01500340 PDF BRITISH STANDARD BS EN 379 1994 Implementing Amendment No 1 not published separately Specification for Welding filters with switchable luminous transmittance and welding filters with dual[.]
Trang 1BRITISH STANDARD BS EN
379:1994
Implementing Amendment No 1 not published separately
Specification for
Welding filters with
switchable luminous
transmittance and
welding filters with
dual luminous
transmittance
The European Standard EN 379:1994, with the incorporation of its
amendment A1:1998, has the status of a British Standard
ICS 13.340.20
Trang 2This British Standard, having
been prepared under the
direction of the Personal
Safety Equipment Standards
Policy Committee, was
published under the authority
of the Standards Board and
comes into effect on
15 May 1994
© BSI 05-1999
The following BSI references
relate to the work on this
standard:
Committee reference PSM/2
Draft for comment 90/44741 DC
ISBN 0 580 21878 3
Cooperating organizations
The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries:
Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y
France Association française de normalisation Germany Deutsches Institut für Normung e.V
Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland
Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portuguès da Qualidade Spain Asociación Española de Normalización y Certificación Sweden Standardiseringskommissionen i Sverige
Switzerland Association suisse de normalisation United Kingdom British Standards Institution
Amendments issued since publication
Amd No Date Comments
10073 September
1998 Indicated by a sideline in the margin
Trang 3BS EN 379:1994
Contents
Page Cooperating organizations Inside front cover
Annex A (informative) Guidance on selection and use 8
Table 2 — Classification of oculars according to the
maximum value of P1, P2 or P3 4 Table 3 — Switching the requirements 6 Table 4 — Assignment of diffusion of light class 6 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back cover
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National foreword
This British Standard has been prepared under the direction of the Personal Safety Equipment Standards Policy Committee and is the English language
version of EN 379:1994 Specification for welding filters with switchable luminous
transmittance and welding filters with dual luminous transmittance, including
Amendment 1:1998, published by the European Committee for Standardization (CEN)
EN 379 was produced as a result of international discussions in which the United Kingdom took an active part
There is no existing equivalent British Standard to EN 379 Attention is drawn
to BS EN 169:1992 Specification for filters for personal eye-protection equipment
used in welding and similar operations, which specifies the requirements for
these more traditional and well-established products
A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application
Compliance with a British Standard does not of itself confer immunity from legal obligations.
Summary of pages
This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 8, an inside back cover and a back cover
This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover
Trang 5EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
EN 379
January 1994
+ A1
May 1998
UDC 614.893-086.52:681.7.014.3:621.791-057.21
ICS 13.340.20
Supersedes EN 137:1986 Descriptors: Safety, accident prevention, eyes, filters, welding, specifications, transmittance, dimensions, tests, marking
English version
Specification for welding filters with switchable
luminous transmittance and welding filters with dual
luminous transmittance
Spécification concernant des filtres de soudage
avec facteur de transmission dans le visible
commutable et des filtres de soudage avec
double facteur de transmission dans le visible
Anforderungen an Schweißerschutzfilter mit umschaltbaren Lichttransmissionsgrad und Schweißerschutzfilter mit zwei
Lichttransmissionsgraden
This European Standard was approved by CEN on 1994-01-07; amendment A1
was approved by CEN on 1998-04-26 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
Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any
CEN member
This European Standard exists 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
Central Secretariat has the same status as the official versions
CEN members are the national standards bodies of Austria, Belgium,
Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland,
Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and United Kingdom
CEN
European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung
