CEN/CLC/TR 16832:2015
(Main)Selection, use, care and maintenance of personal protective equipment for preventing electrostatic risks in hazardous areas (explosion risks)
Selection, use, care and maintenance of personal protective equipment for preventing electrostatic risks in hazardous areas (explosion risks)
This Technical Report sets out guidance for the selection, use, care and maintenance of clothing and related items of personal protective equipment designed to prevent hazards caused by static electricity in hazardous areas.
Static electricity should not be confused with mains supply electricity, or other forms of electric current; the requirements for protection against static electricity are different to the requirements for protection against hazards associated with electric current. Protection against electrostatic risks should not be confused with protection against electric arc; the former is concerned with electrical properties and the latter is concerned with heat, flame and projectile protection.
Directive 89/686/EEC requires that PPE intended for use in explosive atmospheres must be so designed and manufactured that it cannot be the source of an electric, electrostatic or impact-induced arc or spark likely to cause an explosive mixture to ignite. Whereas this Technical Report addresses electrostatic ignition risks, it does not address other possible sources of ignition. Nevertheless, other possible sources of ignition are required to be considered when certifying PPE to the requirements of Directive 89/686/EEC.
NOTE EN 13463-1 gives guidance on assessing possible ignition sources in non-electrical equipment that may be used for some items of PPE.
Izbira, uporaba, nega in vzdrževanje osebne varovalne opreme za preprečevanje elektrostatičnih tveganj v nevarnih območjih (tveganja eksplozije)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2015
,]ELUDXSRUDEDQHJDLQY]GUåHYDQMHRVHEQHYDURYDOQHRSUHPH]DSUHSUHþHYDQMH
HOHNWURVWDWLþQLKWYHJDQMYQHYDUQLKREPRþMLK WYHJDQMDHNVSOR]LMH
Selection, use, care and maintenance of personal protective equipment for preventing
electrostatic risks in hazardous areas (explosion risks)
Ta slovenski standard je istoveten z: CEN/CLC/TR 16832:2015
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
13.340.01 Varovalna oprema na Protective equipment in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT
CEN/CLC/TR 16832
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
April 2015
ICS 13.340.01
English version
Selection, use, care and maintenance of personal protective
equipment for preventing electrostatic risks in hazardous areas
(explosion risks)
This Technical Report was approved by CEN on 21 March 2015. It has been drawn up by the Technical Committee CEN/CLC/JWG 7.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
CEN-CENELEC Management Centre:
Avenue Marnix 17, B-1000 Brussels
© 2015 CEN/CENELEC All rights of exploitation in any form and by any means reserved Ref. No. CEN/CLC/TR 16832:2015 E
worldwide for CEN national Members and for CENELEC
Members.
Contents Page
Foreword. 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Term and definitions . 7
4 Selection . 12
4.1 General. 12
4.2 Risk assessment . 15
4.2.1 Explosive atmospheres. 15
4.2.2 Explosives and pyrotechnic articles . 17
4.3 Selection of electrostatic dissipative protective clothing . 18
4.4 Selection of gloves . 19
4.5 Selection of footwear and leg protection . 19
4.6 Selection of other items of PPE . 20
4.6.1 General. 20
4.6.2 Selection of head protection . 20
4.6.3 Selection of hearing protection . 21
4.6.4 Selection of eye and face protection . 21
4.6.5 Selection of respiratory protection . 21
4.6.6 Selection of hand and arm protection other than gloves . 21
4.6.7 Selection of protection against falls from a height including working belts . 21
4.6.8 Buoyance aids and personal floatation devices . 22
4.7 Marking . 22
5 Use . 22
5.1 Earthing and equipotential bonding . 22
5.1.1 General. 22
5.1.2 Resistance to earth limits . 23
5.1.3 Earthing personnel . 24
5.1.4 Earthing PPE . 25
5.1.5 Verifying resistance to earth . 26
5.2 Instructions for use . 27
5.2.1 Use of electrostatic dissipative protective clothing and general instructions . 27
5.2.2 Use of gloves and hand and arm protection. 28
5.2.3 Use of footwear and leg protection . 28
5.2.4 Use of head protection, eye and face protection, hearing protection and
