Tunnel Application

Quick Resources

Bored Tunnel

Immersed Tube

The animations contained herein are not intended to replace a thorough understanding of Isolatek application guidelines. For further information on all application methods contact Isolatek International or one of our business partners.

Bored Tunnels

Bored tunnels are constructed using Tunnel Boring Machines (TBM’s) that cut through strata using a circular cutting head, removing the excavated material behind it. The TBM then places pre-cast, high strength concrete segments in a circular “ring” to form a primary tunnel lining. In these types of tunnels, the CAFCO® FENDOLITE® M-II / ISOLATEK® Type M-II system is applied to the tunnel segments to prevent spalling under fire exposure conditions.

Cut & Cover Tunnels

Cut and Cover tunnels are constructed using a number of established techniques including:

  • Conventional construction methods
  • Bottom-up construction
  • Top-Down construction
  • Cast-in-Place construction

In these types of tunnels, the CAFCO® FENDOLITE® M-II / ISOLATEK® Type M-II system is normally applied to the tunnel soffits and partially down the supporting walls in order to prevent collapse of the structure under fire exposure conditions.

Immersed Tunnels

Immersed Tube Tunnels are constructed by casting tunnel elements in dry-docks and floating them to their final location. The elements are then sunk into pre-formed trenches on the sea bed and connected to each other. The immersion joints between the elements are sealed using “Gina” and “Omega” gaskets that are a critical part of the construction. In these types of tunnels, the CAFCO® FENDOLITE® M-II / ISOLATEK® Type M-II system is applied to the soffits and external walls and partially down the internal supporting walls to prevent collapse of the structure under fire exposure conditions. Specific solutions, based on the CAFCO FENDOLITE M-II / ISOLATEK Type M-II system can also be developed for the fire protection of the immersion joints.

In order to obtain optimal results, the following spray equipment setup for CAFCO® FENDOLITE® M-II / ISOLATEK® Type M-II on Industrial, Chemical and Petrochemical processing sites is required:

  • A rotor stator type, open throat, screw feed pump with minimum “No. 4” soft rubber stators.
  • Compressed air is required and must be delivered to the spray nozzle at a minimum volume of 15 cfm
    (420 L/min) and a minimum pressure of 50 psi (3.51 kg/cm²).
  • A paddle or ribbon-type mortar mixer with a safety cover, rubber tipped blades and provision for quick dumping of mix directly into the pump hopper is recommended. Mixers with an 8 cu. ft. (227 liters) capacity or larger, capable of operating speeds of 35 to 40 RPM.
  • Screw-on type quick connect/disconnect couplings that do not restrict product flow are required
  • The spray nozzle assembly must consist of a minimum 1 in. (25 mm) ID aluminum pole with a blow-off type nozzle cap, a nozzle orifice and valves for product and air control. Nozzle orifice must be nominal 1/2 in. diameter (13 mm).

CAFCO FENDOLITE TG / ISOLATEK Type TG is mixed and then hand applied using common masonry tools.

Galvanized Mesh

Plastic Coated Galvanized Hexagonal Mesh.

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Stainless Steel Mesh

Grade 316 Stainless steel welded wire mesh.

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Stainless Steel Anchors

Grade 316. Stainless steel mesh reinforcement pins.

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Sprayer Equipment

Rotor stator type with open throat and screw feed.

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Nozzles/ Guns

Minimum 1” ID aluminum pole to provide minimum volume of 420 L / min (15 cfm).

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Hoses/ Couplings/ Reducers

High pressure grout hose for plaster, grout and cement applications. Screw-on type quick connect/disconnect couplings which do not restrict product flow reducers.

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Careful preparation of substrates is important. Correct preparation ensures that the durability of the fire protection system is maintained and the required level of adhesion is achieved. Poorly prepared substrates will compromise the long term protection to the structure. It is required that the substrates are prepared in accordance with Isolatek International’s written application instructions.

The substrate to be protected with the CAFCO® FENDOLITE® M-II / ISOLATEK® Type M-II system must be prepared such that it is free from dirt, dust, oil, curing compounds, mold release agents or other contamination that would impair the adhesion of CAFCO FENDOLITE M-II / ISOLATEK Type M-II system. For heavily contaminated substrates, this may be accomplished by pressure washing the entire concrete surface with a minimum 3000 psi pressure washer.

