ASTM D7487-24

Standard Practice for Polyurethane Raw Materials: Polyurethane Foam Cup Test

SIGNIFICANCE AND USE
5.1 General Utility:  
5.1.1 It is useful to verify catalyst levels in a resin blend or a polyurethane system.  
5.1.2 This practice is suitable for research, quality control, specification testing, and process control.  
5.2 Limitations:  
5.2.1 Several of the measured parameters are subjective. Therefore, operator-to-operator variability and lab-to-lab variability can be much higher than that of a single operator.  
5.2.2 The variability of this practice is dependent on the consistency of mixing of the reactants.  
5.2.3 The estimation of precision in this practice is based on typical formulations for rigid and flexible foams. Formulations with faster reaction times will likely have greater variability, particularly cream time (initiation time). Formulations with slower reaction times will likely have greater variability in the measurement of free rise time.  
5.2.4 It is possible that low-level (ppm, ppb) ingredient contamination will not be detectable using this practice. Confirmation of such contamination will potentially require large-scale (~20 L) tests and is out of the scope of this practice.
SCOPE
1.1 This practice covers the determination of cream time (initiation time), top of cup time, free rise time, free rise height, string gel time (pull time), tack free time, settle back, and free rise density of polyurethane foam formulations using a cup foam test.  
1.2 Typical definitions, terms, and techniques are described; including procedures for mixing and transferring samples to the foaming container; and data gathering and evaluation. However, agreement between the customer and the testing laboratory for all these items must be obtained prior to use.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
Note 1: There is no known ISO equivalent to this standard.  
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

• Status: Published
• Publication Date: 31-Jan-2024
• ICS: 83.080.10 - Thermosetting materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.22 - Cellular Materials - Plastics and Elastomers

Relations

• Replaces: ASTM D7487-18 - Standard Practice for Polyurethane Raw Materials: Polyurethane Foam Cup Test
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM E456-13a(2022)e1 - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022
• Refers: ASTM E456-13a(2022) - Standard Terminology Relating to Quality and Statistics
• Effective Date: 01-Apr-2022

Overview

ASTM D7487-24 is the current edition of the "Standard Practice for Polyurethane Raw Materials: Polyurethane Foam Cup Test," published by ASTM International. This practice outlines standardized procedures for determining critical foaming properties, including cream time, top of cup time, free rise time, free rise height, string gel time, tack free time, settle back, and free rise density for polyurethane foam formulations using a cup test. The method is widely used for assessing both rigid and flexible polyurethane foams within laboratory and production environments.

The standard is designed to support research, quality control, specification testing, and process monitoring of polyurethane materials-helping organizations ensure consistent results and material performance. It is important to note that a high degree of repeatability and reproducibility depends on operator skill and careful adherence to mixing protocols.

Key Topics

• Measurement Parameters: ASTM D7487-24 describes procedures to measure:

  • Cream time (initiation time)
  • Top of cup time
  • Free rise time and free rise height
  • String gel time (pull time)
  • Tack free time
  • Settle back (% sigh or sink back)
  • Free rise density

• Procedure and Equipment: The standard details the apparatus-such as mixers, cups, thermometers, and balances-required to conduct the foam cup test. Accurate measurement and data recording protocols are emphasized.

• Precision and Limitations:

  • The data for some parameters are subjective, potentially increasing operator- and lab-to-lab variability.
  • Consistency in reactant mixing is crucial for reliable results.
  • Fast-reacting or slow-reacting polyurethane systems may exhibit higher variability in certain measurements.
  • Detection of low-level contaminants is beyond the capability of this method.

• Safety Considerations: The standard requires users to ensure appropriate safety, health, and environmental procedures when dealing with polyurethane chemicals, especially isocyanates.

Applications

• Research and Development: Ideal for the comparative study of new polyurethane formulations in laboratory settings.
• Quality Control: Provides foam manufacturers and raw material suppliers with standardized test procedures to ensure consistent batch quality.
• Specification Testing: Enables verification that raw materials or finished products meet customer or regulatory requirements.
• Process Control: Assists production teams in monitoring catalyst levels and formulation consistency.

