ASTM C1055-20

Standard Guide for Heated System Surface Conditions that Produce Contact Burn Injuries

SIGNIFICANCE AND USE
5.1 Most heated apparatus in industrial, commercial, and residential service are insulated, unless thermal insulation interferes with their function; for example, it is inappropriate to insulate the bottom surface of a flatiron. However, surface temperatures of insulated equipment and appliances are potentially high enough to cause burns from contact exposure under certain conditions.  
5.2 This guide has been developed to standardize the determination of acceptable surface operating conditions for heated systems. Current practice for this determination is widely varied. The intent of this guide is to tie together the existing practices into a consensus standard based upon scientific understanding of the thermal physics involved. Flexibility is retained within this guide for the designer, regulator, or consumer to establish specific burn hazard criteria. Most generally, the regulated criterion will be the length of time of contact exposure.  
5.3 It is beyond the scope of this guide to establish appropriate contact times and acceptable levels of injury for particular situations, or determine what surface temperature is “safe.” Clearly, quite different criteria are justified for cases as diverse as those involving infants and domestic appliances, and experienced adults and industrial equipment. In the first case, no more than first degree burns in 60 s might be desirable. In the second case, second degree burns in 5 s might be acceptable.
Note 2: An overview of the medical research leading to the development of this guide was presented at the ASTM Conference on Thermal Insulation, Materials and Systems on Dec. 7, 1984 (14).  
5.4 This guide is meant to serve only as an estimation of the exposure to which an average individual might be subjected. Unusual conditions of exposure, physical health variations, or nonstandard ambients all serve to modify the results.  
5.5 This guide is limited to contact exposure to heated surfaces only. It is noted that conditions ...
SCOPE
1.1 This guide covers a process for the determination of acceptable surface operating conditions for heated systems. The human burn hazard is defined, and methods are presented for use in the design or evaluation of heated systems to prevent serious injury from contact with the exposed surfaces.  
1.2 The maximum acceptable temperature for a particular surface is derived from an estimate of the possible or probable contact time, the surface system configuration, and the level of injury deemed acceptable for a particular situation.  
1.3 For design purposes, the probable contact time for industrial situations has been established at 5 s. For consumer products, a longer (60-s) contact time has been proposed by Wu (1)2 and others to reflect the slower reaction times for children, the elderly, or the infirm.  
1.4 The maximum level of injury recommended here is that causing first degree burns on the average subject. This type of injury is reversible and causes no permanent tissue damage. For cases where more severe conditions are mandated (by space, economic, exposure probability, or other outside considerations), this guide is used to establish a second, less desirable injury level (second degree burns), where some permanent tissue damage is permitted. At no time, however, are conditions that produce third degree burns recommended.  
1.5 This guide addresses the skin contact temperature determination for passive heated surfaces only. The guidelines contained herein are not applicable to chemical, electrical, or other similar hazards that provide a heat generation source at the location of contact.  
1.6 A bibliography of human burn evaluation studies and surface hazard measurement is provided in the list of references at the end of this guide (1-16).  
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.8 This standard does not purport to ...

General Information

• Status: Published
• Publication Date: 31-Mar-2020
• ICS: 97.100.01 - Heating appliances in general
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.30 - Thermal Measurement

Relations

• Replaces: ASTM C1055-03(2014) - Standard Guide for Heated System Surface Conditions that Produce Contact Burn Injuries
• Effective Date: 01-Apr-2020
• Refers: ASTM C680-23a - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-Nov-2023
• Refers: ASTM C680-14 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-Sep-2014
• Refers: ASTM C1057-12 - Standard Practice for Determination of Skin Contact Temperature from Heated Surfaces Using a Mathematical Model and Thermesthesiometer
• Effective Date: 01-Oct-2012
• Refers: ASTM C680-10 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-Nov-2010
• Refers: ASTM C1057-03(2010) - Standard Practice for Determination of Skin Contact Temperature from Heated Surfaces Using A Mathematical Model and Thermesthesiometer
• Effective Date: 01-May-2010
• Refers: ASTM C680-08 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-Aug-2008
• Refers: ASTM C680-04e3 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-May-2006
• Refers: ASTM C680-04 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-May-2004
• Refers: ASTM C680-04e1 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-May-2004
• Refers: ASTM C680-04e4 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-May-2004
• Refers: ASTM C680-03a - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 01-Dec-2003
• Refers: ASTM C1057-03 - Standard Practice for Determination of Skin Contact Temperature from Heated Surfaces Using A Mathematical Model and Thermesthesiometer
• Effective Date: 01-Oct-2003
• Refers: ASTM C680-03e1 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 10-May-2003
• Refers: ASTM C680-03 - Standard Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical Systems by Use of Computer Programs
• Effective Date: 10-May-2003

Overview

ASTM C1055-20: Standard Guide for Heated System Surface Conditions that Produce Contact Burn Injuries is a critical international standard developed by ASTM International. This guide provides a systematic process for determining acceptable surface operating conditions for heated systems in order to prevent contact burn injuries. It addresses both industrial and consumer contexts, focusing on direct contact exposure to heated surfaces and the associated human burn hazards.

