CEN/TC 305/WG 4 - Terminology and Methodology

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:
a)   appropriate design (without using safeguarding);
b)   safeguarding;
c)   information for use;
d)   any other preventive measures.
Measures in accordance with a) (prevention) and b) (protection) against explosions are dealt with in Clause 6, measures according to c) against explosions are dealt with in Clause 7. Measures in accordance with d) are not specified in this document. They are dealt with in EN ISO 12100:2010, Clause 6.
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.
This document is not applicable to:
1)   medical devices intended for use in a medical environment;
2)   equipment, protective systems and components where the explosion hazard results exclusively from the presence of explosive substances or unstable chemical substances;
3)   equipment, protective systems and components where the explosion can occur by reaction of substances with other oxidizers than atmospheric oxygen or by other hazardous reactions or by other than atmospheric conditions;
4)   equipment intended for use in domestic and non-commercial environments where potentially explosive atmospheres may only rarely be created, solely as a result of the accidental leakage of fuel gas;
5)   personal protective equipment covered by Regulation (EU) 2016/425;
6)   seagoing vessels and mobile offshore units together with equipment on board such vessels or units;
7)   means of transport, i.e. vehicles and their trailers intended solely for transporting passengers by air or by road, rail or water networks, as well as means of transport insofar as such means are designed for transporting goods by air, by public road or rail networks or by water; vehicles intended for use in a potentially explosive atmosphere shall not be excluded;
8)   the design and construction of systems containing desired, controlled combustion processes, unless they can act as ignition sources in potentially explosive atmospheres.

ISO/IEC 80079-34:2018 specifies particular requirements and information for establishing and maintaining a quality management system to manufacture Ex Products in accordance with the certificates. While it does not preclude the use of other quality management systems that are compatible with the objectives of ISO 9001:2015 and which provide equivalent results, the minimum requirements are given in this document.
This second edition cancels and replaces the first edition, published in 2011, and constitutes a full technical revision. The significant changes with respect to the previous edition should be considered as minor technical revisions. However, the clause numbering in regard to the previous edition has changed in order to be in line with ISO 9001:2015. The normal “Table of Significant Changes” has not been included for this reason.
This publication is published as a double logo standard. This standard should be read in conjunction with ISO 9001:2015

This European Standard specifies terms and definitions (vocabulary) to be used in suitable standards dealing with equipment and protective systems intended for use in potentially explosive atmospheres.
NOTE   Directive 94/9/EC concerning equipment and protective systems intended for use in potentially explosive atmospheres can be applicable to the type of machine or equipment covered by this European Standard. The present standard is not intended to provide means of complying with the essential health and safety requirements of Directive 94/9/EC.

This European Standard provides guidance on the procedure and information required to allow functional safety assessment to be carried out for the design of protective systems.
The purpose of this European Standard is to assist technical standardization committees responsible for specific families of protective systems in preparing safety standards. Such standards shall be as homogenous as possible and shall have the basic structure of functional safety assessment as it is stated in this standard.
If there are no specific standards for a particular protective system, the manufacturer shall use this standard for functional safety assessment of this protective system.
In this procedure the following information is to be taken into account to ensure a sufficient level of functional safety:
a)   intended use,
b)   possible operating faults,
c)   reliability of protective systems,
d)   misuse which can reasonably be anticipated.
A sufficient level of functional safety is characterized by the following objectives:
1)   System can stop an explosion at a very early stage or reduce the impact of an explosion to an acceptable level.
2)   In the event of faults, failures and/or interference ) the capacity to function remains effective by use e.g. of fail safe techniques or redundancy.
This European Standard does not cover identification of possible ignition sources.
NOTE 1   The identification of possible ignition sources is covered by EN 15198.
This European Standard only deals with the functional behaviour of the protective system i.e. hazards caused by malfunctions, e.g. false activations are excluded.
This European Standard specifies neither specific methods to analyse fault conditions, nor specific requirements for a given type of protective system (see EN 1127 1). It specifies the methodology of functional safety assessment.
(continued)