ASTM D7487-24 supports both rigid and flexible polyurethane foam systems, making it relevant for industries such as insulation, automotive, furniture, packaging, and bedding.

Related Standards

To ensure comprehensive quality and compatibility, ASTM D7487-24 should be considered alongside these related standards:

• ASTM D883 - Terminology Relating to Plastics: Definitions crucial for interpreting the terms used in D7487.
• ASTM E456 - Terminology Relating to Quality and Statistics: Useful for understanding the statistical aspects of precision and variability.
• ASTM E691 - Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method: Methodology for evaluating reproducibility.
• ASTM E2935 - Practice for Evaluating Equivalence of Two Testing Processes: Guidance on comparing methods or labs.

Currently, there is no ISO equivalent to ASTM D7487-24, making it the authoritative source for the polyurethane foam cup test on an international level.

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Keywords: ASTM D7487, polyurethane foam cup test, raw material testing, cream time, free rise density, quality control, polyurethane system, research and development, specification testing, flexible foam, rigid foam, process control, foam performance, standard methods.

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: D7487 − 24
Standard Practice for
Polyurethane Raw Materials: Polyurethane Foam Cup Test
This standard is issued under the fixed designation D7487; 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* Determine the Precision of a Test Method
E2935 Practice for Evaluating Equivalence of Two Testing
1.1 This practice covers the determination of cream time
Processes
(initiation time), top of cup time, free rise time, free rise height,
string gel time (pull time), tack free time, settle back, and free
3. Terminology
rise density of polyurethane foam formulations using a cup
foam test. 3.1 Definitions—Terms used in this standard are defined in
accordance with Terminology D883, unless otherwise speci-
1.2 Typical definitions, terms, and techniques are described;
fied. For terms relating to precision and bias and associated
including procedures for mixing and transferring samples to
issues, the terms used in this standard are defined in accordance
the foaming container; and data gathering and evaluation.
with Terminology E456.
However, agreement between the customer and the testing
3.2 Definitions of Terms Specific to This Standard:
laboratory for all these items must be obtained prior to use.
3.2.1 cream time (initiation time), n—the time between the
1.3 The values stated in SI units are to be regarded as
start of mixing and the point at which fine bubbles begin to
standard. No other units of measurement are included in this
appear.
standard.
3.2.2 final height, n—height of foam after specified time.
1.4 This standard does not purport to address all of the
3.2.3 free rise density, n—the density in kg/m of a poly-
safety concerns, if any, associated with its use. It is the
urethane foam prepared in an open cup.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
3.2.4 free rise height, n—height of the foam at free rise time.
mine the applicability of regulatory limitations prior to use.
3.2.5 free rise time (end of rise time), n—the time at which
NOTE 1—There is no known ISO equivalent to this standard. the foam stops expanding as observed visually.
1.5 This international standard was developed in accor-
3.2.6 resin blend (formulated polyol), n—complete ingredi-
dance with internationally recognized principles on standard-
ent formulation without the isocyanate.
ization established in the Decision on Principles for the
3.2.7 % settle back (% recession, % sigh back, or % sink
Development of International Standards, Guides and Recom-
back), n—percentage decrease from free rise height to final
mendations issued by the World Trade Organization Technical
height.
Barriers to Trade (TBT) Committee.
3.2.8 string gel time (pull time), n—time at which long
“strings” of tacky material can be pulled away from the surface
2. Referenced Documents
of the foam when the surface is touched by the edge of a tongue
2.1 ASTM Standards:
depressor or similar implement.
D883 Terminology Relating to Plastics
3.2.9 tack free time, n—the time at which the surface of the
E456 Terminology Relating to Quality and Statistics
