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ASTM E511-01

(Test Method)

Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Gage

Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Gage

SCOPE
1.1 This test method describes the measurement of radiative or convective heat flux, or both, using a transducer whose sensing element (1, 2) is a thin circular metal foil. While benchmark calibration standards exist for radiative environments, no uniform agreement among practitioners or government entities exists for convective environments.
1.2 The values stated in SI units are to be regarded as the standard. The values stated in parentheses are provided for information only.
1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
09-Oct-2001
ICS
17.200.10 - Heat. Calorimetry
Technical Committee
E21 - Space Simulation and Applications of Space Technology
Drafting Committee
E21.08 - Thermal Protection
Current Stage
Ref Project

Relations

Replaces
ASTM E511-73(1994)e1 - Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Gage
Effective Date
10-Oct-2001
Replaced By
ASTM E511-07 - Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Transducer
Effective Date
01-Nov-2007
Referred By
ASTM E2683-17 - Standard Test Method for Measuring Heat Flux Using Flush-Mounted Insert Temperature-Gradient Gages
Effective Date
10-Oct-2001
Referred By
ASTM E2874-19 - Standard Test Method for Determining the Fire-Test Response Characteristics of a Building Spandrel-Panel Assembly Due to External Spread of Fire
Effective Date
10-Oct-2001
Referred By
ASTM E457-08(2020) - Standard Test Method for Measuring Heat-Transfer Rate Using a Thermal Capacitance (Slug) Calorimeter
Effective Date
10-Oct-2001
Referred By
ASTM E2307-23a - Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-story Test Apparatus
Effective Date
10-Oct-2001
Referred By
ASTM E637-22 - Standard Test Method for Calculation of Stagnation Enthalpy from Heat Transfer Theory and Experimental Measurements of Stagnation-Point Heat Transfer and Pressure
Effective Date
10-Oct-2001
Referred By
ASTM F1387-23 - Standard Specification for Performance of Piping and Tubing Mechanically Attached Fittings
Effective Date
10-Oct-2001
Referred By
ASTM F1930-23 - Standard Test Method for Evaluation of Flame-Resistant Clothing for Protection Against Fire Simulations Using an Instrumented Manikin
Effective Date
10-Oct-2001
Referred By
ASTM E598-08(2020) - Standard Test Method for Measuring Extreme Heat-Transfer Rates from High-Energy Environments Using a Transient, Null-Point Calorimeter
Effective Date
10-Oct-2001
Referred By
ASTM E1529-22 - Standard Test Methods for Determining Effects of Large Hydrocarbon Pool Fires on Structural Members and Assemblies
Effective Date
10-Oct-2001
Referred By
ASTM E458-08(2020) - Standard Test Method for Heat of Ablation
Effective Date
10-Oct-2001
Referred By
ASTM E3057-19 - Standard Test Method for Measuring Heat Flux Using Directional Flame Thermometers with Advanced Data Analysis Techniques
Effective Date
10-Oct-2001

