ASTM C1146-09(2018)

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: C1146 − 09 (Reapproved 2018)
Standard Guide for
Prefabricated Panel and H-bar Insulation Systems for
Vessels, Ducts and Equipment Operating at Temperatures
Above Ambient Air
This standard is issued under the fixed designation C1146; 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 1.5 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
1.1 This guide describes design, fabrication, shipping,
conversions to SI units that are provided for information only
handling, jobsite storage, and installation of prefabricated
and are not considered standard.
panel and H-Bar insulation systems for vessels, ducts, and
1.6 This standard does not purport to address all of the
equipment operating at temperatures above ambient. Typical
safety concerns, if any, associated with its use. It is the
applications include, but are not limited to, air and gas ducts,
responsibility of the user of this standard to establish appro-
steam generating units, air quality control systems, fans,
priate safety, health, and environmental practices and deter-
storage tanks, process vessels, and coke drums
mine the applicability of regulatory limitations prior to use.
1.2 The insulation described herein is limited to systems
consisting of insulating units specially designed to fit the NOTE 1—When prefabricated panel or H-Bar insulation systems are
specified, Test Methods C167, C177 and C1061, Material Specifications
surfaces to be insulated, and engineered for the service and
A36/A36M, A463/A463M, B209, C612, and Terminology C168 should
environmental requirements. The insulation unit may also
be considered.
includespecialdesignfeatureswhichfacilitatetheremovaland
1.7 This international standard was developed in accor-
replacement for maintenance and inspection.
dance with internationally recognized principles on standard-
1.3 When prefabricated panels are used, each insulation unit
ization established in the Decision on Principles for the
factorypreassembledandtypicallycomprisedoftheinsulation,
Development of International Standards, Guides and Recom-
an outer lagging to which the insulation is attached, an inner
mendations issued by the World Trade Organization Technical
retaining wire mesh, optional foil lining, and means for
Barriers to Trade (TBT) Committee.
mechanically securing multiple units together in an assembly.
2. Referenced Documents
1.4 H-bar systems represent insulation units that are typi-
cally comprised of the insulation, outer lagging and a uniquely
2.1 ASTM Standards:
configured subgirt design which both supports the insulation
A36/A36M Specification for Carbon Structural Steel
and provides a means for mechanically securing multiple units
A463/A463M Specification for Steel Sheet, Aluminum-
together in an assembly. The design of the subgirt creates an
Coated, by the Hot-Dip Process
“H” configuration which is fabricated from light gauge sheet
B209 Specification for Aluminum and Aluminum-Alloy
metal. The subgirt components consist of: (1) a “J-bar” shape
Sheet and Plate
which frames the perimeter edges of the surface to be
C167 Test Methods for Thickness and Density of Blanket or
insulated,holdstheinsulationinplacealongtheouteredgeand
Batt Thermal Insulations
providesascreenattachmentpointfortheouterlagging;(2)the
C168 Terminology Relating to Thermal Insulation
“H-bar”shapeisplacedatdefinedintervals.Thewebsectionof
C177 Test Method for Steady-State Heat Flux Measure-
the “H-bar” supports the insulation while the exterior flange
ments and Thermal Transmission Properties by Means of
allows for the outer lagging to be attached with threaded
the Guarded-Hot-Plate Apparatus
fasteners.
C612 Specification for Mineral Fiber Block and Board
Thermal Insulation
C1061 Test Method for Thermal Transmission Properties of
This guide is under the jurisdiction of ASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.40 on Insulation
Systems. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2018. Published December 2018. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1989. Last previous edition approved in 2013 as C1146 – 09 (2013). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/C1146-09R18. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1146 − 09 (2018)
Non-Homogeneous Insulation Panels Installed Vertically 3.2.8 support member (subgrit)—straps, bars, or angles
(Withdrawn 1995) attached to the plate surface or external casing stiffeners being
insulated and to which the insulation units are attached.
3. Terminology
4. Significance and Use
3.1 Terminology C168 shall be considered as applying to
the terms in this specification.