The standard is widely referenced by engineers, facility designers, safety officers, and product manufacturers involved in the thermal insulation and safety evaluation of equipment and appliances. ASTM C1055-20 is aimed at unifying practices in surface temperature determination to reduce the risk of injury due to burns, while allowing flexibility for different types of users and environments.

Key Topics

• Surface Burn Hazard Definition: The guide classifies human burn hazards into first, second, and third degree burns, providing clear definitions of exposure and injury levels.
• Surface Temperature and Contact Time: It emphasizes that the risk of burn injury depends on both the temperature of the heated surface and the duration of direct skin contact.
  • Common design criteria: 5 seconds for industrial environments, 60 seconds for consumer products (to address vulnerable populations like children and the elderly).
• Evaluation Methods:
  • Determination of maximum operating surface temperature through direct measurement (e.g., thermocouples, infrared thermometry) or computational analysis (e.g., as per ASTM C680).
  • Use of a thermesthesiometer or mathematical models for more refined analysis, especially when direct measurement is impractical.
• Acceptable Injury Levels: The standard recommends limiting injury potential to reversible first degree burns (no permanent tissue damage) for most applications. Second degree burns may be permitted only under certain constraints, but third degree burn risks are never to be accepted.
• Flexibility for Different Contexts: The guide allows designers and regulators to set specific burn hazard criteria tailored to unique situations and populations.

Applications

ASTM C1055-20 is used across a wide range of industries and consumer applications to ensure safety in environments where contact with heated surfaces is possible. Key application areas include:

• Industrial Installations: Evaluation of process piping, equipment surfaces, and insulation system design to minimize burn hazards for maintenance staff and operators.
• Consumer Products: Safety assessment of appliances such as irons, ovens, dryers, and other devices with heated surfaces. Criteria are adjusted for users who may have slower reaction times.
• Commercial and Institutional Buildings: Assessment of accessible heated surfaces, such as radiators or hot water supply systems, to ensure occupant safety.
• Design and Safety Compliance: Implementation in product development, facility operations, and regulatory inspection to meet occupational health and consumer safety standards.

This standard is valuable for specifying maximum safe surface temperatures and documenting surface hazard analyses in project reports.

Related Standards

ASTM C1055-20 references and aligns with several important related standards, including:

• ASTM C680: Practice for estimating heat gain or loss and surface temperatures of insulated systems using computational methods. Useful for design calculations.
• ASTM C1057: Practice for determination of skin contact temperature from heated surfaces using mathematical models and thermesthesiometer devices. Provides analytical tools for hazard evaluation.
• Other Standards: While ASTM C1055-20 specifically addresses contact burn hazards from heated surfaces, it excludes non-contact hazards such as those caused by radiant heat or chemical and electrical sources.

For professionals seeking to minimize burn risks and comply with best practices in thermal safety, ASTM C1055-20 provides an authoritative framework for evaluation and design. It supports the creation of safer environments in industrial, commercial, and residential settings by guiding the assessment of surface conditions that may produce contact burn injuries.

