Medium Density

ISOLATEK® Type 400 AC is a gypsum based medium density Wet Mix Spray-Applied Fire Resistive Material (SFRM) designed to provide protection for structural steel in commercial and high rise construction areas which may be subjected to higher levels of abuse such as mechanical and electrical rooms or elevator shafts.

ISOLATEK Type 400 AC offers enhanced strength, durability and excellent fire protection and meets the current IBC bond strength requirement of ≥ 20.6 kpa (430 psf) for buildings over 22.0 meters (75 ft.) in height and ≥ 47.9 kpa (1000 psf) for buildings over 128.1 meters (420 ft.) in height.

ISOLATEK Type 400 AC’s physical properties, combined with superior fire resistive performance and application efficiencies, make it the ideal choice for high rise structures and interior conditioned environments.



  • Offers the most cost effective fire resistance performance per unit thickness and greatest productivity of any medium density SFRM.
  • Less material is needed to achieve required fire ratings.
  • Provides added value as a thermal insulator.
  • Meets current IBC bond strength requirements for building over 420 ft. in height.
  • Meets or exceeds all major fire protection specifications for commercial structures including ANSI/UL 263 and ASTM E119.
  • Offers LEED building credits for recycled content.

Product Uses

Designed to provide fire protection for up to 4 hour ratings to various floor and roof deck assemblies, steel beams, columns, and joists in commercial construction projects.

Fire Tests & Approvals

In order to meet the performance and durability criteria set forth by the American Institute of Architects (AIA) and other major industry specifying organizations, ISOLATEK® Type 400 AC has undergone the most rigorous testing in accordance with the world’s most demanding safety protocols.

UL 263, ASTM E119 - UL-263

Cellulosic – ANSI/UL263 (ASTM E119) – Fire Tests of Building Construction and Materials

This cellulosic fire test is traditionally used to evaluate materials for use in the protection of modern day commercial structures. This test reaches 1000°F (537°C) after 5 minutes and gradually reaches a temperature of 2000°F (1093°C) after a period of up to 4 hours.

ISOLATEK Type 400 AC is classified by Underwriters Laboratories for up to 4 hours protection in accordance with ANSI/ UL263 and is listed within various UL Designs.

UL Logo

UL Classification Mark

The UL Classification Mark indicates compliance with global requirements as it relates to a specific risk or casualty. With the Classification service, UL determines that a manufacturer has demonstrated the ability to produce a product complying with UL’s requirements with respect to one or more of the following:

  • Specific risk, e.g., casualty, fire, etc.
  • Performance under specific conditions
  • Compliance with regulatory codes
  • Compliance with specific standards such as international standards
  • Other condition, as determined by UL

All of the products carrying a UL Classification Mark are covered by UL’s Follow-Up Services program to verify that products carrying the UL Classification Mark continue to be manufactured in compliance with UL’s safety requirements.

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International Code Council – Evaluation Service (ICC-ES) Report

International Code Council-Evaluation Services (ICC-ES) has conducted a technical evaluation of ISOLATEK Type 400 AC. The result of the evaluation process assures that the ISOLATEK Type 400 AC is in compliance with the International Building Code.

Major Specification and Approval Compliance

ISOLATEK Type 400 AC complies with the requirements of the following specifications:

  • General Services Administration (GSA): AIA/SC/GSA:07811
  • Unified Facilities Guide Specification (UFGS): UFGS – 078100
  • Veterans Administration (VA): H-08-1
  • U.S. ARMY Corps of Engineers CEGS-07811
  • U.S. Environmental Protection Agency (EPA): Regulation 40
  • Construction Specification Canada (CSC) TEK-AID

ASTM Physical Performance Standards Test Performance* Spray-Applied Fire Resistive Materials (SFRM’s)
Physical Property ASTM Standard AIA MasterSpec/GSA Performance Requirements ISOLATEK Type 400 AC
Surface Burning Characteristics ASTM E84 Flame Spread: 10 or less
Smoke Developed: 0
Density ASTM E605 22 pcf (353 kg/m3) 22-25 pcf (352-400 kg/m3)
Cohesion / Adhesion (Bond Strength) ASTM E736 430 psf (20.6 kPa) 1849 psf (88.5 kPa)
Deflection ASTM E759 No cracks, spalling, or delamination No cracks, spalling, or delamination
Bond Impact ASTM E760 No cracks, spalling, or delamination No cracks, spalling, or delamination
Compressive Strength ASTM E761 7344 psf (351 kPa) 8719 psf (417.5 kPa)
Corrosion ASTM E937 Does not promote corrosion of steel Does not promote corrosion of steel
Air Erosion ASTM E859 Max. 0.025 g/ft.2 0.000 g/ft.2 (0.000 g/m2)
Fungal Resistance ASTM G21 Zero Growth After 28 days Zero Growth After 28 days
Combustibility ASTM E136 Noncombustible Noncombustible
Thermal Properties ASTM C518 Conductivity[k] – 0.494 BTU in/hr ft2 oF @ 75oF
(0.0712 W/m•K @ 25oC)
Resistance [R/inch]-2.02

*Based on independent laboratory tests under controlled conditions.