This is a critical question for any installer or specifier working with fire-rated doorsets.
Both mastic and PEF backing rod are required components of a compliant fire doorset system. Without using the right tested products, you may jeopardize compliance and put lives at risk.
The short answer:
You must use the specific materials that the fire doorset has been tested with.
We’ll break it down into two parts: mastic, then PEF backing rod.
Mastic: Only Use Infernoguard Mastic for Soteria Fire Doors
All Soteria fire doorsets have been tested and certified with Infernoguard Mastic — a fire-rated mastic provided in 600ml foil sausages that can be applied with a standard caulking gun.
Key facts:
-
Supplied through: Soteria Doors
-
Pack size: Box of 12 foils
-
Recommended usage:
-
3 foils per single door
-
4 foils per double door
-
-
🔧 Installation method: Apply with a caulking gun
The amount required will vary depending on onsite wedging gaps. Adjust based on actual gap sizes.
Warning:
Using anything other than Infernoguard Mastic puts compliance at risk and may result in a system that doesn’t meet fire standards.
Always refer to the installation instructions before starting your install to confirm you’re using the correct mastic.
PEF Backing Rod: Correct Diameter = Correct Seal
PEF (Polyethylene Foam) backing rod is also part of the tested system for Soteria fire doorsets. It helps control the depth of the mastic joint and ensures a tight seal within acceptable tolerances.
Product details:
-
Supplied through: Soteria Doors and most hardware stores
-
Available roll lengths: 20m, 50m, or 250m
-
Diameter: Depends on wedging gap size
Under NZS4520:2010, wedging gaps must not exceed 10mm. Selecting the right PEF diameter is essential to remain within this limit.
Important:
Using the wrong size — or an untested backing rod — can lead to failed inspections and unsafe doorsets.
Why This Matters: Tested Systems Save Lives
Soteria fire doorsets are tested as a system, which means compliance is only assured if you use the exact materials used in the original fire testing.
That includes:
-
Infernoguard Mastic
-
Approved PEF backing rod
Risks of using untested components:
-
Non-compliance with NZS4520:2010
-
Increased liability
-
Voided warranties
-
Potentially life-threatening failure in a fire event
Next time you begin an install, ask yourself:
“Am I using the tested and approved components for this doorset?”
The answer could be the difference between passing inspection — or putting people at risk.
Learn more regarding installation with our related articles:
Do I need a certified installer to install my fire door in New Zealand?
What could go wrong if I install my fire doors into a wall system that hasn’t been tested?
What Is Fire Door Compliance in New Zealand? Step-by-Step Guide