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: C1055 − 20
Standard Guide for
Heated System Surface Conditions that Produce Contact
Burn Injuries
This standard is issued under the fixed designation C1055; 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 1.7 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.1 This guide covers a process for the determination of
standard.
acceptable surface operating conditions for heated systems.
1.8 This standard does not purport to address all of the
The human burn hazard is defined, and methods are presented
safety concerns, if any, associated with its use. It is the
for use in the design or evaluation of heated systems to prevent
responsibility of the user of this standard to establish appro-
serious injury from contact with the exposed surfaces.
priate safety, health, and environmental practices and deter-
1.2 The maximum acceptable temperature for a particular
mine the applicability of regulatory limitations prior to use.
surface is derived from an estimate of the possible or probable
1.9 This international standard was developed in accor-
contact time, the surface system configuration, and the level of
dance with internationally recognized principles on standard-
injury deemed acceptable for a particular situation.
ization established in the Decision on Principles for the
1.3 For design purposes, the probable contact time for
Development of International Standards, Guides and Recom-
industrial situations has been established at 5 s. For consumer
mendations issued by the World Trade Organization Technical
products, a longer (60-s) contact time has been proposed by
Barriers to Trade (TBT) Committee.
Wu (1) and others to reflect the slower reaction times for
2. Referenced Documents
children, the elderly, or the infirm.
2.1 ASTM Standards:
1.4 The maximum level of injury recommended here is that
C680 Practice for Estimate of the Heat Gain or Loss and the
causing first degree burns on the average subject. This type of
Surface Temperatures of Insulated Flat, Cylindrical, and
injury is reversible and causes no permanent tissue damage.
Spherical Systems by Use of Computer Programs
For cases where more severe conditions are mandated (by
C1057 Practice for Determination of Skin Contact Tempera-
space, economic, exposure probability, or other outside
ture from Heated Surfaces Using a Mathematical Model
considerations), this guide is used to establish a second, less
and Thermesthesiometer
desirable injury level (second degree burns), where some
permanenttissuedamageispermitted.Atnotime,however,are
3. Terminology
conditions that produce third degree burns recommended.
3.1 Definitions of Terms Specific to This Standard:
1.5 This guide addresses the skin contact temperature de-
3.1.1 skin:
termination for passive heated surfaces only. The guidelines
3.1.2 epidermis—the outermost layer of skin cells. This
contained herein are not applicable to chemical, electrical, or
layer contains no vascular or nerve cells and acts to protect the
other similar hazards that provide a heat generation source at
skin layers. The thickness of this layer averages 0.08 mm.
the location of contact.
3.1.3 dermis—the second layer of skin tissue. This layer
1.6 A bibliography of human burn evaluation studies and
contains the blood vessels and nerve endings. The thickness of
surface hazard measurement is provided in the list of refer-
this layer averages 2 mm.
ences at the end of this guide (1-16).
3.1.4 necrosis—localized death of living cells. A clinical
term that defines when permanent damage to a skin layer has
occurred.
This guide is under the jurisdiction of ASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal 3.1.5 burns:
Measurement.
Current edition approved April 1, 2020. Published April 2020. Originally
approved in 1986. Last previous edition approved in 2014 as C1055 – 03 (2014). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/C1055-20. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this guide. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1055 − 20
3.1.6 first degree burn—the reaction to an exposure where 4. Summary of Guide
the intensity or duration is insufficient to cause complete
4.1 This guide establishes a means by which the engineer,
necrosis of the epidermis. The normal response to this level of
designer,oroperatordeterminetheacceptablesurfacetempera-
exposure is dilation of the superficial blood vessels (reddening
ture of an existing system where skin potentially contacts a
of the skin).
heated surface.
3.1.7 second degree burn—the reaction to an exposure
4.2 The process used in the analysis follows the outline
where the intensity and duration is sufficient to cause complete
listed below:
necrosis of the epidermis but no significant damage to the
4.2.1 The user must first establish the acceptable contact
dermis. The normal response to this exposure is blistering of
exposure time and the level of acceptable injury for the
the epidermis.
particular system in question.
3.1.8 third degree burn—the reaction to an exposure where
4.2.2 Secondly, the user determines the maximum operating
significant dermal necrosis occurs. Significant dermal necrosis
surface temperature. This determination is made either by
has been defined in the literature (3) as 75% destruction of the
direct measurement (if possible) or by use of a calculation at
dermis.Thenormalresponsetothisexposureisopensoresthat
design conditions using a method conforming to Practice
leave permanent scar tissue upon healing.
C680.
3.1.9 contact exposure—the process by which the surface of 4.2.3 Next, utilizing the contact time (4.2.1), the maximum
skin makes intimate contact with a heated surface such that no surface temperature (4.2.2), and the graph, Fig. 1, the user
determinesthepotentialinjurylevel.Iftheoperatingpointfalls
insulating layer, film, moisture, etc., interferes with the rapid
belowtheinjurylevelspecified(4.2.1),thennofurtheranalysis
transfer of available energy.
is required. (See Note 1.)
3.1.10 insulation system—the combination of an insulation
material or jacket, or both that forms a barrier to the rapid loss
