Every plastic pipe that passes through a fire-rated slab or wall leaves a hole that a fire can travel through once the pipe melts. A fire collar closes that hole: an intumescent strip inside a steel casing swells when heated and crushes the softening pipe shut. The Allproof Low Profile Fire Collar is one of the most-ordered drainage lines we sell, and most questions about it come down to three things: which size, which casing, and whether the install will match what was tested.
What the low profile collar is
Allproof's low profile collar is an intumescent strip encased in a galvanised or stainless steel casing with fixing tabs. Across the 25mm to 80mm sizes the collar is only 27mm high, which matters when it's fixed to the underside of a slab in a tight ceiling void or behind a plasterboard lining. Allproof lists it as tested on a range of plastic plumbing, air-conditioning and electrical services penetrating concrete walls and floors, composite floors and plasterboard walls, to AS 1530.4 (fire-resistance tests) and AS 4072.1 (protection of service penetrations), at accredited fire laboratories.
Two install methods are described on the listing:
- Slabs: face-fixed to the underside of the floor, which is the normal setup for stacks and floor waste drops.
- Plasterboard walls: face-fixed or inverted, following Allproof's fire manuals.
Sizes and prices
The galvanised range runs from 25mm to 150mm. The stainless range starts at 40mm and goes up to 250mm, so a 25mm collar is galvanised only and anything above 150mm is stainless only.
| Size | Galvanised | Stainless steel |
|---|---|---|
| 25mm | $11.99 (ALLFC25GALV) | — |
| 40mm | $13.99 (ALLFC40GALV) | $18.36 (ALLFC40SS) |
| 50mm | $20.99 (ALLFC50GALV) | $28.42 (ALLFC50SS) |
| 65mm | $22.99 (ALLFC65GALV) | $28.79 (ALLFC65SS) |
| 80mm | $25.99 (ALLFC80GALV) | $35.58 (ALLFC80SS) |
| 100mm | $40.99 (ALLFC100GALV) | $49.30 (ALLFC100SS) |
| 150mm | $68.99 (ALLFC150GALV) | $87.10 (ALLFC150SS) |
| 250mm | — | $416.00 (ALLFC250SS) |
Prices as listed at the time of writing. Collar sizes refer to the nominal pipe size, so a 100mm collar goes on a DN100 stack and a 50mm collar on a DN50 waste. Check the pipe material and size against the tested combinations in Allproof's fire manual before ordering, rather than assuming the nominal size alone settles it.
Galvanised or stainless?
Both casings carry the same intumescent strip and do the same job in a fire. The choice is about what the collar lives in for the next few decades:
- Galvanised is the default for dry, internal ceiling voids and wall cavities. It's the cheaper option at every size, roughly 17–27% less than stainless in the common 50–100mm sizes.
- Stainless steel earns its premium where the underside of the slab is damp or exposed: basement car parks, plant rooms, coastal buildings, commercial kitchens below wet areas, and anywhere a rusting casing would be a defect someone has to explain later. It's also the only option above 150mm.
On a typical apartment floor with a DN100 stack and a few DN50 wastes, the difference between the two is a few dollars per penetration, so if the space is borderline, stainless is cheap insurance.
The part that actually decides compliance: matching the tested system
A fire collar doesn't carry a fire rating on its own. The fire resistance level (FRL) belongs to a tested system: that collar, on that pipe material and size, through that substrate and thickness, installed and fixed the way it was in the test. Change one variable — a different pipe type, a thinner wall, a collar fixed on the wrong face — and the install may no longer be covered by the test evidence.
Before the ceiling goes up, check:
- Pipe material and size are a combination listed in Allproof's fire manual for this collar.
- Substrate (concrete slab, composite floor, plasterboard wall) and its thickness match the tested setup.
- Orientation and fixing follow the manual: underside of the slab for floor penetrations; face-fixed or inverted for plasterboard walls as shown.
- The FRL you need is covered by the test data for that combination. The required FRL comes from the building's fire design, not from the collar.
- Labelling and records meet whatever your certifier or fire engineer asks for at sign-off.
If any of these don't line up, talk to the fire engineer or certifier before installing. Fixing a non-conforming penetration after the ceiling is sheeted is far more expensive than getting it right on rough-in.
Where collars fit with the rest of the drainage
Most collars we sell go on stacks and floor waste drops through suspended slabs, so they're usually ordered alongside the floor wastes on the same job. For grade selection on those, see 304 vs 316 stainless floor wastes. If you're testing the stack before the collar and ceiling go on, our guide to test plugs and drain protection covers the testing side.
Frequently Asked Questions
Does every pipe through a slab need a fire collar?
Penetrations through fire-rated elements need protecting to keep the element's fire resistance, and for plastic pipe that is commonly a collar. Which elements are fire-rated, and the FRL required, comes from the building's fire design, so confirm with the certifier or fire engineer on the project.
Should I choose galvanised or stainless steel?
Galvanised suits dry internal voids and is the cheaper option. Choose stainless where the underside of the slab is damp, exposed or corrosive, such as car parks, plant rooms and coastal buildings. Stainless is also the only option at 250mm, and galvanised the only option at 25mm.
How tall is the low profile collar?
Allproof lists the 25mm to 80mm sizes at 27mm high, which helps where the collar sits in a shallow ceiling void.
Can I use it on copper or other metal pipe?
The listing describes testing on plastic plumbing, air-conditioning and electrical services. For any other pipe type, check Allproof's fire manual for a tested combination before using it.