Pipeline Pigging & Launcher/Receiver SWMS

Pipeline pigging runs a device — a pig — through a pipeline to clean it, separate products, dewater or gauge it, or, as an intelligent or smart pig, to inspect the pipe wall for defects. The pig is launched and received through pig traps, which are pressure vessels connected to the pipeline, and the dominant hazards arise at the traps: opening a trap that is still under pressure, or that contains trapped pressure behind the pig, can release product and the pig itself with lethal force, and the product and any sludge removed can be flammable, toxic or under pressure. This document is written on the basis that pigging is carried out under a strict trap-operating procedure in which a trap is never opened until it is proven isolated, depressurised and, where required, purged.

Pigging is high risk construction work because the pig traps are plant that is pressure equipment operating above 50 kilopascals, and the work is carried out on or near chemical or fuel lines and in an area that may have a contaminated or flammable atmosphere when traps are opened and product or sludge is handled — so a safe work method statement is required before the work commences, kept readily accessible, and given to the principal contractor if one is appointed. Pigging of high-pressure pipelines is conducted under the operation and maintenance provisions of the AS 2885 suite and the operator's pig-trap procedures. This document coordinates the pressure-isolation, atmospheric and product-handling controls so pigs are launched and received without an uncontrolled release at the trap.

Hazards identified

9 hazards covered, sorted by priority.

Control measures

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

1. 1Engineering: a defined pig-trap operating procedure with a verified valve line-up, so the trap is correctly isolated from the pipeline before any closure is opened and the pipeline is never pressurised against an open trap.
2. 2Engineering: prove the trap is isolated and fully depressurised — including releasing any pressure trapped behind the pig — through dedicated vent and drain connections before the closure is opened, with pressure indication confirmed.
3. 3Engineering: continuous atmospheric monitoring for flammable gas and oxygen, and for toxic components such as hydrogen sulphide where present, at the trap area when it is opened, with defined evacuation criteria.
4. 4Engineering: manage product, sludge and pyrophoric scale removed by the pig — contained capture, keeping pyrophoric material wet, and controlled handling and disposal.
5. 5Administrative: a permit-to-work system for the pigging operation, exclusion zones at the trap, and competency verification for the trap operators and the permit issuer.
6. 6Administrative: prepare a SWMS before the work for the high risk construction work — work on or near pressure equipment above 50 kilopascals, on or near chemical or fuel lines, and in a potentially flammable atmosphere — and brief the trap sequence and emergency response.
7. 7PPE: flame-resistant clothing, supplied-air or appropriate respiratory protection where the atmosphere or product requires it, and protection against high-pressure injection at vent and drain points, per AS/NZS 1715 and AS/NZS 1716.
8. 8Administrative: all workers must hold a valid White Card (General Construction Induction Training, CPCCWHS1001) before entering any construction workplace, with pipeline and any confined space competencies verified as applicable.
9. 9Administrative: conduct a daily pre-start toolbox talk covering the day's work scope, identified hazards, required PPE, emergency procedures, and any changes since the previous shift, and record attendance in the SWMS consultation section.
10. 10PPE: eye protection to AS/NZS 1337.1, hearing protection where required, gloves, and Class I or Class II safety footwear with protective toecap to AS/NZS 2210.3.
11. 11Administrative: review and update this SWMS whenever the work scope, pipeline conditions or method changes, after any incident or near miss, when a worker or health and safety representative raises a concern, or at minimum every 12 months.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

A pipeline operations crew is running a cleaning pig followed by an intelligent inspection pig through an in-service pipeline, launching and receiving through pig traps. Because the traps are pressure vessels on a pipeline above 50 kilopascals, the work is on a fuel line, and opening the traps can release a flammable atmosphere, a SWMS is prepared and the operation is conducted under the AS 2885 operation and maintenance provisions and the operator's pig-trap procedure. For each trap operation, the valve line-up is verified so the trap is isolated from the pipeline and the line is never pressurised against an open trap. Before any closure is opened, the trap is proven isolated and fully depressurised through dedicated vent and drain connections, including releasing any pressure trapped behind the pig, with pressure indication confirmed. Continuous gas detection monitors for flammable gas, oxygen and hydrogen sulphide at the trap with defined evacuation criteria. Product and sludge removed by the cleaning pig are captured and contained, and any pyrophoric scale is kept wet and handled in a controlled way. A permit-to-work governs the operation, exclusion zones are set at the traps, and the operators are competent and briefed. The trap sequence, valve line-up and monitoring records are 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, including work on or near pressure equipment above 50 kilopascals, on or near chemical or fuel lines, and in a potentially flammable atmosphere; and the SWMS preparation and review duties, as enacted in each jurisdiction.
• AS 2885.3 Pipelines: Gas and liquid petroleum (Operation and maintenance); AS 2885.0 General requirements.
• Pipeline safety legislation administered by the relevant state pipeline or energy safety regulator applies to pigging of licensed transmission pipelines.
• Victoria operates under the Occupational Health and Safety Act 2004 and the Occupational Health and Safety Regulations 2017, with the high risk construction work and pressure-equipment provisions applying in place of the model instruments.

Frequently asked questions