4.1 The purpose of this guide is to ensure that a functional
system will result when considering the use of prefabricated
3.2 Definitions of Terms Specific to This Standard:
panel or H-bar insulation systems. Both systems require a
3.2.1 convection barrier (flue stop)—barriers to internal air
varying degree of pre-engineering and prefabrication so that
flow sometimes refered to as “chimney effect”) which are
the insulation will produce the specified thermal, mechanical
placed between the inner liner and the hot surface being
and environmental design requirements Both the prefabricated
insulated. The barriers are generally a combination of sheet
panels and H-bar systems which can also be used in combina-
metal and with the insulation material mechanically attached.
tion with each other are to be designed to:
Convection barriers are required when the insulation is not in
4.1.1 Limit loss of heat from insulated surface.
direct contact with the plate surface and only on vertical and
4.1.2 Limit exposed surface temperatures for burn protec-
sloping surfaces of less than 45º incline.
tion of personnel.
3.2.2 flashing—sheet metal of the same material as the
4.1.3 Maintain optimum temperatures of the insulated
lagging, used to cover openings in the insulation typically
equipment at or above a specified minimum value required for
occurring at locations, such as corners, penetrations framing of
the proper operation of the equipment.
doors and closures. Flashing may be fixed (permanent) or
4.1.4 Produce a system or assembly that is designed to
removable to allow for inspection and maintenance, that is,
provide allowance for thermal expansion; is structurally ad-
expansion joints.
equate; is of a weathertight construction; and incorporates
3.2.3 inner liner—the innermost surface or cover of the
design features that promote efficient removal for inspection,
prefabricated panel (closest to the hot surface) composed of
repair and maintenance where required.
reflective aluminum foil and wire mesh.
3.2.4 insulation—essentially homogenous insulation, gener-
5. Panel Design Specifications for Prefabricated Panel
ally in semi-rigid board from and, in which relevant properties
and H-bar Systems
arenotafunctionofpositionwithinthematerialitself,butmay
5.1 General:
be a function of such variables as time and temperature.
5.1.1 The purchase specification should clearly indicate the
3.2.5 lagging—the outermost cover or sheet of the prefab-
surfaces to be insulated. Either insulation type and thickness or
ricated panel or H–bar system (farthest from the hot surface),
average heat loss requirements shall be part of the specifica-
which performs a structural function as well as provides
tion.
protection from weather and mechanical abuse. The lagging is
5.1.2 The purchase specification should clearly indicate the
generally fabricated from corrugated, ribbed, or flat sheet;
operating temperature of the item to be insulated. When up-set
smooth or stucco-embossed; mill finish or painted; clad or
or worst-case temperature conditions are to be considered, the
non-clad.
maximum temperature excursion and time duration should be
3.2.6 penetrations—openings through a unit of insulation stated.
from the hot plate surface through to the exterior cold surface. 5.1.3 Heat loss through uninsulated surfaces, or increased
Penetrations such as test ports should be covered with remov- heat loss that results when it is necessary to reduce insulation
able insulation assemblies. The insulation thickness should be thickness to accommodate localized interferences with
equal to the surface being insulated. equipment, supports, hangers, etc., should be considered in the
overall insulation design.
3.2.7 retaining devices
5.1.4 Conduction paths which produce high heat on exterior
3.2.7.1 prefabricated panels—metallic members passing
lagging or “cold spots” on plate interior and are attributed to
through the insulation between the hot surface and the cold
the insulation subgrit design should be minimized. The use of
surface. Generally, these include: pins, prongs, or other accept-
“through-fasteners” or bolts where protruding heads can occur
able means used and secured with washers and speed clips to
should be kept to a minimum. There should be no “rattling” or
hold the assembly together.
“free-play” of the exterior lagging.
3.2.7.2 H-bar systems—H-bar systems includes retaining
5.1.5 Convection barriers (flue stops) are typically installed
devices such as a backing strap or expanded metal between the
at 12 to 15 ft (3657 to 4572 mm) vertical centers as well as to
H-bar. These devices are placed midway between the insula-
close off the corners of p
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