Common Fire System Installation Mistakes We Find During Compliance Audits

What usually goes wrong, why it happens, and what a thorough audit looks for
When we audit the fire safety side of a building's mechanical services, we rarely find deliberate corner-cutting. More often, we find an installer who didn't fully understand the standard they were working to. The work looks finished; it may even be signed off, but a missed detail can matter a great deal when there's an actual fire.
Those details are easy to overlook because most fire safety systems sit idle for years. A smoke exhaust fan or a stair pressurisation system might only run during testing. So the only real chance to find a problem is a proper inspection by someone who knows what to look for.
Here are the issues we come across most often, and why each one matters.
Mistake 1: Standard Cabling on Life-Safety Equipment
Some systems are designed to keep running during a fire. Smoke exhaust fans are the obvious example. Their job is to pull smoke out of a space such as a shopping centre or car park so people can get out and firefighters can get in.
If the power cable feeding that fan is ordinary cable, the fire can burn through it, and the fan stops. That's the moment it's needed most. Equipment like this needs fire-rated cabling, built to keep working for a set period at extreme temperatures.
From the outside, a fire-rated cable and a standard cable can look similar, and the fan runs perfectly well on either during a routine test. That's why this one so often goes unnoticed until someone traces the cabling back and checks what was actually installed.
Mistake 2: Fan Capacity Not Reassessed After the Building Changed
A building's mechanical design is based on how it was drawn. Plans change during construction and over a building's life. Floors get added, tenancies get reconfigured, and occupancy goes up.
A good example is a stair pressurisation system. If a stairwell was designed for a certain number of levels and a couple more are added later, the fan that pressurises it may no longer be big enough. Nobody necessarily went back to check, because the fan still turns on and still moves air. It just doesn't move enough to keep smoke out of the stairs across the full height of the building.
We see the same pattern with car park and smoke exhaust systems. The equipment is fine. It's simply been asked to do more than it was sized for.
Mistake 3: Penetrations Too Close to Fire Dampers
On a busy construction site, many trades are competing for the same ceiling and wall space. Plumbers, electricians and data installers all need to get through walls, and fire dampers sit inside those same walls.
A pipe or cable tray installed too close to a damper can affect its performance or prevent it from closing properly. It can also happen years after handover, when a new fit-out puts a penetration somewhere it shouldn't be. This is one reason scheduled damper inspections are worth doing properly. Our post on fire damper testing explains how that inspection cycle works.
Mistake 4: The System Doesn't Behave the Way the Fire Strategy Intends
In a fire, a building's fans are meant to respond in a set sequence. Some start to exhaust smoke, others stop, and others pressurise stairs or corridors. The building's fire engineering documentation sets out that sequence.
When we test a building, we sometimes find that the sequence doesn't match what the fire strategy actually needs, even where it matches the paperwork. When that happens, we raise it with the fire engineer so we can bring the documentation and the system back in line.
Why These Issues Happen
Most of these problems come down to knowledge, not intent. Fire safety standards are detailed and they change over time. A tradesperson who mainly does general mechanical work may not encounter these requirements often enough to know them inside and out.
That's also why we think an audit should be constructive. The goal is to find genuine risk and fix it, not to blame whoever installed the system.
Why This Work Is Taken So Seriously
The 2017 Grenfell Tower fire in London, which claimed 72 lives, is the best-known recent example of how a building compliance failure can have devastating consequences. That fire involved external cladding, not mechanical services. It still changed how seriously building compliance is treated, including in Australia, where buildings across the country were audited for combustible cladding in the years that followed.
The lesson for building owners is simple. Fire safety systems are only as good as the detail in their installation and upkeep.
What a Thorough Audit Actually Looks For
A proper audit goes beyond switching equipment on and checking that it runs. On our audits, we check:
• Cabling on life-safety equipment, and whether it's rated for fire conditions.
• Fan capacity against the building as it stands today, not as it was originally drawn.
• Clearances and penetrations around fire dampers.
• Airflows and pressures in stairwells and exhaust zones, measured rather than assumed.
• Whether the system's fire mode sequence matches the fire engineering strategy.
Afterwards, we sit down with the building owner, go through what we found, and explain which items need attention first. Where a finding is borderline, a fire engineer may be able to assess it through a performance solution rather than full rectification.
If you'd like a second set of eyes on your building's fire safety systems, talk to the team.
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