ASTM C1055-03(2009)
(Guide)Standard Guide for Heated System Surface Conditions That Produce Contact Burn Injuries
Standard Guide for Heated System Surface Conditions That Produce Contact Burn Injuries
SIGNIFICANCE AND USE
Most heated apparatus in industrial, commercial, and residential service are insulated, unless thermal insulation would interfere 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 high enough to cause burns from contact exposure under certain conditions.
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.
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 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).
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.
This guide is limited to contact exposure to heated surfaces only. It should be noted that conditions of personal ...
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 values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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.
1.4 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.
1.5 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 used to establish a second, less desirable injury level (second degree burns), where some permanent tissue damage can be permitted. At no time, however, are conditions that produce third degree burns recommended.
1.6 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.
1.7 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).
1.8 This standard does not purport to ...
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Designation: C1055 − 03(Reapproved 2009)
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 A bibliography of human burn evaluation studies and
surface hazard measurement is provided in the list of refer-
1.1 This guide covers a process for the determination of
ences at the end of this guide (1-16).
acceptable surface operating conditions for heated systems.
1.8 This standard does not purport to address all the safety
The human burn hazard is defined, and methods are presented
concerns, if any, associated with its use. It is the responsibility
for use in the design or evaluation of heated systems to prevent
of the user of this standard to establish appropriate safety and
serious injury from contact with the exposed surfaces.
health practices and determine the applicability of regulatory
1.2 The values stated in SI units are to be regarded as
limitations prior to its use.
standard. No other units of measurement are included in this
standard.
2. Referenced Documents
1.3 The maximum acceptable temperature for a particular
2.1 ASTM Standards:
surface is derived from an estimate of the possible or probable
C680 Practice for Estimate of the Heat Gain or Loss and the
contact time, the surface system configuration, and the level of
Surface Temperatures of Insulated Flat, Cylindrical, and
injury deemed acceptable for a particular situation.
Spherical Systems by Use of Computer Programs
1.4 For design purposes, the probable contact time for
C1057 Practice for Determination of Skin Contact Tempera-
industrial situations has been established at 5 s. For consumer
ture from Heated Surfaces Using a Mathematical Model
products, a longer (60-s) contact time has been proposed by
and Thermesthesiometer
Wu (1) and others to reflect the slower reaction times for
children, the elderly, or the infirm. 3. Terminology
1.5 The maximum level of injury recommended here is that 3.1 Definitions of Terms Specific to This Standard:
causing first degree burns on the average subject. This type of 3.1.1 skin:
injury is reversible and causes no permanent tissue damage.
3.1.2 epidermis—the outermost layer of skin cells. This
For cases where more severe conditions are mandated (by layer contains no vascular or nerve cells and acts to protect the
space, economic, exposure probability, or other outside skin layers. The thickness of this layer averages 0.08 mm.
considerations), this guide may be used to establish a second,
3.1.3 dermis—the second layer of skin tissue. This layer
less desirable injury level (second degree burns), where some
contains the blood vessels and nerve endings. The thickness of
permanent tissue damage can be permitted. At no time,
this layer averages 2 mm.
however, are conditions that produce third degree burns rec-
3.1.4 necrosis—localized death of living cells. A clinical
ommended.
term that defines when permanent damage to a skin layer has
1.6 This guide addresses the skin contact temperature de-
occurred.
termination for passive heated surfaces only. The guidelines
3.1.5 burns:
contained herein are not applicable to chemical, electrical, or
3.1.6 first degree burn—the reaction to an exposure where
other similar hazards that provide a heat generation source at
the intensity or duration is insufficient to cause complete
the location of contact.
necrosis of the epidermis. The normal response to this level of
exposure is dilation of the superficial blood vessels (reddening
This guide is under the jurisdiction of ASTM Committee C16 on Thermal
of the skin).
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal
Measurement.
