Trenchless Pipe Relining SWMS

Trenchless pipe relining rehabilitates damaged sewer, stormwater and drainage pipelines by inserting a resin-impregnated liner (CIPP) through existing access points, then curing it in place with ambient, hot water, steam or UV light. The work involves entry into or breathing zone exposure to sewer manholes, pits and confined spaces; handling of styrene-based and epoxy resins; hot water, steam and UV curing equipment; high-pressure water jetting for pre-clean; and near-constant work adjacent to live traffic corridors because access points are almost always in roadways or footpaths.

Under the Work Health and Safety Regulation 2025 (NSW), section 291 defines high risk construction work, and section 299 requires a SWMS to be prepared before that work commences. Relining routinely triggers section 291(f) confined space entry, section 291(l) contaminated or flammable atmosphere (styrene vapour, sewer gases, resin fumes), and section 291(n) work on or adjacent to a road or traffic corridor. Controls follow the hierarchy in section 36 — elimination of entry where possible, atmospheric monitoring, ventilation, traffic control and respiratory protection.

Hazards identified

12 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Eliminate physical confined space entry wherever possible by conducting all liner insertion, inversion and cutting from surface using remote CCTV and robotic cutters
2. 2Substitute high-styrene polyester resins with low-styrene, low-VOC or epoxy/silicate systems where the design permits, reducing atmospheric contamination at source
3. 3Establish a permit-to-work confined space entry system compliant with AS 2865-2009 including pre-entry and continuous atmospheric monitoring for O2, LEL, H2S and CO, with defined action levels and rescue plan
4. 4Provide forced mechanical ventilation of the pipeline and access chambers before and throughout curing; discharge exhaust away from workers and public and, where styrene may exceed 50 ppm TWA, apply local exhaust capture at manholes
5. 5Implement a compliant Traffic Guidance Scheme prepared by a TfNSW-accredited person under the Traffic Control at Work Sites Manual (TCWS), including positive protection, tapers, speed reduction and, on classified roads, TfNSW road occupancy approval
6. 6Bond and earth all metallic curing plant; use intrinsically safe gas detection (AS/NZS 60079 series) and keep ignition sources outside the hazardous zone until LEL is confirmed <5%
7. 7Guard, restrain and pressure-test all steam, hot water and cure lines to AS 4041 and AS 2593; fit whipchecks, hose restraints and thermal insulation; exclude personnel from the cure line envelope during pressurisation
8. 8For UV curing, enclose or shield access points, prohibit direct viewing of the light train, and provide UV-rated eye and skin protection to AS/NZS 1337.1 and AS/NZS 4501.2
9. 9Water jetting to AS/NZS 4233.1 — trained operators only, dead-man controls, exclusion zone, and full jetting PPE including cut-resistant boots, apron and face shield
10. 10SDS-driven chemical controls for resins and hardeners under the Hazardous Chemicals provisions of the WHS Regulation 2025 (NSW) Chapter 7; nitrile gloves to AS/NZS 2161.10.3, chemical splash goggles, and half-face APR with A2-P2 cartridges to AS/NZS 1716 selected per AS/NZS 1715
11. 11Health monitoring for workers with significant styrene or isocyanate exposure in accordance with WHS Regulation 2025 (NSW) sections 368–378 and the SafeWork NSW health monitoring guidance
12. 12All workers hold CPCCWHS1001 (White Card) and confined space/gas test/jetting competencies; the SWMS is developed in consultation with workers under section 47 of the WHS Act 2011 (NSW) and reviewed under section 302 of the WHS Regulation 2025 (NSW) whenever the control measure is revised, an incident occurs, or the work method changes

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

A drainage contractor is engaged to reline a 225 mm sewer main under Parramatta Road at Ashfield, with launch and receive manholes located in the traffic lane and adjacent parking bay. The crew is running a styrene-based polyester liner cured with hot water at 85°C, overnight, under a full lane closure. Before starting, the PCBU prepares a SWMS citing sections 291(f), (l) and (n). A TfNSW-accredited traffic controller implements the TGS with positive barrier separation. Prior to any manhole entry, atmospheric testing records O2 20.9%, LEL 0%, H2S 2 ppm and CO 0 ppm; forced ventilation is established and continuous monitoring is worn by the entrant. Styrene monitoring at the receive manhole is undertaken during inversion. The cure line is whip-checked and thermally lagged. All workers hold CPCCWHS1001 plus confined space entry and gas test competencies. The SWMS is signed on by all workers, and reviewed the following night after a hose fitting weep triggers a section 302 review.

Related legislation

• Work Health and Safety Act 2011 (NSW)
• Work Health and Safety Regulation 2025 (NSW) — including Chapter 4 Part 4.3 (Confined Spaces) and Chapter 7 (Hazardous Chemicals)
• Protection of the Environment Operations Act 1997 (NSW) — discharge of cure water and resin waste
• Plumbing and Drainage Act 2011 (NSW) and Plumbing Code of Australia
• Roads Act 1993 (NSW) — road occupancy and works within road reserves
• Public Health Regulation 2022 (NSW) — sewer and cross-connection controls

Frequently asked questions