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ASTM E511-01 - Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux GageASTM E511-01 - Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Gage
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ASTM E511-01 - Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Gage
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Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E511–01
Standard Test Method for
Measuring Heat Flux Using a Copper-Constantan Circular
1
Foil, Heat-Flux Transducer
This standard is issued under the fixed designation E 511; 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 to the heat flux q9 absorbed by the foil. This relationship is
described by the following equation:
1.1 This test method describes the measurement of radiative
or convective heat flux, or both, using a transducer whose E 5 Kq9
2
sensing element (1, 2) is a thin circular metal foil. While
where:
benchmark calibration standards exist for radiative environ-
K = a sensitivity constant determined experimentally.
ments, no uniform agreement among practitioners or govern-
2.3 For linear response, the heat sink of the transducer
ment entities exists for convective environments.
normally is made of copper and the foil of thermocouple grade
1.2 The values stated in SI units are to be regarded as the
constantan. This combination of materials produces a linear
standard. The values stated in parentheses are provided for
output over a temperature range from -45 to 232°C (-50 to
information only.
450°F). The linear range results from offsetting effects of
1.3 This standard does not purport to address all of the
temperature-dependent changes in the thermal conductivity
safety concerns, if any, associated with its use. It is the
and Seebeck coefficient of the constantan. All further discus-
responsibility of the user of this standard to establish appro-
sion is based on the use of these two metals, since engineering
priate safety and health practices and determine the applica-
practice has demonstrated they are commonly the most useful.
bility of regulatory limitations prior to use.
3. Characteristics and Limitations
2. Summary of Test Method
3.1 The principal response characteristics of a circular foil
2.1 The purpose of this test method is to facilitate measure-
heat flux transducer are sensitivity, full-scale range, and the
ment of heat flux from radiant or convective sources, or from
time constant, which are established by the foil diameter and
a combination of the two.
thickness. For a given heat flux, the transducer sensitivity is
2.2 The circular foil heat flux transducer generates a milli-
proportional to the temperature difference between the center
volt output in response to the rate of thermal energy absorbed
and edge of the circular foil. To increase sensitivity, the foil is
(see Fig. 1).The circular metal foil sensing element is mounted
made thinner or its diameter is increased. The full-scale range
in a metal heat sink around its perimeter, forming a reference
ofatransducerislimitedbythemaximumallowedtemperature
thermocouple junction due to their different thermoelectric
at the center of the foil.The range may be increased by making
potentials. A second thermocouple junction is formed at the
the foil smaller in diameter, or thicker. The transducer time
center of the foil using a fine wire of the same metal as the heat
constant approximately is proportional to the square of the foil
sink. When the sensing element is exposed to a heat source,
diameter, and is characterized by (3):
heat energy is absorbed at the surface of the circular foil and
2
conducted radially to the heat sink.This establishes a parabolic
t5rcd /16k
temperature gradient between the center and edge of the foil.
where the foil properties are:
The temperature gradient produces a thermoelectric potential,
r = density,
E, between the center wire and the heat sink that will vary in
c = specific heat,
proportion to the heat flux, q9. With prescribed foil diameter,
d = foil diameter, and
thickness,andmaterials,thepotential Eislinearlyproportional
k = foil conductivity.
3.2 Foil diameters and thicknesses are limited by typical
1 manufacturingconstraints.Maximumoptimumfoildiameterto
This test method is under the jurisdiction of ASTM Committee E21 on Space
thickness ratio is 4 to 1 for sensors less than 2.54 mm diameter.
Simulation andApplications of Space Technology and is the direct responsibility of
Subcommittee E21.08 on Thermal Protection.
Foil diameters range from 25.4 mm to 0.254 mm, with most
Current edition approved Oct. 10, 2001. Published January 2002. Originally
gages between 1.02 and 6.35 mm. The time constants, t, for a
e1
published as E 511 – 73. Last previous edition E 511 – 73 (1994) .
2
The boldface numbers in parentheses refer to the list of references at the end of
this test method.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United St
...

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5.1 The purpose of this test method is to measure extremely high heat-transfer rates to a body immersed in either a static environment or in a high velocity fluid stream. This is usually accomplished while preserving the structural integrity of the measurement device for multiple exposures during the measurement period. Heat-transfer rates ranging up to 2.84 × 102 MW/m2 (2.5 × 104 Btu/ft2-sec) (7) have been measured using null-point calorimeters. Use of copper null-point calorimeters provides a measuring system with good response time and maximum run time to sensor burnout (or ablation). Null-point calorimeters are normally made with sensor body diameters of 2.36 mm (0.093 in.) press-fitted into the nose of an axisymmetric model.  
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Standard Test Method for Measuring Heat Flux Using a Copper-Constantan Circular Foil, Heat-Flux Transducer

