AS 4024 explained: a plain-English guide to machine safety in Australia

AS 4024 is the Australian standard series for the safety of machinery. If you own, run or build machines in Australia, it is the benchmark a regulator, insurer or auditor will measure your guarding and safety systems against. This guide explains what it covers, how it links to your legal duties, and what a compliant project looks like in practice.

What is AS 4024?

AS/NZS 4024.1 is a series of standards titled Safety of machinery. Most parts adopt the international ISO and IEC machine safety standards, so a machine designed properly to AS 4024 is generally aligned with the European and international approach as well. The series covers the whole job:

• Risk assessment and risk reduction: AS/NZS 4024.1201, based on ISO 12100
• Safety-related parts of control systems: AS/NZS 4024.1503, based on ISO 13849-1 (the Performance Level approach)
• Interlocking devices on guards: AS/NZS 4024.1602, based on ISO 14119
• Emergency stop: AS/NZS 4024.1604, based on ISO 13850
• Safety distances and minimum gaps: AS/NZS 4024.1801 and 1803, based on ISO 13857 and ISO 13854

There are also parts covering guard design, preventing unexpected start-up, human body measurements and specific machine types.

Is it the law?

The standard itself is not law. The legal duty sits in the Work Health and Safety laws. Under the WHS Regulations, a business that manages or controls plant must manage the risks it creates, following the hierarchy of controls, with specific requirements for guarding (regulation 208), operator controls (regulation 210) and emergency stops (regulation 211). The model Code of Practice Managing the risks of plant in the workplace explains how to meet those duties.

What counts as "reasonably practicable" depends partly on what is known about the hazard and how to control it, and published standards are a big part of that. In practice, if something goes wrong, AS 4024 is what your guarding and safety circuits will be compared against.

The process, step by step

1. Define the machine and its limits. What it does, who uses, cleans and maintains it, and every mode it runs in, including setting, changeover and fault finding.
2. Identify the hazards. Crushing, shearing, entanglement, drawing-in, stored energy, electrical, thermal and others, for every task, not just normal running.
3. Estimate and evaluate the risk. How badly someone could be hurt, how often they are exposed, and whether they can avoid the hazard.
4. Reduce the risk, in order. First design it out, then guard it (fixed guards, interlocked guards, light curtains, area scanners), then add warnings, procedures and training. Signs and PPE are the last resort, not the first.
5. Set the required Performance Level. Each safety function, such as "opening this door stops the machine", is given a required PL from PLa to PLe.
6. Design and verify the safety circuits. Select the architecture, devices and diagnostics that achieve the PL, and calculate it to prove it.
7. Position guards correctly. Use safety distances and stopping-time measurements so a person cannot reach the hazard before the machine stops.
8. Validate and document. Test every safety function, record the results, and hand over drawings, the risk assessment and the validation report.

Common gaps we find

• Guard interlocks wired through a standard PLC output instead of a safety-rated circuit
• Light curtains mounted too close to the hazard for the machine's actual stopping time
• Interlocks that can be defeated with a spare actuator or a cable tie
• Emergency stops that do not stop every hazardous motion, or cannot be reached from where the operator works
• No written risk assessment or validation record, so compliance cannot be demonstrated
• Machines modified over the years without the safety system being reassessed

Older machines and upgrades

You rarely need to replace a machine to make it safe. Most older plant can be brought up to standard by retrofitting guarding, interlocks, light curtains and a safety relay or safety controller, often during a planned shutdown. A risk assessment tells you which upgrades matter most, so the budget goes where the risk is.

How AMC helps

AMC delivers machine safety from the first walk-around to the signed-off validation report: AS 4024 risk assessments, stopping-distance measurement, safety-circuit design and PL verification, safety panels built in our Griffith workshop, Pilz and SICK safety controllers, light curtains and interlocks, installation, commissioning and documentation. We work across food and beverage, agriculture, packaging and manufacturing, in the Riverina and Australia-wide.

This guide is general information to help you understand the standard. It is not legal advice, and the requirements for a specific machine depend on its risk assessment.