ASTM F955-15(2021)
(Test Method)Standard Test Method for Evaluating Heat Transfer Through Materials for Protective Clothing Upon Contact with Molten Substances
Standard Test Method for Evaluating Heat Transfer Through Materials for Protective Clothing Upon Contact with Molten Substances
SIGNIFICANCE AND USE
5.1 Workers who have the potential to be exposed to molten metal contact shall be permitted to wear protective clothing using materials that have been evaluated for heat transfer using this test method.
5.2 This test method rates materials that are intended for primary protective clothing against potential molten substance contact for their thermal insulating properties and their reaction to the test exposure.
5.3 The protective performance, as determined by this test method, will relate to the actual end-use performance only to the degree that the end-use exposure is identical to the exposure used in the test method.
5.4 Visual inspection of the specimen subjectively notes the material's resistance to molten substance contact.
SCOPE
1.1 This test method covers the evaluation of materials' thermal resistance to heat transfer when exposed to a molten substance pour.
1.1.1 This test method was validated using molten substances of aluminum, brass, and iron. The test shall be permitted to be adapted for use with other substances.
1.2 This test method is applicable to materials from which finished primary protective apparel articles are made.
1.3 This test method does not measure the flammability of materials, nor is it intended for use in evaluating materials exposed to any other thermal exposure.
1.4 Use this test method to measure and describe the properties of materials, products, or assemblies in response to molten substance pour under controlled laboratory conditions and shall not be used to describe or appraise the thermal hazard or fire risk of materials, products, or assemblies under actual conditions. However, it is acceptable to use results of this test as elements of a thermal risk assessment which takes into account all the factors that are pertinent to an assessment of the thermal hazard of a particular end use.
1.5 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. Specific hazard statements are given in Section 8.
1.6 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: F955 − 15 (Reapproved 2021)
Standard Test Method for
Evaluating Heat Transfer Through Materials for Protective
Clothing Upon Contact with Molten Substances
ThisstandardisissuedunderthefixeddesignationF955;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the evaluation of materials’
D123 Terminology Relating to Textiles
thermal resistance to heat transfer when exposed to a molten
E457 Test Method for Measuring Heat-Transfer Rate Using
substance pour.
a Thermal Capacitance (Slug) Calorimeter
1.1.1 This test method was validated using molten sub-
F1002 Performance Specification for Protective Clothing
stances of aluminum, brass, and iron. The test shall be
and Materials for Use by Workers Exposed to Specific
permitted to be adapted for use with other substances.
Molten Substances and Related Thermal Hazards
1.2 This test method is applicable to materials from which
F1494 Terminology Relating to Protective Clothing
finished primary protective apparel articles are made.
3. Terminology
1.3 This test method does not measure the flammability of
3.1 Definitions of Terms Specific to This Standard:
materials, nor is it intended for use in evaluating materials
3.1.1 break-open—in testing thermal protective material, a
exposed to any other thermal exposure.
response evidenced by the formation of a hole in the material
1.4 Use this test method to measure and describe the
which allows the molten substance to pass through the mate-
properties of materials, products, or assemblies in response to
rial.
molten substance pour under controlled laboratory conditions
3.1.2 charring—the formation of carbonaceous residue as
and shall not be used to describe or appraise the thermal hazard
the result of pyrolysis or incomplete combustion.
or fire risk of materials, products, or assemblies under actual
3.1.3 dripping—a material response evidenced by flowing
conditions. However, it is acceptable to use results of this test
of the polymer.
as elements of a thermal risk assessment which takes into
account all the factors that are pertinent to an assessment of the 3.1.4 embrittlement—the formation of a brittle residue as
thermal hazard of a particular end use.
the result of pyrolysis or incomplete combustion.
3.1.5 heat flux—the thermal intensity indicated by the
1.5 This standard does not purport to address all of the
amount of energy transmitted divided by area and time, W/m
safety concerns, if any, associated with its use. It is the
(cal/cm s).
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.1.6 human tissue burn tolerance (heat tolerance)—in the
mine the applicability of regulatory limitations prior to use.
testing of thermal protective materials, the amount of thermal
Specific hazard statements are given in Section 8.
energy predicted to cause a second-degree burn injury in
1.6 This international standard was developed in accor- human tissue.
dance with internationally recognized principles on standard-
3.1.7 ignition—the initiation of combustion.
ization established in the Decision on Principles for the
3.1.8 melting—a material response evidenced by softening
Development of International Standards, Guides and Recom-
of the polymer.
mendations issued by the World Trade Organization Technical
3.1.9 primary protective clothing—protective clothing de-
Barriers to Trade (TBT) Committee.
signed to be worn for work activities during which significant
exposure to molten substance splash, radiant heat, and flame is
likely to occur.