Central Secretariat: rue de Stassart 36, B-1050 Brussels
© 1994 Copyright reserved to CEN members
Ref No EN 379:1994\A1:1998 E
Trang 6© BSI 05-1999
2
Foreword
This European Standard was drawn up by the
CEN/TC 85 Technical Committee, Eye protection
equipment, of which the Secretariat is held by
AFNOR
This European Standard has been prepared under a
mandate given to CEN by the European
Communities and the European Free Trade
Association, and supports essential requirements of
EC Directive(s)
This European Standard shall be given the status of
a national standard, either by publication of an
identical text or by endorsement, at the latest by
July 1994, and conflicting national standards shall
be withdrawn at the latest by July 1994
In accordance with the CEN/CENELEC Internal
Regulations, the following countries are bound to
implement this European Standard: Austria,
Belgium, Denmark, Finland, France, Germany,
Greece, Iceland, Ireland, Italy, Luxembourg,
Netherlands, Norway, Portugal, Spain, Sweden,
Switzerland and United Kingdom
Foreword to A1:1998
This Amendment EN 379:1994/A1:1998 to
EN 379:1994 has been prepared by Technical Committee CEN/TC 85, Eye-protective equipment, the secretariat of which is held by AFNOR
This Amendment to the European Standard
EN 379:1994 shall be given the status of a national standard, either by publication of an identical text
or by endorsement, at the latest by November 1998, and conflicting national standards shall be
withdrawn at the latest by November 1998
This Amendment to the European Standard
EN 379:1994 has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s)
According to CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium,
Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom
Trang 7EN 379:1994
1 Scope
This standard specifies requirements for welding
filters which automatically switch their luminous
transmittance to a lower value when a welding arc
is ignited (referred to as welding filters with
switchable scale numbers) The requirements of this
standard apply if such a filter is to be used for
continuous viewing of the welding process and if it
is to be used only during the period when the arc is
being ignited
This standard also specifies requirements for
welding filters with zones of differing luminous
transmittance (referred to as welding filters with
dual scale number)
These filters are used in welders’ eye protectors (as
specified in standards in preparation) or are fixed to
equipment
2 Normative references
EN 165, Personal eye protection — Vocabulary
EN 166:1995, Personal eye protection —
Fundamental specifications
EN 167:1995, Personal eye protection — Optical test
methods
EN 168, Personal eye protection — Non-optical
test methods
EN 169:1992, Personal eye protection — Filters for
welding and related processes — Transmittance and
recommended applications
EN 175, Personal eye protection — Equipment for
eye and face protection during welding and allied
processes (excluding hoods)
ISO/CIE 10526, CIE standard colorimetric
illuminants
3 Definitions
For the purposes of this European Standard the
definitions given in EN 165 apply together with the
following
3.1
welding filter with switchable scale number
a protective filter which automatically switches its
scale number from a lower value (light state scale
number) to a higher value (dark state scale number)
when the welding arc is ignited
3.2
welding filter with dual scale number
a protective filter with two different scale numbers
(light and dark zones) which are divided into a
maximum of three areas of the filter The light zone
is used for brief viewing when setting the electrode
to the weld and igniting it The dark zone is used for
viewing the welding process
3.3 light state scale number
the scale number corresponding to the maximum value of luminous transmittance E1
3.4 dark state scale number
the scale number corresponding to the minimum value of luminous transmittance Ù2
3.5 switching time
the time dependence of luminous transmittance is
described by function Ù(t) the switching time ts is defined by the following integral:
where:
NOTE In the case of short term exposure to light, the glare is approximately proportional to the product of the illuminance at the eye and time The time relationship of the darkening process can be very different depending on the construction of the welding filter with switchable scale number It is therefore appropriate to define the switching time as an integral of the luminous transmittance over time and not merely by the initial and final luminous transmittances.
