ASTM E285-08(2020)
(Test Method)Standard Test Method for Oxyacetylene Ablation Testing of Thermal Insulation Materials
Standard Test Method for Oxyacetylene Ablation Testing of Thermal Insulation Materials
SIGNIFICANCE AND USE
4.1 This test method is intended to screen the most obvious poor materials from further consideration. Since the combustion gases more closely resemble the environment generated in rocket motors, this test method is more applicable to screening materials for nozzles and motor liners than for aerodynamic heating.
4.2 The environment for any specific high-temperature thermal protection problem is peculiar to that particular application. The conditions generated by the oxyacetylene heat source in this test method represent only one set of conditions; they do not simulate any specific application. Thus, the test results cannot be used to predict directly the behavior of materials for specific environments, nor can they be used for design purposes. However, over a number of years, the test has been useful in determining the relative merit of materials, particularly in weeding out obviously poor materials from more advanced data-generation programs. It has also been considered for use as a production quality-control test for rocket insulation materials.
4.3 The tester is cautioned to use prudence in extending the usefulness of the test method beyond its original intent, namely, screening. For situations having environments widely different from those of the test, the user is urged to modify the oxyacetylene burner conditions to suit his requirements or perhaps change to a different heat-generating device that provides better simulation.
SCOPE
1.1 This test method covers the screening of ablative materials to determine the relative thermal insulation effectiveness when tested as a flat panel in an environment of a steady flow of hot gas provided by an oxyacetylene burner.
1.2 This test method should be used to measure and describe the properties of materials, products, or assemblies in response to heat and flame under controlled laboratory conditions and should not be used to describe or appraise the fire hazard of materials, products, or assemblies under actual fire conditions. However, results of this test method may be used as elements of a fire risk assessment which takes into account all of the factors which are pertinent to an assessment of the fire hazard of a particular end use.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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.
1.5 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
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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: E285 − 08 (Reapproved 2020)
Standard Test Method for
Oxyacetylene Ablation Testing of Thermal Insulation
Materials
This standard is issued under the fixed designation E285; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Federal Standards:
BB-A-106CAcetylene, Technical, Dissolved
1.1 This test method covers the screening of ablative mate-
BB-O-925AOxygen, Technical, Gas and Liquid
rials to determine the relative thermal insulation effectiveness
when tested as a flat panel in an environment of a steady flow
3. Summary of Test Method
of hot gas provided by an oxyacetylene burner.
3.1 Hot combustion gases are directed along the normal to
1.2 Thistestmethodshouldbeusedtomeasureanddescribe
the specimen until burn-through is achieved. The erosion rate
the properties of materials, products, or assemblies in response
ofthematerialisdeterminedbydividingtheoriginalthickness
to heat and flame under controlled laboratory conditions and
by the time to burn-through. The insulating effectiveness is
should not be used to describe or appraise the fire hazard of
determined from back-face temperature measurements. Insula-
materials, products, or assemblies under actual fire conditions.
tion index numbers are computed by dividing the times for
However, results of this test method may be used as elements
temperature changes of 80, 180, and 380°C, from the initial
of a fire risk assessment which takes into account all of the
ambient temperature, by the original thickness.The insulation-
factors which are pertinent to an assessment of the fire hazard
to-density performance is computed by dividing the insulation
of a particular end use.
index by the density of the panel.
1.3 The values stated in SI units are to be regarded as the
3.2 The general characteristics of the oxyacetylene heat
standard.
source are:
1.4 This standard does not purport to address all of the
3.2.1 Heat Flux—835 W/cm (cold-wall calorimeter).
safety concerns, if any, associated with its use. It is the
3.2.2 Velocity—210 m/s (cold, unreacted gases).
responsibility of the user of this standard to establish appro-
3.2.3 Neutral flame conditions.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4. Significance and Use
1.5 This international standard was developed in accor-
4.1 This test method is intended to screen the most obvious
dance with internationally recognized principles on standard-
poor materials from further consideration. Since the combus-
ization established in the Decision on Principles for the
tiongasesmorecloselyresembletheenvironmentgeneratedin
Development of International Standards, Guides and Recom-
rocket motors, this test method is more applicable to screening
mendations issued by the World Trade Organization Technical
materials for nozzles and motor liners than for aerodynamic
Barriers to Trade (TBT) Committee.
heating.
2. Referenced Documents
4.2 Theenvironmentforanyspecifichigh-temperaturether-
mal protection problem is peculiar to that particular applica-
2.1 ASTM Standards:
tion.Theconditionsgeneratedbytheoxyacetyleneheatsource
D792Test Methods for Density and Specific Gravity (Rela-
inthistestmethodrepresentonlyonesetofconditions;theydo
tive Density) of Plastics by Displacement
not simulate any specific application. Thus, the test results
cannot be used to predict directly the behavior of materials for
This test method is under the jurisdiction of ASTM Committee E21 on Space
specific environments, nor can they be used for design pur-
Simulation andApplications of SpaceTechnology and is the direct responsibility of
poses. However, over a number of years, the test has been
Subcommittee E21.08 on Thermal Protection.
Current edition approved Nov. 1, 2020. Published December 2020. Originally useful in determining the relative merit of materials, particu-
approvedin1965.Lastpreviouseditionapprovedin2015asE285–08(2015).DOI:
larly in weeding out obviously poor materials from more
10.1520/E0285-08R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
the ASTM website. Robbins Ave., Philadelphia, PA 19111-5098, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E285 − 08 (2020)
advanced data-generation programs. It has also been consid- 5.2.2 Torch Tip—The tip shall be a Victor welding nozzle,
ered for use as a production quality-control test for rocket Type 4, No. 7, equipped with a water jacket to minimize
insulation materials. damage to the tip (Note 2). Details of the water jacket are
shown in Figs. 2 and 3 and the torch tip is shown in Fig. 4.