SIGNIFICANCE AND USE
3.1 Fig. 1 is a sectional view of an example circular foil heat-flux transducer. It consists of a circular Constantan foil attached by a metallic bonding process to a heat sink of oxygen-free high conductivity copper (OFHC), with copper leads attached at the center of the circular foil and at any point on the heat-sink body. The transducer impedance is usually less than 1 V. To minimize current flow, the data acquisition system (DAS) should be a potentiometric system or have an input impedance of at least 100 000 Ω.  
3.2 As noted in 2.3, an approximately linear output (versus heat flux) is produced when the body and center wire of the transducer are constructed of copper and the circular foil is constantan. Other metal combinations may be employed for use at higher temperatures, but most (4) are nonlinear.  
3.3 Because the thermocouple junction at the edge of the foil is the reference for the center thermocouple, no cold junction compensation is required with this instrument. The wire leads used to convey the signal from the transducer to the readout device are normally made of stranded, tinned copper, insulated with TFE-fluorocarbon and shielded with a braid over-wrap that is also TFE-fluorocarbon-covered.  
3.4 Transducers with a heat-sink thermocouple can be used to indicate the foil center temperature. Once the edge temperature is known, the temperature difference from the foil edge to its center may be directly read from the copper-constantan (Type T) thermocouple table. This temperature difference then is added to the body temperature, indicating the foil center temperature.  
3.5 Water-Cooled Transducer:  
3.5.1 A water-cooled transducer should be used in any application where the copper heat-sink would rise above 235 °C (450 °F) without cooling. Examples of cooled transducers are shown in Fig. 2. The coolant flow must be sufficient to prevent local boiling of the coolant inside the transducer body, with its characteristic pulsations (“chugging”) of t...
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1.1 This test method describes the measurement of radiative heat flux using a transducer whose sensing element (1, 2)2 is a thin circular metal foil. These sensors are often called Gardon Gauges.  
1.2 The values stated in SI units are to be regarded as the standard. The values stated in parentheses are provided for information only.  
1.3 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.  
1.4 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.

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ASTM
ASTM E3057-19(Test Method)
Standard Test Method for Measuring Heat Flux Using Directional Flame Thermometers with Advanced Data Analysis Techniques

SIGNIFICANCE AND USE
5.1 Need for Heat Flux Measurements:  
5.1.1 Independent measurements of temperature and heat flux support the development and validation of engineering models of fires and other high environments, such as furnaces. For tests of fire protection materials and structural assemblies, temperature and heat flux are necessary to fully specify the boundary conditions, also known as the thermal exposure. Temperature measurements alone cannot provide a complete set of boundary conditions.  
5.1.2 Temperature is a scalar variable and a primary variable. Heat Flux is a vector quantity, and it is a derived variable. As a result, they should be measured separately just as current and voltage are in electrical systems. For steady-state or quasi-steady state conditions, analysis basically uses a thermal analog of Ohm's Law. The thermal circuit uses the temperature difference instead of voltage drop, the heat flux in place of the current and thermal resistance in place of electrical resistance. As with electrical systems, the thermal performance is not fully specified without knowing at least two of these three parameters (temperature drop, heat flux, or thermal resistance). For dynamic thermal experiments like fires or fire safety tests, the electrical capacitance is replaced by the volumetric heat capacity.  
5.1.3 The net heat flux, which is measured by a DFT, is likely different than the heat flux into the test item of interest because of different surface temperatures. An alternative measurement is the total cold wall heat flux which is measured by water-cooled Gardon or S-B gauges. The incident radiative flux can be estimated from either measurement by use of an energy balance [Keltner, 2007 and 2008 (16, 17)]. The convective flux can be estimated from gas temperatures and the convective heat transfer coefficient, h [Janssens, 2007 (18)]. Assuming the sensor is physically close to the test item of interest; one can use the incident radiative and convective fluxes from the...
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1.1 This test method describes the continuous measurement of the hemispherical heat flux to one or both surfaces of an uncooled sensor called a “Directional Flame Thermometer” (DFT).  
1.2 DFTs consist of two heavily oxidized, Inconel 600 plates with mineral insulated, metal-sheathed (MIMS) thermocouples (TCs, type K) attached to the unexposed faces and a layer of ceramic fiber insulation placed between the plates.  
1.3 Post-test calculations of the net heat flux can be made using several methods. The most accurate method uses an inverse heat conduction code. Nonlinear inverse heat conduction analysis uses a thermal model of the DFT with temperature dependent thermal properties along with the two plate temperature measurement histories. The code provides transient heat flux on both exposed faces, temperature histories within the DFT as well as statistical information on the quality of the analysis.  
1.4 A second method uses a transient energy balance on the DFT sensing surface and insulation, which uses the same temperature measurements as in the inverse calculations to estimate the net heat flux.  
1.5 A third method uses Inverse Filter Functions (IFFs) to provide a near real time estimate of the net flux. The heat flux history for the “front face” (either surface exposed to the heat source) of a DFT can be calculated in real-time using a convolution type of digital filter algorithm.  
1.6 Although developed for use in fires and fire safety testing, this measurement method is quite broad in potential fields of application because of the size of the DFTs and their construction. It has been used to measure heat flux levels above 300 kW/m2 in high temperature environments, up to about 1250 °C, which is the generally accepted upper limit of Type K or N thermocouples.  
1.7 The transient response of the DFTs is limited by the response of the MIMS TCs. The larger the thermocouple the slower the transient response. Res...

