High density, cementitious fireproofing for tunnels and severe environmental exposure

Product Description

MONOKOTE® Z-146T high density cementitious fireproofing has been developed by GCP Applied Technologies to meet specialty and industrial fireproofing requirements requiring greater resistance to harsh environmental conditions.

MONOKOTE® Z-146T is a Portland cement-based, factory-mixed material requiring only the addition of water on the job site for application. It is spray applied, providing up to 4 hours of fire resistance. Its physical characteristics are excellent for areas exposed to environmental or climatic conditions. MONOKOTE® Z-146T may be used in areas where high durability and corrosion resistance is required such as substrates subjected to exterior exposure.


MONOKOTE® Z-146T may be used in roadway tunnels and in exterior environments where a highly durable fireproofing is required and a threat of steel corrosion is present.


  • Up to 4 hours in accordance with the Rijkswaterstaat (RWS) fire curve
  • Up to 4 hours in accordance with UL 1709 hydrocarbon test
  • Jet fire testing in accordance with HSE standard OTI 95 634
  • Up to 4 hours in accordance with UL 263 (ASTM E119)
  • Investigated by UL for exterior use

Delivery & Storage

  • All material to be used for fireproofing should be delivered in original unopened packages bearing the name of the manufacturer, the brand and proper Underwriters Laboratories Inc. labels for fire hazard and fire resistance classifications.
  • The material should be kept dry until ready for use. Keep packages of material off of the ground, under cover and away from sweating walls and other damp surfaces. All bags that have been exposed to water before use should be discarded. Stock of material is to be rotated and used before its expiration date.

Features & Benefits

MONOKOTE® Z-146T offers the following advantages to architects, engineers and applicators:

  • Factory pre-mixed - Ready to use. No job site proportioning required. Simply add water in a standard paddle-type plaster mixer and apply with conventional plastering equipment.
  • Non-toxic - The factory-mixed blend of common Portland cement and other inert materials requires only the addition of water for mixing and application.
  • Attractive finishes - MONOKOTE® Z-146T may be sprayed or hand troweled after spraying to achieve a lightly textured appearance.
  • Equipment versatility - MONOKOTE® Z-146T can be mixed in a standard plaster mixer. After mixing, MONOKOTE® Z-146T may be spray-applied with commonly available pumping and spraying equipment.
  • Corrosion inhibition - MONOKOTE® Z-146T neither prevents nor promotes the corrosion of steel, however, the inclusion of calcium nitrite as a corrosion inhibitor has been shown to retard the rate of corrosion due to salt and other aggressive environmental conditions.
  • Moisture resistant - The Portland cement base affords excellent fire protection characteristics in areas subjected to high humidity.
  • Durable - Hardness and durability help resist accidental physical damage.
  • Weatherable - Able to withstand freeze/thaw, wind, rain and other climatic conditions.

Performance Characteristics

Physical Properties Recommended Specification Laboratory Tested* Values Test Method **
Dry density, minimum average Min. 40 pcf (640 kg/m3) See note below*** ASTM E605
Bond strength Min. 10,000 psf (478 kN/m2) 16,727 psf (800 kPa) ASTM E736
Compression, 10% deformation 500 psi (3.45 MPa) 561 psi (3.87 MPa) ASTM E761
Air erosion Max 0.000 g/ft2 (0.00 g/m2) 0.000 g/ft2 (0.00 g/m2) ASTM E859
High velocity air erosion No continued erosion after 4 hours No continued erosion after 4 hours ASTM E859
Hardness 40 49 ASTM D2240
Bond impact No cracking, spalling or delamination No cracking, spalling or delamination ASTM E760
Deflection No cracking, spalling or delamination No cracking, spalling or delamination ASTM E759
Resistance to mold growth No growth after 28 days No growth after 28 days ASTM G21
Surface burning characteristics Flame spread = 0 Smoke developed = 0 Flame spread = 0 Smoke developed = 0 ASTM E84
Combustibility Less than 5 MJ/m2 total,
20 kw/m2 peak heat release
Less than 5 MJ/m2 total,
20 kw/m2 peak heat release
ASTM E1354

* Independent laboratory tested value. Report available upon request.
** ASTM International test methods modified for Bond Strength and Compressive Strength, where required, for high density, high performance products.
*** All in-place performance tests should be conducted at or below the minimum recommended specification density.