4.3 The tester is cautioned to use prudence in extending the
usefulness of the test method beyond its original intent,
NOTE 2—Proprietary designation cannot be avoided because of the
broad spectrum of heat flux and flame patterns produced by competitive
namely, screening. For situations having environments widely
torch tips of similar size.TheVictor torch tip was selected on the basis of
different from those of the test, the user is urged to modify the
popularity, reproducibility of test results, and the relatively high heat flux
oxyacetylene burner conditions to suit his requirements or
it produces.
perhaps change to a different heat-generating device that
5.2.3 Fuel Storage and Manifold—A minimum of three
provides better simulation.
acetylene cylinders shall be tapped simultaneously through a
5. Apparatus manifold and suitable pressure regulators. Cylinders shall be
stored in an upright position and held at room temperature for
5.1 General—The apparatus shall consist of an oxyacety-
at least 1 h, or until at equilibrium with room temperature,
lene burner, a specimen holder, and means for measuring the
before using.The complete bank of cylinders shall be changed
time to burn-through and for recording the back-face tempera-
when the gage reads 0.7 MPa (100 psi). Acetylene storage
ture history of the specimen.Auxiliary apparatus all consist of
tanks shall be protected by a check valve against accidental
a calorimetric device to measure heat-transfer rate as specified
backflow from the torch. The acetylene shall be maintained at
in 5.5.
294.2 K (70°F) when possible (Note 3). The purity of
5.2 Heat Source—The hot-gas source shall consist of a
acetylene gas shall conform with Federal Specification BB-A-
welding torch with suitable storage for acetylene and oxygen,
106C. The minimum acetylene content shall be 98%.
together with suitable manifolds, flow regulators, and flow and
NOTE3—Ifthisisnotpossible,theflowrateshallbecorrectedto294.2
pressure indicators, as shown schematically in Fig. 1.
K in accordance with the flow rate specified in 5.2.7.The gas temperature
shall not be allowed to exceed 299 K (79°F) or go below 289 K (61°F).
Flow rates are corrected to 294.2 K because most manufacturers use this
temperature as standard for calibration charts.
5.2.4 Oxygen Storage—A minimum of one oxygen tank
shall be tapped through suitable pressure regulators. The
oxygenshallbemaintainedat294.2Kwhenpossible(Note4).
The purity of oxygen gas shall conform with Federal Specifi-
cation BB-O-925A. The minimum oxygen content shall be
99.5%.
5.2.5 Safety Wall—The acetylene and oxygen storage area
shall be isolated from the torch and the operating area by a
suitable safety wall. For convenience, a two-stage regulator
shallbelocatedinthestoragespaceandasingle-stagepressure
regulator located in the operating area.
5.2.6 Pressure Regulators—The regulators for the oxygen
and the acetylene shall be capable of supplying the flow of
gases specified in 5.2.7.
5.2.7 Flowmeters—The flowmeters for the acetylene and
the oxygen shall be capable of supplying an accurate flow of
gases. Avariation of 65% in gas flow rate due to instrumen-
tation inaccuracies shall be permissible. The total flow rate of
unreactedgasesshallbe6.37standardm /h(294.2K,0.1MPa)
(225 standard ft /h (70.0°F, 14.7 psia)), and the volume ratio
of oxygen to acetylene shall be 1.20, which corresponds to
essentially a neutral (oxygen-free) atmosphere.
FIG. 1 Schematic Diagram of Gas System
NOTE 4—Flowmeter and pressure-gage settings are not specified
becausetheywillvarywiththesizeandbrandofflowmeterused.Consult
manufacturers’ instructions and calibration charts that are furnished with
5.2.1 Torch—The torch shall be a Victor Model 315 and
the flowmeters.
shall be mounted so that the flame can be made to contact the
5.2.8 Flow-Pressure Gages—Suitable pressure gages shall
specimen in less than ⁄2 s from the time of actuation.
be located at the exit (downstream) side of the flowmeters to
NOTE 1—Both a solenoid-powered mechanism and a hand-operated
monitor metered gas pressure. These gages shall be capable of
system of levers and push rods have been found to be adequate for this
purpose.
Fischer-Porter Meter size 4, Fig. 1735, float shape BSVT, equivalent capacity
4 3
Victor Equipment Co., 2800 Airport Rd., Denton, TX 76207. 3.35 standard ft /min air, has been found satisfactory for this purpose.
E285 − 08 (2020)
FIG. 2 Details of Water Jacket for Oxyacetylene Torch
5.3 Specimen Holder—The specimen and the calorimeter
shall be supported in a suitable fixture arranged in such a
fashion that it can be moved to align and set the distance and
angle (see 8.4 for specifications) between the specimen, or
calorimeter, and the torch tip (Note 6).The back surface of the
specimen shall be unobstructed by the holder for a distance of
25.4 mm (1.00 in.) out from the center of the specimen. Only
materials with a thermal conductivity of 0.2 W/m·K (1.4
Btu·in./h·ft ·°F) or less shall contact the back of the specimen.
The front surface of the specimen shall be unobstructed for a
distance of 48.0 mm (1.89 in.) out from the center of the
specimen. The total area of contact with front and back
2 2
surfaces shall not exceed 52.0 cm (8.06 in. ).
FIG. 3 Assembly of Water Jacket for Oxyacetylene Torch
NOTE 6—A lathe bed with the specimen holder mounted on the tool
carriage has been found to be adequate for the purpose. Water cooling of
the holder is recommended to prolong service life.
supplying pressure measurements to maintain an accurate flow
5.4 Back-Fa
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