Sanitary Drainage Rough-In SWMS

Sanitary drainage rough-in is the first-fix plumbing trade that sets out and lays below-slab and in-wall drainage: connecting pits and sumps, making solvent-cement and rubber-ring joints, and testing the system before the slab is poured or the wall is closed up. The dominant hazards are atmospheric hazards and asphyxiation entering a pit, sump or chamber, exposure to sewer gas and hydrogen sulphide when opening live drainage, trench collapse where below-slab runs exceed 1.5 metres, solvent-cement vapour, and striking an underground service. This SWMS covers the below-slab and in-wall drainage rough-in and testing; it does not cover the connection to the authority sewer main, the above-ground stack and vent, or the fixtures, which are documented separately.

Under the model Work Health and Safety Act 2011 and the harmonised Work Health and Safety Regulations adopted in each state and territory, this is high risk construction work because it is carried out in or near a confined space and in or near a trench deeper than 1.5 metres; Victoria operates the equivalent provisions under the Occupational Health and Safety Act 2004 and Occupational Health and Safety Regulations 2017. Sanitary plumbing and drainage design, installation and testing follow AS/NZS 3500.2, confined-space entry follows AS 2865, the excavation provisions of the harmonised regulations govern trenching, and the work must be carried out by a licensed plumber or drainer under the applicable state licensing scheme.

Failure to meet the primary duty of care is prosecuted under the Category 1 to 3 offences in the Work Health and Safety Act (and the equivalent provisions in Victoria's Occupational Health and Safety Act 2004), with maximum penalties indexed in most jurisdictions, imprisonment available for individuals, and a separate industrial manslaughter offence; current figures follow the prevailing penalty schedule of the responsible state regulator. This document is structured to satisfy the safe work method statement content requirements of the harmonised regulations and documents controlled drainage rough-in.

Hazards identified

10 hazards covered, sorted by priority.

Control measures

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

1. 1Elimination: Work from outside the space where possible; mechanically ventilate the space; and use a confined-space entry permit to AS 2865 with atmospheric monitoring, a trained standby person and rescue arrangements.
2. 2Elimination: Isolate or cap flows before opening live drainage; ventilate and purge; monitor for gas, limit time in the space, and maintain hygiene; wear gloves and eye protection.
3. 3Elimination: Lay from outside a battered trench; otherwise benching, battering or shoring designed for the soil, with no entry to an unsupported trench deeper than 1.5 metres.
4. 4Substitution: Use rubber-ring jointing where the system allows; otherwise ventilate at the jointing point, allow no ignition sources, keep the safety data sheet on hand and limit exposure.
5. 5Engineering: Use mechanical handling for spoil and long runs, a 25 kg single-person limit, two-person handling and the Hazardous Manual Tasks Code of Practice.
6. 6Engineering: Use pipe cutters in preference to saws, deburr and handle carefully, and wear cut-resistant gloves to AS/NZS 2161.3.
7. 7Engineering: Set spoil back from the edge with edge protection, exclude workers from the trench during plant operation, and stack no materials at the lip; wear a hard hat.
8. 8Elimination: Pothole located services, hand-dig within tolerance of located assets, and complete a Before You Dig Australia enquiry before excavation.
9. 9Engineering: Dewater the area and provide access boards, with housekeeping and defined access; wear safety footwear.
10. 10Engineering: Use guarded cutting and take care during jointing, and wear sealed eye protection to AS/NZS 1337.1.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

A drainage subcontractor is laying below-slab sanitary drainage for a new building, connecting to an existing pit and running a line that drops below 1.5 metres at the far end before the slab is poured. The work is high risk construction work both because it involves entering and working near a confined space and because part of the trench is deeper than 1.5 metres, so the supervisor builds the safe work method statement around the confined space and the excavation before any digging starts. Before the deep run is dug, located services are potholed, a Before You Dig Australia enquiry is completed, and hand-digging is used within tolerance of located assets; the trench is then battered or shored to a design for the soil, with spoil set well back from the edge and no entry to an unsupported trench. Where a pit must be entered, work is first attempted from outside the space; if entry is needed, a confined-space entry permit to AS 2865 is raised, the space is mechanically ventilated, the atmosphere is monitored continuously, and a trained standby person and rescue arrangements are in place before anyone goes in. Flows are isolated or capped before live drainage is opened, and the space is purged and gas-monitored to control sewer gas and hydrogen sulphide, with hygiene measures and gloves and eye protection worn. Rubber-ring jointing is used where the system allows; solvent-cement jointing is done with ventilation at the joint, no ignition sources and the safety data sheet on hand. Pipe and spoil are moved with mechanical handling and a 25 kg limit, access boards and dewatering control slips, and the drainage is tested to AS/NZS 3500.2 before the slab is poured. Workers sign on to the statement before starting, the entry permit and gas-monitoring records are kept, and the signed statement is held on site for the responsible state regulator.

Related legislation

• Work Health and Safety Act 2011 (harmonised; enacted in all states and territories except Victoria, which applies the Occupational Health and Safety Act 2004), s.19 — Primary duty of care to workers and to other persons at or near the workplace
• Harmonised Work Health and Safety Regulations, section 291 — Defines high risk construction work (Victoria: Occupational Health and Safety Regulations 2017, Part 5.1)
• Harmonised Work Health and Safety Regulations, section 299 — Content and review requirements for a safe work method statement for high risk construction work (Victoria: regulation 327; Tasmania: regulation 312)
• Harmonised Work Health and Safety Regulations — Excavation work and trenches, including the duty to prevent the collapse of an excavation deeper than 1.5 metres (Victoria applies the equivalent provisions of the Occupational Health and Safety Regulations 2017)
• Harmonised Work Health and Safety Regulations — Confined spaces: entry permit, atmospheric monitoring, standby and rescue duties
• State plumbing and drainage licensing legislation — Sanitary drainage rough-in must be carried out by a licensed plumber or drainer and inspected as required

Frequently asked questions