respiratory protection . 28
5.2.5 Use of protection against falls from a height . 28
5.2.6 Use of personal floatation devices . 29
6 Care . 29
6.1 Care of electrostatic dissipative protective clothing . 29
6.1.1 General. 29
6.1.2 Storage. 29
6.1.3 Cleaning . 29
6.2 Care of footwear and leg protection . 30
6.2.1 General. 30
6.2.2 Storage. 30
6.2.3 Cleaning . 30
6.3 Care of other items of PPE . 30
6.3.1 General . 30
6.3.2 Storage . 30
6.3.3 Cleaning. 31
7 Maintenance . 31
7.1 Visual inspection . 31
7.2 Testing . 31
7.3 Repair . 31
8 Disposal . 31
Annex A (informative) Introduction to electrostatics and electrostatic hazards . 32
A.1 How static electricity is generated . 32
A.2 Flammable atmospheres and minimum ignition energy . 33
A.3 Electrostatic discharges . 34
A.3.1 Types of electrostatic discharge . 34
A.3.2 Spark discharges from charged conductors . 34
A.3.3 The capacitance of conductive objects and ignition risk . 34
A.3.4 Brush discharges from insulating surface . 35
A.4 How to avoid electrostatic ignitions . 35
A.4.1 General . 35
A.4.2 Restriction of area of insulating materials . 36
A.4.3 Earthing conductive objects . 36
A.4.4 Methods of making electrostatic dissipative protective clothing . 37
Annex B (informative) Classification of hazardous areas and zones . 39
Annex C (informative) Questions and Answers . 41
C.1 Introduction . 41
C.2 General questions and answers . 41
C.3 Questions and answers relating to selection . 41
C.4 Questions and answers relating to use . 48
C.5 Questions and answers relating to care . 50
Bibliography . 51
Foreword
This document (CEN/CLC/TR 16832:2015) has been prepared by Technical Committee
CEN/CLC/JWG 7 “PPE against electrostatic risks”, the secretariat of which is held by NEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent
rights.
Introduction
European Standards for personal protective equipment (PPE) are developed to ensure compliance
with the European Directive 89/686/EEC. Since the primary aim of this directive is to guarantee a free
market in the European Union, these standards are made to meet the needs for a common set of
safety requirements and test methods.
The actual use of PPE is not covered by this directive, nor by related standards.
This Technical Report has been developed to meet the needs for a document on selection, use, care
and maintenance. Regulations on health and safety are based on Directive 89/686/EEC, giving
minimum requirements on the selection and use of PPE in the workplace. EU Member States may
impose more stringent requirements and may define exposure limits.
The information in this Technical Report has been produced to assist employers in making the
necessary decisions regarding the selection, use, care and maintenance of PPE. The guidance given
may also be useful for other parties such as suppliers of PPE or services, inspection agencies,
insurance companies, etc.
The purpose of this Technical Report is to highlight the main areas that an employer needs to
consider.
This Technical Report may serve as guidance and as a checklist when a company is preparing its own
management system or programme for PPE.
1 Scope
This Technical Report sets out guidance for the selection, use, care and maintenance of clothing and
related items of personal protective equipment designed to prevent hazards caused by static electricity
in hazardous areas.
Static electricity should not be confused with mains supply electricity, or other forms of electric current;
the requirements for protection against static electricity are different to the requirements for protection
against hazards associated with electric current. Protection against electrostatic risks should not be
confused with protection against electric arc; the former is concerned with electrical properties and the
latter is concerned with heat, flame and projectile protection.
Directive 89/686/EEC requires that PPE intended for use in explosive atmospheres must be so
designed and manufactured that it cannot be the source of an electric, electrostatic or impact-induced
arc or spark likely to cause an explosive mixture to ignite. Whereas this Technical Report addresses
electrostatic ignition risks, it does not address other possible sources of ignition. Nevertheless, other
possible sources of ignition are required to be considered when certifying PPE to the requirements of
Directive 89/686/EEC.