For direct application to concrete surfaces, a CAFCO FENDOLITE M-II / ISOLATEK Type M-II / ISOLATEK SBR keycoat is applied to increase the surface area to be protected by CAFCO FENDOLITE M-II / ISOLATEK Type M-II. The specified method of mesh retention (i.e. plastic coated galvanized or stainless steel profile mesh) may then be installed prior to the application of CAFCO FENDOLITE M-II / ISOLATEK Type M-II.

For applications onto metal lath substrates, concrete surface cleaning and the application of an SBR keycoat is not normally required.

Refer to our Application Techniques section for more details regarding the step by step processes used.

Inspection and Repair Procedures of the CAFCO® FENDOLITE® M-II / ISOLATEK® Type M-II and CAFCO FENDOLITE TG / ISOLATEK Type TG System for Tunnel Applications – Short Form

Routine annual inspections may be carried out on the Spray-Applied Fire Resistive Materials (SFRMs) to ensure that the product will continue to perform its intended function.

Tunnel walls may be subjected to vehicle impact. As a result, any damage to the fire protection system can be easily repaired in accordance with Isolatek International’s application instructions.

An annual inspection program is recommended to ensure that the integrity of a completely installed fireproofing system is maintained.

This inspection survey must be conducted by qualified QA/QC personnel with knowledge of the fireproofing system, and recommended and approved by Isolatek International.

The procedures outlined below are intended as a guide for conducting your inspection program. The QA/QC personnel will need a complete copy of the as-built drawings of the system for mark up, along with access to the site. The inspection report and drawings are to remain with the owner and/or owner’s rep upon completion of survey.

Download Maintenance and Repair Procedures PDF


1.1 The QA/QC personnel will inspect and record on the drawings all areas of concern including but not limited to locations where:
  1. Fireproofing system is damaged
  2. Retention system is damaged
  3. Previous repaired areas
  4. Delamination areas
  5. Cracking
  6. Mildew
  7. Chemical stain/damage areas
  8. Wet areas
  9. Top coat/sealer failure
  10. Damaged joints and seals
1.2 The QA/QC personnel shall submit to the owner and/or owners representative all of the drawings with the mark ups, along with a written procedure to complete all of the necessary repairs of the fireproofing system in accordance with Isolatek International’s guidelines.


2.1 QA/QC personnel must ascertain which observed items require attention within the current maintenance cycle, based on one or
both of the following criteria:
  1. A repair (i.e. fissure or crack) which may allow moisture and chemical ingress / accumulation behind the fireproofing material.
  2. Aesthetic appeal.


3.1 Termination Seal Delamination and/or Cracking.
  1. Strip away the old damaged joint seals to reveal the original surfaces. The seals must be reinstated in accordance with the original specifications.
3.2 Topcoat Damage
  1. Remove all peeling topcoat by following the SSPC-SP 2 (hand tool cleaning) specification.
  2. Ensure surface is free from dust and other contaminants.
  3. Re-apply topcoat in accordance with original specifications.
3.3 Repair of the fire protection system
  1. Remove existing/damaged material.
  2. Reinstate all damaged components in accordance with the original specification.
  3. Pre-wet the existing CAFCO FENDOLITE / ISOLATEK Type fireproofing material.
  4. Apply CAFCO FENDOLITE M-II or TG / ISOLATEK Type M-II or TG into the repair area, taking care to push the material behind the reinforcement and completely filling any voids.
  5. Wait approximately 7 to 10 days before re-applying the approved topcoat (if necessary).

Should you have further questions pertaining to this matter, please contact the Isolatek International Technical Service Department at 800.631.9600, extension 269.

Quality Control Test Data Report (Form # C01A)

In order to provide a method for our customers to monitor and maintain product quality during installation, we have developed the Quality Control Test Data Report (Form # C01A). This method provides a record of quality data as the product is installed and allows means to address non-conformities. At the end of the project there is a record that the product and the installation have met all performance standards. This minimizes future risk and gives applicators, engineers and architects the highest degree of confidence in their fire resistive system.

View Quality Control Test Data Report PDF

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Quality Risk Assessment

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ISOLATEK INTERNATIONAL provides passive fireproofing materials under the CAFCO® and FENDOLITE® trademarks throughout the Americas and under the ISOLATEK® trademark throughout the world.

Isolatek International
41 Furnace Street
Stanhope, NJ 07874
800-631-9600 | 973-347-1200

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