Current edition approved Sept. 1, 2009. Published September 2009. Originally
approved in 1986. Last previous edition approved in 2003 as C1055–03. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/C1055-03R09. contact ASTM Customer Service at service@astm.org. 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 − 03 (2009)
3.1.7 second degree burn—the reaction to an exposure 4.2.2 Secondly, the user determines the maximum operating
where the intensity and duration is sufficient to cause complete surface temperature. This determination is made either by
necrosis of the epidermis but no significant damage to the direct measurement (if possible) or by use of a calculation at
dermis. The normal response to this exposure is blistering of design conditions using a method conforming to Practice
the epidermis. C680.
4.2.3 Next, utilizing the contact time (4.2.1), the maximum
3.1.8 third degree burn—the reaction to an exposure where
surface temperature (4.2.2), and the graph, Fig. 1, the user
significant dermal necrosis occurs. Significant dermal necrosis
determinesthepotentialinjurylevel.Iftheoperatingpointfalls
has been defined in the literature (3) as 75% destruction of the
belowtheinjurylevelspecified(4.2.1),thennofurtheranalysis
dermis.Thenormalresponsetothisexposureisopensoresthat
is required. (See Note 1.)
leave permanent scar tissue upon healing.
3.1.9 contact exposure—the process by which the surface of
NOTE 1—The following equations have been developed from the
skin makes intimate contact with a heated surface such that no original data used to generate Fig. 1 for easier use of this figure.
insulating layer, film, moisture, etc., interferes with the rapid
T 5 15.00510.51907 3Ln time 31000 1352.97/ Ln time 31000
~ ! ~ ~ !!
A
transfer of available energy.
(1)
3.1.10 insulation system—the combination of an insulation
T 5 39.468 2 0.41352 3Ln time 31000 1 190.60/ Ln time
~ ! ~ ~
B
material or jacket, or both that forms a barrier to the rapid loss
31000 (2)
!!
of energy from a heated surface. The insulation system may
involve a broad range of types and configurations of materials.
where:
T = critical contact temperature for complete transepidermal
3.1.11 jacket—the protective barrier placed on the exposed
A
necrosis, °C.
sideofaninsulationtoprotecttheinsulationfromdeterioration
T = critical contact temperature for reversible epidermal injury, °C.
B
or abuse. The jacket material can be made of paper, plastic,
time = elapsed contact time, s.
metal, canvas cloth, or combinations of the above or similar
Ln = natural logarithm.
materials.
4.2.4 If the injury level exceeds that specified, further
3.1.12 thermesthesiometer—a probe device developed by
analysis of the system is required using either the thermesthe-
Marzetta (13) that simulates the thermal physical response of
siometer (a direct method) or an additional calculation. Both
the human finger to contact with heated surfaces.
methods are described in Practice C1057.
4. Summary of Guide
4.2.5 Ifafterthisadditionalanalysisthesystemstillexceeds
the injury level criterion, then the system is unacceptable for
4.1 This guide establishes a means by which the engineer,
the criterion specified and the design should be revised.
designer, or operator can determine the acceptable surface
temperature of an existing system where skin contact may be
5. Significance and Use
made with a heated surface.
4.2 The process used in the analysis follows the outline 5.1 Most heated apparatus in industrial, commercial, and
residential service are insulated, unless thermal insulation
listed below:
4.2.1 The user must first establish the acceptable contact would interfere with their function; for example, it is inappro-
priate to insulate the bottom surface of a flatiron. However,
exposure time and the level of acceptable injury for the
particular system in question. surface temperatures of insulated equipment and appliances
FIG. 1 Temperature-Time Relationship for Burns
C1055 − 03 (2009)
may still be high enough to cause burns from contact exposure 6.2.2 Acceptable Injury Levels—The acceptable injury level
under certain conditions. is that of first degree burns as defined in 3.1.6 and is the limit
represented by the bottom curve in Fig. 1.
