ASTM F1959/F1959M-99

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Designation: F 1959/F 1959M – 99
Standard Test Method for
Determining the Arc Thermal Performance Value of
Materials for Clothing
This standard is issued under the fixed designation F 1959/F 1959M; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope bility of regulatory limitations prior to use. For specific
precautions, see Section 7.
1.1 This test method is used to measure the arc thermal
performance value of materials intended for use as flame
2. Referenced Documents
resistant clothing for workers exposed to electric arcs that
2 2.1 ASTM Standards:
would generate heat flux rates from 2 to 600 cal/cm s.
D 123 Terminology Relating to Textiles
1.2 This test method will measure the arc thermal perfor-
D 4391 Terminology Relating to the Burning Behavior of
mance value of materials which meet the following require-
Textiles
ments: less than 6 in. char length and less than 2 s afterflame
F 1494 Terminology Relating to Protective Clothing
when tested in accordance with Federal Test Method 191A
2.2 ANSI/IEEE Standard:
Method 5903.1.
Standard Dictionary of Electrical and Electronics Terms
1.2.1 It is not the intent of this procedure to evaluate non
2.3 Federal Standard:
flame resistant materials except where used as under layers in
Federal Test Method Standard (FTMS) No. 191A Method
multiple layer specimens.
5903.1, Flame Resistance Cloth Vertical
1.3 The materials used in this test method are in the form of
flat specimens.
3. Terminology
1.4 This test method may be used to generate information
3.1 Definitions:
for the development of smaller scale test methods.
3.1.1 See also Terminology D 4391.
1.5 This standard shall be used to measure and describe the
3.1.2 arc duration, n—time duration of the arc, s.
properties of materials, products, or assemblies in response to
3.1.3 arc energy, vi dt, n—sum of the instantaneous arc
convective and radiant energy generated by an electric arc
voltage values multiplied by the instantaneous arc current
under controlled laboratory conditions.
values multiplied by the incremental time values during the
1.6 The values stated in either SI units or in other units shall
arc, J.
be regarded separately as standard. The values stated in each
3.1.4 arc gap, n—distance between the arc electrodes, in.
system may not be exact equivalents, therefore each system
3.1.5 arc thermal performance value (ATPV), n—in arc
must be used independently of the other, without combining
testing, the incident energy on a fabric or material that results
values in any way.
insufficientheattransferthroughthefabricormaterialtocause
1.7 This standard shall not be used to describe or appraise
the onset of a second-degree burn based on the Stoll curve.
the fire hazard or fire risk of materials, products, or assemblies
3.1.6 arc voltage, n—voltage across the gap caused by the
under actual fire conditions. However, results of this test may
current flowing through the resistance created by the arc gap,
be used as elements of a fire assessment which takes into
V.
account all of the factors which are pertinent to an assessment
3.1.7 asymmetrical arc current, n—the total arc current
of the fire hazard of a particular end use.
produced during closure; it includes a direct component and a
1.8 This standard does not purport to address all of the
symmetrical component, A.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
Annual Book of ASTM Standards, Vol 07.01.
Annual Book of ASTM Standards, Vol 07.02.
1 4
This test method is under the jurisdiction of ASTM Committee F-18 on Annual Book of ASTM Standards, Vol 11.03.
Electrical Protective Equipment for Workers and is the direct responsibility of Available from the Institute of Electrical and Electronics Engineers, Inc., 345
Subcommittee F18.65 on Wearing Apparel. E. 47th St., New York, NY 10017.
Current edition approved April 10, 1999. Published November 1999. Originally Available from Standardization Documents Order Desk, Bldg. 4, Section D,
published as PS 58 – 97. 700 Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F 1959/F 1959M
3.1.8 blowout, n—the extinguishing of the arc caused by a 3.1.24 material response, n—material response to an elec-
magnetic field. tricarcisindicatedbythefollowingterms:breakopen,melting,
dripping, charring, embrittlement, shrinkage, and ignition.
3.1.9 closure, n—point on supply current wave form where
3.1.25 melting, n—in testing flame resistant clothing, a
arc is initiated.
material response evidenced by softening of the fiber polymer.
3.1.10 breakopen, n—in electric arc testing, a material
3.1.26 peak arc current, n—maximum value of the AC arc
response evidenced by the formation of one or more holes in
current, A.
the material which may allow thermal energy to pass through
3.1.27 RMS arc current, n—root mean square of theAC arc
the material.
current, A.
