ASTM F2522-12(2022)
(Test Method)Standard Test Method for Determining the Protective Performance of a Shield Attached on Live Line Tools or on Racking Rods for Electric Arc Hazards
Standard Test Method for Determining the Protective Performance of a Shield Attached on Live Line Tools or on Racking Rods for Electric Arc Hazards
SIGNIFICANCE AND USE
5.1 This test method is intended for determining the heat attenuation factor (HAF) of a shield material and the effective heat attenuation factor (EHAF) at the location of the worker. This can be obtained by measuring the reduction of the arc incident energy levels caused by a shield attached on a live line tool (hot stick) or on a racking rod and designed for protection for workers exposed to electric arcs. The shield mechanical strength (SMS) can be obtained from visual observations of the high speed video recordings of each shot during HAF tests.
5.1.1 Because of the variability of the arc exposure, different heat transmission values and pressure may result for individual sensors. The results of each sensor are evaluated in accordance with Section 12.
5.2 This test method maintains the shield and the heat sensors in a static, vertical position and does not involve movement except that resulting from the exposure.
5.3 This test method specifies a standard set of exposure conditions. Different exposure conditions may produce different results.
Note 1: In addition to the standard set of exposure conditions, other conditions representative of the expected hazard may be used and shall be reported should this data be cited.
SCOPE
1.1 This test method is used to determine the heat attenuation factor (HAF), the effective heat attenuation factor (EHAF), and the shields mechanical strength (SMS) of a shield attached on live line tools or racking rods intended for protection of workers exposed to electric arcs.
1.2 The materials used in this test method of worker protection are in the form of a shield attached on live line tools or on the racking rods.
1.3 The protective shield described in this test method shall be transparent and shall be easily attached and removed from live line tools or from racking rods.
1.4 The protective shield described in this test method has 24-in. (0.61-m) diameter and can be used for most applications, however for special cases, the shield can have different sizes to suit the protective requirements of the application.
1.5 This standard shall be used to measure and describe the properties of materials, products, or assemblies in response to incident energies (thermal-convective, and radiant and pressure wave) generated by an electric arc under controlled laboratory conditions and does not purport to predict damage from light, resultant pressure impact other than the pressure and thermal aspects measured.
1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.7 This standard shall not be used to describe or appraise the fire hazard or fire risk of materials, products, or assemblies under actual fire conditions. However, results of this test may be used as elements of a fire assessment, which takes into account all of the factors, which are pertinent to an assessment of the fire hazard of a particular end use.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.For specific precautions, see Section 7.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2522 − 12 (Reapproved 2022)
Standard Test Method for
Determining the Protective Performance of a Shield
Attached on Live Line Tools or on Racking Rods for Electric
Arc Hazards
This standard is issued under the fixed designation F2522; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.8 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method is used to determine the heat attenua-
responsibility of the user of this standard to establish appro-
tionfactor(HAF),theeffectiveheatattenuationfactor(EHAF),
priate safety, health, and environmental practices and deter-
and the shields mechanical strength (SMS) of a shield attached
mine the applicability of regulatory limitations prior to use.For
on live line tools or racking rods intended for protection of
specific precautions, see Section 7.
workers exposed to electric arcs.
1.9 This international standard was developed in accor-
1.2 The materials used in this test method of worker
dance with internationally recognized principles on standard-
protection are in the form of a shield attached on live line tools
ization established in the Decision on Principles for the
or on the racking rods.
Development of International Standards, Guides and Recom-
1.3 The protective shield described in this test method shall mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
be transparent and shall be easily attached and removed from
live line tools or from racking rods.
2. Referenced Documents
1.4 The protective shield described in this test method has
24-in.(0.61-m)diameterandcanbeusedformostapplications, 2.1 ASTM Standards:
D4391 Terminology Relating to The Burning Behavior of
however for special cases, the shield can have different sizes to
suit the protective requirements of the application. Textiles
F1959/F1959M TestMethodforDeterminingtheArcRating
1.5 This standard shall be used to measure and describe the
of Materials for Clothing
properties of materials, products, or assemblies in response to
incidentenergies(thermal-convective,andradiantandpressure
3. Terminology
wave) generated by an electric arc under controlled laboratory
conditions and does not purport to predict damage from light,
3.1 Definitions:
resultant pressure impact other than the pressure and thermal 3.1.1 arc, n—conductive path in air for the electric current
aspects measured.
caused by ionization of air between two electrodes.
3.1.2 arc duration, n—time duration of the arc, s.
1.6 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
3.1.3 arc energy, vi dt, n—sum of the instantaneous arc
conversions to SI units that are provided for information only
voltage values multiplied by the instantaneous arc current
and are not considered standard.
values multiplied by the incremental time values during the
arc, J.
1.7 This standard shall not be used to describe or appraise
the fire hazard or fire risk of materials, products, or assemblies
3.1.4 arc gap, n—distance between the arc electrodes, cm
under actual fire conditions. However, results of this test may
[in.].
be used as elements of a fire assessment, which takes into
3.1.5 arc voltage, n—voltage across the gap caused by the
account all of the factors, which are pertinent to an assessment
current flowing through the resistance created by the arc gap,
of the fire hazard of a particular end use.
