Asbestos cement, commonly called AC cement or fibro, was used for water and drainage pipe in Australian residential and commercial construction from the 1940s through to the mid-1980s. If your Central Coast home was built during this period, there is a genuine possibility that some of your stormwater or drainage infrastructure contains AC cement pipe. This guide explains the actual risk, how to identify AC cement pipes and why drain relining is the preferred remediation approach.
Quick answer (BLUF)
AC cement pipes in the ground, intact and carrying water, pose no day-to-day health risk. The asbestos fibres are bound within the cement matrix and cannot become airborne while the pipe is undisturbed. The risk arises when AC cement pipe is physically broken, cut, drilled or crushed, activities that occur during excavation and replacement. Drain relining, which requires no excavation, is the lowest-risk remediation option. Digging up and replacing AC cement pipes generates asbestos waste that must be handled and disposed of by licensed asbestos removalists.
What is AC cement pipe?
Asbestos cement (AC cement) pipe is manufactured from a mixture of Portland cement and asbestos fibres. The asbestos fibres, typically chrysotile (white asbestos) or amosite (brown asbestos), were added to increase the pipe’s tensile strength and resistance to fracture.
AC cement pipe was used extensively for:
- Residential stormwater drainage
- Subsoil drainage
- Downpipe connections to underground drains
- Water pressure mains (a different, thicker-wall specification)
- Some sewer applications in light commercial settings
The material looks similar to grey concrete. It has a matte grey surface, is heavy for its diameter, and unlike terracotta, has a uniform wall thickness without the sectional joints of clay pipe.
Where AC cement pipe is found on the Central Coast
The highest concentration of AC cement drainage pipe is in properties built between 1950 and 1985. On the Central Coast, this covers a significant portion of the housing stock in:
Gosford and North Gosford: Post-war residential development through the 1950s, 1970s used AC cement extensively for stormwater.
Wyong and surrounding suburbs (Tuggerah, Kanwal, Lake Haven): The rapid housing estate development of the 1970s, 80s in this area used AC cement for stormwater connections, particularly downpipe-to-drain connections.
Woy Woy and Umina Beach: Older fibro construction on the peninsula commonly included AC cement stormwater systems.
Gosford Light Industrial areas: Some commercial and light industrial buildings from this era have AC cement drain infrastructure that is now ageing and in need of rehabilitation.
Health risk: understanding the actual situation
It is important to distinguish between the theoretical hazard of asbestos and the actual risk in context. The hazard of asbestos is well documented, long-term inhalation of asbestos fibres causes mesothelioma and asbestosis. But hazard becomes risk only when fibres can become airborne and be inhaled.
In-ground AC cement pipe carrying water: The fibres are embedded in the cement matrix. They cannot become airborne. No aerosol or water spray from a flowing pipe presents a material inhalation risk.
Degraded AC cement pipe (crumbling, friable): If the cement matrix has broken down to the point where the pipe material is friable (crumbles in the hand), the fibre-release potential increases, but the pipe must still be physically disturbed to release fibres. In-ground, even degraded AC cement pipe presents no ambient air quality concern.
Excavation and physical breakup: This is the risk scenario. When AC cement pipe is excavated, cut with tools, broken with a pick or removed from the ground, it can release fibres. This is why AC cement pipe removal is classified as licensed asbestos removal work in NSW.
Regulations for AC cement pipe in NSW
In NSW, asbestos-containing material (ACM) handling and disposal is regulated under the Work Health and Safety Act 2011 and the Waste Avoidance and Resource Recovery Act 2001.
Key regulatory points for property owners:
- Removal of asbestos material up to 10 m² can be done by an owner-occupier (not a tenant or contractor) if the material is non-friable and specific procedures are followed. However, in practice, many property owners and all contractors hire licensed removalists.
- Any removal of friable asbestos material requires a licensed asbestos removalist (Class A licence) regardless of quantity.
- AC cement pipe disposal: Asbestos waste must be double-bagged in heavy-duty plastic and disposed of at an approved asbestos disposal facility. Not all landfills accept asbestos. On the Central Coast, Mangrove Mountain Landfill is an approved disposal point.
- A licensed asbestos assessor is required to certify that the area is clear after asbestos removal works above certain thresholds.
The Safe Work Australia Code of Practice for How to Manage and Control Asbestos in the Workplace sets out the procedural requirements in detail.
Why drain relining is the preferred approach for AC cement stormwater
Given the above, the case for relining rather than excavating AC cement drainage pipes is compelling:
No fibre release: Drain relining accesses the pipe through existing inspection openings. The AC cement pipe wall is never cut, broken or removed. No asbestos waste is generated. No licensed asbestos removal is required.
Cost: The licensed asbestos removal, disposal and certification required for excavating and replacing AC cement pipe adds $2,000, $8,000 to what would already be an expensive excavation job. Relining is typically 40-60% of the total cost of excavation-and-replacement even before asbestos handling costs are factored in.
Encapsulation: The cured liner inside the AC cement pipe acts as an encapsulant. It bonds to the host pipe interior and creates a smooth, sealed surface. The AC cement beneath the liner is permanently protected from further internal degradation.
Compliance: Relining through existing access points, by a licensed plumber, generates no asbestos waste and does not trigger asbestos removal regulations.
FAQs
How do I know if my stormwater pipes are AC cement?
Visual identification is possible if you have access to a pipe surface or an inspection point. AC cement has a uniform grey matte appearance, is heavier than PVC or clay, and does not have the sectional joint pattern of terracotta. A CCTV inspection is the most reliable method, experienced operators can identify AC cement from the internal appearance.
Should I tell potential buyers if my property has AC cement drains?
In NSW, vendors are not specifically required to disclose the material composition of underground drainage as part of standard conveyancing. However, if asked directly, a truthful answer is both legally and ethically required. A pre-sale CCTV inspection that reports AC cement pipe in sound condition (or recently relined) is better disclosure than silence.
Are AC cement water pressure mains (the big ones on the street) the same issue?
Pressure mains are a different application, thicker wall, different specification, but still AC cement and subject to the same regulatory framework if disturbed. Water authority mains are the responsibility of Sydney Water or Hunter Water, not the property owner.
Can I have AC cement pipe professionally identified without digging?
Yes. A CCTV drain inspection will allow experienced operators to identify pipe material type. Ground penetrating radar (GPR) can also indicate pipe material type in some circumstances. Both methods are non-invasive.