NOTE 1—The following equations have been developed from the
original data used to generate Fig. 1 for easier use of this figure.
of energy from a heated surface. The insulation system
potentially involves a broad range of types and configurations
T 5 15.00510.51907 3Ln ~time 31000!1352.97/~Ln ~time 31000!!
A
of materials.
(1)
3.1.11 jacket—the protective barrier placed on the exposed
T 5 39.468 2 0.41352 3Ln time 31000 1 190.60/ Ln time
~ ! ~ ~
B
sideofaninsulationtoprotecttheinsulationfromdeterioration
31000 (2)
!!
or abuse. The jacket material is potentially made of paper,
where:
plastic, metal, canvas cloth, or combinations of the above or
T = critical contact temperature for complete transepidermal
A
similar materials.
necrosis, °C.
T = critical contact temperature for reversible epidermal injury, °C.
3.1.12 thermesthesiometer—a probe device developed by
B
time = elapsed contact time, s.
Marzetta (13) that simulates the thermal physical response of
Ln = natural logarithm.
the human finger to contact with heated surfaces.
FIG. 1 Temperature-Time Relationship for Burns
C1055 − 20
4.2.4 If the injury level exceeds that specified, further mentation of the rationale for each decision and intermediate
analysis of the system is required using either the thermesthe- result is an important part of this evaluation process.
siometer (a direct method) or an additional calculation. Both
6.2 The first phase in the use of this guide is to establish the
methods are described in Practice C1057.
acceptable limits for contact exposure time and the acceptable
4.2.5 Ifafterthisadditionalanalysisthesystemstillexceeds
level of injury for the system in question. Where no available
the injury level criterion, then the system is unacceptable for
standards for these limits are prescribed, the following limits
the criterion specified and the design shall be revised.
are recommended based upon a survey of the existing medical
literature.
5. Significance and Use
6.2.1 Acceptable Contact Times:
5.1 Most heated apparatus in industrial, commercial, and
6.2.1.1 Industrial Process—5s.
residential service are insulated, unless thermal insulation
6.2.1.2 Consumer Items—60 s.
interfereswiththeirfunction;forexample,itisinappropriateto
6.2.2 Acceptable Injury Levels—The acceptable injury level
insulate the bottom surface of a flatiron. However, surface
is that of first degree burns as defined in 3.1.6 and is the limit
temperatures of insulated equipment and appliances are poten-
represented by the bottom curve in Fig. 1.
tially high enough to cause burns from contact exposure under
certain conditions.
6.3 The next phase in the process is to establish the
5.2 This guide has been developed to standardize the maximum operating surface temperature under worst case
conditions. This evaluation is made either by direct measure-
determination of acceptable surface operating conditions for
heated systems. Current practice for this determination is ment (but only at worst case conditions) or by using a
calculation approximation. The steps required for determining
widely varied. The intent of this guide is to tie together the
existing practices into a consensus standard based upon scien- the maximum surface temperature are as follows:
tific understanding of the thermal physics involved. Flexibility
6.3.1 The initial step is to establish the operating system
is retained within this guide for the designer, regulator, or
parameters. This step provides input information to the analy-
consumer to establish specific burn hazard criteria. Most
sis and will preclude any further work concerning burn hazard.
generally, the regulated criterion will be the length of time of
The items that need to be identified and recorded are as
contact exposure.
follows:
6.3.1.1 System Description—Shape, size, materials, includ-
5.3 It is beyond the scope of this guide to establish appro-
priate contact times and acceptable levels of injury for particu- ing jacket material, thickness, and surface emittance.
lar situations, or determine what surface temperature is “safe.”
6.3.1.2 Operation Conditions—Temperatures of heated
Clearly, quite different criteria are justified for cases as diverse
system, times of year, cycle, etc.
as those involving infants and domestic appliances, and expe-
6.3.1.3 Ambient Conditions—Worstcasedesigntemperature
rienced adults and industrial equipment. In the first case, no
forburnhazardstypicallyisatsummerdesigndrybulb.Or,for
more than first degree burns in 60 s might be desirable. In the
inside conditions, the maximum expected room ambient air
second case, second degree burns in 5 s might be acceptable.
temperature. Include the ambient air velocity, if known.
NOTE 2—An overview of the medical research leading to the develop-
NOTE3—Designconditionsforburnhazardevaluationmaybedifferent
ment of this guide was presented at the ASTM Conference on Thermal
from those used for heat loss analysis. For example, the highest ambient
Insulation, Materials and Systems on Dec. 7, 1984 (14).
is used for burn hazard analysis versus the lowest for heat loss.
5.4 This guide is meant to serve only as an estimation of the
6.3.2 The second step is to determine the temperature of the
exposure to which an average individual might be subjected.
system surface at the worst design condition by one of the
Unusual conditions of exposure, physical health variations, or
following methods.
nonstandard ambients all serve to modify the results.
6.3.2.1 Insert the system dimensions, material properties,
5.5 This guide is limited to contact exposure to heated
andoperatingconditionsintoananalysistechniqueconforming
surfaces only. It is noted that conditions of personal exposure
to Practice C680. This technique is used during design or
to periods of high ambient temperature or high radiant fluxes
where the system surface temperatures cannot be physically
potentially cause human injury with no direct contact.
measured at worst case conditions.
5.6 This guide is not intended to cover hazards for cold
6.3.2.2 Direct contact thermometry (thermocouple or resis-
temperature exposure, that is, refrigeration or cryogenic appli-