NOTE EN 13463–1 gives guidance on assessing possible ignition sources in non-electrical equipment that
may be used for some items of PPE.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 1081, Resilient floor coverings — Determination of the electrical resistance
EN 1149-1, Protective clothing — Electrostatic properties — Part 1: Test method for measurement of
surface resistivity
EN 1149-2, Protective clothing — Electrostatic properties — Part 2: Test method for measurement of
the electrical resistance through a material (vertical resistance)
EN 1149-3, Protective clothing — Electrostatic properties — Part 3: Test methods for measurement of
charge decay
EN 1149-5, Protective clothing — Electrostatic properties — Part 5: Material performance and design
requirements
CEN/TR 15321:2006, Guidelines on the selection, use, care and maintenance of protective clothing
EN 16350, Protective gloves — Electrostatic properties
EN 60079-10-1, Explosive atmospheres — Part 10-1: Classification of areas — Explosive gas
atmospheres (IEC 60079-10-1)
EN 60079-10-2, Explosive atmospheres — Classification of areas — Combustible dust atmospheres
(IEC 60079-10-2)
CLC/TR 60079-32-1:2015, Explosive atmospheres — Part 32-1: Electrostatic hazards, Guidance
(IEC/TS 60079-32-1:2013)
EN 60079-32-2:2015, Explosive atmospheres — Part 32-2: Electrostatics hazards — Tests (under
consideration) (IEC 60079-32-2:2015)
EN 61340-4-1, Electrostatics — Part 4-1: Standard test methods for specific applications — Electrical
resistance of floor coverings and installed floors (IEC 61340-4-1)
EN 61340-4-3, Electrostatics — Part 4-3: Standard test methods for specific applications — Footwear
(IEC 61340-4-3)
EN 61340-4-5, Electrostatics — Part 4-5: Standard test methods for specific applications — Methods
for characterizing the electrostatic protection of footwear and flooring in combination with a person
(IEC 61340-4-5)
EN ISO 11611, Protective clothing for use in welding and allied processes (ISO 11611)
EN ISO 13688, Protective clothing — General requirements (ISO 13688)
CEN ISO/TR 18690, Guidance for the selection, use and maintenance of safety and occupational
footwear and other personal protective equipment offering foot and leg protection (ISO/TR 18690)
EN ISO 20344, Personal protective equipment — Test methods for footwear (ISO 20344)
EN ISO 20345, Personal protective equipment — Safety footwear (ISO 20345)
EN ISO 20346, Personal protective equipment — Protective footwear (ISO 20346)
EN ISO 20347, Personal protective equipment — Occupational footwear (ISO 20347)
ISO 7000, Graphical symbols for use on equipment — Registered symbols
ISO 10965, Textile floor coverings — Determination of electrical resistance
3 Term and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
hazard
situation which can be the cause of harm or damage to the health of the human body
[SOURCE: CEN/TR 15321:2006, 2.1]
Note 1 to entry: The effects of static electricity can be a nuisance. Electrostatic attraction of dirt and
electrostatic shocks to personnel, for example, are not directly harmful, but they are nonetheless undesirable.
Nuisance effects may cause hazards indirectly. For example, a person working on a ladder may fall off the ladder
because of an involuntary reflex after receiving an electrostatic shock. If nuisance shocks are felt, it is an
indication that there is an electrostatic ignition risk, if the person concerned is in a hazardous area.
3.2
risk
combination of the frequency, or probability, of occurrence and the consequence of a specified
hazardous event
[SOURCE: CEN/TR 15321:2006, 2.2]
3.3
selection
process of determining the type of protective equipment (garments) that is necessary for the required
protection
[SOURCE: CEN/TR 15321:2006, 2.3]
3.4
use
application of protective clothing including its limitations
[SOURCE: CEN/TR 15321:2006, 2.4]
3.5
care
to keep in good working order, including procedures for cleaning, decontamination and storage
[SOURCE: CEN/TR 15321:2006, 2.5]
3.6
maintenance
to preserve from loss or deterioration, to include procedures for inspection, repair and ultimate removal
from service
[SOURCE: CEN/TR 15321:2006, 2.6]
3.7
explosive atmosphere
mixture with air, under atmospheric conditions, of flammable substances in the form of gas, vapour,
dust, fibres, or flyings which, after ignition, permits self-sustaining propagation
[SOURCE: IEV 426-01-06]
3.8
hazardous area
area in which an explosive material, pyrotechnic article or explosive atmosphere is present, or may be
expected to be present, in quantities such as to require special precautions for construction and use of
personal protective equipment
[SOURCE: IEV 426-03-01, modified — The definition has been modified and the original Notes to the
definition are not reproduced here.]
3.9
hazardous zone
hazardous area classified based on the frequency of the occurrence and duration of an explosive
atmosphere
Note 1 to entry: See Annex B.
