ASTM C795-08(2013)

Standard Specification for Thermal Insulation for Use in Contact with Austenitic Stainless Steel

ABSTRACT
This specification covers non-metallic thermal insulation for use in contact with austenitic stainless steel piping and equipment. The material shall conform to the established requirements of the basic material specification. The physical and chemical requirements shall conform to the requirements of the basic material specification. Preproduction corrosion test and chemical analysis shall be performed to conform to the specified requirements.
SCOPE
1.1 This specification covers non-metallic thermal insulation for use in contact with austenitic stainless steel piping and equipment. In addition to meeting the requirements specified in their individual material specifications, issued under the jurisdiction of ASTM Committee C16, these insulations must pass the preproduction test requirements of Test Method C692, for stress corrosion effects on austenitic stainless steel, and the confirming quality control, chemical requirements, when tested in accordance with the Test Methods C871.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Apr-2013
• ICS: 27.220 - Heat recovery. Thermal insulation
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.20 - Homogeneous Inorganic Thermal Insulations

Relations

• Replaces: ASTM C795-08 - Standard Specification for Thermal Insulation for Use in Contact with Austenitic Stainless Steel
• Effective Date: 01-May-2013
• Referred By: ASTM C929-14(2019) - Standard Practice for Handling, Transporting, Shipping, Storage, Receiving, and Application of Thermal Insulation Materials For Use in Contact with Austenitic Stainless Steel
• Effective Date: 01-May-2013
• Referred By: ASTM C1393-19 - Standard Specification for Perpendicularly Oriented Mineral Fiber Roll and Sheet Thermal Insulation for Pipes and Tanks
• Effective Date: 01-May-2013
• Referred By: ASTM C610-17(2023) - Standard Specification for Molded Expanded Perlite Block and Pipe Thermal Insulation
• Effective Date: 01-May-2013
• Referred By: ASTM C553-13(2019) - Standard Specification for Mineral Fiber Blanket Thermal Insulation for Commercial and Industrial Applications
• Effective Date: 01-May-2013
• Referred By: ASTM C449-07(2019) - Standard Specification for Mineral Fiber Hydraulic-Setting Thermal Insulating and Finishing Cement
• Effective Date: 01-May-2013
• Referred By: ASTM C1728-23 - Standard Specification for Flexible Aerogel Insulation
• Effective Date: 01-May-2013
• Referred By: ASTM C1685-15(2021) - Standard Specification for Pneumatically Applied High-Temperature Fiber Thermal Insulation for Industrial Applications
• Effective Date: 01-May-2013
• Referred By: ASTM C1617-19 - Standard Practice for Quantitative Accelerated Laboratory Evaluation of Extraction Solutions Containing Ions Leached from Thermal Insulation on Aqueous Corrosion of Metals
• Effective Date: 01-May-2013
• Referred By: ASTM C1696-20 - Standard Guide for Industrial Thermal Insulation Systems
• Effective Date: 01-May-2013
• Referred By: ASTM C592-22a - Standard Specification for Mineral Fiber Blanket Insulation and Blanket-Type Pipe Insulation (Metal-Mesh Covered) (Industrial Type)
• Effective Date: 01-May-2013
• Referred By: ASTM C547-22a - Standard Specification for Mineral Fiber Pipe Insulation
• Effective Date: 01-May-2013
• Referred By: ASTM C692-13(2023) - Standard Test Method for Evaluating the Influence of Thermal Insulations on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel
• Effective Date: 01-May-2013
• Referred By: ASTM C1676/C1676M-23 - Standard Specification for Microporous Thermal Insulation
• Effective Date: 01-May-2013
• Referred By: ASTM C534/C534M-23 - Standard Specification for Preformed Flexible Elastomeric Cellular Thermal Insulation in Sheet and Tubular Form
• Effective Date: 01-May-2013