tance device) or infrared, noncontact thermometry.
cations.
NOTE 4—(1) Care should be used in attaching measurement devices on
5.7 The procedure found in this guide has been described in
hot systems since burns can result; and (2) Proper installation techniques
theliteratureasapplicabletoallheatedsurfaces.Forextremely
must be used with direct contact thermometry to prevent heat sinking of
high-temperature metallic surfaces (>70°C), damage occurs the surface and obtaining incorrect temperature readings.
almost instantaneously upon contact.
6.4 In many situations, surface temperatures exceed the
range of applicability of this guide and thus the evaluation is
6. Procedure
made through interpretation of the surface temperature data
6.1 This procedure requires the user to make several deci- and the system properties. The limiting conditions below shall
sions that are based upon the results obtained. Careful docu- first be examined to see if further analysis is required.
C1055 − 20
6.4.1 If the surface temperature is below 44°C, no short since it must be applied at worst case conditions if the hazard
term (that is, less than 6 h) hazard exists and the remaining potential is to be evaluated. Practice C1057 outlines the correct
sections are ignored. procedures for use of this device for surface hazard evaluation.
6.4.2 If the surface temperature exceeds 70°C and the The output from the thermesthesiometer is the maximum
surface is metallic, it will likely present a hazard regardless of contacttemperatureoftheskinthatarerelatedtoFig.1withno
contact duration. Attempts shall be made to lower the surface corrections for surface type needed.
temperature below 70°C as a first step in protection. Nonme-
6.8 If, after analysis using Practice C1057, the system
tallicskinsarepotentiallysafeforlimitedexposureattempera-
temperature still fails to meet the selected criterion, then
tures above 70°C. In these cases, as with all cases between 44
increasing insulation, changing jacketing, or other means must
and 70°C, the analysis shall be completed.
beusedtolowerthesurfacetemperature.PracticeC680willbe
6.5 With the measurement or estimation of surface tempera- helpful in determining the levels required.
ture for the system in question, utilize the graph (Fig. 1) and
6.9 Once a new level of jacket and insulation is determined,
check if the intersection of the operating surface temperature
the analysis above is repeated to confirm safe operating
and the selected time of contact falls below the threshold
conditions.
temperature.
7. Report
NOTE 5—The threshold temperature used will depend on the limits of
acceptable burn chosen in 6.2.2. If the burn level is first degree, use
7.1 Any report citing the use of this guide shall include the
threshold line B in Fig. 1. If second degree burns are acceptable, use
following information:
threshold line A in Fig. 1.
7.1.1 System description,
6.6 If the operating surface temperature and time are below
7.1.2 System operating conditions (either measured or
the threshold (line B) curve, then the system meets the selected
design),
criteria.
7.1.3 Ambient conditions (either measured or design),
7.1.4 Method of surface temperature evaluation used, cal-
6.7 If, however, the point falls above the curve, it is feasible
culation or measurement,
that the system will meet the selected criterion only if certain
7.1.5 Method of analysis of hazard potential, calculation,
combinations of insulation or jacketing, or both, are used.
thermesthesiometer, contact time, and hazard level selected,
Analysis procedures for the jacketing/insulation effects are
and
outlined in Practice C1057. Two methods provided in Practice
7.1.6 Statement of analysis of results and conclusions.
C1057 are briefly described below.
6.7.1 The calculation technique provided in Practice C1057
8. Precision and Bias
uses system geometry, material properties, and temperature
8.1 As stated in the Scope, this procedure is valid for the
conditions to estimate the maximum contact temperature used
averageperson.Individualsarepotentiallytolerantorsensitive
in Fig. 1 when the heat capacity effects of the surface are to be
to burns depending upon physical condition, age, ambient
considered. Once this maximum contact temperature is
conditions, emotional state, etc. The literature (1, 4, 5) has
determined, the user returns to steps 6.5 – 6.7 for the refined
analysis. shown, however, agreement on pain response and tissue
damage for a panel of subjects to within approximately 10 %.
6.7.2 An alternative to calculation of the contact tempera-
ture is available for those systems that are already operating.
9. Keywords
The thermesthesiometer (13) provides an analogue measure-
ment of the same phenomenon as the computer method models 9.1 burns; epidermal injury; heat; injuries; skin contact
(6.7.1). Care is necessary in applying the thermesthesiometer temperatures; thermal insulation
APPENDIX
(Nonmandatory Information)
X1. RATIONALE
X1.1 Background—General was exposed.The greatest improvement to these systems came
since the industrial revolution where the use of high tempera-
X1.1.1 Man has faced the potential of skin burns from
ture power and process systems dictated the development of
touching hot surfaces since the discovery of fire in prehistoric
modern insulation systems, that not only conserve energy but
times. He was concerned more with treatment of the injury
also protect process products during manufacture. As technol-
than with the development of some means to prevent its
ogy expanded to include higher temperatures, more complex
occurrence. As civilization advanced, man developed crude
processes, and thus more worker exposure situations, worker
insulation forms to control the extremes of heat to which he
C1055 − 20
organizations and later governmental agencies demanded the common battle problem and the military began to support
increased use of insulation for personal protection. research to study the relationships between burn damage and
the severity of exposure. At that time, little was known about
X1.1.2 At the same time that the workplace was becoming
the mechanism by which hyperthermia (hig
...

