Your LEV System Is Running — But Is It Actually Protecting Anyone?

The fan is on. The hood is in place. The extraction unit hums away in the background. So your local exhaust ventilation system is doing its job, right? Not necessarily — and that assumption is putting people at risk in workplaces across the UK every single day.

It's one of the most common misconceptions we encounter at Ventxlabs Ltd: that a running LEV system is a safe LEV system. In reality, the two things are not the same. A system can be switched on, drawing air, and still be capturing only a fraction of the contaminants it was designed to remove. The shortfall is invisible. The harm isn't.

We've walked into labs, workshops, and production facilities where the LEV had been in place for years — inspected on schedule, certified on paper — and still wasn't performing to the standard needed to genuinely protect the people working in that space. Not because anyone was negligent, but because performance drift is real, it's gradual, and it's almost impossible to detect without proper measurement.

A fan that's lost 15% of its airflow won't announce itself. Ductwork that's developed a slow leak won't set off an alarm. But that quiet, invisible degradation is the difference between a system that protects and one that merely appears to.

So What Does "Actually Protecting" Look Like?

Effective local exhaust ventilation means capturing airborne contaminants — dust, fumes, vapours, gases — at the point where they're generated, before they can drift into the breathing zone of the person doing the work. That's the whole point. Not diluting them across the room. Not extracting some of them. Capturing them at source, consistently, every time.

To do that reliably, every component of the system has to be performing as it was designed to. Hood position. Airflow velocity. Duct integrity. Fan performance. Filtration. These things don't stay static over time, and any one of them drifting off-spec affects the whole system's ability to do its job.

Signs your LEV may not be performing

• Staff reporting irritation, headaches, or respiratory symptoms after shifts

• Visible dust or fume settling on surfaces near the extraction point

• The system hasn't been tested against its original commissioning data

• Processes or substances have changed since the system was designed

• The last inspection was a tick-box exercise with no airflow measurements taken

Under COSHH regulations, employers are legally required to have their local exhaust ventilation systems thoroughly examined and tested at least every 14 months. But a compliant inspection and an effective inspection aren't always the same thing. At Ventxlabs Ltd, our thorough examination and test — TExT — involves actual airflow measurement at every hood and key duct point, comparison against original commissioning data, and a detailed written report with any performance shortfalls clearly documented.

If your current provider completes your LEV inspection in under 30 minutes and hands you a single-page certificate, it's worth asking what was actually measured — and what wasn't.

Good LEV Starts at the Design Stage

The best time to get local exhaust ventilation right is before a single piece of equipment is installed. A system that's been properly designed for the specific contaminants, processes, and workspace involved will outperform a retrofitted solution every time — and it'll be easier to maintain and verify over its working life.

Ventxlabs Ltd designs LEV systems from first principles: understanding the substance being generated, the quantities involved, the work patterns of the people using the space, and the structural constraints of the building. That information shapes every element of the system — hood type, duct routing, fan selection, filtration specification — so that what gets installed actually works for the environment it's in.

Related service

Laboratory Fit Out — The Right Moment to Get Ventilation Right

If you're planning a new laboratory — whether that's a university research facility, a pharmaceutical R&D space, an industrial testing environment, or a school science block — there is no better moment to get your local exhaust ventilation right than during the laboratory fit out itself.

A laboratory fit out is the complete process of designing and building out a lab space from scratch or from shell — the benching, the services, the storage, the safety infrastructure, the specialist equipment. It's a significant undertaking, and the decisions made at this stage define how the environment performs for the next decade or more.

When LEV is designed and installed as part of the laboratory fit out, everything works together as it was intended. Fume cupboards sit in the positions that make sense for the workflow. Ductwork runs efficiently through the building's structure without unnecessary bends or compromises. The system is balanced, commissioned, and handed over performing exactly as designed — from day one.

Retrofitting ventilation into a completed laboratory tells a different story. It's disruptive, expensive, and almost always involves compromises: hoods placed where the duct can reach rather than where the work happens, ductwork routed the long way round, systems that are never quite as effective or as efficient as they should be. We see the results of those compromises regularly, and they're almost always avoidable.

Ventxlabs Ltd offers complete laboratory fit out services — from initial space planning and services design through to full installation, commissioning, and aftercare. Every project is built around the specific scientific work being carried out in that space, because a pharmaceutical testing lab and a school chemistry room have genuinely different requirements, and a good fit out starts by understanding the difference.

Don't Wait for a Problem to Find Out You Have One

The difficult truth about LEV failure is that it rarely announces itself dramatically. There's no alarm, no obvious breakdown, no single moment where something clearly goes wrong. Instead, performance erodes gradually — and the people working in the space absorb the consequences before anyone realises the system isn't doing its job.

The right approach is proactive: regular testing against meaningful performance benchmarks, prompt action on any shortfalls, and a design philosophy that builds effectiveness in from the start rather than hoping it can be patched in later. That's what Ventxlabs Ltd is built around — and it's the standard every workplace that uses LEV deserves.

Not sure if your LEV is actually working?

Talk to the team at Ventxlabs Ltd. We'll assess what you have, test what matters, and tell you honestly what we find — no jargon, no upselling, no guesswork.