5.2 This guide has been developed to standardize the
6.3 The next phase in the process is to establish the
determination of acceptable surface operating conditions for
heated systems. Current practice for this determination is maximum operating surface temperature under worst case
conditions. This evaluation may be made either by direct
widely varied. The intent of this guide is to tie together the
measurement (but only at worst case conditions) or by using a
existing practices into a consensus standard based upon scien-
calculation approximation. The steps required for determining
tific understanding of the thermal physics involved. Flexibility
the maximum surface temperature are as follows:
is retained within this guide for the designer, regulator, or
consumer to establish specific burn hazard criteria. Most
6.3.1 The initial step is to establish the operating system
generally, the regulated criterion will be the length of time of
parameters. This step provides input information to the analy-
contact exposure.
sisandmayprecludeanyfurtherworkconcerningburnhazard.
The items that need to be identified and recorded are as
5.3 It is beyond the scope of this guide to establish appro-
follows:
priate contact times and acceptable levels of injury for particu-
6.3.1.1 System Description—Shape, size, materials, includ-
lar situations, or determine what surface temperature is “safe.”
ing jacket material, thickness, and surface emittance.
Clearly, quite different criteria may be justified for cases as
6.3.1.2 Operation Conditions—Temperatures of heated
diverseasthoseinvolvinginfantsanddomesticappliances,and
system, times of year, cycle, etc.
experienced adults and industrial equipment. In the first case,
6.3.1.3 Ambient Conditions—Worstcasedesigntemperature
no more than first degree burns in 60 s might be desirable. In
for burn hazards would be summer design dry bulb. Or, for
the second case, second degree burns in 5 s might be
inside conditions, the maximum expected room ambient air
acceptable.
temperature. Include the ambient air velocity, if known.
NOTE 2—An overview of the medical research leading to the develop-
ment of this guide was presented at the ASTM Conference on Thermal NOTE3—Designconditionsforburnhazardevaluationmaybedifferent
Insulation, Materials and Systems on Dec. 7, 1984 (14). from those used for heat loss analysis. For example, the highest ambient
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 should be noted that conditions of personal
to Practice C680. This technique should be used during design
exposure to periods of high ambient temperature or high
or where the system surface temperatures cannot be physically
radiant fluxes may 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
hot systems since burns can result; and (2) Proper installation techniques
5.7 The procedure found in this guide has been described in
must be used with direct contact thermometry to prevent heat sinking of
theliteratureasapplicabletoallheatedsurfaces.Forextremely
the surface and obtaining incorrect temperature readings.
high-temperature metallic surfaces (>70°C), damage occurs
6.4 In many situations, surface temperatures exceed the
almost instantaneously upon contact.
range of applicability of this guide and thus the evaluation is
made through interpretation of the surface temperature data
6. Procedure
and the system properties. The limiting conditions below
6.1 This procedure requires the user to make several deci-
should first be examined to see if further analysis is required.
sions that are based upon the results obtained. Careful docu-
6.4.1 If the surface temperature is below 44°C, no short
mentation of the rationale for each decision and intermediate
term (that is, less than 6 h) hazard exists and the remaining
result is an important part of this evaluation process.
sections can be ignored.
6.2 The first phase in the use of this guide is to establish the
6.4.2 If the surface temperature exceeds 70°C and the
acceptable limits for contact exposure time and the acceptable surface is metallic, it may present a hazard regardless of
level of injury for the system in question. Where no available
contact duration.Attempts should be made to lower the surface
standards for these limits are prescribed, the following limits temperature below 70°C. Nonmetallic skins may be safe for
are recommended based upon a survey of the existing medical
limitedexposureattemperaturesabove70°C.Inthesecases,as
literature. with all cases between 44°C and 70°C, the analysis should be
completed.
