FIREFLY Intubatt Concrete Protection System for New Build and Retrofit Applications

Concrete is well known for its high compressive strength. When reinforced with steel, structural members such as load-bearing floors, columns, beams, and walls with high resistance to deflection are created. However, when it comes to fire resistance, maintaining adequate structural performance during a fire almost doubles the thickness of concrete needed, compared to concrete structures that are not exposed to fire.

The Patent Pending FIREFLY™ Intubatt® Concrete Protection System enables structural engineers to design fire-resistant concrete structures with 40% reduction in concrete and maintain structural adequacy under fire due to its superior insulation at high temperatures.

The Fire Resistance Level (FRL), or Fire Resistance Period (FRP) for concrete is defined by 3 criteria when subject to a standard fire endurance test:

• Structural Adequacy- the duration that the element will resist collapse
• Integrity- the duration that the element will prevent the passage of fire from one side to the other
• Insulation- the resistance to heat transfer from the fire-exposed side of the element to the unexposed side.

Table 1 compares the slab thickness requirements for a range of AS1530.4 fire exposure durations, and additionally describes the depth of concrete required to protect the embedded steel reinforcing (axis distance).

Table 1 - Fire Resistance Periods (FRP) for insulation and structural adequacy-

Adapted from AS3600 (2018), tables 5.5.1 & 5.5.2(a)

Reduction of concrete thickness- Using FIREFLY Intubatt System.

The FIREFLY Intubatt is a lightweight, 50 mm thick, highly insulative mineral fibre board made from basalt rock, with an endothermic & ablative coating on each side. It is typically used to fire-stop large holes in floors and walls (with or without service penetrations), as well as linear gap seals.

This innovative and lightweight system has been recently tested to AS1530.4 (2014), using a 120 mm thick concrete slab protected with the 50 mm lining of TBA Firefly Inubatt, and subjected to 4 hours of the AS1530.4 (2014) fire endurance curve- which reaches 1133 ° C at 240 minutes. At the same time, the slab was point-loaded with 2400 kg and the deflection and temperatures were measured at critical locations.

Figure 1- Cross section / Arrangement of 120 mm thick reinforced concrete floor slab with 50 mm thick FIREFLY Intubatt fastened to the underside (exposed side).

The test data demonstrates that 50 mm FIREFLY Intubatt installed on the underside only of floors, or both sides of walls can:

• Upgrade 100 mm concrete steel reinforced elements to provide 240/240/240.
• provides the equivalent insulation as 145 mm of concrete for 4 hours FRP.

Benefits for Building Designers

• Potential Retrofit for "change of use". For example, where occupancy type for a building is changed requiring a greater FRL of floors and walls.
• Lighter structures for new build- 40% reduction in concrete mass to achieve equivalent fire resistance incorporating FIREFLY Intubatt protection.
• Thinner floors, saving up to 100 mm per floor where an unprotected 250 mm floor slab is required.

Please contact FIREFLY for a copy of the Intubatt Concrete Protection System Laboratory Report and Technical data.