GIB Fire Rated Systems: reading FRR the right way

GIB Fire Rated Systems (CBI 5113) are tested wall and ceiling build-ups that deliver a set Fire Resistance Rating, written as three numbers — and the rating only holds if you fix and seal them exactly as tested.

Quote a job free Browse the code guide

GIB® Fire Rated Systems (CBI 5113) are wall and ceiling systems tested to AS 1530.4 so a specified build-up carries a known fire rating. For a builder, this is the detail that keeps a fire wall, intertenancy wall or boundary wall doing its job — get the sheet, the fixings or the penetrations wrong and the rating you signed up for is gone.

How to read the FRR

The Fire Resistance Rating is written as three numbers separated by slashes — -/-/- — each a time in minutes:

Structural Adequacy – how long the element keeps carrying load.
Integrity – how long it stops flames and hot gases passing through.
Insulation – how long it keeps the unexposed face cool enough.

A dash means that criterion isn’t rated for that system — for example a non-load-bearing wall carries no structural number, so it reads -/60/60 rather than 60/60/60.

Timber-framed wall systems

These are the tested timber-framed build-ups. NLB means non-load-bearing, LB means load-bearing, and STC is the sound rating that comes with the system:

GBT 15 NLB — -/15/15, STC 36: 1× 10mm Standard each side.
GBT 30a NLB — -/30/30, STC 36: 1× 10mm Fyreline each side.
GBT 60a NLB — -/60/60, STC 36: 1× 13mm Fyreline each side (27 kg/m²).
GBTL 60b LB — 60/60/60, STC 42: 2× 10mm Fyreline each side (39 kg/m²), load-bearing.
GBT 90 — -/90/90, STC 37: 1× 16mm Fyreline each side (36 kg/m²).
GBT 120a NLB — -/120/120, STC 43: 2× 13mm Fyreline each side (47 kg/m²).

Fixing & framing

The tested rating relies on the framing and fastening being set out as specified:

Fix with 41×6g GIB Grabber HighThread screws at 300mm centres.
Screw 12mm in from a bound edge, 18mm in from a cut edge.
Stud spacing 600mm maximum.
Nogs at 1200mm maximum where sheets are fixed horizontally.

Penetrations — where ratings get voided

Anything passing through a fire wall has to be treated so the FRR is maintained:

Pipes, cables and ducts through a fire wall must be sleeved and sealed with an intumescent product (for example Hilti CP 606, Promat) that maintains the FRR.
Untreated penetrations void the rating — the wall no longer performs to the tested number.

Plain-English guide, not advice. This page helps you understand and navigate the rules — it is general information, not design, engineering or consent advice, and it does not reproduce the copyrighted tables of NZS 3604 or any Standard. Always check the current Standard or Acceptable Solution and your BCA, and use a suitably qualified LBP, engineer or QS where it matters.

Do it in Toolie

Put this into practice with the GIB calculator · the builder calculators. Try Toolie free — no signup — or open this topic in the Toolie app.

Common questions

What does an FRR like -/60/60 actually mean?

It’s the Fire Resistance Rating in minutes, written as Structural Adequacy / Integrity / Insulation. A dash means that criterion isn’t rated for the system, so -/60/60 is a non-load-bearing wall that gives 60 minutes of integrity and 60 minutes of insulation with no structural rating.

What’s the difference between GBT and GBTL systems?

In these tested timber-framed systems, GBT covers non-load-bearing walls (for example GBT 60a NLB at -/60/60) while GBTL denotes a load-bearing wall — GBTL 60b LB is rated 60/60/60 and carries a structural number because it’s load-bearing.

How do I fix GIB Fire Rated linings so the rating holds?

Use 41×6g GIB Grabber HighThread screws at 300mm centres, 12mm in from bound edges and 18mm in from cut edges, with studs at 600mm maximum and nogs at 1200mm maximum where sheets are fixed horizontally.

Do penetrations affect the fire rating?

Yes. Pipes, cables and ducts through a fire wall must be sleeved and sealed with an intumescent product (such as Hilti CP 606 or Promat) that maintains the FRR. Untreated penetrations void the rating.

More in Linings & GIB

All Linings & GIB topics → · Full NZ Building Code index

Quote it, comply, get paid — in one app

Toolie turns this knowledge into the job: NZS 3604 take-off, H1 & Healthy Homes, consents, retentions and invoicing — one flat NZD price.

Quote a job free →