6.2.1 Acceptable Contact Times:
6.2.1.1 Industrial Process—5s.
6.5 With the measurement or estimation of surface tempera-
6.2.1.2 Consumer Items—60 s. ture for the system in question, utilize the graph (Fig. 1) and
C1055 − 03 (2009)
check if the intersection of the operating surface temperature 6.8 If, after analysis using Practice C1057, the system
and the selected time of contact falls below the threshold temperature still fails to meet the selected criterion, then
temperature. increasing insulation, changing jacketing, or other means must
beusedtolowerthesurfacetemperature.PracticeC680willbe
NOTE 5—The threshold temperature used will depend
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:C1055–99 Designation:C1055–03 (Reapproved 2009)
Standard Guide for
Heated System Surface Conditions That that Produce
Contact Burn Injuries
This standard is issued under the fixed designation C 1055; 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 establishescovers 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 VThe values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 Themaximumacceptabletemperatureforaparticularsurfaceisderivedfromanestimateofthepossibleorprobablecontact
time, the surface system configuration, and the level of injury deemed acceptable for a particular situation.
1.4 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.
1.5 Themaximumlevelofinjuryrecommendedhereisthatcausingfirstdegreeburnsonthe averagesubject.Thistypeofinjury
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 used to establish a second, less desirable injury level
(second degree burns), where some permanent tissue damage can be permitted.At no time, however, are conditions that produce
third degree burns recommended.
1.6Abibliography of human burn evaluation studies and surface hazard measurement is provided in the list of references at the
end of this guide
1.6 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.
1.7 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
1.8 This standard does not purport to address all 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 its use.
2. Referenced Documents
2.1 ASTM Standards:
C 680 Practice for DeterminationEstimate of the Heat Gain or Loss and the Surface Temperatures of Insulated Pipe Flat,
Cylindrical, and EquipmentSpherical Systems by Use of a Computer ProgramPrograms
C 1057 Practice for Determination of Skin Contact Temperature from Heated Surfaces Using a Mathematical Model and the
Thermesthesiometer
3. Terminology
3.1 Definitions of Terms Specific to This Standard: Descriptions of Terms Specific to This Standard:
3.1.1 skin:
ThisguideisunderthejurisdictionofASTMCommitteeC-16onThermalInsulationandisthedirectresponsibilityofSubcommitteeC16.24onHealthandSafetyHazard
Potentials.
Current edition approved March 10, 1999. Published May 1999. Originally published as C1055–86. Last previous edition C1055–92.C16 on Thermal Insulation and is
the direct responsibility of Subcommittee C16.30 on Thermal Measurement.
Current edition approved Sept. 1, 2009. Published September 2009. Originally approved in 1986. Last previous edition approved in 2003 as C 1055–03.
The boldface numbers in parentheses refer to the list of references at the end of this guide.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
, Vol 04.06.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.
C1055–03 (2009)
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—localizeddeathoflivingcells.Aclinicaltermthatdefineswhenpermanentdamagetoaskinlayerhasoccurred.
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 involve 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 be 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 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 C 680.
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. ), 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 15.005 1 0.51907 3 Ln time 3 1000! 1 352.97 Ln time 3 1000!! (1)
~ ~ ~
A
/
T 5 39.468 – 0.41352 3 Ln ~time 3 1000! 1 190.60 ~Ln ~time 3 1000!! (2)
B /
FIG. 1 Temperature-Time Relationship for Burns
C1055–03 (2009)
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 C 1057.
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 should be revised.
5. Significance and Use
5.1 Most heated apparatus in industrial, commercial, and residential service are insulated, unless thermal insulation would
interfere 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 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 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.
NOTE1—An 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 noted that conditions of personal exposure
to periods of high ambient temperature or high radiant fluxes may 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—60s.
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 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
may 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 summer design dry bulb. Or, for inside
conditions, the maximum expected room ambient air temperature. Include the ambient air velocity, if known.
NOTE2—Design 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 Thesecondstepistodeterminethetemperatureofthesystemsurfaceatthe worstdesignconditionbyoneofthefollowing
methods.
C1055–03 (2009)
6.3.2.1 Insert the system dimensions, material properties, and operating conditions into an analysis technique conforming to
Practice C 680. This technique should be 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.
NOTE3—( 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 should 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 ignored.
6.4.2 If the surface temperature exceeds 70°C and the surface is metallic, it may present a hazard re
...
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