4 Requirements
4.1 General requirements
Welding filters with switchable scale number and welding filters with dual scale number shall comply with the requirements given in Table 1
4.2 Particular requirements
Where a manufacturer wishes to claim compliance with particular requirements, these requirements
shall be as specified in clauses 7.2.2 to 7.2.7 of
EN 166:1995
4.3 Additional requirements for welding filters with switchable scale numbers 4.3.1 Power off
When tested in accordance with 5.1, welding filters
with switchable scale numbers shall be no more than nine scale numbers lighter than the highest scale number in the dark state
t = 0 is the time at which the arc
ignites;
t = t (Ù = 3Ù2) is the time at which the
luminous transmittance falls
to 3 times the luminous transmittance in the dark state
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Table 1 — General requirements
Table 2 — Classification of oculars according to the maximum value
of P1 , P2 or P3 as specified in 4.3.3
4.3.2 Transmittance
4.3.2.1 The requirements of clauses 4.3.2.2, 4.3.2.3
and 4.3.2.4 shall be satisfied when the
transmittances are measured as described in
clause 6 of EN 167:1995 using standard
Illuminant A
4.3.2.2 The minimum luminous transmittance in
the light state shall be 0,16 % when measured at
both (– 5 ± 2) °C and (55 ± 2) °C
4.3.2.3 The luminous transmittance requirements
given in Table 1 of EN 169:1992 shall apply to both
light and dark states The measurements shall be
taken at both (– 5 ± 2) °C and (55 ± 2) °C
4.3.2.4 The spectral transmittance in the ultraviolet and the mean transmittance in the infra-red as given in Table 1 of EN 169:1992 and the additional
requirements a) to d) of clause 4.1 of EN 169:1992
required for the dark state shall also apply to the light state The measurements shall be taken at a temperature of (23 ± 5) °C
4.3.3 Variations in luminous transmittance
When measured in accordance with Clause 7.2 of
EN 167:1995 at a temperature of (23 ± 5) °C the
values of P1, P2 and P3 of welding filters with switchable scale number shall not exceed the values
in Table 2 for the assigned class This requirement shall apply to both light and dark states
4.3.4 Switching times of welding filters with switchable scale number
4.3.4.1 The switching times shall satisfy either
clause 4.3.4.2 or clause 4.3.4.3 for the darkest state
Property General requirements for welding
filters with switchable scale number General requirements for welding filters with dual scale number
Spherical, astigmatic and
prismatic refractive powers As specified in clause 7.1.2.1.2 of EN 166:1995 As specified in clause 7.1.2.1.2 of EN 166:1995 Variations in luminous
transmittance As specified in clause 4.3.3 As specified in clause 7.1.2.2.3 of EN 166:1995 Diffusion of light As specified in clause 4.3.7 As specified in clause 7.1.2.3 of
EN 166:1995 Quality of material and surface As specified in clause 7.1.3
EN 166:1995 As specified in clause 7.1.3 of EN 166:1995 Robustness of construction As specified in clause 7.1.4 of
EN 166:1995 As specified in clause 7.1.4 of EN 166:1995
Stability at elevated temperature As specified in clause 7.1.5.1 of
EN 166:1995 As specified in clause 7.1.5.1 of EN 166:1995 Resistance to ultraviolet
radiation As specified in clause 7.1.5.2 of EN 166:1995, but replacing
clause 7.1.5.2 b) by clause 4.3.7 of
this European standard
As specified in clause 7.1.5.2 of
EN 166:1995
Resistance to ignition As specified in clause 7.1.8 of
EN 166:1995 As specified in clause 7.1.8 of EN 166:1995
Luminous transmittance in dark
state Maximum value of P1 or P2 Maximum value of P3
max min Class 1 Class 2 Class 3 Class 1 Class 2 Class 3
100
17,9
0,44
0,023
0,0012
17,9 0,44 0,023 0,0012 0,000023
5 10 15 20 30
10 15 20 30 40
15 20 30 40 60
20 20 20 20 30
20 20 20 30 40
20 20 30 40 60
Trang 9EN 379:1994
Where the requirements of clause 4.3.4.2 are
satisfied, no further marking is required
Where the requirements of clause 4.3.4.3 are
satisfied but the requirements of clause 4.3.4.2 are
not satisfied, the warning notice
DO NOT USE BELOW 10 °C
shall be permanently and legibly marked on the
device
4.3.4.2 The switching time shall be measured as
described in clause 5.2 at temperatures
of (– 5 ± 2) °C and (55 ± 2) °C The switching time
given in Table 3 shall not be exceeded at either of
these temperatures
4.3.4.3 The switching time shall be measured as
described in clause 5.2 at temperatures
of (10 ± 2 ) °C and (55 ± 2) °C The switching time
given in Table 3 shall not be exceeded at either of
these temperatures
4.3.5 Manual control of dark scale number
When a manual control of the dark scale number is
provided, the means of control shall meet the
following requirements
a) There shall be a digital indication of the scale
number for each position of the manual control
b) The scale number in the dark state(s) shall not
deviate by more than ±1 from the set scale
number with an illuminance of (104 ± 103) lx on
the switching light source (5.2.1.1).
c) If the range of control is more than five scale
numbers, it shall be divided into two sub-ranges
with separate manual controls Each manual
control shall control a sub-range of no more
than 5 scale numbers
4.3.6 Dimensions
The minimum dimensions of the viewing area when
mounted in appropriate equipment shall be 90 mm
by 35 mm
4.3.7 Diffusion of light
The diffusion of light shall be measured in
accordance with one of the reference methods
described in clause 4 of EN 167:1995.