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: C1055 − 03 (Reapproved 2014) C1055 − 20
Standard Guide for
Heated System Surface Conditions that Produce Contact
Burn Injuries
This standard is issued under the fixed designation C1055; 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 guide covers a process for the determination of acceptable surface operating conditions for heated systems. The human
burn hazard is defined, and methods are presented for use in the design or evaluation of heated systems to prevent serious injury
from contact with the exposed surfaces.
1.2 The maximum acceptable temperature for a particular surface is derived from an estimate of the possible or probable contact
time, the surface system configuration, and the level of injury deemed acceptable for a particular situation.
1.3 For design purposes, the probable contact time for industrial situations has been established at 5 s. For consumer products,
a longer (60-s) contact time has been proposed by Wu (1) and others to reflect the slower reaction times for children, the elderly,
or the infirm.
1.4 The maximum level of injury recommended here is that causing first degree burns on the average subject. This type of injury
is reversible and causes no permanent tissue damage. For cases where more severe conditions are mandated (by space, economic,
exposure probability, or other outside considerations), this guide may be is used to establish a second, less desirable injury level
(second degree burns), where some permanent tissue damage can be is permitted. At no time, however, are conditions that produce
third degree burns recommended.
1.5 This guide addresses the skin contact temperature determination for passive heated surfaces only. The guidelines contained
herein are not applicable to chemical, electrical, or other similar hazards that provide a heat generation source at the location of
contact.
1.6 A bibliography of human burn evaluation studies and surface hazard measurement is provided in the list of references at
the end of this guide (1-16).
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.8 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to its use.
1.9 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:
C680 Practice for Estimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Flat, Cylindrical, and Spherical
Systems by Use of Computer Programs
C1057 Practice for Determination of Skin Contact Temperature from Heated Surfaces Using a Mathematical Model and
Thermesthesiometer
This guide is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal Measurement.
Current edition approved Feb. 1, 2014April 1, 2020. Published March 2014April 2020. Originally approved in 1986. Last previous edition approved in 20092014 as
C1055–03(2009).C1055 – 03 (2014). DOI: 10.1520/C1055-03R14.10.1520/C1055-20.
The boldface numbers in parentheses refer to the list of references at the end of this guide.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 skin:
3.1.2 epidermis—the outermost layer of skin cells. This layer contains no vascular or nerve cells and acts to protect the skin
layers. The thickness of this layer averages 0.08 mm.
3.1.3 dermis—the second layer of skin tissue. This layer contains the blood vessels and nerve endings. The thickness of this
layer averages 2 mm.
3.1.4 necrosis—localized death of living cells. A clinical term that defines when permanent damage to a skin layer has occurred.
3.1.5 burns:
3.1.6 first degree burn—the reaction to an exposure where the intensity or duration is insufficient to cause complete necrosis
of the epidermis. The normal response to this level of exposure is dilation of the superficial blood vessels (reddening of the skin).
3.1.7 second degree burn—the reaction to an exposure where the intensity and duration is sufficient to cause complete necrosis
of the epidermis but no significant damage to the dermis. The normal response to this exposure is blistering of the epidermis.
3.1.8 third degree burn—the reaction to an exposure where significant dermal necrosis occurs. Significant dermal necrosis has
been defined in the literature (3) as 75% destruction of the dermis. The normal response to this exposure is open sores that leave
permanent scar tissue upon healing.
3.1.9 contact exposure—the process by which the surface of skin makes intimate contact with a heated surface such that no
insulating layer, film, moisture, etc., interferes with the rapid transfer of available energy.
3.1.10 insulation system—the combination of an insulation material or jacket, or both that forms a barrier to the rapid loss of
energy from a heated surface. The insulation system may involvepotentially involves a broad range of types and configurations of
materials.
3.1.11 jacket—the protective barrier placed on the exposed side of an insulation to protect the insulation from deterioration or
abuse. The jacket material can beis potentially made of paper, plastic, metal, canvas cloth, or combinations of the above or similar
materials.
3.1.12 thermesthesiometer—a probe device developed by Marzetta (13) that simulates the thermal physical response of the
human finger to contact with heated surfaces.
4. Summary of Guide
4.1 This guide establishes a means by which the engineer, designer, or operator can determine the acceptable surface
temperature of an existing system where skin contact may be made with potentially contacts a heated surface.
4.2 The process used in the analysis follows the outline listed below:
4.2.1 The user must first establish the acceptable contact exposure time and the level of acceptable injury for the particular
system in question.
4.2.2 Secondly, the user determines the maximum operating surface temperature. This determination is made either by direct
measurement (if possible) or by use of a calculation at design conditions using a method conforming to Practice C680.
4.2.3 Next, utilizing the contact time (4.2.1), the maximum surface temperature (4.2.2), and the graph, Fig. 1, the user