3.10
electricity
set of the phenomena associated with electric charges and electric currents
[SOURCE: IEV 121-11-76]
3.11
electric current
electric charges that continuously move through a conductor under the influence of a potential gradient
3.12
electric field
electrostatic field
vector field that surrounds electric charge
3.13
electric induction
electrostatic induction
phenomenon in which the electric charge distribution in a body is modified by an electric field
[SOURCE: IEV 121-11-68]
3.14
static electricity
accumulation of electric charge on an object or surface
3.15
electrostatic
associated with static electricity
3.16
electrostatic discharge
ESD
transfer of electric charge between bodies of different electrostatic potential in proximity or through
direct contact
[SOURCE: IEV 161-01-22, modified — "Electric" is here replaced with "electrostatic" and the original
Note to the definition is not reproduced here.]
3.17
brush discharge
type of electrostatic discharge that occurs when rounded (as opposed to sharp) earthed conductors
are moved towards charged insulating objects or surfaces; characterized by branching discharge
channels
3.18
spark discharge
spark
type of electrostatic discharge that occurs between two conductors; characterized by a well-defined
luminous discharge channel carrying a high density current
3.19
corona discharge
corona
type of electrostatic discharge with slight luminosity produced in the neighbourhood of a pointed, or
small radius conductor and limited to the region surrounding the conductor in which the electric field
exceeds a certain value
Note 1 to entry: Other types of electrostatic discharge exist (e.g. propagating brush discharge, cone
discharge, lightning, etc.), but they are not normally associated with PPE in the context of this document.
3.20
electrostatic shock
physiological effect resulting from an electrostatic discharge passing through a human body
3.21
tribocharging
triboelectric charging
triboelectrification
electrical charging process in which net charge is generated by the contact and separation of two
surfaces which may be solid, liquid or particle-carrying gases
3.22
triboelectric series
list of materials ranked in order of how they charge when in contact with one another
Note 1 to entry: See Annex A.
3.23
antistatic
antielectrostatic
property of a material or object that reduces its tendency to acquire charge by contact or rubbing, or
that reduces the time taken for charge to dissipate to an acceptable level
Note 1 to entry: Although “antistatic” is a commonly used term, it is deprecated in some standards documents
because it has many different meanings, depending on the context in which it is used, and this can lead to
confusion.
3.24
low charging
a-static
property of a material or object that reduces its tendency to acquire charge by contact or rubbing
3.25
conductive
describing materials or objects that allow charge to be dissipated rapidly by conduction to earth
3.26
insulating
describing materials or objects that retain charge for long periods of time even when connected to
earth
Note 1 to entry: Conductive and insulating materials and objects are commonly defined quantitatively by their
resistance or resistivity. The range of acceptable values of resistance or resistivity can vary significantly
depending on the material or object and its application.
3.27
electrostatic dissipative (used in EN 1149 (all parts))
static dissipative
dissipative
describing materials or objects that dissipate charge to an acceptable level within an acceptable period
of time
Note 1 to entry: Electrostatic dissipative materials and objects may be defined quantitatively by their
resistance or resistivity, or by other parameters such as decay time, shielding factor, etc. If resistance or resistivity
is used to define electrostatic dissipative materials or objects, the acceptable range of values is between that of
conductive materials and objects and insulating materials and objects.
3.28
oxygen-enriched atmosphere
atmosphere in which the oxygen content exceeds 21,5 % volume fraction of air
Note 1 to entry: Minimum ignition energy values are commonly specified for mixtures with air containing
normal levels of oxygen, i.e. (21,0 ± 0,5) % volume fraction.
Note 2 to entry: In normal industrial situations, it is unlikely that people will be working in an oxygen-enriched
atmosphere. Nevertheless, an oxygen-enriched atmosphere can occur inadvertently, for example when gas
welding is carried out. Oxygen-enriched atmospheres can also occur in medical applications.
3.29
earth (verb)
ground
to connect a conductor to the main body of the Earth to ensure that it is at earth potential
3.30
earth (noun)
ground
part of the Earth which is in electric contact with an earth electrode and the electric potential of which
is not necessarily equal to zero
[SOURCE: IEV 195-01-03]
NOTE In some contexts, earth can have a different meaning to ground, but for the purposes of this
document earth and ground are synonyms.
3.31
equipotential bonding
to electrically connect all conductors and static dissipative materials and objects within a system
together to ensure that no hazardous potential differences exist within the system
Note 1 to entry: For the purposes of this document, and unless otherwise stated, equipotential bonding may
be used in cases where earthing is impossible or impractical.
