Horizontal Directional Drilling (HDD) for Plumbing SWMS
Safe work method statement for trenchless horizontal directional drilling for plumbing service installation including service detection, drilling fluid management, and reinstatement.
SWMS variants reference your state’s WHS legislation. Instant download after payment.
Horizontal directional drilling (HDD) covers the trenchless installation of underground pipe and conduit by drilling a steerable bore along a designed path and pulling the pipe back through it — installing water, sewer, gas or service pipe under roads, waterways and obstacles without open-trench excavation along the line. It is specialised trenchless work whose defining hazards are the strike of existing underground services by the drill, the inadvertent return of drilling fluid to the surface, the high forces and rotating drill string, the entry and exit pits, and electrocution where the drill contacts an energised cable. This document is written on the basis that HDD is carried out by competent operators with the services-location, drill, drilling-fluid and electrical hazards rigorously controlled.
Horizontal directional drilling is trenchless pipe installation carried out in connection with the relevant parts of AS/NZS 3500 and the relevant utility requirements, using a steerable drilling rig. The strike of an existing underground service — particularly an energised electrical cable or a gas main — is the most serious hazard, so services are located and the bore designed and tracked to avoid them. Drilling fluid under pressure can return inadvertently to the surface, and the rotating drill string and high forces are significant hazards. This document coordinates the services-location, drill, drilling-fluid, electrical and excavation controls so the bore is drilled and the pipe installed safely.
Hazards identified
9 hazards covered, sorted by priority.
Electrocution and arc-flash from drilling into an energised cable
Gas release, explosion or service damage from drilling into a service
Surface fluid return affecting the surface, traffic and the public
Entanglement and crush injury from the rotating drill string and high forces
Excavation collapse and atmospheric hazards at the pits
Injection or pressure injury from the drilling fluid under pressure
Electrocution where a cable strike energises the drill string and rig
Musculoskeletal injury from heavy pipe, rods and equipment
Crush and entanglement hazards around the operating rig
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1Engineering: locate, prove and protect existing underground services before any ground penetration using plans, Dial Before You Dig information, a service locator and potholing, so services are not struck.
- 2Engineering: design and track the bore to avoid located services, using a steering and locating system to follow the designed path and confirm the position of the drill head throughout.
- 3Administrative: where a cable strike is possible, treat the drill string and rig as potentially energised, apply the electrical controls and safe approach distances, and have the supply located and isolated where required.
- 4Engineering: operate the drilling rig to its safe working requirements — keeping clear of the rotating drill string and high forces, using rated equipment, and not exceeding capacity.
- 5Engineering: manage the drilling fluid and bore pressure, monitor for inadvertent surface return and respond to it, and control the drilling-fluid injection and pressure hazard.
- 6Engineering: control the entry and exit pit excavations to the excavation Code of Practice with shoring, with a SWMS, and apply the confined space controls where a pit meets the confined space definition.
- 7Engineering: maintain plant-and-pedestrian separation around the work with a spotter, and exclude workers from the operating plant and its hazard zone.
- 8Administrative: ensure the work is carried out and certified by an appropriately licensed plumber or drainer under the relevant state or territory plumbing licensing scheme, with the relevant competencies and a compliance certificate issued where required.
- 9Administrative: all workers must hold a valid White Card (General Construction Induction Training, CPCCWHS1001) before entering any construction workplace, with the plumbing, excavation, confined space and any other competencies and licences required for the work.
- 10Administrative: conduct a daily pre-start toolbox talk covering the day's work, identified hazards, isolations, required PPE and emergency procedures, and record attendance in the consultation section.
- 11Administrative: consult workers and any health and safety representatives on the work and its risks, record the consultation, and keep this document available at the workplace.
- 12PPE: eye protection to AS/NZS 1337.1, hearing protection where required, gloves appropriate to the task, high-visibility clothing, and Class I or Class II safety footwear with protective toecap to AS/NZS 2210.3.
- 13Administrative: review and update this SWMS whenever the work scope changes, after any incident or near miss, when a worker or health and safety representative raises a concern, when new hazards are identified, or at minimum every 12 months.
Applicable Codes of Practice
The plumbing and drainage standards for the pipe being installed by directional drilling.
Trenching and excavation controls including support against collapse, ground assessment and existing services.
Electrical safety and the treatment of the drill string as potentially energised where a cable strike is possible.
Controls for the plant and equipment used in the work, including guarding and plant-and-pedestrian separation.
The risk management process and hierarchy of controls applied to the hazards of the work.
High-Risk Construction Work triggered
The entry and exit pits for directional drilling can be excavations deeper than 1.5 metres, which is high risk construction work requiring a SWMS before the work commences.
Directional drilling can encounter energised electrical cables, and a strike energises the drill string and rig, bringing the work within this high risk construction work category and requiring a SWMS where it applies.
This is licensed plumbing, drainage or specialist work that, in the circumstances described, is high risk construction work — in or near a shaft or trench with an excavated depth greater than 1.5 metres; and on or near energised electrical installations or services — so a SWMS must be prepared before the work commences, kept readily accessible, reviewed as necessary, and given to the principal contractor if one is appointed. The work is carried out to the relevant AS/NZS 3500 plumbing and drainage standards, the excavation, confined space and pressure-equipment requirements, and the relevant utility requirements, which are called up by the relevant legislation, with the excavation, confined-space, electrical, pressurised-pipe or work-at-height controls applied as relevant. A failure in this work can cause burial, an atmospheric incident, a service strike, a loss of containment or serious injury, and breaches of the relevant legislation and the primary duty of care under the model WHS Act are actively enforced, with offence categories running from failure-to-comply through to reckless conduct, and the most serious breaches carrying imprisonment for individuals. Body-corporate maxima are substantial and indexed; the current maximum follows the prevailing schedule of the responsible regulator.
