The 70mm Steel Firebreak Supplementary Washer is designed for use with MLN metal firebreak fixings in external wall insulation (EWI/ETICS) systems. Manufactured from zinc-coated steel and classified as A1 non-combustible, this washer provides additional bearing surface and pull-through resistance when installing mineral wool insulation. The 70 mm plate enhances fixing stability in high-load and firebreak zones and is suitable for use on a range of solid substrates.

Suitable Insulation Boards

Compatible Substrates (ETA Categories A, B, D & E)

If the substrate condition is uncertain, carry out a pull-out test to confirm suitability.

Key Features

• A1 fire-class steel plate suitable for firebreak areas in mineral wool systems.
• 70 mm diameter for increased load distribution and pull-through resistance.
• Compatible with MLN metal lamella firebreak fixings.
• Ideal for mid- and high-rise fire-rated façades.
• Zinc-coated steel for durability and long-term corrosion resistance.
• Quick installation — no expansion pin required (used in conjunction with MLN fixing).

Sizes & Box Quantities

Designed specifically for use with MLN firebreak fixings for mineral wool systems.

Application

Preparation

• Ensure substrate and insulation layout comply with project firebreak design.
• Confirm mineral wool lamella or slab boards are correctly positioned and adhered.
• Check MLN fixing length suits insulation thickness and embedment requirements.

Installation steps

1. Position insulation boards tightly together with staggered joints.
2. Place the 70 mm supplementary washer over the fixing point.
3. Insert the MLN metal fixing through the washer and insulation.
4. Hammer the pin until the washer sits flush without deforming the insulation face.
5. Continue in accordance with fire break layout and system engineer guidance.

Fixing pattern & density

• Follow project-specific firebreak and fixing density design.
• As a guide for mineral wool lamella zones:
  • Up to 15 m height: 8 pcs/m² typical field, 10 pcs/m² in corner zones.
  • Above 15 m height: 10 pcs/m² typical field, 12 pcs/m² in corner zones.

Quality checks

• Verify washers sit flush and evenly distribute load.
• Check random pull-out tests where substrate varies.
• Replace and re-install if washer lifts or fixing spins.