3.32
resistance to earth
leakage resistance
total electrical resistance through a system between a person or item or component of PPE and earth
3.33
capacitance
Q
relationship between charge on a conductor ( Q ) and its electrical potential (V ) given by C=
V
Note 1 to entry: Capacitance is variable and is dependent on the proximity of the conductor relative to other
large bodies or earth planes
3.34
minimum ignition energy
MIE (abbreviation)
minimum energy that can ignite a mixture of a specified flammable material with air or oxygen,
measured by a standard procedure
Note 1 to entry: ASTM E582 defines standard procedures for determining MIE of gas and vapours;
IEC 61241–2-3, EN 13821 and ASTM E2019 define standard procedures for determining MIE of dusts.
Note 2 to entry: Annex A of this Technical Report and CLC/TR 60079–32–1:2015, C.6 give additional
information on minimum ignition energy.
3.35
probability of charging
probability of a charge mechanism occurring
Note 1 to entry: Probability of charging is only concerned with the occurrence of a charging mechanism, not
the quantity of charge generated.
4 Selection
4.1 General
The primary defence against hazardous electrostatic discharges from personnel is to ensure that they
are properly earthed (see 5.1). When people are earthed there is no possibility of electrostatic
discharges occurring from their bodies. However, electrostatic discharges from their clothing and other
items of PPE may still be possible and consideration should be given to the need for electrostatic
dissipative protective clothing and equipment.
Depending of the sensitivity to ignition, and the probability of an explosive atmosphere being present,
it may be possible to safely use PPE that has limited areas or limited widths of insulating materials.
The size limitations for insulating materials that can be safely used in hazardous areas are given in
CLC/TR 60079–32–1:2015, Table 3. For example, in Zone 1 with gases of explosion group IIA and IIB,
it is permissible to have continuous areas of insulating material up to 10 000 mm and up to 30 mm in
width. Smaller items of PPE may fall within the permissible limits, but clothing and other large items of
PPE will generally exceed the permissible size limits for insulating materials and it is for these items of
PPE that there is normally a need for electrostatic dissipative materials to be used.
It is important to note that the use of electrostatic dissipative protective clothing and equipment cannot
eliminate the risk of hazardous electrostatic discharges from isolated personnel. Some items of PPE,
e.g. conductive or antistatic footwear is intended to provide an adequate connection between
personnel and earth, but such items of PPE are only effective if the connection to earth is not
compromised. For example, conductive or antistatic footwear is only effective if used in conjunction
with conductive or dissipative flooring. Although electrostatic dissipative protective clothing and
equipment may help to reduce the risk of hazardous electrostatic discharges, they cannot be used as
a substitute for proper earthing.
Directive 1999/92/EC requires employers to eliminate all possible ignition sources from areas where it
is identified that explosive atmospheres exist. If, for example, a person is working with a flammable
gas – may be at a hydrogen filling station – there is a risk that a brush discharge from plain clothing
could ignite the gas because the energy in a brush discharge may be greater than the minimum
ignition energy (MIE) of the gas. In this case the employer has an obligation under Directive
1999/92/EC to provide electrostatic dissipative protective clothing if the hazard associated with
explosive atmosphere cannot be eliminated by technical measures.
On the other hand, if a powder with MIE of a greater than 1 mJ is being handled, there is no risk of a
brush discharge from plain clothing causing an ignition of the powder. In this case the employer can
still comply with Directive 1999/92/EC by providing insulating clothing and ensuring that personnel are
properly earthed.
The risk associated with electrostatic discharges from clothing depends on the presence and
sensitivity to ignition of explosive atmospheres. To assist in identifying different levels of risk,
EN 60079-10-1 and EN 60079-10-2 classify hazardous areas into zones depending on the nature of
the flammable material (gas and vapour, or dust) and on the probability of an explosive atmosphere
being present (see Annex B).
Another factor in determining risk is the probability of a charging mechanism occurring. The most
common way in which clothing becomes charged is by contact and rubbing, a process known as
tribocharging. A jacket, for example, may be tribocharged when a person sits in and then rises from a
seat, the jacket having rubbed against the surface of the seat. A jacket, therefore, may be considered
to have a high probability of being exposed to a charging mechanism. Conversely, a hat may not come
in contact with other objects and may, therefore, be considered to have a low probability of being
exposed to a charging mechanism. Clothing and other items of PPE can also become charged by
exposure to equipment that generates ions, charged sprays or aerosols.