The maximum value of the reduced luminance
factor in the light or dark state shall determine the
diffusion of light class of the welding filter as shown
in Table 4
4.4 Additional requirements for welding
filters with dual scale number
4.4.1 Difference in scale number
The difference in scale number between the light
and dark zones shall be no more than five
4.4.2 Transmittance
4.4.2.1 The requirements of clauses 4.4.2.2 and 4.4.2.3 shall be satisfied when
the transmittances are measured as described in
clause 6 of EN 167:1995 at a temperature
of (23 ± 5) °C
4.4.2.2 The minimum luminous transmittance in the light zone shall be 0,16 %
4.4.2.3 The spectral transmittance in the ultraviolet and the mean transmittance in the infra-red given
in Table 1 of EN 169:1992 and the additional
requirements a) to c) in clause 4.1 of EN 169:1992
required for the dark zone shall also apply to the light zone
4.4.3 Dimensions
These shall be as given in clause 7.1.1 of
EN 166:1995
The dark zone shall be at least 25 mm vertical depth across the horizontal length
Any region separating the light and dark zones shall not exceed 2 mm vertical depth across the
horizontal length This region shall be opaque
5 Test methods
5.1 Power off test
Measure the luminous transmittance with the device in the dark state Disconnect all power supplies Repeat the measurement of the luminous transmittance
5.2 Measurement of switching time 5.2.1 Test equipment
5.2.1.1 Switching light source This consists of a
high pressure xenon lamp as a source of radiation, producing an illuminance of (104± 103) lx at the test specimen
5.2.1.2 High speed optical shutter A device capable
of switching on the switching light source at a speed
meeting the requirements of 5.2.2.
5.2.1.3 Measurement light source A source of
illuminant A (see ISO/CIE 10526)
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Table 3 — Switching time requirements
Table 4 — Assignment of diffusion of light
class
5.2.1.4 Light detector and recording apparatus A
device capable of detecting and recording the light
from the measurement light source transmitted by
the welding filter
5.2.2 Performance of test equipment
Check that when the light beam is switched by the
high speed shutter, the rise time between 10 %
and 90 % of the light transmitted by the shutter is
no greater than 10 % of the switching time required
for the scale number difference to be measured
See Table 3
5.2.3 Measurement
Maintain the test specimen at the appropriate test
temperature for a minimum of 2 h before testing
and during the period of the test
Set up the measurement light source (5.2.1.3) and
the test specimen so that the plane of the test
specimen and the light detector (5.2.1.4) are
at (90 ± 5) ° to the measurement beam
With the switching light source on, switch the high
speed shutter to allow the light through to the test
specimen, thereby switching the test specimen to its
dark state Record the measurement light
transmitted through the test specimen during the
switching period
5.2.4 Calculation
Calculate the switching time ts from the equation
given in 3.5, with t = 0 as the time when the
illuminance at the test specimen reaches about half
the value given in 5.2.1.1.
6 Marking This shall be as specified in clause 9 of EN 166:1995
with the following additional details
6.1 Welding filter with switchable scale number
The light state scale number and the dark state scale number(s), separated by an oblique stroke, shall be used instead of the single scale number Where the dark state is manually controlled, the limits of the range of attainable scale numbers shall
be marked separated by a hyphen
The diffusion of light class and uniformity of luminous transmittance class shall be added, separated by oblique strokes, to the optical class as
specified in EN 166:1995, clause 7.1.2.1.2 e.g 1/3/2.
NOTE Examples of marking are as follows.
a) A simple device with one light state and one dark state: 5/11
b) A device with one light state and manual control of the dark state in one range: 4/9-13 c) A device with one light state and manual control of the dark state in two
ranges: 4/5-7/10-13
Switching time ms
7 300 400 500 700 1 000 No requirement No requirement
Diffusion of light Maximum value reduced
luminance factor
(cd/m2)/lx
class
1
2
3
1,0 2,0 3,0