This test method is under the jurisdiction ofASTM Committee F23 on Personal
Protective Clothing and Equipment and is the direct responsibility of Subcommittee
F23.80 on Flame and Thermal. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2021. Published November 2021. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1985. Last previous edition approved in 2015 as F955 – 15. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/F0955-15R21. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F955 − 15 (2021)
3.1.9.1 Discussion—Primary protective clothing is used in 5. Significance and Use
work activities that include charging, tapping, and pouring,
5.1 Workers who have the potential to be exposed to molten
during which work is carried out in close proximity to molten
metal contact shall be permitted to wear protective clothing
substances and hot surfaces where contact with either is likely.
using materials that have been evaluated for heat transfer using
this test method.
3.1.10 response to molten substance pour—in testing ther-
mal protective material, the observed effect of molten sub-
5.2 This test method rates materials that are intended for
stance contact on textile properties or deterioration of the
primary protective clothing against potential molten substance
material.
contactfortheirthermalinsulatingpropertiesandtheirreaction
to the test exposure.
3.1.11 shrinkage—a decrease in one or more dimensions of
an object or material.
5.3 The protective performance, as determined by this test
method, will relate to the actual end-use performance only to
3.1.12 thermal end point—in the testing of thermal protec-
the degree that the end-use exposure is identical to the
tive materials, the point where the copper slug calorimeter
exposure used in the test method.
sensor response (heat energy measured) intersects with a
5.4 Visual inspection of the specimen subjectively notes the
predicted skin burn injury model.
material’s resistance to molten substance contact.
3.2 For definitions of other textile terms used in this test
method, refer to Terminology D123.
6. Apparatus
6.1 The test apparatus consists of four major components as
4. Summary of Test Method
follows:
6.1.1 An inclined specimen mounting and exposure board
4.1 Amaterialspecimenismountedonaverticalinclineand
with two copper slug calorimeter thermal sensors and supports,
is exposed to a molten substance pour of prescribed minimum
6.1.2 A pouring crucible and pouring mechanism,
temperature, volume, pour rate, and vertical height.
6.1.3 A furnace for melting the test metal, and
4.2 The amount of heat energy that is transmitted through
6.1.4 Instruments for measuring test conditions and test
the test specimen during and after the molten substance
results.
exposure is measured using two copper slug calorimeters. The
6.2 Sensor Construction:
heat transport response is assessed versus the Stoll curve, an
6.2.1 Each copper slug calorimeter shall be 18 6 1g,
approximate human tissue tolerance predictive model that
40 mm diameter and 1.6 mm thick, and shall be constructed
projects the onset of a second-degree skin burn injury as
from electrical grade copper with a single 30 gage, iron/
manifested by a blister (see 12.2).
constantan thermocouple wire and shall be installed as identi-
4.3 A specific set of subjective evaluations is performed on
fied in Fig. 1.
the test specimen response to the molten substance exposure 6.2.2 The exposed surface of each copper slug calorimeter
using a standardized rating scale for appraisal (found in Annex
shall be painted with a thin coating of a flat black high-
A1). temperature spray paint with an emissivity of 0.9. The painted
NOTE 1—Sensor Construction—Place a straight, bare tip thermocouple wire into the hole located in the center of the copper disk. Place a short “copper
plug” into the center hole with the thermocouple junction by clipping a section of bare copper wire of appropriate diameter that, when combined with
the thermocouple wire, will just fit into the center hole. Use a center punch to mechanically wedge the wire bundle into place. Peen around the hole to
further secure the thermocouple into the copper disk. Take care not to cut the thermocouple wire during this assembly process. Check the electrical
continuity and thermal response prior to using the completed copper slug calorimeter.
FIG. 1 Sensor Construction
F955 − 15 (2021)
sensor shall be dried before use and present a uniformly 6.5 Furnace—Asuitablefurnaceformeltingandheatingthe
appliedcoating(novisiblethickspotsorsurfaceirregularities). test substance is needed. The furnace and lining must be of a
Note that an external heat source, for example, an external heat type that the chemistry of the substance is not changed during
lamp, has been used to completely drive off any remaining contact with the furnace nor throughout the term of the test
organic carriers on a freshly painted surface. series.
6.3 Specimen/Sensor Board: 6.6 Pouring height shall be 305 mm [12 in.] (see Fig. 2).
6.3.1 The specimen/sensor board shall be nominally
6.7 Data Acquisition System—The system shall be capable
250 mm by 406 mm [10 in. by 16 in.] and fabricated of a flame
of recording the calorimeter outputs as required by the test.
and heat resistant material with a thermal conductivity value of
6.7.1 The temperature data (calorimeter outputs) shall be
≤0.15 W/m·K, high temperature stability, and resistance to
acquired at a minimum sampling rate of four samples per
thermalshock.Theboardshallbenominally13mm[0.5in.]or
second per calorimeter. The acquisition system shall be able to
greater in thickness.
record temperatures to 150 °C [300 °F], have at least a reso-
6.3.2 The copper slug calorimeters shall be located in the
lution of 0.1 °C [0.2 °F], and measuring accuracy of 60.75 °C
centerline of the sensor board and mounted as shown in Fig. 1.