foam can be touched with a gloved finger or tongue depressor
E691 Practice for Conducting an Interlaboratory Study to
without sticking.
3.2.10 top of cup time, n—the time at which the crown of the
rising foam reaches the plane of the top of the cup.
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and
is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics
and Elastomers.
4. Summary of Practice
Current edition approved Feb. 1, 2024. Published February 2024. Originally
4.1 Specific events (cream time, initiation time, top of cup
approved in 2008. Last previous edition approved in 2018 as D7487 – 18.
DOI:10.1520/D7487-24.
time, free rise time, free rise height, string gel time, and tack
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
free time) from a polyurethane foamed in a cup are measured
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
to verify the resin blend composition or levels of ingredients in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. formulations used to make polyurethane foams.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7487 − 24
4.2 An estimation of the method precision is given. An to diisocyanates. Use a combination of engineering controls
estimation of bias is not given because there is no suitable and personal protective equipment, including respiratory, skin
reference method. and eye protection, to prevent over-exposure to diisocyanates.
Consult the product suppliers’ Safety Data Sheet (SDS) for
5. Significance and Use
more detailed information about potential health effects and
other specific safety and handling instructions for the product.)
5.1 General Utility:
5.1.1 It is useful to verify catalyst levels in a resin blend or
8. Procedure
a polyurethane system.
8.1 Check the stirrer speed with a tachometer and rotation
5.1.2 This practice is suitable for research, quality control,
direction in air with no load and turn the stirrer off after
specification testing, and process control.
checking.
5.2 Limitations:
8.2 Weigh an empty cup and record the weight.
5.2.1 Several of the measured parameters are subjective.
Therefore, operator-to-operator variability and lab-to-lab vari-
8.3 Weigh reactants into the cup in accordance with previ-
ability can be much higher than that of a single operator.
ously established order of addition.
5.2.2 The variability of this practice is dependent on the
NOTE 2—Ensure that the temperature of the reactants is as specified
consistency of mixing of the reactants.
prior to use.
5.2.3 The estimation of precision in this practice is based on
NOTE 3—This cup is then nested into another cup to prevent spilling
typical formulations for rigid and flexible foams. Formulations chemicals in case the propeller cuts the first cup. Some practitioners use
plastic cups with thicker walls and omit the second cup.
with faster reaction times will likely have greater variability,
NOTE 4—If users elect to mix in one cup and pour into a second cup,
particularly cream time (initiation time). Formulations with
results may vary.
slower reaction times will likely have greater variability in the
8.4 Immerse the stirrer blade completely to a starting
measurement of free rise time.
position in contact with the bottom of the cup and retract it
5.2.4 It is possible that low-level (ppm, ppb) ingredient
slightly.
contamination will not be detectable using this practice.
Confirmation of such contamination will potentially require
8.5 Simultaneously, turn on the mixer switch, and start the
large-scale (~20 L) tests and is out of the scope of this practice.
stopwatch.
NOTE 5—In some cases, it is better to ramp up the mixer speed. Such
6. Apparatus
modifications need to be established prior to testing.
6.1 Stirrer for Mixing:
8.6 Mix the materials for a specified time then, remove the
6.1.1 Stirring motor,
cup from the spinning mixing blade.
6.1.2 Propeller or other type of mixing apparatus, and
NOTE 6—Care must be taken to remove the cup slowly so that splashing
6.1.3 Stainless steel shaft.
of the reaction mixture does not occur. If appropriate, stop the mixer at the
6.2 Cups
end of the specified time and then remove the cup.
6.3 Knife—Cutting length of the blade must be large enough
8.7 Place the cup in a fume hood and record the times as
to cleanly cut through the risen foam at the top of the cup. defined in Section 3.
6.4 Thermometers—Accurate to 60.5 °C.
8.8 Clean the stirrer blade thoroughly after each test.
