Mechanical Ventilation Installation SWMS

Mechanical ventilation installation involves the fabrication, hoisting and connection of sheet metal ductwork, air handling units (AHUs), fans, variable air volume (VAV) boxes, grilles and associated controls within ceiling voids, plant rooms and service risers. Work routinely occurs from elevated work platforms, ladders and scaffolds, in confined ceiling spaces above 2 metres, and in proximity to energised electrical distribution boards, live cabling and adjacent trades. Hazards compound quickly: heavy duct sections manoeuvred overhead, sharp galvanised edges, hot works during flange modification, silica dust from core-drilling penetrations, and the possibility of disturbing asbestos-containing materials in pre-2004 buildings.

Under the Work Health and Safety Regulation 2025 (NSW), section 291 defines high risk construction work to include work with a risk of a person falling more than 2 metres and work on or near energised electrical installations or services — both routinely present in ductwork installation. Section 299 requires a Safe Work Method Statement to be prepared before this work commences, identifying hazards, documenting controls in accordance with the hierarchy of control, and describing how controls will be implemented, monitored and reviewed.

Hazards identified

12 hazards covered, sorted by priority.

Control measures

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

1. 1Eliminate work at height where practicable by pre-fabricating duct spool pieces at ground level and lifting complete assemblies into position, reducing time spent on EWPs and ladders.
2. 2Substitute powered core-drilling with wet-cutting methods and use pre-formed penetrations coordinated with the builder to eliminate on-site silica-generating dry cutting where possible.
3. 3Engineer fall protection using mobile scissor lifts or boom lifts (operator holding HRW licence WP) with harness anchorage, in preference to A-frame ladders; where EWP access is not feasible, install fixed edge protection or a compliant scaffold to AS/NZS 1576.1 and AS/NZS 4576.
4. 4Verify de-energisation of all electrical services in the work zone via a licensed electrician using test-before-touch, apply personal locks and danger tags under a documented isolation permit, and treat all unknown cabling as live until proven dead in accordance with AS/NZS 4836.
5. 5Obtain and review an asbestos register before ceiling access in any structure built or refurbished before 31 December 2003; if ACM is suspected, stop work and engage a licensed asbestos assessor — refer to the SafeWork NSW Code of Practice: How to Manage and Control Asbestos in the Workplace.
6. 6Control respirable crystalline silica using on-tool water suppression or H-class HEPA extraction, exclusion zones, and half-face respirators fitted to AS/NZS 1715 with P2 filters to AS/NZS 1716; conduct air monitoring where the workplace exposure standard (0.05 mg/m³ 8-hour TWA) may be approached.
7. 7Establish exclusion zones beneath overhead duct installation using bunting and signage, secure tools with lanyards, and use rated lifting equipment inspected in accordance with AS 2550 for hoisting duct sections and AHUs.
8. 8Implement a hot works permit for all brazing, grinding and oxy-cutting: remove or shield combustibles within 10 m, station a trained fire watch with a serviceable extinguisher, and maintain the watch for 60 minutes post-completion.
9. 9Lock out and tag out fans, VSDs and AHU starters before final impeller and belt connections; verify zero energy state and use captive-key isolation where multiple trades are involved.
10. 10Provide task-specific PPE: cut-5 rated gloves for sheet metal handling, safety glasses to AS/NZS 1337.1, hearing protection to AS/NZS 1270 where noise exceeds 85 dB(A), hard hat to AS/NZS 1801, and Type 5 coveralls when handling insulation.
11. 11Provide hydration, rotate workers and schedule ceiling void work outside peak heat where feasible; monitor for early signs of heat illness in accordance with the SafeWork NSW Code of Practice: Managing the Work Environment and Facilities.
12. 12All workers to hold General Construction Induction (CPCCWHS1001 White Card); the SWMS is to be consulted on with workers under section 47 of the WHS Act 2011 (NSW), signed before work commences, and reviewed under section 302 of the WHS Regulation 2025 (NSW) whenever controls are revised, an incident occurs or the work method changes.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

A mechanical services subcontractor is installing a new supply and return air ductwork system across Level 4 of a commercial refit in Parramatta. The ceiling void is 3.2 m above the finished floor, with existing energised lighting circuits and a 400 V sub-main routed through the plenum. Installation crews use scissor lifts to hoist 1200 x 600 mm rectangular duct sections into hangers, core-drill two 250 mm penetrations through a post-tensioned slab for riser duct, and braze copper refrigerant lines to a rooftop condenser. The SWMS identifies section 291(a) fall >2 m and section 291(k) work near energised services as HRCW, mandates a lockout permit witnessed by the site's licensed electrician before slab drilling, requires wet core-drilling with slurry containment for silica control, and applies a hot works permit with a 60-minute fire watch for the brazing. The document is consulted on with the four-person install crew and signed before work commences.

Related legislation

• Work Health and Safety Act 2011 (NSW)
• Work Health and Safety Regulation 2025 (NSW)
• Electricity Supply Act 1995 (NSW)
• Environmental Planning and Assessment Act 1979 (NSW)
• Protection of the Environment Operations Act 1997 (NSW)
• Dangerous Goods (Road and Rail Transport) Act 2008 (NSW)

Frequently asked questions