IEC 61779-1:1998

Electrical apparatus for the detection and measurement of flammable gases - Part 1: General requirements and test methods

Specifies general requirements for construction and testing and describes the test methods that apply to portable, transportable and fixed apparatus for the detection and measurement of flammable gas or vapour concentrations with air. The apparatus, or parts thereof, are intended for use in potentially explosive atmospheres and in mines susceptible to firedamp.

General Information

• Status: Replaced
• Publication Date: 22-Apr-1998
• ICS: 17.060 - Measurement of volume, mass, density, viscosity
• ICS: 29.260.20 - Electrical apparatus for explosive atmospheres
• Technical Committee: TC 31 - Equipment for explosive atmospheres
• Drafting Committee: MT 60079-29 - TC 31/MT 60079-29
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 09-Aug-2007

Relations

• Replaced By: IEC 60079-29-1:2007 - Explosive atmospheres - Part 29-1: Gas detectors - Performance requirements of detectors for flammable gases
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL
IEC
STANDARD
61779-1
First edition
1998-04
Electrical apparatus for the detection
and measurement of flammable gases –
Part 1:
General requirements and test methods
Appareils électriques de détection et de mesure
des gaz combustibles –
Partie 1:
Règles générales et méthodes d’essai

Reference number
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are

available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the

base publication, the base publication incorporating amendment 1 and the base
publication incorporating amendments 1 and 2.

Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC,

thus ensuring that the content reflects current technology.
Information relating to the date of the reconfirmation of the publication is available
in the IEC catalogue.
Information on the subjects under consideration and work in progress undertaken by
the technical committee which has prepared this publication, as well as the list of
publications issued, is to be found at the following IEC sources:
• IEC web site*
• Catalogue of IEC publications
Published yearly with regular updates
(On-line catalogue)*
• IEC Bulletin
Available both at the IEC web site* and as a printed periodical
Terminology, graphical and letter
symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

INTERNATIONAL
IEC
STANDARD
61779-1
First edition
1998-04
Electrical apparatus for the detection
and measurement of flammable gases –
Part 1:
General requirements and test methods
Appareils électriques de détection et de mesure
des gaz combustibles –
Partie 1:
Règles générales et méthodes d’essai

 IEC 1998  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http: //www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
XA
International Electrotechnical Commission
Pour prix, voir catalogue en vigueur
For price, see current catalogue

– 2 – 61779-1 © IEC:1998(E)
CONTENTS
Page
FOREWORD . 3

INTRODUCTION . 4

Clause
1 General. 5

1.1 Scope. 5
1.2 Normative references. 6
2 Definitions. 7
2.1 Gas properties. 7
2.2 Types of instruments. 8
2.3 Sensors. 9
2.4 Supply of gas to instrument. 9
2.5 Signals and alarms . 10
2.6 Times. 10
2.7 Miscellaneous. 11
3 General requirements. 13
3.1 Introduction. 13
3.2 Construction. 13
3.3 Labelling and marking . 15
3.4 Instruction manual. 15
3.5 Diffusion sensors. 17
4 Test methods. 17
4.1 Introduction. 17
4.2 General requirements for tests . 17
4.3 Normal conditions for test . 19
4.4 Test methods. 21

5 Field calibration kit. 29
Annex A (normative) Flammability limits (i.e. LFL and UFL) of some flammable gases
and vapours . 30
Annex B (informative) Determination of time of response . 47
Annex C (informative) Bibliography. 54

61779-1 © IEC:1998(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
ELECTRICAL APPARATUS FOR THE DETECTION

AND MEASUREMENT OF FLAMMABLE GASES –

Part 1: General requirements and test methods

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61779-1 has been prepared by subcommittee 31L: Electrical
apparatus for the detection of flammable gases, of IEC technical committee 31: Electrical
apparatus for explosive atmospheres.
The text of this standard is based on the following documents:
FDIS Report on voting
31L/47/FDIS 31L/52/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annex A forms an integral part of this standard.
Annexes B and C are for information only.
A bilingual version of this standard may be issued at a later date.