6.5 Stopwatch—Capable of measuring to 0.1 s. 8.9 After a specified time, cut off the crown of the foam as
close to the top edge of the paper cup as possible.
6.6 Balance—Capacity of 100 g and capable of weighing to
the nearest 0.1 g. 8.10 Record the weight of the cup plus remaining foam to
the nearest 0.1 g.
6.7 Tachometer—Capable of measuring to the nearest rpm.
9. Calculation
6.8 Ruler—Capable of measuring to the nearest 1 mm.
9.1 Calculate the Free Rise Density and express as kg/m .
7. Test Conditions
9.1.1 An example of how Free Rise Density can be deter-
7.1 Since isocyanates react with moisture, keep laboratory mined is as follows:
humidity low, preferably around 50 % relative humidity.
9.1.1.1 Calculate the weight of the foam in the cup as
follows:
7.2 Some of the parameters are influenced by atmospheric
pressure. The quantitative influence is not known at this time.
W 5 W 2 W
@ #
~foam! ~cup1cut foam! ~empty cup!
If results are to be compared between laboratories located at
where:
significantly different elevations above sea level, it is advisable
W = weight in grams of the remaining foam in
(foam)
to measure the barometric pressure and develop a suitable,
the cup,
empirical correction factor. (Warning—Diisocyanates are eye,
W = weight in grams of the cup plus remaining
(cup + cut foam)
skin, and respiratory irritants at concentrations above the
foam, and
occupational exposure limit (TLV or PEL). Diisocyanates can
W = weight in grams of the empty cup.
(empty cup)
cause skin and respiratory sensitization (asthma) in some
people. Once sensitized, it is essential to limit further exposure 9.1.1.2 Calculate the Free Rise Density as follows:
D7487 − 24
Free Rise Density kg/m 5 g/L 5 W /V 10.3 Report % Settle Back as previously agreed, generally
~ !
foam cup
~ ! ~ !
to the nearest percent.
where:
11. Precision and Bias
W = weight in grams of the remaining foam in the cup,
(foam)
and 11.1 Precision—Attempts to develop a precision and bias
V = the volume of the cup in litres.
statement for this practice have not been successful. For this
(cup)
reason, only estimates of data on precision and bias can be
9.1.2 An example of how to calculate % Settle Back as
given. Because this practice does not contain an acceptable
follows:
numerical precision and bias statement, it shall not be used as
% Settle Back 5 H 2 H × 100 %/H
~ ! a referee test method in case of dispute. Anyone wishing to
rise final rise
participate in the development of precision and bias data is to
where:
contact the Chairman, Subcommittee D20.22 (Section
H = free rise height of foam in millimeters, and
rise
D20.22.01), ASTM, 100 Barr Harbor Drive, West
H = final foam height in millimeters.
final
Cons
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7487 − 18 D7487 − 24
Standard Practice for
Polyurethane Raw Materials: Polyurethane Foam Cup Test
This standard is issued under the fixed designation D7487; 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*
1.1 This practice covers the determination of cream time (initiation time), top of cup time, free rise time, free rise height, string
gel time (pull time), tack free time, settle back, and free rise density of polyurethane foam formulations using a cup foam test.
1.2 Typical definitions, terms, and techniques are described; including procedures for mixing and transferring samples to the
foaming container; and data gathering and evaluation. However, agreement between the customer and the testing laboratory for
all these items must be obtained prior to use.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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.
NOTE 1—There is no known ISO equivalent to this standard.
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.
2. Referenced Documents
2.1 ASTM Standards:
D883 Terminology Relating to Plastics
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2935 Practice for Evaluating Equivalence of Two Testing Processes
3. Terminology
3.1 Definitions—TerminologyTerms used in this practice follows that standard are defined in accordance with Terminology D883.
, unless otherwise specified. For terms relating to precision and bias and associated issues, the terms used in this standard are
defined in accordance with Terminology E456.
This practice is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.22 on Cellular Materials - Plastics and
