Nullifire FV125 Large Ventilated Cavity Barrier is a fire rated product designed to act as an external wall cavity barrier at the required locations such as compartment floors, around windows, doors, etc. and within uninsulated cavities requiring permanent (open-state) ventilation, to reinstate fire resistance performance.

In the event of a fire FV125 will expand to close the final gap between its leading edge and the internal face of the cladding. It provides effective fire resistance, for integrity and insulation for up to 180 minutes depending upon the construction of the external walls.

FV125 is designed for use within a designed cavity of up to 450mm cavity, and once installed will close the remaining free air gap (in front of the 4mm thick cavity barrier) of 25mm.

Quick Links - Click To Jump To Section:

   
• Features & Benefits
• Available Sizes and Order References
• Necessary Tools & Preparation
• Application Instructions
• Important Information
• Technical Information
• Maintenance

Features & Benefits

   
• Up to 180 minutes fire resistance tested in accordance with ASFP TGD19 guidance
• Designed for use within a designed cavity of up to 450mm cavity, and once installed will close the remaining free air gap (in front of the 4mm thick cavity barrier) of 25mm
• Maintains a 25mm air gap
• Up to 450mm cavities tested
• Fixing brackets included as standard
• Allows ventilation of cavities reducing the need for cavity trays or weepholes
• Lightweight for easy and quick installations
• No maintenance required after installation
• Available in a wide range of sizes from 35mm to 425mm wide

Available Sizes and Order References

Necessary Tools & Preparation

Necessary Tools

• Masonry drill
• Screwdriver
• Saw/knife for cutting product
• Measuring tape
• Stainless steel fixings suited to the substrate

Preparation

• Ensure the installation area is free from dust, oil and any corrosive material
• Check the mounting substrate is solid and free from damage and degradation before beginning
• Double check for any obstructions, ensure that if there are any that could allow fire to pass vertically, they are fire stopped separately using an approved and applicable Fire Stopping product

Application Instructions

FV125 from 40 mm up to 100 mm wide - NO brackets required and directly faced fixed

• Use stainless steel countersunk head screws, with a maximum head diameter of 11.5mm and with a length suitable for the size of cavity barrier and sufficient fixing depth into the substrate
• Fixings must have an appropriate fixing depth (embedment) into the substrate (with a minimum of 50mm for masonry fixings and minimum 25 mm for timber unless otherwise specified by the fixing manufacturers guidance for their fixing type)
• Ensure that the countersunk screw head does not fully penetrate the face of the cavity barrier, the screw head should sit flush or slightly proud. See figure below
• Care should be taken not to over tighten as this may affect the performance of the intumescent seal
• Position the first screw fixing through the centre line of the face of the cavity barrier at a maximum 125mm from one end, continue to face fix through at maximum 250mm centres (4 screws per linear metre), ensuring that the final fixing is a maximum 125 mm from the opposite end of the cavity barrier. This will ensure that face fixings are positioned at 250mm maximum centres across the continuous run of cavity barrier

NOTES:

• Where sections of cavity barrier are less than 1 linear metre in length, ensure that face fixings are positioned at a maximum 125mm from each end with additional fixing being positioned at maximum 250mm centres between the end fixings
• For cut sections of cavity barrier less than or equal to 250 mm in length a minimum of 2 fixings are required

Bracket Fixing

• FV125 is supplied with 2 or 3 fixing spikes, FO306 Small Steel brackets, dependent on requirement
• The central section is pre-drilled to secure the bracket to the substrate
• Option A, from the image below, will protrude 65mm or Option B will protrude 160mm from the face of the substrate
• If the bracket protrusion is greater than 75% of the product width, the bracket shall be cut down in length
• The bracket should never be less than 50% of the product width

NOTES:

• FV125 above 100mm are required to be mounted on Stainless Steel brackets (FO306 Small Steel Brackets 65mm)
• The number of brackets required is dependent upon the width of the overall cavity

Application Instructions with Brackets

• To secure the bracket use nom. 5mm stainless steel screws/fixings, with a maximum head diameter of 13mm and with a length and type suitable for the substrate. See Performance Data Table
  • Notes:
  • Ensure that the screw head sits as flush as possible with the substrate
  • Fix through both of the fixing holes
  • Fixings must have an appropriate fixing depth for the substrate (with a minimum of 50mm for masonry and minimum 25mm for timber unless otherwise specified by the fixing manufacturers guidance for their fixing type)

• Fix the required number of brackets, per linear metre, to the substrate at maximum 250mm from the end of the cavity barrier, with a maximum spacing between brackets of 500mm
  • Notes:
  • Excluding cavity width 241mm to 425mm which requires 3 brackets
  • Where sections of cavity barrier are less than 1 linear metre in length, ensure that the brackets are positioned at a maximum 250mm from each end. For cut sections of cavity barrier less than or equal to 500mm in length two brackets are required

• Push the cavity barrier onto the bracket spike, the brackets should impale FV125 to mid barrier depth and must not protrude through the intumescent element
• Ensure the cavity barrier should be pushed fully onto the bracket spike and sit flush with the substrate at the rear of the cavity barrier, ensuring that there are  no gaps behind the cavity barrier                                             
• Ensure that the spike does not pierce through the face of the intumescing material

Important Information

• Maximum free air gap for this cavity barrier is 25mm, the space in front of the intumescing strip on the face of the cavity barrier to the rear of the external wall surface
• Ventilated cavity barriers should be installed in a continuous run (with the exception of abutting up to full fill vertical cavity barriers). Where this is not possible, details should be agreed with the project's principal designer and a fire engineer
• Horizontal cavity barriers should be installed adjacent and tightly abutted to any vertical cavity barriers, the vertical cavity barriers should be installed first
• An identification label is attached to the intumescing face of the cavity barrier, ensure this faces out into the open cavity. Also ensure the label is visible and legible and reads the right way up. If the identification label is not legible please contact Technical Support, the label is important in terms of identifying the product in the future, for example during fire risk assessments or fire safety inspections
• Cavity barrier fixing brackets, both Small (FO306 Stainless Steel Brackets) or Large Steel Brackets (FO307 Large Steel Brackets) must not penetrate through the face of the cavity barrier. Screws for direct fixing and fixings to secure brackets are not supplied by Nullifire
• The brackets used to fix the horizontal cavity barrier must be installed with the spike inserted centrally (horizontally) to the rock mineral wool section of the cavity barrier with the bracket fixed above and not below the cavity barrier
• The use of tape is not required over the joints between the lengths of cavity barrier, and if used should not be applied over the face of intumescent material
• The cavity barrier must be installed following the installation methods described above. The cavity barrier must not be penetrated by any other mechanical or electrical services

Technical Information

Maintenance

• No active maintenance required
• Where alterations are made around the product it should be checked visually to ensure that the product is still installed as per the approved original design and fitting instructions at the time of original installation

IMPORTANT FIRE PRODUCTS NOTICE: The information displayed on this website should be used as a guide ONLY and our Technical Department should be contacted to obtain a tailored specification and any advice necessary before you place an order for fire protection products. Fire protection products are non-returnable except in accordance with Condition 8 of the Terms and Conditions and should be applied only by an individual with the necessary expertise and experience. We will not be held liable for any resulting damage to property, human life or monetary costs incurred due to the incorrect specification you have prepared or use of fire protection products caused by your negligence, including your failure to have contacted us to obtain the relevant advice/specification.