Another charging mechanism, only applicable to isolated conductors, is induction, which is the
separation of charge in the presence of an electric field. Standards and codes of practice require that
conductors, which in this context includes people, are properly and securely earthed in hazardous
areas, so in most cases the risk of induction charging is not significant. However, care should be
exercised in selecting PPE that may include small conductors that cannot be earthed for practical
reasons.
Table 1 gives some examples of different situations with high and low probability of charging. The
situations described in Table 1 are illustrative examples only and should not be considered as
definitive statements of actual charging behaviour. Charging is dependent on a number of factors and
should be evaluated on a case by case basis. Expert advice should be obtained if the probability of
charging is not understood, particularly when evaluating new situations.
Although the nature of materials largely determines their propensity for charging, environmental
factors, i.e. temperature and humidity, also have an influence. In general, as relative humidity,
decreases, the propensity of materials to acquire and retain charge increases. Risk assessment
should take account of the full range of environmental conditions workers are likely to be exposed to,
including seasonal variations, outdoor or indoor working (or both), and the presence of heating and air
conditioning in the workplace. A typical conditioning environment specified in test standards
(e.g. EN 1149-1 and EN 1149-3) is (23 ± 1) °C and (25 ± 5) %RH. This conditioning environment is a
compromise between the worst case conditions likely to occur in practice, and the practical limitations
of testing. However, if risk assessment shows that workers are likely to be exposed for prolonged
periods to drier conditions than this, testing of PPE should be done under correspondingly lower
humidity conditions.
Table 1 — Some examples of high and low probability charging situations
Situation Probability Comments
of Charging
PPE rubbed when rising from a seat High
PPE rubbed against other items of PPE being High Charging does occur between layers
worn by the same person, e.g.: of clothing (e.g. outer jacket rubbing
against a shirt). However, the charge
• Sleeve rubbing against body of jacket;
on one layer is balanced by opposite
• One trouser leg rubbing against
charge on the other layer. The
another;
electrostatic risk is low provided the
• Clothing rubbing against a fall arrest
layers are not separated, i.e.
harness
provided the jacket is not removed,
not opened and not excessively
loose.
Exposure to charged mists or aerosols, e.g. High
paint spraying
Exposure to fire extinguishers emitting High
charged sprays or particles
Helmets not normally subjected to rubbing Low
Removal of helmets – harness rubs against High PPE should not be removed while in
hair hazardous areas.
Wiping of visors High
Opening hook-and-loop fasteners High PPE should not be opened while in
hazardous areas.
PPE with no isolated conductive parts Low Insulating materials are not easily
exposed to high electric or electrostatic fields charged by induction when exposed
to high fields.
PPE with isolated conductive parts exposed to High Hazardous voltages can be induced
electric or electrostatic fields on isolated conductive parts. Such
components should be earthed to
prevent charging, or should be of
such low capacitance that incendiary
discharges cannot occur.
PPE is specifically excluded from the scope of Directive 2014/34/EU (and previously
Directive 94/9/EC). Some PPE can be fitted with electrical or electronic components. Such
components are required to comply with Directive 2014/34/EU if they shall be used in hazardous
areas, whereas the PPE is required to comply separately with Directive 89/686/EEC. The fitting of
electrical or electronic components within PPE that has been certified to comply with Directive
89/686/EEC does not mitigate the requirement for certifying the electrical or electronic components in
accordance with Directive 2014/34/EU.
At the time of writing this Technical Report, ATEX Guidelines suggested that following the Essential
Health and Safety Requirements in Directive 94/9/EC is one way of demonstrating compliance with the
Basic Health and Safety Requirements in Directive 89/686/EEC. This guidance should not be taken to
mean that PPE shall comply with the Directive 94/9/EC, nor should it be taken to mean that PPE that
does not comply with Directive 94/9/EC, does not comply with Directive 89/686/EEC. Any item of PPE
that has been certified by a Notified Body in accordance with Directive 89/686/EEC for use in
explosive atmospheres has complied with all necessary legislation to be placed on the market in the
EU territory. The meaning of the ATEX Guidelines on this issue is that a Notified Body, when
examining the technical file of an item of PPE, may accept evidence of compliance with the Essential
Health and Safety Requirements in Directive 94/9/EC, as being one form of evidence of compliance
with Basic Health and Safety Requirements in Directive 89/686/EEC. The decision on whether such
evidence is acceptable is entirely within the responsibility and authority of Notified Bodies operating
under Directive 89/686/EEC.
