Flamex XT - Fire Rated Elastomeric Joint Sealant

Product Overview

Flamex XT is a high-performance fire and acoustic rated elastomeric joint sealant based on Silyl Modified Polymers. It combines the weathering and adhesion performance of a silicone sealant with the toughness and stain-free properties of a polyurethane sealant. The product is supplied in 600ml sausages and is designed for use in fire and acoustic rated construction applications.

Key Features & Advantages

Fire & Acoustic Performance

• Fire rated for up to 4 hours in properly configured joints
• Meets BCA requirements for fire and acoustic sealing
• Acoustic rating up to 50Rw(CT;CTR), providing sound insulation performance
• Tested and certified to AS1530.4-2014 and AS1530.3-1999 standards

Application Benefits

• 40% joint movement capability (±20%), accommodating structural movement
• Outstanding weathering and UV resistance, maintaining colour and integrity in external applications
• Excellent primerless adhesion to concrete, timber, masonry, aluminium, metals, and ceramics
• Will not stain masonry or other surfaces during or after application
• Blister-free cure in high humidity or on damp surfaces
• Easy to extrude even at low temperatures
• Low odour and very low VOC at 13g/litre

Safety & Environmental Properties

• Contains no isocyanate in its formulation
• Halogen free, meeting safety and environmental standards

Technical Specifications

Physical Properties

Fire Resistance Test Results (AS1530.4:2014)

The following table summarizes fire performance in concrete wall panel joints (180mm thick):

*denotes "no failure" at 243 minutes when the test was terminated

Fire Test Compliance

• Ignitability Indices: 16
• Spread of Flame Index: 0
• Heat Evolved Index: 1
• Smoke Developed Index: 0-1

Application Areas

Flamex XT is suitable for:

• External and internal non-trafficable control joints in concrete, masonry, AAC, and brick fire-rated construction
• Acoustic sealing between common building materials including concrete, masonry, AAC, plasterboard, fibre cement, metals, and timber
• Building facades and high-performance construction applications

Design Criteria

For fire-rated joints, Flamex XT should be applied in joints:

• Width: 20mm to 40mm
• Minimum depth: 10mm or half the width for joints wider than 20mm
• Backing rod: Required to control sealant depth and prevent contact with joint backs

Surface Preparation

Required Steps

• Joint surfaces must be clean, dry, and free from frost
• Remove all dirt, laitance, loose materials, and foreign matter
• Remove all rust, scale, and protective lacquers from metal surfaces
• Degrease non-porous surfaces using Fosroc Solvent 10
• Bond breaker required: Use self-adhesive polyethylene tape for shallow joints or backing strips like Expandafoam for deep joints

Priming Requirements

No primer required - Excellent adhesion achieved on concrete, timber, metals, ceramics, brickwork, and most coating surfaces without primers.

Application Instructions

Gun Loading & Application

• Apply using a suitable sausage gun
• Insert sausage, cut slit at top, replace end cap and nozzle
• Extrude firmly into joint to ensure complete contact with joint faces
• Tool the sealant into the joint to achieve smooth finish

Tooling

• Flamex XT is easily tooled without soapy water or tooling aids
• If tooling aids are used, apply only after initial tooling to prevent joint face contamination

Cleaning

• Clean tools immediately after use with alcohol-based solvent

Paintability

• Paintable with water-based paints typically after thick skin development
• Painting can be done as soon as sealant skins but risk of damage exists
• Best results: Paint within 7 days of application
• For solvent-based paints: Prime surface with water-based paint first
• Ensure applied coatings have sufficient flexibility to accommodate joint movement

Storage & Shelf Life

• Shelf life: 12 months when kept in original, unopened packaging
• Storage conditions: Dry conditions between +10°C and 25°C with 55% relative humidity
• Store away from direct sunlight and moisture

Supply Information

• Product Code: FC920045-600ML (Concrete Grey)
• Pack Size: 600ml sausages in cartons of 12
• Coverage: One 600ml sausage supplies approximately 3 metres of 20mm x 10mm sealant bead

Limitations

• Not suitable for permanent immersion or below water line use
• Do not apply to wet surfaces

References

• [1] Fosroc_Flamex_XT_TDS.pdf