[61.4 °F].
The calorimeters shall be located 101 mm and 203 mm [4 in.
and 8 in.] respectively, from the top of the board to the
7. Materials
calorimeter centers as indicated in Fig. 2.
7.1 Description of standard substances for test purposes is
6.3.3 An attachment method shall be provided that affixes
included in Table 1.
the test specimen to the board such that it covers both sensors
and extends at least 25 mm [1 in.] beyond all edges.
8. Hazards
6.3.4 The sensor board shall be inclined at an angle of 70°
8.1 Perform the test in a ventilated area to carry away
from horizontal.
combustion products, smoke, and fumes. Care shall be exer-
6.3.5 The sensor board shall be located so that it meets the
cised in handling the hot substance. A full fire extinguisher,
pour geometry illustrated in Fig. 2, where the molten substance
preferably of the carbon dioxide type, shall be readily avail-
is introduced at the centerline of the board.
able.Usenormalsafetypracticesforthehandlingofthemolten
6.4 Pouring Crucible—The pouring crucible shall be suit-
substance and potentially flammable materials. Place a catch
able for the substance being poured and for handling tempera-
pan filled with dry sand under the assembly. Extreme care shall
tures up to at least 56 °C [100 °F] above the pouring tempera-
be taken to prevent contact between the molten substance and
ture. Crucible sizes appropriate for specific substances are
water because explosive quantities of steam can result.
shown in Table 1. The crucible shall be attached to a tilting
8.2 The sensor board and calorimeter assembly become
mechanism capable of turning the ladle at the rate of one
heated during prolonged testing. Use protective gloves when
revolution per 4.7 6 0.2 s. The crucible shall be pivoted at a
handling these hot objects and during the pour.
point 25 mm [1 in.] below the top of the crucible on the
vertical. When tilted, the tilted action shall be stopped me-
9. Sampling and Specimen Preparation
chanically after a rotation of 10 6 5° from the vertical (Fig. 2).
See also Annex A2.
9.1 Lot Size—For acceptance sampling purposes, a lot is
defined as 4572 m [5000 yd] or a single shipment of a single
style of material, whichever is smaller.Alot shall be permitted
to constitute all or part of a single customer order.
9.2 Lot Sample—As a lot sample, takea2m [2.2 yd]
full-widthpieceofmaterialfromboththebeginningandendof
the lot.
9.3 Test Specimens—Cut and identify three test specimens
from each sample. Make each test specimen at least 305 6
1 1
2mmby460 62mm[12 6 ⁄16 by 18 6 ⁄16 in.]. Do not cut
samples closer than 10 % of the material width from the edge
and arrange the specimens across the sample swatch so as to
get as representative a sampling as possible.
9.4 Sensor Care:
9.4.1 Initial Temperature—Cool the sensor after a pour
exposure with a jet of air to approximately 21 °C [70 °F] just
prior to positioning the test specimen.
9.4.2 Surface Reconditioning—Wipe the sensor face with a
nonabrasive material immediately after each run, while it is
hot, to remove any decomposition products which condense,
since these could be a source of error. If there is a deposit on
FIG. 2 Schematic of Test Apparatus the surface of the sensor that appears to be thicker than a thin
F955 − 15 (2021)
A
TABLE 1 Test Parameters
NOTE 1—When this test method is used for substances other than below, use a pour temperature equal to use temperature or sufficiently above the
melting point to give reproducible pouring characteristics.
Substance Pour Temperature (min) Weight of Test Substance Substance Specification
B
A Iron 2800 °F [1538 °C] 2.2 lb [1000 g] Eutectic iron
B Aluminum 1400 °F [760 °C] 2.2 lb [1000 g] Alloy 1100
C
C Brass 2100 °F [1149 °C] 2.2 lb [1000 g] Alloy 875
A
See Annex A3.
Si P
B
Carbon equivalent = 4.3 ± 0.15 %. Carbon equivalent5% C1 1 sapproximately 2 % Sid.
4 2
C
82 ⁄14 ⁄4 %, Cu/Zn/Sn.
layer of paint, or is irregular, the sensor surface requires 10.2.5 Ifthetemperatureriseofthetwotestsdiffersbymore
reconditioning. Carefully clean the cooled sensor with acetone than 10 %, test a third specimen and average the results of the
orpetroleumsolvent,makingcertainthereisnoignitionsource three tests. Note any explainable reason for the variation.
nearby. Repaint the surface, if bare copper is showing, with a 10.2.6 Post-Test Inspection—After the pour, inspect the
thin layer of flat black spray paint as identified in 6.2.2 above. ladle to be sure that all of the test substance has been poured
out of the crucible and onto the test m
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.