oSIST prEN 1127-1:2025

Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts, methodology and design

This document specifies methods for the identification and assessment of hazardous situations leading to explosion and the design and construction measures appropriate for the required safety. This is achieved by:
—   risk assessment;
—   risk reduction.
The safety of equipment, protective systems and components can be achieved by eliminating hazards and/or limiting the risk, i.e. by steps (figure below from ISO EN 12100):
a)   appropriate design (without using safeguarding) – Step 1;
b)   safeguarding – Step 2;
c)   information for use – Step 3;
d)   any other preventive measures.
In this standard the measures in accordance with
a) (prevention) and
b) (protection) against explosions are dealt with in Clause 6.
The measures according to
c) against explosions are dealt with in Clause 7.
Measures in accordance with d) are not specified in this standard.
Refer to EN ISO 12100:2010 for complementary preventive and protective measures
Inherently safe design measures are the first and most important step in the risk reduction process. This is because protective measures inherent to the characteristics of the product or system are likely to remain effective, whereas experience has shown that even well-designed guards and protective devices can fail or be violated, and information for use might not be followed.
Guards and protective devices shall be used whenever an inherently safe design measure does not reasonably make it possible either to remove hazards or to sufficiently reduce risks. Complementary protective measures involving additional equipment (e.g. emergency stop equipment) might have to be implemented.
The end user has a role to play in the risk reduction procedure by complying with the information provided by the designer/supplier. However, information for use shall not be a substitute for the correct application of inherently safe design measures, guards or complementary protective measures.
The preventive and protective measures described in this document will not provide the required level of safety unless the equipment, protective systems and components are operated within their intended use and are installed and maintained according to the relevant codes of practice or requirements.
This document specifies general design and construction methods to help designers and manufacturers in achieving explosion safety in the design of equipment, protective systems and components.
This document is applicable to any equipment, protective systems and components intended to be used in potentially explosive atmospheres, under atmospheric conditions. These atmospheres can arise from flammable/combustible substances processed, used or released by the equipment, protective systems and components or from materials in the vicinity of the equipment, protective systems and components and/or from the materials of construction of the equipment, protective systems and components.
This document is applicable to equipment, protective systems and components at all stages of its use.
This document is only applicable to equipment group II which is intended for use in other places than underground parts of mines and those parts of surface installations of such mines endangered by firedamp and/or combustible dust.

Explosionsfähige Atmosphären - Explosionsschutz - Teil 1: Grundlegende Konzepte, Methodik und konstruktive Auslegung

Atmosphères explosives - Prévention de l'explosion et protection contre l'explosion - Partie 1 : Notions fondamentales, méthodologie et conception constructive

Eksplozivne atmosfere - Protieksplozijska zaščita - 1. del: Osnovni pojmi, metodologija in zasnova

General Information

• Status: Not Published
• Public Enquiry End Date: 29-Sep-2025
• ICS: 13.230 - Explosion protection
• Technical Committee: EXP - Product for explosive atmospheres
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 16-Jul-2025
• Due Date: 03-Dec-2025
• Directive: 2006/42/EC - Directive 2006/42/EC of the European Parliament and of the Council of 17 May 2006 on machinery, and amending Directive 95/16/EC (recast)
• Directive: 2014/34/EU - Directive 2014/34/EU Of The European Parliament And Of The Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres (recast)
• Directive: 2023/1230 - Regulation (EU) 2023/1230 of the European Parliament and of the Council of 14 June 2023 on machinery and repealing Directive 2006/42/EC of the European Parliament and of the Council and Council Directive 73/361/EEC (Text with EEA relevance)
• Mandate: M/396 - Mandate to CEN and Cenelec for standardisation in the field of machinery
• Mandate: M/596 - [C(2023)4798] Commission Implementing Decision of 20.7.2023 on a standardisation request as regards equipment and protective systems intended for use in potentially explosive atmospheres in support of Directive 2014/34/EU (ATEX) of the European Parliament and of the Council
• Mandate: M/605 - COMMISSION IMPLEMENTING DECISION of 20.1.2025 on a standardisation request to the European Committee for Standardization and to the European Committee for Electrotechnical Standardization as regards machinery and related products in support of Regulation (EU) 2023/1230 of the European Parliament and of the Council
• Mandate: M/BC/CEN/92/46 - Standardization mandate assigned to CEN/CENELEC concerning equipment and protective systems intended for use in potentially explosive atmospheres
• Ref Project: prEN 1127-1 - Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts, methodology and design

