ASTM C1146 - 09(2013)

    Standard Guide for Prefabricated Panel and H–bar Insulation Systems for Vessels, Ducts and Equipment Operating at Temperatures Above Ambient Air

    Active Standard ASTM C1146 | Developed by Subcommittee: C16.40

    Book of Standards Volume: 04.06


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    ASTM C1146

    Significance and Use

    4.1 The purpose of this guide is to ensure that a functional system will result when considering the use of prefabricated panel or H-bar insulation systems. Both systems require a varying degree of pre-engineering and prefabrication so that the insulation will produce the specified thermal, mechanical and environmental design requirements Both the prefabricated panels and H-bar systems which can also be used in combination with each other are to be designed to:

    4.1.1 Limit loss of heat from insulated surface.

    4.1.2 Limit exposed surface temperatures for burn protection of personnel.

    4.1.3 Maintain optimum temperatures of the insulated equipment at or above a specified minimum value required for the proper operation of the equipment.

    4.1.4  Produce a system or assembly that is designed to provide allowance for thermal expansion; is structurally adequate; is of a weathertight construction; and incorporates design features that promote efficient removal for inspection, repair and maintenance where required.

    1. Scope

    1.1 This guide describes design, fabrication, shipping, handling, jobsite storage, and installation of prefabricated panel and H-Bar insulation systems for vessels, ducts, and equipment operating at temperatures above ambient. Typical applications include, but are not limited to, air and gas ducts, steam generating units, air quality control systems, fans, storage tanks, process vessels, and coke drums

    1.2 The insulation described herein is limited to systems consisting of insulating units specially designed to fit the surfaces to be insulated, and engineered for the service and environmental requirements. The insulation unit may also include special design features which facilitate the removal and replacement for maintenance and inspection.

    1.3 When prefabricated panels are used, each insulation unit factory preassembled and typically comprised of the insulation, an outer lagging to which the insulation is attached, an inner retaining wire mesh, optional foil lining, and means for mechanically securing multiple units together in an assembly.

    1.4 H-bar systems represent insulation units that are typically comprised of the insulation, outer lagging and a uniquely configured subgirt design which both supports the insulation and provides a means for mechanically securing multiple units together in an assembly. The design of the subgirt creates an “H” configuration which is fabricated from light gauge sheet metal. The subgirt components consist of: (1) a “J-bar” shape which frames the perimeter edges of the surface to be insulated, holds the insulation in place along the outer edge and provides a screen attachment point for the outer lagging; (2) the “H-bar” shape is placed at defined intervals. The web section of the “H-bar” supports the insulation while the exterior flange allows for the outer lagging to be attached with threaded fasteners.

    1.5 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.

    1.6 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.

    Note 1When prefabricated panel or H-Bar insulation systems are specified, Test Methods C167, C177 and C1061, Material Specifications A36/A36M, A463/A463M, B209, C612, and Terminology C168 should be considered.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    A36/A36M Specification for Carbon Structural Steel

    A463/A463M Specification for Steel Sheet, Aluminum-Coated, by the Hot-Dip Process

    B209 Specification for Aluminum and Aluminum-Alloy Sheet and Plate

    C167 Test Methods for Thickness and Density of Blanket or Batt Thermal Insulations

    C168 Terminology Relating to Thermal Insulation

    C177 Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus

    C612 Specification for Mineral Fiber Block and Board Thermal Insulation

    C1061 Test Method for Thermal Transmission Properties of Non-Homogeneous Insulation Panels Installed Vertically


    ICS Code

    ICS Number Code 91.100.60 (Thermal and sound insulating materials)

    UNSPSC Code

    UNSPSC Code 30140000(Insulation)


    DOI: 10.1520/C1146

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