V. See also Terminology D4391.
This test method is under the jurisdiction of ASTM Committee F18 on
Electrical Protective Equipment for Workers and is the direct responsibility of
Subcommittee F18.35 on Tools & Equipment. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2022. Published December 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approvedin2005.Lastpreviouseditionapprovedin2017asF2522-12(2017).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/F2522-12R22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2522 − 12 (2022)
3.1.6 asymmetrical arc current, n—the total arc current attached, and the shield mechanical strength (SMS). The
produced during closure; it includes a direct component and a copper calorimeters (incident energy monitoring sensors) are
symmetrical component, A. placed for the HAF at the shield (front and back), and for the
EHAF test at the probable location of the worker’s hand, head,
3.1.7 blowout, n—the extinguishing of the arc caused by a
side of the face, chest, and legs when exposed to the heat
magnetic field.
energy from a controlled electric arc. The SMS value of the
3.1.8 closure, n—point on supply current wave form where
shield is obtained from visual observations of the HAF test for
arc is initiated.
the ability of the shield to absorb and deflect the fragmentation
3.1.9 effective heat attenuation (EHAF)/cone of protection
shrapnel, not break or ignite, not to move from its attachment,
(COP) factor, n—the percentage of the incident heat energy
and not to bend more then 20 degrees.
that is attenuated by the shield at the location of the worker.
4.2 During HAF and EHAF tests, the center of the shield is
3.1.10 fragmentation, n—molten metal fragments or other
aligned with the mid point of the arc gap. During this
fragments emitted from an electric arc.
procedure, the amount of heat energy reduced (blocked) by the
shield is measured during exposure to an electric arc.
3.1.11 heat attenuation factor (HAF), n—the percentage of
the incident heat energy that is blocked by the safety shield
4.3 The heat energy of the arc exposure is measured with
material.
calorimeters. The rate at which the temperature of the calorim-
3.1.12 heat flux, n—the thermal intensity indicated by the
eters increases is a direct measure of the heat energy received.
amount of energy transmitted divided by area and time
4.4 Theshieldprotectiveperformanceforthistestmethodis
2 2
W/m [cal⁄cm s].
determined from the heat attenuation factor (in percent) at the
3.1.13 i t, n—sum of the instantaneous arc current values
shield location, and from the effective heat attenuation factor at
squared multiplied by the incremental time values during the
the worker location. The effective heat attenuation factor in
arc, A /s.
percentisthedifferenceintheincidentenergygeneratedbythe
arc flash before and after the shield was used.
3.1.14 ignitability, n (ignitable, adj)—in electric arc
exposure, the property of a material involving ignition accom-
4.5 Heat transfer data can be used to predict the onset of
panied by heat and light, and continued burning resulting in
second degree burn using the Stoll curve.
consumption of at least 25 % of the exposed area of the test
4.6 This procedure incorporates incident heat energy moni-
specimen.
toring sensors.
3.1.15 ignition, n—the initiation of combustion.
4.7 Further description of the shield reduction of the electric
3.1.16 incident energy (E), n—the amount of energy (total
i
arc exposure on the worker is presented in Sections 12 and 13.
heat, cal/cm ) received at a surface as a direct result of an
5. Significance and Use
electrical arc discharge as measured by temperature rise on
copper calorimeters.
5.1 This test method is intended for determining the heat
attenuation factor (HAF) of a shield material and the effective
3.1.17 peak arc current, n—maximum value of the AC arc
heat attenuation factor (EHAF) at the location of the worker.
current, A.
This can be obtained by measuring the reduction of the arc
3.1.18 pressure wave, n—a certain force over an area
incident energy levels caused by a shield attached on a live line
created by air movement caused by an electric arc.
tool (hot stick) or on a racking rod and designed for protection
3.1.19 RMS arc current, n—root mean square of theAC arc
for workers exposed to electric arcs. The shield mechanical
current, A.
strength(SMS)canbeobtainedfromvisualobservationsofthe
3.1.20 sensors, n—copper calorimeter, instrumented with a high speed video recordings of each shot during HAF tests.
thermocouple contained in a dielectric, heat protective housing 5.1.1 Because of the variability of the arc exposure, differ-
for use in measuring energy. ent heat transmission values and pressure may result for
individual sensors. The results of each sensor are evaluated in
3.1.21 shield mechanical strength value (SMS) factor,
accordance with Section 12.
n—the mechanical ability of the shield to withstand the electric
arc pressure wave and fragmentation. 5.2 This test method maintains the shield and the heat
sensors in a static, vertical position and does not involve
3.1.22 X/R ratio, n—the ratio of system inductive reactance
movement except that resulting from the exposure.
toresistance.ItisproportionaltotheL/Rratiooftimeconstant,
and is, therefore, indicative of the rate of decay of any DC
5.3 This test method specifies a standard set of exposure
offset. A large X/R ratio corresponds to a large time constant
conditions. Different exposure conditions may produce differ-
and a slow rate of decay.
ent results.