3.1.10.1 Discussion—The specimen is considered to exhibit
3.1.28 shrinkage, n—in testing flame resistant clothing,a
breakopen when any hole is at least one-half square inch in
material response evidenced by reduction in specimen size.
area or at least one inch in any dimension. Single threads
3.1.29 Stoll curve, n—curve produced from data on human
across the opening or hole do not reduce the size of the hole for
tissue tolerance to heat and used to predict the onset of second
the purposes of this test method. In multiple layer specimens of
degree burn injury, (see Table 1).
flame resistant material, all the layers must breakopen to meet
3.1.30 time to delta peak temperature, n—the time from
the definition. In multiple layer specimens, if some of the
beginning of the initiation of the arc to the time the delta peak
layers are ignitable, breakopen occurs when these layers are
temperature is reached, s.
exposed.
3.1.31 X/R ratio—The ratio of system inductive reactance
3.1.11 breakopen threshold energy (E ), n—the average of
BT
toresistance.ItisproportionaltotheL/Rratiooftimeconstant,
the five highest incident energy exposure values below the
and is, therefore, indicative of the rate of decay of any DC
Stoll curve where the specimens do not exhibit breakopen.
offset. A large X/R ratio corresponds to a large time constant
3.1.12 charring, n—the formation of carbonaceous residue
and a slow rate of decay.
as the result of pyrolysis or incomplete combustion.
3.2 Fordefinitionsofothertextiletermsusedinthismethod,
3.1.13 closure,n—pointonsupplycurrentwaveformwhere refer to Terminologies D 123 and F 1494.
arc is initiated.
4. Summary of Test Method
3.1.14 delta peak temperature, n—difference between the
maximum temperature and the initial temperature of the sensor
4.1 This test method determines the incident energy which
during the test, C. would predict a second degree burn injury when the material(s)
is exposed to heat energy from an electric arc.
3.1.15 dripping, n—in testing flame-resistant clothing,a
4.1.1 During this procedure, the amount of heat energy
material response evidenced by flowing of the fiber polymer.
transferred by the material(s) is measured during and after
3.1.16 embrittlement, n—the formation of a brittle residue
exposure to an electric arc.
as the result of pyrolysis or incomplete combustion.
4.1.1.1 The heat flux of the exposure and that transferred by
3.1.17 heat attenuation factor HAF, n—in electric arc
the test specimen(s) are both measured with calorimeters. The
testing, the percent of the incident energy which is blocked by
a material at an incident energy level equal to ATPV.
A
3.1.18 heatflux, n—the thermal intensity indicated by the
TABLE 1 Human Tissue Tolerance to Heat, Second Degree Burn
amount of energy transmitted per unit area and time (cal/
Exposure
B
Heat Flux Total Heat Calorimeter Equivalent
2 2
Time
cm s)(W/cm ).
2 2 2 2 2
s kW/m cal/cm s kWs/m cal/cm DT °C DT °F DmV
3.1.19 i t, n—sum of the instantaneous arc current values
1 50 1.2 50 1.20 8.9 16.0 0.46
squared multiplied by the incremental time values during the
2 31 0.73 61 1.46 10.8 19.5 0.57
arc, A /s.
3 23 0.55 69 1.65 12.2 22.0 0.63
4 19 0.45 75 1.80 13.3 24.0 0.69
3.1.20 ignitability, n (ignitable, adj)—in electric arc expo-
5 16 0.38 80 1.90 14.1 25.3 0.72
sure, the property of a material involving ignition accompanied
6 14 0.34 85 2.04 15.1 27.2 0.78
7 13 0.30 88 2.10 15.5 28.0 0.80
by heat and light, and continued burning resulting in consump-
8 11.5 0.274 92 2.19 16.2 29.2 0.83
tion of at least 25 % of the exposed area of the test specimen.
9 10.6 0.252 95 2.27 16.8 30.2 0.86
3.1.21 ignition, n—the initiation of combustion. 10 9.8 0.233 98 2.33 17.3 31.1 0.89
11 9.2 0.219 101 2.41 17.8 32.1 0.92
3.1.22 incident energy monitoring sensors, n—sensors
12 8.6 0.205 103 2.46 18.2 32.8 0.94
mounted on each side of the panel, using the calorimeters 13 8.1 0.194 106 2.52 18.7 33.6 0.97
14 7.7 0.184 108 2.58 19.1 34.3 0.99
described in 6.3, not covered by fabric, used to measure
15 7.4 0.177 111 2.66 19.7 35.4 1.02
incident energy.
16 7.0 0.168 113 2.69 19.8 35.8 1.03
17 6.7 0.160 114 2.72 20.2 36.3 1.04
3.1.23 incident energy (E), n—in electric arc testing, the
i
18 6.4 0.154 116 2.77 20.6 37.0 1.06
total heat energy received at a surface as a direct result of an
19 6.2 0.148 118 2.81 20.8 37.5 1.08
electric arc.