Elastomers.
Current edition approved Aug. 1, 2018Feb. 1, 2024. Published August 2018February 2024. Originally approved in 2008. Last previous edition approved in 20132018 as
ɛ1
D7487D7487 – 18. - 13DOI:10.1520/D7487-24. . DOI:10.1520/D7487-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7487 − 24
3.2 Definitions of Terms Specific to This Standard:
3.2.1 cream time (initiation time)—time), n—the time between the start of mixing and the point at which fine bubbles begin to
appear.
3.2.2 final height, n—height of foam after specified time.
3.2.3 top of cupfree rise density, time—n—the time at whichdensity in kg/m the crown of the rising foam reaches the plane of
the top of the of a polyurethane foam prepared in an open cup.
3.2.4 free rise height, n—height of the foam at free rise time.
3.2.5 free rise time (end of rise time)—time), n—the time at which the foam stops expanding as observed visually.
3.2.6 resin blend (formulated polyol), n—complete ingredient formulation without the isocyanate.
3.2.7 % settle back (% recession, % sigh back, or % sink back), n—percentage decrease from free rise height to final height.
3.2.8 string gel time (pull time)—time), n—time at which long “strings” of tacky material can be pulled away from the surface of
the foam when the surface is touched by the edge of a tongue depressor or similar implement.
3.2.9 tack free time—time, n—the time at which the surface of the foam can be touched with a gloved finger or tongue depressor
without sticking.
3.2.10 free rise density—top of cup time, n—the density in kg/mtime at which of a polyurethane foam prepared in an open the
crown of the rising foam reaches the plane of the top of the cup.
3.2.7 free rise height—height of the foam at free rise time
3.2.8 final height—height of foam after specified time
3.2.9 % settle back (% recession, % sigh back, or % sink back)—percentage decrease from free rise height to final height
3.2.10 resin blend (formulated polyol)—complete ingredient formulation without the isocyanate
4. Summary of Practice
4.1 Specific events (cream time, initiation time, top of cup time, free rise time, free rise height, string gel time, and tack free time)
from a polyurethane foamed in a cup are measured to verify the resin blend composition or levels of ingredients in formulations
used to make polyurethane foams.
4.2 An estimation of the method precision is given. An estimation of bias is not given because there is no suitable reference
method.
5. Significance and Use
5.1 General Utility:
5.1.1 It is useful to verify catalyst levels in a resin blend or a polyurethane system.
5.1.2 This practice is suitable for research, quality control, specification testing, and process control.
5.2 Limitations:
D7487 − 24
5.2.1 Several of the measured parameters are subjective. Therefore, operator-to-operator variability and lab-to-lab variability can
be much higher than that of a single operator.
5.2.2 The variability of this practice is dependent on the consistency of mixing of the reactants.
5.2.3 The estimation of precision in this practice is based on typical formulations for rigid and flexible foams. Formulations with
faster reaction times will likely have greater variability, particularly cream time (initiation time). Formulations with slower reaction
times will likely have greater variability in the measurement of free rise time.
5.2.4 It is possible that low-level (ppm, ppb) ingredient contamination will not be detectable using this practice. Confirmation of
such contamination will potentially require large-scale (~ 20 liters) (~20 L) tests and is out of the scope of this practice.
6. Apparatus
6.1 Stirrer for Mixing:
6.1.1 Stirring motor,
6.1.2 Propeller or other type of mixing apparatus, and
6.1.3 Stainless steel shaft.
6.2 Cups
6.3 Knife—Cutting length of the blade must be large enough to cleanly cut through the risen foam at the top of the cup.
6.4 Thermometers—Accurate to 60.5°C.60.5 °C.
6.5 Stopwatch—Capable of measuring to 0.1 s.
6.6 Balance—Capacity of 100 g and capable of weighing to the nearest 0.1 g.
6.7 Tachometer—Capable of measuring to the nearest rpm.
6.8 Ruler—Capable of measuring to the nearest 1 mm.
7. Test Conditions
7.1 Since isocyanates react with moisture, keep laboratory humidity low, preferably around 50 % relative humidity.
7.2 Some of the parameters are influenced by atmospheric pressure. The quantitative influence is not known at this time. If results
