Permit to Dig and Excavation Permit

What Is a Permit to Dig and Excavation Permit?

A Permit to Dig or Excavation Permit is a formal document used in the Australian construction and civil industries to authorise ground breaking work. It serves as a final check to ensure all safety hazards have been identified and controlled before an excavator or shovel hits the dirt. This document is not just administrative paperwork. It is a critical control measure used to manage the high risks associated with excavation, such as ground collapse, contact with underground services, and falling into trenches.

In Australia, the primary duty of care falls on the Person Conducting a Business or Undertaking (PCBU). The Permit to Dig acts as evidence that the PCBU has taken reasonable steps to comply with the Work Health and Safety (WHS) Act and Regulations. It verifies that a risk assessment has taken place, that necessary approvals are secured, and that the workers on the ground are aware of the specific dangers for that site.

While often used interchangeably, there is a slight nuance. An "Excavation Permit" is generally broader, covering the entire project phase of earthworks. A "Permit to Dig" is often a specific, daily or task-based authority to open the ground at a precise location. Both serve the same core purpose: to prevent injury and damage through rigorous planning and verification.

When to Use This Document

You must use a Permit to Dig whenever you plan to excavate, regardless of the depth. However, the law mandates strict additional procedures when the work meets certain criteria.

High Risk Construction Work

Under the Work Health and Safety Regulations 2011, excavation work is classified as "High Risk Construction Work" if the excavated depth is likely to be greater than 1.5 metres or if a tunnel is involved. When these triggers are met, you must prepare a Safe Work Method Statement (SWMS) before work starts. The Permit to Dig is the operational tool that confirms the controls listed in your SWMS are actually in place on the day.

Proximity to Underground Services

Any time you are digging near infrastructure, you need this document. State legislation, such as the Gas Supply Act 1996 (NSW) and the Electricity Safety Act 1998 (VIC), imposes a duty to locate underground assets. The permit records that you have completed the necessary "Dial Before You Dig" inquiries and physical verification steps.

Civil and Infrastructure Projects

On major infrastructure projects, mining sites, and refineries, a "No Permit, No Dig" policy is standard industry practice. Site principals will not allow machinery to commence work without a signed permit visible at the work face. This applies whether you are using a 20-tonne excavator or hand digging with post-hole diggers.

Shallow Excavations

Even for shallow work under 1.5 metres, such as trenching for irrigation or installing garden beds, a permit is best practice. It forces the crew to stop and consider the location of sewer lines or electric cables, which are often laid at shallow depths in residential areas.

Key Sections and Required Elements

A robust Permit to Dig must be more than a permission slip. It functions as a checklist for safety. To be effective and legally defensible, the document should include the following key sections.

Scope of Work and Location

This section defines exactly where the work happens. It must include the site address, a description of the work (e.g., "Excavation for sewer pit installation"), and specific dimensions (depth, width, length). Attaching a site plan or map with the excavation area clearly marked is highly recommended. This prevents "scope creep" where the operator digs outside the agreed risk-assessed zone.

Hazard Identification and Service Checks

This is the most critical part of the permit for preventing asset strikes. It must require the following:

• Reference Number: A field to enter the "Dial Before You Dig" (BYDA) enquiry reference number.
• CAT and Genny Scanning: Confirmation that a Cable Avoidance Tool and Signal Generator have been used to scan the area.
• Potholing: A check box to confirm that "potholing" (hydro excavation) has been used to visually verify the depth and location of services.

Risk Control Measures

This section outlines how the risks will be managed. For trenches deeper than 1.5 metres, the permit must specify the ground support method. This aligns with the hierarchy of controls. You cannot simply rely on "be careful." The permit should list engineering controls such as:

• Shoring (using timber or hydraulic shores to support trench walls).
• Benching (stepping the trench walls).
• Battering (sloping the trench walls back).

It must also address traffic management, barriers, and signage, referencing Australian standards like AS 3745 for emergency procedures.

Authorization and Sign-Off

The permit must be signed by a "Competent Person." This is usually the Site Supervisor or Project Manager. Their signature declares that all controls are in place. Crucially, the excavator operator must also sign to acknowledge they understand the risks and the boundaries of the work. The document should include a time limit. A permit usually lasts for a single shift. If work continues the next day, conditions may have changed, requiring a new permit.

Disclaimer

A legal disclaimer must state that the permit does not absolve the contractor of their duty to identify hazards. If the worker finds an unexpected pipe or unstable soil, work must stop immediately until the hazard is reassessed.

How to Write a Permit to Dig and Excavation Permit (Step by Step)

Creating a permit requires a systematic approach. You can use a Permit to Dig Template to streamline the process, but you must fill it out with site-specific data.

Step 1: Conduct Initial Risk Assessment

Before writing the permit, review the site plans. Identify the location of underground utilities using BYDA. Obtain a geotechnical report if the excavation is deep or if the soil conditions are unknown. The report will classify the soil (Type A, B, or C) and tell you if you need specific shoring.

Step 2: Complete the Scope Details

Fill out the top section of the form. Be precise. Instead of writing "digging hole," write "Excavate trench 2 metres deep, 1 metre wide, 10 metres long for stormwater drainage." Pinpoint the location on a map.

Step 3: Verify Services

Do not rely solely on old "As-Built" plans. Plans are often inaccurate. You must physically verify. Use the CAT and Genny to scan the area. Mark the ground with paint or flags. Perform potholing if you are close to a main line. Record the BYDA reference number and the dates of your physical scans on the permit.

