What are the two approaches for fire protecting a services riser in Australia?

There are two approaches under the NCC. Floor-to-floor separation seals every service where it passes through each floor slab, so the riser walls do not need a fire rating. A fire-rated riser shaft encloses services in walls with the required FRL, allowing services to pass through floor slabs inside the shaft without individual seals at each level. Services exiting the shaft through walls still need tested seals in both approaches.

What does AS 4072.1 require for fire stopping in services risers?

AS 4072.1-2005 requires that fire stopping systems be tested as a complete assembly to AS 1530.4. The penetration seal must achieve the same FRL as the wall or slab it passes through, for integrity and insulation (expressed as -/YY/ZZ). The specific combination of pipe type, wall type, gap size, and sealant must match the tested configuration exactly.

What NCC clauses cover service penetrations through fire-rated elements?

NCC 2025 C4D15 is the primary clause for service penetrations through fire-rated elements. It requires penetration seals tested to AS 4072.1 and AS 1530.4. Specification 13 covers specific service types including metal pipes (S13C3), cables (S13C5), electrical outlets (S13C6), and fire-stopping materials (S13C7). Part C3 covers compartmentation requirements for shafts.

What is the most common passive fire protection defect in multi-storey buildings?

According to Victorian Building Authority research, service penetrations through fire-rated walls are the most common passive fire defect. The main causes are late-stage penetrations by trades after fire stopping is done, knowledge gaps among practitioners, poor trade coordination, and missing documentation. Building certifiers will not issue an occupation certificate without compliant penetration seals.

Passive Fire Protection for Services Risers

Section 1

What You Need to Know

Services risers carry pipes, cables, and ducts between floors. Without fire stopping, they become chimneys that spread fire and smoke through the building. The NCC (National Construction Code) requires every penetration through a fire-rated wall or floor to maintain its fire rating. This memo covers the two riser design approaches, the fire stopping rules, and the defects that hold up occupation certificates.

Section 2

The Rules

A non-loadbearing shaft for pipes, ventilation, or services must be of non-combustible construction in Type A and Type B buildings (NCC 2025 C3D11)
Every service penetration through a fire-rated element must maintain the element's FRL (Fire Resistance Level) for integrity and insulation (NCC 2025 C4D15)
Fire stopping systems must be tested as a complete assembly to AS 4072.1 and AS 1530.4, matching the exact service type, pipe size, gap size, and wall type (NCC 2025 C4D15)
Fire-stopping material in hollow construction must be packed to 25 mm thickness around the service for the full length of the penetration (NCC 2025 S13C7)
Metal pipes need 100 mm clearance from combustible materials for 2 m either side of the penetration (NCC 2025 S13C3)
Access panels to fire-rated shafts in Type A buildings need a minimum FRL of –/60/30 (NCC 2025 C4D14)
Electrical outlets on opposite sides of a fire-rated wall must be offset by at least 300 mm horizontally or 600 mm vertically (NCC 2025 S13C6)

Section 3

What This Means in Practice

There are two ways to handle fire protection in a services riser. The first is floor-to-floor separation: seal every pipe, cable, and duct where it passes through each floor slab. The riser walls do not need a fire rating. This suits risers with fewer services and keeps costs down because you avoid fire doors and rated access panels.

The second approach is a fire-rated riser shaft. The shaft walls carry the fire rating, so services can pass through floor slabs inside the shaft without individual seals at each level. But every service that exits the shaft through a wall still needs a tested seal. This approach suits buildings with large numbers of grouped services. It also means fire doors and rated access panels at every level.

In practice, the biggest problem is late-stage penetrations. A data or electrical contractor drills through a fire-rated wall after the fire stopping is done. Nobody re-seals it. That single hole can void the fire rating of the wall. The Victorian Building Authority found that service penetrations through fire-rated walls are the most common passive fire defect in multi-storey buildings. Causes include knowledge gaps, poor trade coordination, and missing documentation.

Section 4

Key Design Decisions

1

Floor-to-Floor Sealing vs. Fire-Rated Shaft

For risers with fewer than 10 services, floor-to-floor sealing is simpler and cheaper. For risers with dense, grouped services (hydraulic, electrical, comms, mechanical), a fire-rated shaft reduces the total number of individual penetration seals. Pick one approach per riser early in design and mark it on the drawings.

Trade-off: Floor-to-floor sealing avoids the cost of fire doors and rated access panels (typically $800–1,500 per level) but needs every single penetration sealed and documented individually.

2

Fire Stopping Product Selection

Match the product to the service type. Fire collars suit plastic pipes (PVC, HDPE) in new construction. Fire wraps suit retrofit or tight spaces. Intumescent sealants suit cables and small services. Fire pillows suit cable trays where future access is needed. Every product must have AS 1530.4 test evidence for the exact combination of service, substrate, and gap size.

Trade-off: Fire pillows typically cost more per opening (around $50–150) but allow re-entry for future cabling without breaking a permanent seal.

3

Passive Fire Documentation

Start a passive fire register at the beginning of construction. Record every sealed penetration with a photo, the product data sheet, and the test report reference. Tag each penetration with a unique ID that matches the coordination drawings. Certifiers and fire auditors expect this register at handover.

Trade-off: Takes 5–10 minutes per penetration to document, but without it, certifiers will not issue an occupation certificate.

4

Trade Coordination and Inspection

Require all trades to mark penetration locations on coordination drawings before any core drilling. Schedule a passive fire inspection after all services are roughed in but before ceilings are closed. A second inspection before handover catches late-stage breaches.

Trade-off: Two inspections add 1–2 days to the program but prevent the most common cause of passive fire defects: unsealed late-stage penetrations.

Section 5

Who Needs to Know What

Section 6

References

National Construction Code 2022, Volume One, Part C3 — Compartmentation and separation
National Construction Code 2022, Volume One, Part C4 — Protection of openings (C4D15)
National Construction Code 2022, Volume One, Specification 13 — Penetration of walls, floors and ceilings by services
AS 4072.1-2005 (R2016), Components for the protection of openings in fire-resistant separating elements — Part 1: Service penetrations and control joints
AS 1530.4-2014, Methods for fire tests on building materials, components and structures — Part 4: Fire-resistance tests for elements of construction
AS/NZS 1668.1-2015, The use of ventilation and airconditioning in buildings — Part 1: Fire and smoke control in buildings
AS 1851-2012, Routine service of fire protection systems and equipment

Passive Fire Protection for Services Risers

What You Need to Know

The Rules

What This Means in Practice

Key Design Decisions

Floor-to-Floor Sealing vs. Fire-Rated Shaft

Fire Stopping Product Selection

Passive Fire Documentation

Trade Coordination and Inspection

Who Needs to Know What

Need this engineered for your project?

References

Related design memos

Fire Damper and Smoke Damper Requirements

Smoke and Fire Damper Testing After Installation

Fire Rated Ceilings and Service Penetrations