Relations

• Revises: SIST EN 1127-1:2019 - Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts and methodology
• Effective Date: 09-Aug-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2025
Eksplozivne atmosfere - Protieksplozijska zaščita - 1. del: Osnovni pojmi,
metodologija in zasnova
Explosive atmospheres - Explosion prevention and protection - Part 1: Basic concepts,
methodology and design
Explosionsfähige Atmosphären - Explosionsschutz - Teil 1: Grundlegende Konzepte,
Methodik und konstruktive Auslegung
Atmosphères explosives - Prévention de l'explosion et protection contre l'explosion -
Partie 1 : Notions fondamentales, méthodologie et conception constructive
Ta slovenski standard je istoveten z: prEN 1127-1
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2025
ICS 13.230 Will supersede EN 1127-1:2019
English Version
Explosive atmospheres - Explosion prevention and
protection - Part 1: Basic concepts, methodology and
design
Atmosphères explosives - Prévention de l'explosion et Explosionsfähige Atmosphären - Explosionsschutz -
protection contre l'explosion - Partie 1 : Notions Teil 1: Grundlegende Konzepte, Methodik und
fondamentales, méthodologie et conception konstruktive Auslegung
constructive
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 305.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1127-1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 11
3 Terms and definitions . 12
4 Risk assessment . 15
4.1 General. 15
4.2 Identification of explosion hazards . 17
4.2.1 General. 17
4.2.2 Flammability properties . 17
4.2.3 Explosion behaviour . 18
4.2.4 Likelihood of occurrence of a hazardous explosive atmosphere . 18
4.3 Identification of ignition hazards. 20
4.3.1 General. 20
4.3.2 Ignition properties . 21
4.3.3 Likelihood of occurrence of effective ignition sources . 21
4.4 Estimation of the possible effects of an explosion . 22
5 Hazards arising from possible ignition sources . 23
5.1 Hot surfaces . 23
5.2 Flames and hot gases (including hot particles) . 23
5.3 Mechanically generated impact, friction and abrasion . 24
5.4 Electrical equipment and components . 24
5.5 Stray electric currents, cathodic corrosion protection . 25
5.6 Static electricity . 25
5.7 Lightning . 25
4 11
5.8 Radio frequency (RF) electromagnetic waves from 10 Hz to 3 × 10 Hz . 26
11 15
5.9 Electromagnetic waves from 3 × 10 Hz to 3 × 10 Hz . 26
5.10 Ionizing radiation . 26
5.11 Ultrasonic waves . 27
5.12 Adiabatic compression and shock waves . 27
5.13 Exothermic reactions . 27
5.13.1 Exothermic reactions including self-ignition of dusts . 27
5.13.2 Thermal runaway of cells and battery (Lithium) . 28
6 Risk reduction . 29
6.1 Fundamental principles . 29
6.2 Reduction and mitigation of the presence of hazardous explosive atmospheres
(avoidance) . 29
6.2.1 Process parameters . 29
6.2.2 Design and construction of equipment, protective systems and components . 32
6.3 Hazardous areas classification . 34
6.4 Requirements for the design and construction of equipment, protective systems and
components for avoidance of effective ignition sources . 35
6.4.1 General. 35
6.4.2 Hot surfaces . 37
6.4.3 Flames and hot gases . 38
6.4.4 Mechanically generated impact, friction and grinding . 38
6.4.5 Electrical equipment . 39
6.4.6 Stray electric currents and cathodic corrosion protection . 40
6.4.7 Static electricity . 41
6.4.8 Lightning . 41
4 11
6.4.9 Radio frequency (RF) electromagnetic waves from 10 Hz to 3 × 10 Hz . 42
11 15
6.4.10 Electromagnetic waves from 3 × 10 Hz to 3 × 10 Hz . 43
6.4.11 Ionizing radiation . 43
6.4.12 Ultrasonic waves . 44
6.4.13 Adiabatic compression and shock waves . 45
6.4.14 Exothermic reactions, including self-ignition of dusts . 46
6.5 Requirements for the design and construction of equipment, protective systems and
components to reduce the explosion effects . 46
6.6 Provisions for emergency measures . 47
6.7 Principles of measuring and control systems for explosion prevention and
protection . 47
7 Information for use . 48
7.1 General . 48
7.2 Information for commissioning, maintenance and repair to prevent explosion . 50
7.3 Qualifications and training . 50
Annex A (informative) Information for the use of tools in potentially explosive
atmospheres . 51
Annex B (informative) Tightness of equipment . 52
B.1 General . 52
B.2 Normal tightness . 52
B.3 Enhanced tightness . 53
Annex C (normative) Verification procedure for the threshold limit of ultrasound in liquids . 54
Annex D (informative) Significant technical changes between this document and the
previous edition of this document . 56
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/34/EU aimed to be covered . 59
Annex ZB (informative) Relationship between this European Standard and the essential
requirements of EU Regulation 2023/1230 aimed to be covered . 62
Bibliography . 65

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