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ASTM
ASTM E2684-17(Test Method)
Standard Test Method for Measuring Heat Flux Using Surface-Mounted One-Dimensional Flat Gages

SIGNIFICANCE AND USE
5.1 This test method will provide guidance for the measurement of the net heat flux to or from a surface location. To determine the radiant energy component the emissivity or absorptivity of the gage surface coating is required and should be matched with the surrounding surface. The potential physical and thermal disruptions of the surface due to the presence of the gage should be minimized and characterized. For the case of convection and low source temperature radiation to or from the surface it is important to consider how the presence of the gage alters the surface heat flux. The desired quantity is usually the heat flux at the surface location without the presence of the gage.  
5.1.1 Temperature limitations are determined by the gage material properties and the method of application to the surface. The range of heat flux that can be measured and the time response are limited by the gage design and construction details. Measurements from 10 W/m2 to above 100 kW/m2 are easily obtained with current sensors. Time constants as low as 10 ms are possible, while thicker sensors may have response times greater than 1 s. It is important to choose the sensor style and characteristics to match the range and time response of the required application.  
5.2 The measured heat flux is based on one-dimensional analysis with a uniform heat flux over the surface of the gage surface. Because of the thermal disruption caused by the placement of the gage on the surface, this may not be true. Wesley (3) and Baba et al. (4) have analyzed the effect of the gage on the thermal field and heat transfer within the surface substrate and determined that the one-dimensional assumption is valid when:
   where:
  ks  =   the thermal conductivity of the substrate material,    R   =  the effective radius of the gage,    δ  =  the combined thickness, and     k  =  the effective thermal conductivity of the gage and adhesive layers.    
5.3 Measurements of convective heat flux are part...
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1.1 This test method describes the measurement of the net heat flux normal to a surface using flat gages mounted onto the surface. Conduction heat flux is not the focus of this standard. Conduction applications related to insulation materials are covered by Test Method C518 and Practices C1041 and C1046. The sensors covered by this test method all use a measurement of the temperature difference between two parallel planes normal to the surface to determine the heat that is exchanged to or from the surface in keeping with Fourier’s Law. The gages operate by the same principles for heat transfer in either direction.  
1.2 This test method is quite broad in its field of application, size and construction. Different sensor types are described in detail in later sections as examples of the general method for measuring heat flux from the temperature gradient normal to a surface (1).2 Applications include both radiation and convection heat transfer. The gages have broad application from aerospace to biomedical engineering with measurements ranging form 0.01 to 50 kW/m 2. The gages are usually square or rectangular and vary in size from 1 mm to 10 cm or more on a side. The thicknesses range from 0.05 to 3 mm.  
1.3 The values stated in SI units are to be regarded as the standard. The values stated in parentheses are provided for information only.  
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 and health 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...

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