determines the potential injury level. If the operating point falls below the injury level specified (4.2.1), then no further analysis
is required. (See Note 1.)
NOTE 1—The following equations have been developed from the original data used to generate Fig. 1 for easier use of this figure.
T 5 15.00510.51907 3Ln time 31000 1352.97/ Ln time 31000 (1)
~ ! ~ ~ !!
A
T 5 39.468 2 0.41352 3Ln ~time 31000!1 190.60/~Ln ~time 31000!! (2)
B
where:
T = critical contact temperature for complete transepidermal necrosis, °C.
A
T = critical contact temperature for reversible epidermal injury, °C.
B
time = elapsed contact time, s.
Ln = natural logarithm.
4.2.4 If the injury level exceeds that specified, further analysis of the system is required using either the thermesthesiometer (a
direct method) or an additional calculation. Both methods are described in Practice C1057.
4.2.5 If after this additional analysis the system still exceeds the injury level criterion, then the system is unacceptable for the
criterion specified and the design shouldshall be revised.
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FIG. 1 Temperature-Time Relationship for Burns
5. Significance and Use
5.1 Most heated apparatus in industrial, commercial, and residential service are insulated, unless thermal insulation would
interfere interferes with their function; for example, it is inappropriate to insulate the bottom surface of a flatiron. However, surface
temperatures of insulated equipment and appliances may still be are potentially high enough to cause burns from contact exposure
under certain conditions.
5.2 This guide has been developed to standardize the determination of acceptable surface operating conditions for heated
systems. Current practice for this determination is widely varied. The intent of this guide is to tie together the existing practices
into a consensus standard based upon scientific understanding of the thermal physics involved. Flexibility is retained within this
guide for the designer, regulator, or consumer to establish specific burn hazard criteria. Most generally, the regulated criterion will
be the length of time of contact exposure.
5.3 It is beyond the scope of this guide to establish appropriate contact times and acceptable levels of injury for particular
situations, or determine what surface temperature is “safe.” Clearly, quite different criteria may be are justified for cases as diverse
as those involving infants and domestic appliances, and experienced adults and industrial equipment. In the first case, no more than
first degree burns in 60 s might be desirable. In the second case, second degree burns in 5 s might be acceptable.
NOTE 2—An overview of the medical research leading to the development of this guide was presented at the ASTM Conference on Thermal Insulation,
Materials and Systems on Dec. 7, 1984 (14).
5.4 This guide is meant to serve only as an estimation of the exposure to which an average individual might be subjected.
Unusual conditions of exposure, physical health variations, or nonstandard ambients all serve to modify the results.
5.5 This guide is limited to contact exposure to heated surfaces only. It should be is noted that conditions of personal exposure
to periods of high ambient temperature or high radiant fluxes maypotentially cause human injury with no direct contact.
5.6 This guide is not intended to cover hazards for cold temperature exposure, that is, refrigeration or cryogenic applications.
5.7 The procedure found in this guide has been described in the literature as applicable to all heated surfaces. For extremely
high-temperature metallic surfaces (>70°C), damage occurs almost instantaneously upon contact.
6. Procedure
6.1 This procedure requires the user to make several decisions that are based upon the results obtained. Careful documentation
of the rationale for each decision and intermediate result is an important part of this evaluation process.
6.2 The first phase in the use of this guide is to establish the acceptable limits for contact exposure time and the acceptable level
of injury for the system in question. Where no available standards for these limits are prescribed, the following limits are
recommended based upon a survey of the existing medical literature.
6.2.1 Acceptable Contact Times:
6.2.1.1 Industrial Process—5 s.
6.2.1.2 Consumer Items—60 s.
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6.2.2 Acceptable Injury Levels—The acceptable injury level is that of first degree burns as defined in 3.1.6 and is the limit
represented by the bottom curve in Fig. 1.
6.3 The next phase in the process is to establish the maximum operating surface temperature under worst case conditions. This
evaluation may be is made either by direct measurement (but only at worst case conditions) or by using a calculation
approximation. The steps required for determining the maximum surface temperature are as follows:
6.3.1 The initial step is to establish the operating system parameters. This step provides input information to the analysis and
maywill preclude any further work concerning burn hazard. The items that need to be identified and recorded are as follows:
6.3.1.1 System Description—Shape, size, materials, including jacket material, thickness, and surface emittance.
6.3.1.2 Operation Conditions—Temperatures of heated system, times of year, cycle, etc.
6.3.1.3 Ambient Conditions—Worst case design temperature for burn hazards would be typically is at summer design dry bulb.
Or, for inside conditions, the maximum expected room ambient air temperature. Include the ambient air velocity, if known.
NOTE 3—Design conditions for burn hazard evaluation may be different from those used for heat loss analysis. For example, the highest ambient is
used for burn hazard analysis versus the lowest for heat loss.
6.3.2 The second step is to determine the temperature of the system surface at the worst design condition by one of the following
methods.
6.3.2.1 Insert the system dimensions, material properties, and operating conditions into an analysis technique conforming to