4.2 Risk assessment
4.2.1 Explosive atmospheres
A risk assessment conducted in order to determine if electrostatic dissipative protective clothing and
equipment is required should include the following:
a) identification of hazardous areas;
b) classification of hazardous zones (Zones 0, 1, 2, 20, 21 and 22);
NOTE It is not usual for people to work in a Zone 0.
c) classification of explosive atmosphere (Explosion Groups I, IIA, IIB, IIC, IIIA, IIIB and IIIC);
d) determination of minimum ignition energy of explosive atmospheres;
e) oxygen enrichment;
NOTE It is not usual for people to work in an oxygen-enriched atmosphere.
f) size (area or width) of clothing and other PPE;
g) mechanisms for and probability of charging clothing and other PPE; account should be taken of
normal worker habits and working practices;
h) environmental factors (temperature and humidity).
Having conducted such a risk assessment, Table 2 can be used to determine if electrostatic
dissipative protective clothing and other electrostatic dissipative PPE are required.
The subdivision of gases and vapours into explosion groups IIA, IIB and IIC is based on the maximum
experimental safe gap (MESG) or the minimum ignition current ratio (MIC ratio) of the explosive
atmosphere. Explosion group classification is widely used in industry and provides a simple way for
electrical equipment manufacturers and users to determine the level of protection required.
CLC/TR 60079–32–1 gives a more detailed account of the origin and development of explosion group
classification.
When considering the risks of electrostatic discharges from non-electrical equipment such as
protective clothing and other items of PPE, the relevant parameter is the minimum ignition energy
(MIE) of the explosive atmosphere (see Annex A). There is a degree of correspondence between
explosion groups and MIE. The range of MIE values for group IIC is lower than any MIE value in
groups IIA and IIB. However, there is a significant overlap in the range of MIE values for groups IIA
and IIB, as can be seen in Table B.3. For this reason, MIE should be used as the primary basis for
determining ignition risk. The guidance given in Table 2 is based on MIE limits; explosion groups are
shown for reference. If the explosive atmosphere is group IIB but the MIE is not known, the guidance
given for 0,016 mJ ≤ MIE ≤ 0,2 mJ should be used.
The performance requirements for electrostatic dissipative protective clothing specified in EN 1149-5
are based on explosive atmospheres with MIE equal to or greater than that of the most easily ignitable
mixture of hydrogen in air. For the purposes of this Technical Report, the lowest MIE of hydrogen/air is
taken as 0,016 mJ, as quoted in CLC/TR 60079–32–1.
In standards for ATEX equipment, different levels of protection are specified to correspond to different
levels of risk. On the other hand, electrostatic dissipative protective clothing is required to protect
against worst case conditions. Table 2 provides guidance on when electrostatic dissipative protective
clothing and other PPE is required, recommended or not required based on the overall risk, which is a
combination of the probability of an explosive atmosphere occurring, the probability of a charging
mechanism occurring and the sensitivity of the explosive atmosphere to ignition by electrostatic
discharges. Table 2 represents different levels of risk in a similar way to standards for ATEX
equipment. When “Required” or “Recommended” is indicated, it relates to PPE that has a single level
of protection. However, as this level corresponds to worst case conditions, the PPE required or
recommended is safe for use in all zones and for all MIE within the range specified in Table 2.
When “Not Required” is indicated, this means that electrostatic dissipative protective clothing or other
PPE is not required, but other precautions for preventing electrostatic ignition sources are still
required, specifically earthing of personnel and other conductors.
The present state of knowledge indicates that irrespective of MIE, powders and dusts (i.e. groups IIIA,
IIIB and IIIC) cannot be ignited by brush discharges from insulators. Therefore, provided personnel
and other conductors are earthed, PPE for use in explosive atmospheres where only dust or powder is
present is not required to be electrostatic dissipative.
Table 2 — Requirement for electrostatic dissipative protective clothing and other PPE
Hazardous Zone Probability MIE > 0,2 mJ
0,016 mJ ≤ MIE ≤ 0,2 mJ
of Charging
Explosion
Explosion Groups IIB, IIC
Explosion
Groups IIIA, IIIB,
Groups IIA, IIB
IIIC
High
Zone 0
Low Required
Required
High
Zone 1
Low
Recommended
High Recommended
Zone 2
Low Not Required Not Required
High
Zones 20, 21, 22 Not Required
Low
The MIE of oxygen-enriched atmospheres may be less than the MIE of the flammable
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...