Steel & Concrete Surfaces

  • Prior to the application of MONOKOTE® Z-146T, an inspection should be made to determine that all steel surfaces are acceptable to receive fireproofing. The steel to be fireproofed should be free of oil, grease, excess rolling compounds or lubricants, loose mill scale, excess rust, noncompatible primer, lock down agent or any other substance that will impair proper adhesion. Where necessary, the cleaning of steel surfaces to receive fireproofing will be the responsibility of the general contractor.
  • Prior to application of MONOKOTE® Z-146T, a bonding agent, approved by the fireproofing manufacturer, should be applied to all concrete substrates to receive MONOKOTE® Z-146T.
  • The project architect will determine if the painted/ primed steel to receive fireproofing has been tested to provide the required fire resistance rating.


  • MONOKOTE® Z-146T should be mixed by machine in a conventional, plaster-type mixer or a continuous mixer specifically modified for cementitious fireproofing. The mixer should be kept clean and free of all previously mixed material. Adjust the mixer speed in a conventional mixer to the lowest speed which gives adequate blending of the material and a mixer density of 52 to 59 pcf (833 to 945 kg/m3) of material.
  • Using a suitable metering device and a conventional mixer, add all water to the mixer as the blades turn. Mixing should continue until the mix is lump-free, with a creamy texture. All material is to be thoroughly wet. Overmixing MONOKOTE® Z-146T will reduce pumping rate and will negatively affect inplace density and mechanical properties.

Temperature & Ventilation

  • The substrate temperature shall be a minimum of 40°F (4.5°C) for at least 1-hour prior to the application of the MONOKOTE®.
  • Additionally, the air and substrate temperature during application and for a minimum or 72 hours after application shall be no less than 40°F (4.5°C).
  • Provisions shall be made for ventilation to properly dry the fireproofing after application.
  • In enclosed areas lacking natural ventilation, air circulation and ventilation must be provided to achieve a minimum total fresh air exchange rate of 4 times per hour until the material is substantially dry.

Field Tests

The architect will select an independent testing laboratory (for which the owner will pay) to sample and verify the thickness and density of the fireproofing in accordance with the the applicable building code. The architect will select an independent testing laboratory (for which the owner will pay) to randomly sample and verify the bond strength of the fireproofing.

Note:  No recognized field bond strength test procedure exists for sprayed fireproofing materials with bond strengths greater than 1,000 psf (4,882 kg/m2) such as MONOKOTE® Z-146. Where bond strength specifications exceed 1,000 psf (4,882 kg/m2) it is recommended that independent laboratory test data based upon a modified version of ASTM E736 be submitted to verify specification compliance. Results of the above tests will be made available to all parties at the completion of pre-designated areas which shall have been determined at a pre-job conference.


  • MONOKOTE® Z-146T is slippery when wet. Signs reading “SLIPPERY WHEN WET” should be posted in all areas in contact with wet fireproofing material. Anti-slip surfaces should be used on all working surfaces.
  • SDS (Safety Data Sheet) for MONOKOTE® Z-146T are available on our web site or call toll free at 866-333-3SBM. | North America customer service: 1-877-4AD-MIX (1-877-423-6491)

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.

MONOKOTE® is a trademark, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

© Copyright 2018 GCP Applied Technologies Inc. All rights reserved.

GCP Applied Technologies Inc., 2325 Lakeview Parkway, Suite 450, Alpharetta, GA 30009, USA
GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6.
This document is only current as of the last updated date stated below and is valid only for use in the Canada. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2023-06-29