Practice C680. This technique should be is used during design or where the system surface temperatures cannot be physically
measured at worst case conditions.
6.3.2.2 Direct contact thermometry (thermocouple or resistance device) or infrared, noncontact thermometry.
NOTE 4—(1) Care should be used in attaching measurement devices on hot systems since burns can result; and (2) Proper installation techniques must
be used with direct contact thermometry to prevent heat sinking of the surface and obtaining incorrect temperature readings.
6.4 In many situations, surface temperatures exceed the range of applicability of this guide and thus the evaluation is made
through interpretation of the surface temperature data and the system properties. The limiting conditions below shouldshall first
be examined to see if further analysis is required.
6.4.1 If the surface temperature is below 44°C, no short term (that is, less than 6 h) hazard exists and the remaining sections
can be are ignored.
6.4.2 If the surface temperature exceeds 70°C and the surface is metallic, it may will likely present a hazard regardless of contact
duration. Attempts shouldshall be made to lower the surface temperature below 70°C. Nonmetallic skins may be70°C as a first step
in protection. Nonmetallic skins are potentially safe for limited exposure at temperatures above 70°C. In these cases, as with all
cases between 44°C44 and 70°C, the analysis shouldshall be completed.
6.5 With the measurement or estimation of surface temperature for the system in question, utilize the graph (Fig. 1) and check
if the intersection of the operating surface temperature and the selected time of contact falls below the threshold temperature.
NOTE 5—The threshold temperature used will depend on the limits of acceptable burn chosen in 6.2.2. If the burn level is first degree, use threshold
line B in Fig. 1. If second degree burns are acceptable, use threshold line A in Fig. 1.
6.6 If the operating surface temperature and time are below the threshold (line B) curve, then the system meets the selected
criteria.
6.7 If, however, the point falls above the curve, it is feasible that the system maywill meet the selected criterion only if certain
combinations of insulation or jacketing, or both, are used. Analysis procedures for the jacketing/insulation effects are outlined in
Practice C1057. Two methods provided in Practice C1057 are briefly described below.
6.7.1 The calculation technique provided in Practice C1057 uses system geometry, material properties, and temperature
conditions to estimate the maximum contact temperature used in Fig. 1 when the heat capacity effects of the surface are to be
considered. Once this maximum contact temperature is determined, the user returns to steps 6.5 – 6.7 for the refined analysis.
6.7.2 An alternative to calculation of the contact temperature is available for those systems that are already operating. The
thermesthesiometer (13) provides an analogue measurement of the same phenomenon as the computer method models (6.7.1). Care
should be used is necessary in applying the thermesthesiometer since it must be applied at worst case conditions if the hazard
potential is to be evaluated. Practice C1057 outlines the correct procedures for use of this device for surface hazard evaluation.
The output from the thermesthesiometer is the maximum contact temperature of the skin that can be are related to Fig. 1 with no
corrections for surface type needed.
6.8 If, after analysis using Practice C1057, the system temperature still fails to meet the selected criterion, then increasing
insulation, changing jacketing, or other means must be used to lower the surface temperature. Practice C680 will be helpful in
determining the levels required.
6.9 Once a new level of jacket and insulation is determined, the analysis above should be is repeated to confirm safe operating
conditions.
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7. Report
7.1 Any report citing the use of this guide shouldshall include the following information:
7.1.1 System description,
7.1.2 System operating conditions (either measured or design),
7.1.3 Ambient conditions (either measured or design),
7.1.4 Method of surface temperature evaluation used, calculation or measurement,
7.1.5 Method of analysis of hazard potential, calculation, thermesthesiometer, contact time, and hazard level selected, and
7.1.6 Statement of analysis of results and conclusions.
8. Precision and Bias
8.1 As stated in the Scope, this procedure is valid for the average person. Individuals may beare potentially tolerant or sensitive
to burns depending upon physical condition, age, ambient conditions, emotional state, etc. The literature (1, 4, 5) has shown,
however, agreement on pain response and tissue damage for a panel of subjects to within approximately 10 %.
9. Keywords
9.1 burns; epidermal injury; heat; injuries; skin contact temperatures; thermal insulation
APPENDIX
(Nonmandatory Information)
X1. RATIONALE
X1.1 Background—General
X1.1.1 Man has faced the potential of skin burns from touching hot surfaces since the discovery of fire in prehistoric times. He
was concerned more with treatment of the injury than with the development of some means to prevent its occurrence. As
civilization advanced, man developed crude insulation forms to control the extremes of heat to which he was exposed. The greatest
improvement to these systems came since the industrial revolution where the use of high temperature power and process systems
dictated the development of modern insulation systems, that not only conserve energy but also protect process products during
manufacture. As technology expanded to include higher temperatures, more complex processes, and thus more worker exposure
situations, worker organizations and later governmental agencies demanded the increased use of insulation for personal protection.
X1.1.2 At the same time that the workplace was becoming more hazardous, the increased development of consumer products that
heated, steamed, or cooke
...