are to be compared between laboratories located at significantly different elevations above sea level, it is advisable to measure the
barometric pressure and develop a suitable, empirical correction factor. (Warning—Diisocyanates are eye, skin, and respiratory
irritants at concentrations above the occupational exposure limit (TLV or PEL). Diisocyanates can cause skin and respiratory
sensitization (asthma) in some people. Once sensitized, it is essential to limit further exposure to diisocyanates. Use a combination
of engineering controls and personal protective equipment, including respiratory, skin and eye protection, to prevent over-exposure
to diisocyanates. Consult the product suppliers’ Safety Data Sheet (SDS) for more detailed information about potential health
effects and other specific safety and handling instructions for the productproduct.)
8. Procedure
8.1 Check the stirrer speed with a tachometer and rotation direction in air with no load and turn the stirrer off after checking.
8.2 Weigh an empty cup and record the weight.
D7487 − 24
8.3 Weigh reactants into the cup in accordance with previously established order of addition.
NOTE 2—Ensure that the temperature of the reactants is as specified prior to use.
NOTE 3—This cup is then nested into another cup to prevent spilling chemicals in case the propeller cuts the first cup. Some practitioners use plastic cups
with thicker walls and omit the second cup.
NOTE 4—If users elect to mix in one cup and pour into a second cup, results may vary.
8.4 Immerse the stirrer blade completely to a starting position in contact with the bottom of the cup and retract it slightly.
8.5 Simultaneously, turn on the mixer switch, and start the stopwatch.
NOTE 5—In some cases, it is better to ramp up the mixer speed. Such modifications need to be established prior to testing.
8.6 Mix the materials for a specified time then, remove the cup from the spinning mixing blade.
NOTE 6—Care must be taken to remove the cup slowly so that splashing of the reaction mixture does not occur. If appropriate, stop the mixer at the end
of the specified time and then remove the cup.
8.7 Place the cup in a fume hood and record the times as defined in Section 3.
8.8 Clean the stirrer blade thoroughly after each test.
8.9 After a specified time, cut off the crown of the foam as close to the top edge of the paper cup as possible.
8.10 Record the weight of the cup plus remaining foam to the nearest 0.1 g.
9. Calculation
9.1 Calculate the Free Rise Density and express as kg/m .
9.1.1 An example of how Free Rise Density can be determined is as follows:
9.1.1.1 Calculate the weight of the foam in the cup as follows:
W 5 W 2 W
@ #
~foam! ~cup1cut foam! ~empty cup!
where:
where:
W = weight in grams of the remaining foam in the cup
(foam)
W = weight in grams of the cup plus remaining foam
(cup + cut foam)
W = weight in grams of the empty cup
(empty cup)
W = weight in grams of the remaining foam in the cup,
(foam)
W = weight in grams of the cup plus remaining foam, and
(cup + cut foam)
W = weight in grams of the empty cup.
(empty cup)
9.1.1.2 Calculate the Free Rise Density as follows:
Free Rise Density ~kg/m !5 g/L 5 W /V
~foam! ~cup!
where:
where:
W = weight in grams of the remaining foam in the cup
(foam)
D7487 − 24
V = the volume of the cup in litres
(cup)
W = weight in grams of the remaining foam in the cup, and
(foam)
V = the volume of the cup in litres.
(cup)
9.1.2 An example of how to calculate % Settle Back as follows:
% Settle Back 5 H 2 H ×100 %/H
~ !
rise final rise
where:
where:
H = free rise height of foam in millimeters
rise
H = final foam height in millimeters
final
H = free rise height of foam in millimeters, and
rise
H = final foam height in millimeters.
final
10. Report
10.1 Report all time results as previously agreed, typically to the nearest whole second.
10.2 Report Free Rise Density as previously agreed, generally, Free Rise Density is reported to two decimal places.
10.3 Report % Settle Back as previously agreed, generally to the nearest percent.
11. Precision and Bias
11.1 Precision—Attempts to develop a precision and bias statement for this practice have not been successful. For this reason, only
estimates of data on precision and bias can be given. Because this practice does not contain an acceptable numerical precision and
bias statement, it shall not
...