 "Gas detectors for explosive atmospheres Part 2: Combustible gas and oxygen detectors Compared with GB/T 20936.2-2017, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

--- The scope adds Class I equipment (see Chapter 1);

--- Added the content of open path detector (see Chapter 3, 4.6, 6.2.3.5, 8.2, 8.6, 8.7, 8.8, Chapter 11, A.4);

--- Added specific application of gas detectors (see 4.5);

--- Added the content of sampling system (see 6.2.3.4, 8.2.3, 8.5, 11.2.2).

This document is modified to adopt IEC 60079-29-2:2015 "Explosive atmospheres Part 29-2.Gas detectors for flammable gases and oxygen "Detector selection, installation, use and maintenance".

This document has made the following structural adjustments compared to IEC 60079-29-2:2015.

--- Appendix D corresponds to Appendix E of IEC 60079-29-2:2015;

--- Appendix E corresponds to Appendix D of IEC 60079-29-2:2015.

The technical differences between this document and IEC 60079-29-2:2015 and their reasons are as follows.

--- The normative reference GB/T 3836.1 replaces IEC 60079-0 (see Chapter 3, 6.2.2, 8.11.1) to adapt to the technical requirements of my country.

Technical conditions and increase operability;

--- Replaced IEC 60079-19 (see 11.1) with the normative reference GB/T 3836.13 to adapt to my country's technical conditions and increase Operability;

--- Replaced IEC 60079-10-1:2008 (see 6.3.2) with the normative reference GB 3836.14 to adapt to my country's technical conditions, Increase operability;

--- Replaced IEC 60079-17 (see 11.1) with the normative reference GB/T 3836.16 to adapt to my country's technical conditions and increase Operability;

--- Replaced IEC 60079-13 (see 4.5.3) with the normative reference GB/T 3836.17 to adapt to my country's technical conditions and increase Operability;

--- The normative reference GB/T 3836.35 replaces IEC 60079-10-2 (see 6.3.2) to adapt to my country's technical conditions and increase Increase operability;

--- The normative reference GB/T 29812 replaces IEC 61285 (see 4.5.3) to adapt to my country's technical conditions and increase operability.

Sex;

--- Deleted the specific content on measurement principles in Chapter 5 because it has been included in Appendix A.

The following editorial changes were made to this document.

--- To be consistent with the existing standard series, the document name is changed to "Gas detectors for explosive atmospheres Part 2: Combustible gases and Selection, installation, use and maintenance of oxygen detectors";

--- Added information about the addresses of ISO and IEC terminology databases in the terms and definitions;

--- GB/T 20936.1 and GB/T 20936.4 replaced the informative references IEC 60079-29-1:2007 and IEC 60079-29-4:2009;

--- Deleted the information about relevant documents in the United States and Europe in Note 4.1.2;

--- Deleted the note on training in 10.1;

--- Changed the environmental parameter values in Table B.1;

---Replace the international documents cited for informational purposes with Chinese documents.

Introduction

GB/T 20936 "Gas detectors for explosive atmospheres" aims to establish the basic requirements for the performance of various types of flammable gas detectors and provide Provides application guidance in the form of a partial standard, including the following parts.

--- Part 1: Performance requirements for combustible gas detectors;

--- Part 2: Selection, installation, use and maintenance of combustible gas and oxygen detectors;

--- Part 3: Guidelines for functional safety of fixed gas detection systems;

--- Part 4: Performance requirements for open path combustible gas detectors.

my country adopted the IEC 61779 series from 2007 to 2009 and formulated the GB 20936 "Electrical Equipment for Combustible Gas Detection" series.

It is divided into four parts, which respectively stipulate the general requirements and test methods as well as the performance requirements of Class I and Class II detectors with different measurement ranges.

Subsequently, the IEC 60079-29 series was adopted for revision, forming the new GB/T 20936 "Gas detectors for explosive atmospheres" series.

The GB/T 20936.1 is mainly based on the original Part 1 and integrates the original Parts 2 to 4, while GB/T 20936.2, GB/T 20936.3 and GB/T 20936.4 are newly formulated parts (only the original standard codes are used).

This revision adopts IEC 60079-29-2:2015 "Explosive atmospheres Part 29-2.Gas detectors for flammable gases and oxygen Based on the main technical contents of "Detector selection, installation, use and maintenance", appropriate modifications have been made.

The following should be understood when using this document.

Combustible gas detectors can be used when the mixture of flammable gas and air accumulates and may cause harm to life or property.

Detectors reduce risk by detecting the presence of flammable gases and issuing appropriate audible and visual alarms. Gas detectors can also be used to initiate preventive Actions (e.g., equipment shutdown, personnel evacuation, and initiation of fire-fighting procedures).