Step 4: Define Controls

List the control measures. If the trench is 1.6 metres deep, write "Trench shields to be used." If there is mobile plant nearby, define the exclusion zone to prevent workers from being struck. Ensure you have a traffic management plan in place if the excavation affects public footpaths or roads.

Step 5: Emergency Planning

Consider what could go wrong. If the trench collapses, how do you get the worker out? The permit should reference emergency contact numbers and the location of the nearest first aid kit. Ensure there is a clear ladder or ramp in the trench for egress.

Step 6: Authorisation and Briefing

Take the permit to the site. The supervisor must review it physically on the ground. They must sight the hazards and the controls with their own eyes before signing. Once signed, the supervisor must handover the permit to the excavation crew. This is the time for a "Take 5" or pre-start talk to run through the points on the permit.

Step 7: Display and Monitor

The permit must be kept at the workplace. It should not stay in the site office. It needs to be near the excavation so an inspector or worker can refer to it. The supervisor must monitor the work to ensure the conditions described in the permit remain accurate. If it starts raining heavily, the soil stability may change, and the permit may need to be revoked.

Common Mistakes to Avoid

Many contractors treat permits as a tick-and-flick exercise. This approach leads to accidents and legal liability. Avoid these common pitfalls.

Relying on Old Plans

One of the biggest mistakes is trusting "As-Built" drawings without verification. Utility records are often outdated or incomplete. If you strike a gas main because you relied only on a plan, you are liable. Always use locating tools and potholing.

Generic Soil Assumptions

Never assume the ground is stable rock or "Type A" soil. If you dig into clay that becomes saturated after rain, it can behave like liquid. Excavating without shoring based on a generic assumption is a breach of the WHS Regulations. Always refer to a geotechnical report for deep excavations.

Ignoring the "Competent Person" Requirement

The person signing off the permit must be competent. This means they have the necessary training, knowledge, and experience. In many Australian states, a "Competent Person" for trenching is someone who can identify ground stability risks. Do not have an office administrator sign the permit if they have not visited the site.

Missing the Exclusion Zone

Excavators are powerful machines. A common mistake is failing to establish an exclusion zone around the moving parts of the plant. If a worker is within the radius of the excavator and the machine swings, the result can be fatal. The permit must clearly define this zone.

Not Updating the Permit

If the scope changes, the permit must change. If you originally planned to dig 2 metres but now need to go to 4 metres, the original permit is invalid. You must stop work, reassess the risks (likely requiring new shoring), and issue a new permit.

Legal Considerations (AU)

Operating in Australia requires strict adherence to a framework of laws and standards. Excavation is heavily regulated because it is inherently dangerous.

Model WHS Laws

The Model WHS Regulations classify excavation deeper than 1.5 metres as High Risk Construction Work. This means you must have a SWMS. Failure to produce a SWMS or a Permit to Dig upon request by a Safe Work inspector can result in significant fines. inspectors treat the absence of these documents as a primary indicator of a safety culture failure.

State Variations

While most states have adopted the Model WHS laws, Western Australia and Victoria have their own Acts (Occupational Safety and Health Act 1984 (WA) and Occupational Health and Safety Act 2004 (VIC)). While the principles are similar, you must check the specific regulations for your state regarding notification of work. For example, some types of excavation near public infrastructure may require notification to the state regulator 24 hours prior to commencement.

"Dial Before You Dig" Legislation

There is no single federal law for BYDA, but state legislation mandates the protection of assets. For example, damaging an electricity asset in Queensland can lead to prosecution under the Electricity Safety Act 2002 (QLD). The Permit to Dig is your primary defense in these cases, proving that you took all reasonable steps to identify and avoid the asset.

Standard AS 5488:2019

The Australian Standard AS 5488:2019 Classification of Subsurface Utility Information sets out quality levels for utility data. Best practice contracts often require verification to Quality Level B (using geophysical locating) or Quality Level A (visual verification via potholing). Your Excavation Permit should reference these quality levels to demonstrate compliance with industry best practice.

Duty of Care

Under section 19 of the WHS Act, the PCBU has the primary duty of care. This duty cannot be transferred. Even if you hire a subcontractor to do the digging, as the head contractor or property owner, you have a duty to ensure they are working safely. Issuing a Permit to Dig is a key way you exercise this duty. It shows you are actively managing the risk, rather than leaving it entirely to the subcontractor.

Frequently Asked Questions (preview)

Do I need a permit for hand digging? Yes, if there is a risk of underground services. Even hand digging can cut a fibre optic cable or a gas pipe. The permit process ensures you have checked the locations before breaking ground.

Who is considered a "Competent Person" to sign the permit? A competent person is someone who has acquired through training, qualification or experience the knowledge and skills to carry out the task. For excavation, this is typically a site supervisor or engineer with experience in ground works and trenching safety.

How long is a permit valid for? Most permits are valid for one shift only. If work stops overnight, soil conditions can change, and new hazards may arise. You must review and re-issue the permit for the next shift.

What happens if I find a pipe not shown on the plans? Stop work immediately. Do not attempt to uncover it further. Secure the area and contact the asset owner. The permit must have a condition that work stops if unidentified hazards are found.

Is a Permit to Dig the same as a Safe Work Method Statement (SWMS)? No. The SWMS is the broader document outlining how you will do the job safely. The Permit to Dig is a specific authorisation that confirms the controls in the SWMS are in place at that specific moment and location. You usually need a SWMS before you can get a Permit to Dig.