Identify intervention tasks
List clearing, cleaning, adjustment, inspection and maintenance work that brings people close to or inside danger zones.
UNEXPECTED START-UP
AS/NZS 4024.1603 prevention of unexpected machine start-up
A commercial overview for projects where people may enter or reach into danger zones for cleaning, clearing, adjustment, service or maintenance.
FROM STANDARD TO SCOPE
Four conversations to have before the layout is locked
Use AS/NZS 4024.1603 to make safe intervention part of the machinery design—not an afterthought. The exact decisions still depend on the machine, tasks, risk assessment and current authorised standard.
Identify energy sources
Consider supplied energy, stored energy, gravity and other influences that could cause movement or start-up.
Define the safe state
Establish how hazardous functions are stopped, isolated, dissipated or otherwise prevented from starting during the task.
Make status unambiguous
The person intervening needs a reliable basis for knowing the machine cannot unexpectedly start.
WHY IT MATTERS
Access without energy control is not a complete guarding strategy
Perimeter fencing and doors manage access. Safe intervention also depends on what happens to every hazardous energy source once somebody needs to work inside the boundary.
THE COMPLETE DESIGN PICTURE
One standard rarely works alone
Risk assessment, physical guards, safety distances, interlocking, unexpected start-up and emergency-stop functions are connected. Follow the regional hub to move between the relevant guides without losing the project context.
Edition and jurisdiction note
AS/NZS 4024.1603:2019, with Amendment 1:2020, is publicly identified as addressing prevention of unexpected start-up. Confirm current status before use. Standards and guidance support—not replace—a project-specific risk assessment, applicable WHS/HSWA duties, regulator guidance and competent professional advice.
COMMON QUESTIONS
AS/NZS 4024.1603 FAQs
Is this the same as lockout/tagout?
It is closely related, but the standard focuses on designed-in prevention of unexpected start-up. Site isolation and lockout procedures remain part of the wider system of work.
Does pressing an emergency stop isolate energy?
An emergency-stop function should not be treated as energy isolation. The safe method depends on the task, hazards and machine design.
Who should define the isolation method?
It should involve competent people who understand the machine, its energy sources, control system, interventions and workplace procedures.
Turn the standard conversation into a buildable guard layout.
Send the machine layout, photos and access requirements. We’ll help shape a practical modular guarding concept for your project team to assess.
Start the guarding conversationCommercial information only. This page is not legal, engineering or certification advice and does not reproduce the controlled requirements of the standard.
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