The detector can also be used to monitor the atmosphere for gases below the lower flammable limit, where accumulation of gases can also cause the gas/air mixture to the concentration reaches a potential explosion level. The performance requirements of gas detectors used for this purpose are specified in GB/T 20936.1 and GB/T 20936.4.

For the functional safety guide of fixed gas detection systems, see GB/T 20936.3.

However, where flammable gases may be present, detector performance alone cannot ensure the safety of life and property.

The design, installation, calibration and regular maintenance of the detector, as well as an understanding of the limitations of the detection technology, have a significant impact on the level of safety that needs to be achieved.

Only through comprehensive and reliable management can the goal of safety be achieved.

The vapors of some gases and of all liquids (except water) are toxic and dangerous to life. All flammable vapors, even in concentrated Even a small fraction of the lower flammable limit may be toxic. The detectors involved in GB/T 20936.1 and GB/T 20936.4 are not special Anti-toxic equipment. If personnel may be exposed to toxic vapors, additional personal protective measures are usually required.

Portable detectors covered by GB/T 20936.1 and GB/T 20936.2 are usually equipped with specific toxic gas and oxygen-deficient gas detectors.

Users should be aware that some other gases or vapors with toxic components may cause a slight oxygen deficiency that may not be detected by the detector used, or the situation cannot be adequately detected.

GB/T 20936.1 and GB/T 20936.4 specify the general requirements for specific combustible gas detectors.

Provides the necessary background knowledge.

This document covers all the functions required for gas detection from selection to ongoing maintenance. The requirements of different chapters are applicable to different each chapter is as independent as possible. Although some chapters have repeated contents, they focus on different points.

Table 1 gives the relevant clauses and requirements for performing typical tasks.

Table 1 Requirements for performing typical tasks

Definition of applicable objects Gas and Steam base this feature information Measurement principle equipment Selection Gas Release Placement method Fixed Gas Detector Measurement system the design of and installation Portable and mobile Flammable Gas Detector Detector use Operation Personnel Training maintain, Regular itinerary Preface, Summary Body Management control Measurement principle Principle (full Details) (Normative) environment parameter (Informative) Function (Chapter) 3 4 5 6 7 8 9 10 11 Appendix A Appendix B Authorization - - - - -General Management - - -Selection -Design Engineering/Management - - -Installation Engineering/Management - - -Installation, technology - - -Trial run - - -Operation Management Operation training Use/Calibration - - -Repair - - -Note. " " indicates the most suitable; " " indicates recommended; " " indicates useful; "-" indicates not applicable.

This document provides recommendations on how to determine maintenance and calibration intervals. If there are general or industry-specific mandatory regulations, these regulations should be used as is the minimum requirement.

Gas detectors for explosive atmospheres Part 2: Combustible gas and oxygen detectors Selection, installation, use and maintenance

1 Scope

This document provides Class II flammable gases that meet the requirements of GB/T 20936.1 or GB/T 20936.4 and are used in industrial and commercial safety applications.

Guidelines and recommended operating procedures for the selection, installation, safe use and maintenance of Class I combustible gas detectors and Class I combustible gas detectors for underground coal mines.

This document applies to oxygen detectors that achieve explosion protection requirements by excluding oxygen through inertization rather than excluding flammable gases or vapors.

A similar application is the measurement of oxygen during the inerting of goafs in underground coal mines.

This document is a collection of practical knowledge applicable to the use of electronic signals from gas sensors to form meter readings and to activate preset audible and visual alarms.

A device that indicates the presence of a flammable or potentially explosive gas or vapor/air mixture by activating an alarm, or activating other devices, or a combination of the above Because the accumulation of flammable gas/air mixtures may be hazardous to life and property, such equipment may be used to it can also be used to initiate specific safety measures (e.g. equipment shutdown, evacuation, initiation of fire-fighting procedures).

This document applies to fixed installations and mobile equipment. This document also applies to the safe use of portable detectors.

Modern equipment of this type also includes oxygen deficiency detection and/or specific toxic gas sensors, for which additional guidance is given.

In this document, flammable gases include flammable vapors unless otherwise specified.

Due to the measurement techniques currently used, haze is not included in this document.

This document applies to Class II detectors (used in industrial and commercial safety applications, in places divided into areas according to GB 3836.14).

equipment) and Class I detectors.

Equipment included in this document.

a) Fixed detectors, including equipment mounted on vehicles;

b) Mobile detectors;

c) Portable detectors.

The following equipment is not covered by this document but may provide useful information.

a) Detectors that only detect non-flammable toxic gases;

b) Experimental or scientific research equipment used only for analysis or measurement;

c) detectors used only for process control;

d) Detectors used in the manufacture and processing of explosives;

e) Detectors used to detect explosive atmospheres caused by dust or mist in the air.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 3836.1 Explosive atmospheres Part 1: General requirements for equipment (GB/T 3836.1-2021, IEC 60079-0.

2017,MOD)