Repair Systems — 06
Intumescent joint sealants — passive fire protection
Technical product reference for intumescent and fire-rated joint sealants used in passive fire protection systems for Australian Class 2 strata and commercial buildings. Covers intumescent chemistry, fire rating classifications, FRL requirements, pipe and service penetration sealing, and brand comparisons.
What are intumescent joint sealants?
Intumescent joint sealants are passive fire protection products used to seal service penetrations — pipes, cables, conduits and small ducts — and perimeter gaps through fire-rated walls and floors in Australian Class 2 and commercial buildings. Unlike standard construction sealants, intumescent sealants contain an intumescent agent that expands dramatically when exposed to heat, sealing the void left by a burning or deforming service and maintaining the fire resistance of the assembly. They are assessed against AS 1530.4 and assigned a Fire Resistance Level (FRL) for specific tested assembly combinations.
Selection must be based on the required FRL, the substrate (concrete, masonry, plasterboard, fibre cement), the service type (combustible plastic pipe, metallic pipe, cable bundle, conduit), the annular space dimension, and the depth of fill — all of which must match a tested, certified combination. Intumescent sealants must be installed by qualified passive fire protection contractors and must be certified before occupancy.
Critical note: FRL applies to tested assembly combinations only. No FRL can be assumed, extrapolated or transferred from one assembly configuration to another. Always confirm the current LABC certificate or test report against the exact project conditions before specifying.
Do not confuse with:
- Acoustic sealant — flexible sealant used to control sound transmission through joints and penetrations — does not provide fire resistance
- Standard construction sealant — silicone, polyurethane or polysulfide sealants used for weatherproofing — not fire-rated and must not be used in fire-rated assemblies
- Intumescent strips — solid intumescent material used in door frames and glazing systems — different product form, not a paste sealant
- Intumescent duct collars — mechanical collars used around combustible ductwork penetrations — separate product category from firestop sealant
- Fire-rated caulk (colloquial term) — always confirm whether the product is an independently tested and certified firestop system before use in a fire-rated assembly
Product Reference
3 products — 3 brands — intumescent acrylic firestop sealants — scroll to view all
System Description
TODO: owner confirm — Hilti CP 601S is described in older documentation as an elastomeric (silicone-based, not acrylic) intumescent firestop sealant. However, CP 601S does not appear on the current Hilti Australia sealants product listing (hilti.com.au). The current Hilti Australia firestop sealant range includes CP 611A (intumescent, water-based), CP 606 (acrylic fire caulk) and CFS-SP SIL (silicone joint sealant spray). Confirm with Hilti Australia whether CP 601S is available or whether a current replacement product should be specified before using this card.
Technical Properties
- TODO: owner confirm — CP 601S not found on current Hilti Australia product listing — verify availability
- Described in international documentation as elastomeric (silicone-based) intumescent sealant — not acrylic
- FRL ratings available for tested combinations only — confirm from current Hilti LABC
Limitations
- TODO: owner confirm — product availability on Hilti Australia site not confirmed — may be discontinued or renamed
- FRL only applies to tested substrate/penetration combinations — never extrapolate
- Must be installed by qualified passive fire protection contractor
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Description
3M Fire Barrier Sealant CP 25WB+ is a water-based intumescent acrylic sealant used for sealing pipe, cable and conduit penetrations and perimeter gaps in fire-rated wall and floor assemblies. It is one of the most widely specified intumescent sealants in Australian Class 2 and commercial building passive fire protection work. FRL ratings apply to tested assemblies only; confirm from 3M LABC certification or Warnock Hersey listing before specifying. Installation must be by a qualified passive fire protection contractor.
Technical Properties
- Water-based — easy cleanup before cure
- Expands under fire to seal penetrations and gaps
- Suitable for penetrations and perimeter joints in fire-rated assemblies
Limitations
- FRL only valid for tested assembly — never substitute substrates or services without re-testing
- Not paintable after cure (unlike CP 601S)
- Requires correct depth of fill
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Description
Bostik Fireban One is a fire-rated intumescent one-component polyurethane sealant, Australian manufactured, used for sealing linear joints in fire-rated concrete, masonry, plasterboard and fibre cement wall and floor assemblies in Class 2 and commercial buildings. Fire resistance up to 4 hours. Joint movement capability ±25% of original width. Paintable to match surrounding surfaces after cure. Tested to AS 1530.4. Note: Bostik Fireban One is designed for linear joint sealing, not primarily for pipe/cable penetrations — for pipe and cable penetrations through fire-rated elements, confirm the correct Bostik product and tested assembly with Bostik Australia before specifying.
Technical Properties
- Intumescent polyurethane — one-component — Australian manufactured
- Fire resistance up to 4 hours — joint movement capability ±25% — AS 1530.4 tested
- Paintable after cure — suitable for colour-matched joint sealing in visible locations
Limitations
- FRL valid for tested combinations only — confirm LABC or test report for exact assembly before specifying
- Primarily for linear joint sealing — confirm suitability for pipe/cable penetrations separately
- Qualified passive fire installer required for installation in fire-rated elements
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Brand Equivalents by Application
Intumescent firestop sealant product equivalents by application type across the three brands listed. Confirm tested assembly with current LABC or certification before specifying.
| Application | Hilti | 3M | Bostik |
|---|---|---|---|
| Pipe penetrations | CP 601S (TODO: confirm AU avail.) | CP 25WB+ | Confirm with Bostik AU |
| Cable penetrations | CP 601S (TODO: confirm AU avail.) | CP 25WB+ | Confirm with Bostik AU |
| Perimeter/linear joints | — | CP 25WB+ | Fireban One |
| Paintable after cure | TODO: confirm | — | Fireban One |
System Comparison
Side-by-side property comparison for the three intumescent firestop sealants listed on this page.
| Property | Hilti CP 601S (TODO: confirm) | 3M CP 25WB+ | Bostik Fireban One |
|---|---|---|---|
| Type | Intumescent elastomeric (silicone-based) | Intumescent acrylic | Intumescent PU |
| Water-based | No (solvent/silicone-based) | Yes | No (1C PU) |
| Paintable | Yes (historical) | — | Yes |
| Linear joint use | — | Yes | Yes (primary use) |
| Pipe penetration | Yes (confirm AU avail.) | Yes | Confirm with Bostik AU |
| Cable penetration | Yes (confirm AU avail.) | Yes | Confirm with Bostik AU |
| AS 1530.4 tested | Confirm current LABC | Yes | Yes |
| AU product status | TODO: confirm availability | Current | Current (Fireban One) |
Critical — FRL Applies to Tested Assemblies Only
- FRL is not a property of the sealant product — it is a property of the tested assembly combination, which includes the substrate, service type, annular space, depth of fill and the specific sealant product used in the test
- Never assume or extrapolate FRL from a different assembly — a different pipe material, a different wall substrate, a different annular space or a different depth of fill will invalidate the tested FRL
- Always confirm the LABC certificate or Warnock Hersey test report before specifying — the current certificate must list the exact assembly configuration used in the project
- Intumescent firestop sealants must be installed by a qualified passive fire protection contractor — unqualified installation is not compliant under NCC Section C regardless of product used
- Do not paint over intumescent sealant unless the product is confirmed as paintable and painting does not compromise the intumescent expansion performance
Disclaimer
This page provides general technical information only. Intumescent and fire-rated joint sealant selection MUST be confirmed against the FRL requirement, substrate, service type, NCC Section C fire provisions, AS 1530.4 test evidence, and the certifier's passive fire protection schedule. Do not install or specify fire-rated sealant without confirming the approved system against the required FRL.