Who this is for
- →Competent operators carrying out horizontal directional drilling.
- →Trenchless and civil contractors installing pipe by directional drilling.
- →Utility and plumbing contractors boring under roads and obstacles.
- →Asset owners and PCBUs commissioning directional drilling.
- →PCBU safety managers and supervisors coordinating the services-location, drill and electrical controls.
What you receive
- ✓Editable Microsoft Word document (.docx) fully compatible with Microsoft Word 2016 and newer, Google Docs, and LibreOffice Writer.
- ✓Title page with editable fields for PCBU name, ABN, site address, project name, principal contractor details, and document revision date.
- ✓Hazard register with the horizontal directional drilling hazards — each with a documented consequence, inherent risk rating on a 5x5 likelihood-consequence matrix, hierarchy-of-control measures, and residual risk rating.
- ✓Directional drilling prompts referencing the trenchless method and AS/NZS 3500, a services-location and bore-tracking section, an electrical-strike and energised-drill-string section, and a drilling-fluid and excavation section.
- ✓Licensing, competency and permit prompts for the relevant plumbing, excavation, confined space and specialist work, and a respiratory protection selection and fit-test record per AS/NZS 1715 where relevant.
- ✓Worker consultation record per the model WHS Act consultation duty and a worker sign-on register (blank, expandable).
- ✓Applicable legislation and Codes of Practice schedule pre-populated for the model WHS jurisdiction with a state-variance reference table covering the harmonised states, plus Victoria.
- ✓Emergency procedure template and a revision log.
Worked example
A trenchless contractor is engaged to install a water service under a road by horizontal directional drilling. Existing underground services are located, proved and protected before drilling using plans, Dial Before You Dig information, a service locator and potholing, and the bore is designed and tracked with a steering and locating system to follow the designed path and avoid the located services, confirming the drill head position throughout. Because a cable strike is possible, the drill string and rig are treated as potentially energised, the electrical controls and safe approach distances applied, and the relevant supply located. The drilling rig is operated to its safe working requirements with workers clear of the rotating drill string and high forces. The drilling fluid and bore pressure are managed, with monitoring for inadvertent surface return. The entry and exit pits are controlled to the excavation Code of Practice with shoring and a SWMS, and the confined space controls applied where a pit meets the definition. Plant-and-pedestrian separation is maintained. The pipe is pulled back through the bore, the connection completed, and the records retained.
Related legislation
- Model Work Health and Safety Act — primary duty of care; the duty to consult workers; the reckless-conduct offence; and notifiable-incident provisions, as enacted in each jurisdiction.
- Model Work Health and Safety Regulations — Section 291 high risk construction work and the SWMS preparation and review duties, and the excavation, confined space and pressurised-pipe provisions where applicable, as enacted in each jurisdiction.
- The relevant plumbing and drainage standards AS/NZS 3500 (Parts 0–5), the excavation and confined space Codes of Practice, the pressure equipment and pipework standards, and the silica Code of Practice where cutting concrete, are called up by the relevant legislation, together with the Before You Dig Australia information and the relevant utility requirements.
- Plumbing and drainage work is licensed under each state and territory's plumbing licensing scheme, with the relevant competencies for excavation, confined space and specialist work, and compliance certification required for notifiable work; electrical work is carried out by a licensed electrician.
- Victoria operates under the Occupational Health and Safety Act 2004 and the Occupational Health and Safety Regulations 2017, with the high risk construction work, excavation and confined space provisions applying in place of the model instruments.
Frequently asked questions
What is horizontal directional drilling?
Horizontal directional drilling (HDD) is a trenchless method of installing underground pipe and conduit by drilling a steerable bore along a designed path and pulling the pipe back through it. It installs water, sewer, gas or service pipe under roads, waterways and obstacles without open-trench excavation along the line, using entry and exit pits.
What is the most serious hazard in directional drilling?
The most serious hazard is the strike of an existing underground service by the drill — particularly an energised electrical cable, which can electrocute, or a gas main, which can release gas or explode. Services are located and the bore designed and tracked to avoid them, and where a cable strike is possible the drill string and rig are treated as potentially energised.
How are services avoided during drilling?
Existing underground services are located, proved and protected before drilling using plans, Dial Before You Dig information, a service locator and potholing, and the bore is designed and tracked with a steering and locating system to follow the designed path and avoid the located services. The drill head position is confirmed throughout the bore.
What is inadvertent drilling fluid return?
Inadvertent return is when the drilling fluid under pressure finds a path to the surface rather than staying in the bore, returning to the surface where it can affect the surface, traffic and the public. The drilling fluid and bore pressure are managed and monitored for inadvertent return, with a response in place where it occurs.
Why is electrical strike such a concern?
If the drill strikes an energised electrical cable, it can energise the drill string and rig and electrocute the operators, as well as causing arc-flash. For that reason, where a cable strike is possible, the drill string and rig are treated as potentially energised, the electrical controls and safe approach distances apply, and the supply is located and isolated where required.