ASTM C656-17(2023) PDF

Overview

ASTM C656-17(2023) - Standard Specification for Structural Insulating Board, Calcium Silicate outlines the requirements for rigid, preformed calcium silicate structural insulating boards. This standard from ASTM International is widely referenced for boards used in general thermal insulation, fire-resistive, and marine bulkhead applications. Covering both Types I and II and a range of eight grades with varying densities and strength properties, the specification ensures consistent quality and safety for end users across a host of demanding environments.

These calcium silicate boards are composed of hydrated calcium silicate with natural or synthetic fibers or fillers, specifically excluding asbestos. Designed to perform at service temperatures up to 1700°F (927°C), calcium silicate insulation boards maintain structural integrity after immersion in water and are resistant to fire and thermal transmission.

Key Topics

• Material Composition and Structure

  • Hydrated calcium silicate base
  • Use of natural or man-made fibers and fillers
  • Asbestos-free formulation

• Types and Grades

  • Type I: Rated for maximum use temperature of 1400°F (760°C)
  • Type II: Rated up to 1700°F (927°C)
  • Grades 1-8: Range in density and mechanical properties to suit different application needs

• Critical Performance Characteristics

  • Thermal insulating properties
  • Fire-resistance (including marine fireproofing)
  • Structural integrity after water exposure
  • Compressive and flexural strength
  • Screw holding strength for installation
  • Dimensional stability and low linear shrinkage
  • Apparent thermal conductivity values at multiple temperatures

• Testing and Quality

  • Testing methods for density, strength, thermal conductivity, and combustibility
  • Requirements for certification, inspection, and packaging
  • Compliance with international standardization principles

Applications

Calcium silicate structural insulating boards manufactured to ASTM C656 specifications are vital in several industries and environments where both thermal management and fire safety are critical:

• Building and Construction

  • Used as fire-rated wall panels, ceilings, and partitions
  • Insulation for mechanical rooms, ductwork, and boilers

• Marine and Shipbuilding

  • Effective as fire-resistive bulkhead panels and deck insulation for ships
  • Maintains performance integrity even in moist or wet conditions

• Industrial Facilities

  • Provides reliable thermal insulation for high-temperature process equipment
  • Used to line furnaces, kilns, and incinerators due to high temperature tolerance

• OEM and Custom Applications

  • Appliance manufacturing, specialty enclosures, and laboratory environments

Note: Actual maximum temperature limits should be confirmed for each application. The specification advises against rapid temperature cycling to prevent thermal shock and material damage.

Related Standards

Several ASTM standards are referenced to ensure proper testing and alignment with industry best practices. Notable related standards include:

• ASTM C165 – Compressive Properties of Thermal Insulations
• ASTM C168 – Terminology Relating to Thermal Insulation
• ASTM C177 – Steady-State Heat Flux Measurements
• ASTM C203 – Flexural Properties of Block-Type Thermal Insulation
• ASTM C303 – Dimensions and Density of Preformed Thermal Insulation
• ASTM C356 – Linear Shrinkage during Soaking Heat
• ASTM C390 – Sampling and Acceptance of Thermal Insulation Lots
• ASTM E136 – Combustibility Testing for Materials

For additional requirements and best installation practices, users should consult the full set of referenced ASTM standards and ensure compliance with local regulatory codes before use.

Keywords: calcium silicate board, structural insulation, thermal insulation, fire-resistive insulation, marine bulkhead panels, ASTM C656, building insulation standards, industrial thermal insulation, high-temperature insulation.