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C795 −08 (Reapproved 2013)
Standard Specification for
Thermal Insulation for Use in Contact with Austenitic
Stainless Steel
This standard is issued under the fixed designation C795; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 3. Terminology
1.1 This specification covers non-metallic thermal insula- 3.1 Definitions—Terminology C168 applies to the terms
tion for use in contact with austenitic stainless steel piping and used in this specification.
equipment.Inadditiontomeetingtherequirementsspecifiedin 3.2 Definitions of Terms Specific to This Standard:
their individual material specifications, issued under the juris- 3.2.1 basic material specification—any of the material
diction of ASTM Committee C16, these insulations must pass specifications for homogeneous insulation covered in any of
the preproduction test requirements of Test Method C692, for the pertinent Annual Book of ASTM Standards.
stress corrosion effects on austenitic stainless steel, and the
3.2.2 lot—a lot shall be defined in accordance with Practice
confirmingqualitycontrol,chemicalrequirements,whentested
C390 by agreement between the purchaser and the manufac-
in accordance with the Test Methods C871.
turer.
1.2 The values stated in inch-pound units are to be regarded
3.2.3 stress corrosion cracking (SCC)—the failure of metal,
as standard. The values given in parentheses are mathematical
taking the form of cracks that potentially occur under the
conversions to SI units that are provided for information only
combined influence of certain corrosive environments and
and are not considered standard.
applied or residual stresses.
1.3 This standard does not purport to address all of the
3.2.4 wicking-type insulation—insulation material that, by
safety concerns, if any, associated with its use. It is the
virtue of its physical characteristics, permits a wetting liquid to
responsibility of the user of this standard to establish appro-
infiltrate it by capillary attraction.
priate safety and health practices and determine the applica-
4. Significance and Use
bility of regulatory limitations prior to use.
4.1 Stress corrosion cracking of austenitic stainless steel is a
2. Referenced Documents
metallurgical phenomenon. One cause of stress corrosion
2.1 ASTM Standards:
cracking is the presence of contaminants in water solution,
C168 Terminology Relating to Thermal Insulation
which can be concentrated at the stressed surface by evapora-
C390 Practice for Sampling and Acceptance of Thermal
tion of the water.
Insulation Lots
4.2 There is an apparent correlation between stress corro-
C692 Test Method for Evaluating the Influence of Thermal
sion cracking of austenitic stainless steel and the use of
Insulations on External Stress Corrosion Cracking Ten-
insulationwhicheithercontainswater-leachablechlorideor,by
dency of Austenitic Stainless Steel
reasonofitswaterabsorptivity,actsasavehiclethroughwhich
C871 Test Methods for ChemicalAnalysis of Thermal Insu-
chlorides from outside the system are concentrated at the
lationMaterialsforLeachableChloride,Fluoride,Silicate,
3,4,5
surface of the stainless steel.
and Sodium Ions
4.3 Studies have shown that insulation containing certain
water-solublecompoundshavethecapacitytoretardorprevent
This specification is under the jurisdiction of ASTM Committee C16 on
Thermal Insulation and is the direct responsibility of Subcommittee C16.20 on
Homogeneous Inorganic Thermal Insulations. Schaffer, L. D., and Klapper, J. A., “Investigation of the Effects of Wet,
Current edition approved May 1, 2013. Published May 2013. Originally Chloride-Bearing, Thermal Insulation on Austenitic Stainless Steel,” Report No.
approved in 1977. Last previous edition approved in 2008 as C795 – 08. DOI: ESI-25-(a)-1, Oak Ridge National Laboratory, and Ebasco Services Inc., November
10.1520/C0795-08R13. 1, 1961.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Dana, A. W., Jr., “Stress-Corrosion Cracking of Insulated Austenitic Stainless
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Steel,” ASTM Bulletin, October 1957.
Standards volume information, refer to the standard’s Document Summary page on Louthan, M. R., Jr., “Initial Stages of Stress Corrosion Cracking in Austenitic
the ASTM website. Stainless Steels,” Corrosion, NACE, September 1965.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C795−08 (2013)
FIG. 1 Acceptability of Insulation Material on the Basis of the Plot Points of the (Cl + F) and the (Na+SiO ) Analyses.
stress corrosion. Numerous materials thought to inhibit stress fluoride ions to be included with chloride ions when evaluating
corrosion cracking have been tried with varying degrees of the extractable ions and plotting them on the Fig. 1 acceptabil-
success. An inhibiting compound commonly used is sodium ity graph. Fluoride has been added to chloride in Section 13
silicate. Present knowledge indicates that the sodium silicate and on Fig. 1 to be consistent with the other standards.
dissociates in the presence of water, leaving the silicate ion to
4.6 Physical and chemical changes can occur when thermal
form a protective mechanism that inhibits or prevents the
insulation, various binders, or adhesives, or a combinations
chloride ion from attacking the stainless steel. Under adverse
thereof, are heated. Insulation materials are often exposed to
environmentalconditions,thisprotectiveagentwillpossiblybe
process temperatures that are sufficient to cause changes.
leached from the product with time and permanent protection
Various compounds thermally decompose increasing the solu-
is not afforded.
bility of some ions that leach out when exposed to water. Other
4.4 Test Method C692 contains a procedure for determining compounds have the potential to become less soluble after
whetherornotstresscorrosioncrackingwilloccurwithagiven thermal exposure.
thermalinsulation.Theprocedureisusedtoevaluateinsulation
4.7 The inhibitory qualities of sodium silicate compounds
materials have the potential to inhibit, to be passive, or actively
have been found to be different for different molar ratios of
contribute to stress corrosion cracking of austenitic stainless
sodium to silicate. The current specifications treat them as
steels. 6
being added together for a total ppm value.
4.5 Research has indicated that in addition to the halide ion
4.8 A variety of acids and ionic chemical solutions are
chloride, fluoride ions have the potential to induce SCC in the
known to induce metal pitting, hydrogen embrittlement, inter-
absence of inhibiting ions. Two widely used insulation speci-
granular corrosion and stress corrosion cracking on sensitized
fications that are similar to C795 and are specific to SCC allow
austenitic stainless steel. The results of Test Methods C692
t
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