– 4 – 61779-1 © IEC:1998(E)
INTRODUCTION
Guidance for the selection, installation, use and maintenance of gas detecting apparatus are

set out in IEC 61779-6: Electrical apparatus for the detection and measurement of flammable
1)
gases – Part 6: Guidelines for the selection, installation, use and maintenance .

___________
1)
To be published.
61779-1 © IEC:1998(E) – 5 –
ELECTRICAL APPARATUS FOR THE DETECTION

AND MEASUREMENT OF FLAMMABLE GASES –

Part 1: General requirements and test methods

1 General
1.1 Scope
1.1.1 This part of IEC 61779 specifies general requirements for construction and testing and
describes the test methods that apply to portable, transportable and fixed apparatus for the
detection and measurement of flammable gas or vapour concentrations with air. The
apparatus, or parts thereof, are intended for use in potentially explosive atmospheres (see
2.1.8) and in mines susceptible to firedamp. This standard is supplemented by the following
standards, concerning the specific requirements for the performance of the various types of
apparatus:
IEC 61779-2: Performance requirements for group I apparatus indicating up to a volume
fraction of 5 % methane in air
IEC 61779-3: Performance requirements for group I apparatus indicating up to a volume
fraction of 100 % methane in air
IEC 61779-4: Performance requirements for group II apparatus indicating up to a volume
fraction of 100 % lower explosive limit
IEC 61779-5: Performance requirements for group II apparatus indicating up to a volume
fraction of 100 % gas
NOTE 1 – IEC 61779-1, in association with the standards referred to above, is intended to provide for the supply of
apparatus giving a level of safety and performance suitable for general purpose applications. However, for specific
applications, a prospective purchaser (or an appropriate authority) may additionally require the apparatus to be
submitted to particular tests or approval. For example, group I apparatus (i.e. apparatus to be used in mines
susceptible to firedamp) may not be permitted to be used without the additional, prior approval of the relevant
authority in mines under its jurisdiction. Such particular tests/approval are to be regarded as additional to and
separate from the provisions of the standards referred to above and do not preclude certification to or compliance
with these standards.
NOTE 2 – Group I and group II apparatus indicating up to a volume fraction of 100 % methane and group II
apparatus indicating up to a volume fraction of 100 % gas are suitable for use only with the specific gases for which
they have been calibrated.
NOTE 3 – For the purpose of this standard, the terms "lower flammable limit (LFL)" and "lower explosive limit (LEL)"

are deemed to be synonymous, and likewise the terms "upper flammable limit (UFL)" and "upper explosive limit
(UEL)" are deemed to be synonymous. For ease of reference, the two abbreviations LFL and UFL may be used
hereinafter to denote these two sets of terms. It should be recognized that particular authorities having jurisdiction
may have overriding requirements that dictate the use of one of these sets of terms and not the other.
1.1.2 This standard is applicable when an apparatus manufacturer makes any claims
regarding any special features of construction or superior performance that exceed these
minimum requirements. All such claims shall be verified and the test procedures shall be
extended or supplemented, where necessary, to verify the claimed performance. The additional
tests shall be agreed between the manufacturer and test laboratory.
1.1.3 This standard is applicable to flammable gas detection apparatus intended to provide an
indication, alarm or other output function, the purpose of which is to give a warning of a
potential explosion hazard and, in some cases, to initiate automatic or manual protective
action(s).
– 6 – 61779-1 © IEC:1998(E)
1.1.4 This standard is applicable to apparatus, including the integral sampling systems of

aspirated apparatus, intended to be used for commercial and industrial safety applications.

1.1.5 This standard does not apply to external sampling systems, or to apparatus of

laboratory or scientific type, or to apparatus used only for process control purposes.

1.2 Normative references
The following normative documents contain provisions which, through reference in this text,

constitute provisions of this part of IEC 61779. At the time of publication, the editions indicated

were valid. All normative documents are subject to revision, and parties to agreements based

on this part of IEC 61779 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60050(351):1975, International Electrotechnical Vocabulary (IEV) – Chapter 351:
Automatic control
IEC 60079-0:1983, Electrical apparatus for explosive gas atmospheres – Pa
...