This European Standard specifies basic methodology used in achieving safety of equipment for intended use in potentially explosive atmospheres.
The provisions specified in this European Standard are intended for the designer. It also specifies a strategy for standard makers.
This European Standard specifies the procedure and information required to allow ignition risk assessment to be carried out for the design of equipment or component.
This European Standard provides advice for a decision to be made for the categorisation of equipment but does not provide means to prove the conformity of equipment categories.
In this procedure the following information is to be taken into account:
a)   Possible occurrence of an explosive atmosphere inside the equipment or component or penetrating the equipment or component from the outside (in normal operation or during malfunctions) and the amount of explosive atmosphere involved leading to possible explosion impact inside of the equipment or component;
b)   equipment or components surrounded by an explosive atmosphere (in normal operation or during malfunctions);
c)   equipment or components wholly or partly surrounded by an explosive atmosphere considering also any explosive atmosphere in connection (in normal operation or during malfunctions);
d)   presence and likelihood (effectiveness) of ignition sources.
The final objective is designing and manufacturing equipment or components intended for use in potentially explosive atmospheres. For this purpose equipment or components if necessary shall be designed with adequate preventive and/or protective measures.
This European Standard specifies neither specific methods of analysis associated with ignition risk assessment, nor specific requirements for a category of equipment. It describes the methodology of ignition risk assessment.
(continued)

This document specifies terms and definitions (vocabulary) to be used in suitable standards dealing with equipment and protective systems intended for use in potentially explosive atmospheres.
NOTE   Directive 2014/34/EU concerning equipment and protective systems intended for use in potentially explosive atmospheres can be applicable to the type of machine or equipment covered by this document. This document is not intended to provide means of complying with the essential health and safety requirements of Directive 2014/34/EU.

This European Standard 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:
a)   appropriate design (without using safeguarding);
b)   safeguarding;
c)   information for use;
d)   any other preventive measures.
Measures in accordance with a) (prevention) and b) (protection) against explosions are dealt with in Clause 6, measures according to c) against explosions are dealt with in Clause 7. Measures in accordance with d) are not specified in this European Standard. They are dealt with in EN ISO 12100:2010, Clause 6.
The preventive and protective measures described in this European Standard 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 standard 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 European Standard 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 materials 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 European Standard is applicable to equipment, protective systems and components at all stages of its use.
(....)

This European Standard specifies terms and definitions (vocabulary) to be used in suitable standards dealing with equipment and protective systems intended for use in potentially explosive atmospheres.

This European Standard 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:
   hazard identification;
   risk assessment;
   reduction of risk;
   information for use.
The safety of equipment, protective systems and components can be achieved by eliminating of hazards and/or limiting the risk, i.e. by:
a)   design without using safeguarding;
b)   safeguarding;
c)   communication links if necessary to convey information to the user;
d)   any other precautions.
Measures in accordance with a) (prevention) and b) (protection) against explosions are dealt with in Clause 6, measures according to c) against explosions are dealt with in Clause 7. Measures in accordance with d) are not specified in this European Standard. They are dealt with in EN ISO 12100-1:2003, Clause 5.
The preventive and protective measures described in this European Standard 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 standard 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 European Standard 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 materials 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 European Standard is applicable to equipment, protective systems and compon

1.1   General
This European Standard specifies particular requirements and information for establishing and maintaining a quality system in accordance with the requirements of Annex IV and Annex VII of Directive 94/9/EC.
It is intended for use by manufacturers, notified bodies and regulatory authorities.
Therefore, when notified bodies assess the quality systems of manufacturers this document is intended to be the basis of the initial assessment and subsequent visits.
1.2   Application
Only those requirements in clause 7 of this European Standard pertaining to the difference between Annex IV and VII of the Directive may be excluded, provided that conformity of the product can still be demonstrated.
Permissible exclusions with respect to Annex VII of Directive 94/9/EC are as follows:
7.1      Planning of product realisation;
7.2.3   Customer communication;
7.4      Purchasing;
7.5.1   Control of production and service provision;
7.5.2   Validation of processes for production and service provision;
7.5.3   Identification and traceability.
No explicit requirements in Annex IV and VII relate to the concept of "continuous improvement". As a consequence, references in this European Standard to the requirements of EN¬ ISO¬ 9001:2000 exclude this concept.