20 6.0 0.143 120 2.86 21.2 38.1 1.10
25 5.1 0.122 128 3.05 22.6 40.7 1.17
3.1.23.1 Discussion—In an arc test, incident energy for a
30 4.5 0.107 134 3.21 23.8 42.8 1.23
specimen is determined from the average temperature rise
A
Stoll, A. M. And Chianta, M. A., “Method and Rating System for Evaluation of
response of the two monitor sensors adjacent to the test
Thermal Protection,” Aerospace Medicine, Vol 40, 1968, pp. 1232–1238.
B
specimen. Iron/constantan thermocouple.
F 1959/F 1959M
rate at which the temperature of the calorimeters increases is a
direct measure of the heat energy received.
4.2 Material performance for this procedure is determined
from the amount of heat transferred by the specimen(s).
4.3 Heat transfer data is used to predict the onset of second
degree burn using the Stoll curve.
4.4 This procedure incorporates incident energy monitoring
sensors.
4.5 Material response shall be further described by record-
ing the observed effects of the electric arc exposure on the
specimens using the terms in 12.4.
5. Significance and Use
5.1 This test method is intended for the determination of the
arc thermal performance value of a material, a combination of
materials or a comparison of different materials will measure
thearcthermalperformancevalueofmaterialsintendedforuse
in flame resistant clothing for workers exposed to electric arcs.
5.1.1 This test method is intended for the determination of
FIG. 1 Arrangement of Three Panel Sensors with Monitor
the arc thermal performance value of a material, a combination
Sensors
of materials, or a comparison of different materials.
5.1.2 Because of the variability of the arc exposure, differ-
ent heat transmission values may result for individual sensors.
Evaluate the results of each sensor in accordance with Section
12.
5.2 This test method maintains the specimen 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 differ-
ent results. In addition to the standard set of exposure condi-
tions, other conditions representative of the expected hazard
may be used.
6. Apparatus
6.1 General Arrangement For Determining Arc Thermal
Performance Using Three Two-Sensor Panels and Monitor
Sensors—The test apparatus shall consist of supply bus, arc
controller, recorder, arc electrodes, three two-sensor panels,
FIG. 2 Two Sensor Panel (Face View) with Monitor Sensors
and monitor sensors.
6.1.1 Arrangement of the Two-Sensor Panels—Three two-
sensor panels shall be used for each test and spaced as 120 6.2.2 Monitor sensor response is converted to incident
degrees as shown in Fig. 1. Each two-sensor panel shall have
energy in units of cal/cm by multiplying the deltaTC (DT)by
two monitoring sensors. One monitoring sensor shall be the constant factor 0.135 cal/cm C.
positioned on each side of the two-sensor panel as shown in
6.3 Sensor Construction—The sensor mount used to hold
Fig. 2. the calorimeter shall be constructed from non-conductive heat
6.1.2 Panel Construction—Each two sensor panel and each
resistant material as shown in Fig. 4. The calorimeter shall be
monitor sensor holder shall be constructed from non- constructed from electrical grade copper with four thermo-
conductive heat resistant material. Each two-sensor panel shall
couple wires installed in the arrangement as shown in Fig. 5.
be 8 by 21.5 in. 6 0.5 in. as shown in Fig. 2. Each two sensor The thermocouple wire shall be installed in the calorimeter as
panel and monitoring sensors shall be adjustable from 8 in.
shown in Fig. 6. For test exposures above 40 cal/cm only,
(200 mm) to 24 in. [600 mm] from the centerline of the arc alternate calorimeters for the monitor sensors may be used
electrodes as shown in Figs. 1 and 3. Two sensors shall be
provided they are calibrated and have a similar response.
mounted in the panel as shown in Fig. 2. Each sensor shall be 6.4 Supply Bus and Electrodes—A typical arrangement of
mounted flush with the surface of the mounting board.
the supply bus and arc electrodes is shown in Fig. 7. The arc
6.2 Sensor Response: shall be in a vertical position as shown.
6.2.1 PanelsensorresponseshallbecomparedwiththeStoll 6.4.1 Electrodes—Make the electrodes from stainless steel
Curve. (Alloy Type 303 or Type 304) rod of a nominal ⁄4 in. [19 mm]
F 1959/F 1959M
FIG. 3 Sliding Two Sensor Panel
diameter. Lengths of 18 in. [450 mm] long initially have been systems, the system should be able to record temperatures to
found to be adequate. 400 C. The system should have a resolution of 0.1°C and an
6.4.2 Fuse Wire—A fuse wire, connecting the ends of accuracy of 1.5°C.
6.8 Data Acquisition System Protection—Due to the nature
opposing electrodes tips, is used to initiate the arc. This wire is
consumed during the test; therefore, its mass shall be very of this type of testing, the use of isolatin
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