NOTE 1—In addition to the standard set of exposure conditions, other
conditions representative of the expected hazard may be used and shall be
4. Summary of Test Method
reported should this data be cited.
4.1 This test method determines the heat attenuation factor
6. Apparatus
(HAF) of the shield material, the effective heat attenuation
factor (EHAF) at the location where the worker may be while 6.1 GeneralArrangement for Determining HeatAttenuation
holding the hot stick or racking rod to which the shield is Factor (HAF) of the Shield—The test apparatus shall consist of
F2522 − 12 (2022)
supply bus, arc controller, recorder, arc electrodes, the shield, to absorb and deflect the fragmentation shrapnel, not break or
and incident energy monitoring sensors. The arc exposure in ignite, not to move from its attachment, and not to bend more
the form of heat attenuation factor at the shield location shall then 20 degrees.
be monitored with two incident energy monitoring sensors.
6.4 Electrodes—Atypical arrangement of the arc electrodes
Figs. 1 and 2 show the test set-up and the location of the shield
is shown in Fig. 1. The arc shall be in a vertical position as
on the hot stick and on the racking rod and the location of
shown.
sensors. Fig. 2 has the same test set-up as Fig. 1, except the
6.5 Electrodes—Make the electrodes from electrical grade
shield is attached on the racking rod.
copper (alloy type 110) rod of a nominal ⁄4-in. (0.019-m)
6.2 General Arrangement for Determining Effective Heat
diameter. Lengths of 18 in. (0.460 m) long have been found to
Attenuation Factor (EHAF) at the Location of the Worker—
be adequate.
The test apparatus shall consist of supply bus, arc controller,
6.6 Fuse Wire—A fuse wire, connecting the ends of oppos-
recorder, arc electrodes, a shield, and incident energy monitor-
ing electrodes tips, is used to initiate the arc. This wire is
ing sensors. The arc exposure in the form of effective heat
consumed during the test; therefore, its mass shall be very
attenuation factor at the location of the worker shall be
small to reduce the chance of molten metal burns. The fuse
monitored with a minimum of six incident energy monitoring
wire shall be a copper wire with a diameter no greater than
sensors. Figs. 3 and 4 show the test set-up and the location of
0.02 in. (0.0005 m).
the shield and the sensors. The shield for the EHAF test is at
the same location as in the HAF tests (Figs. 1 and 2) and the
6.7 Electric Supply—The electric supply should be suffi-
sensors are located approximately 5 ft (1.52 m) from the cient to allow for the discharge of an electric arc with a gap of
electric arc center. Fig. 4 has the same test set-up as Fig. 3,
up to 12 in. (0.305 m), with alternating arc current from 4000
except the shield in Fig. 4 is attached on the racking rod, and up to 25 000Aand with arc duration from 3 cycles (0.05 s) up
in Fig. 3 the shield is attached on a hotstick.
to 90 cycles (1.5 s) from a 60 Hz supply. The X/R ratio of the
test circuit shall be such that the test current contains a DC
6.3 General Arrangement for Determining Shield’s Me-
component resulting in the first peak of the test current having
chanical Strength (SMS)—The evaluation of shield’s mechani-
a magnitude of 2.3 times the symmetrical RMS value.
cal strength value (SMS) is based on visual observations of the
high speed video recordings of the arc tests made in 6.1 (HAF 6.8 Test Circuit Control—Repeat exposures of the arc cur-
tests). The purpose of the SMS test is to determine the rents shall not deviate more than 2 % per test from the selected
mechanical ability of the shield to withstand the electric arc test level. The make switch shall be capable of point on wave
pressure wave and fragmentation. The SMS value is deter- closing within 0.2 cycles from test to test, such that the closing
mined by observing the HAF tests for the ability of the shield angle will produce maximum asymmetrical current with an
d1 = 24 in. (0.61 m), distance from the wall (back plate) to the arc electrodes
d2=6in.(0.15m)(gap) between electrodes
d3 = 53 in. (1.35 m), parallel distance of the hot stick or the racking rod above the floor
d4 = 24 in. (0.61 m), distance of the shield from the electrodes
d5=4in.(0.10m),vertical distance between centers of S’1 and S’2
S’1 and S’2 = 24.5 in. (0.62 m), approximate horizontal distance of the sensors from the electrodes
S1, S2, S3, S4, S5, and S6 are located vertically, and S1 is 5 ft (1.52 m) from the arc center
FIG. 1 Test Set-up for HAF Measurements with Shield on a Live Line Tool
F2522 − 12 (2022)
d1 = 24 in. (0.61 m), distance from the wall (back plate) to the arc electrodes
d2=6in.(0.15m)(gap) between electrodes
d3 = 53 in. (1.35 m), parallel distance of the hot stick or the racking rod above the floor
d4 = 24 in. (0.61 m), distance of the shield from the electrodes
d5=4in.(0.10m),vertical distance between centers of S’1 and S’2
S’1 and S’2 = 24
...
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