You can’t manage what you can’t see — and most of a ventilation system is hidden behind ceilings, risers and plant rooms. Our CCTV surveys and scientific testing show you exactly what’s inside your ductwork, with photographic, video and laboratory evidence you can put in front of an insurer, fire risk assessor or building control officer.
Ventilation ductwork quietly accumulates dust, debris and — in kitchen extract systems — grease. Left unchecked, that build-up degrades air quality, restricts airflow, drives up energy costs and creates a serious fire risk: contaminated extract ductwork is a well-documented route for fire spread in commercial buildings, and under the Regulatory Reform (Fire Safety) Order 2005 the responsible person must be able to demonstrate that ductwork risks are being managed.
The problem is evidence. A cleaning invoice doesn’t prove a system is clean, and a glance through an access panel doesn’t tell you what’s 20 metres further in. Our surveys and testing produce the verified, quantified evidence that BESA TR19® and BS EN 15780 actually call for.
High-resolution cameras on flexible rods and robotic crawlers travel deep into supply, extract and kitchen ductwork — including vertical risers — transmitting live footage to our engineers. Surveys identify dust and grease build-up, blockages, structural damage, failed joints, moisture ingress, pest activity and unrecorded modifications.
Where a system is underperforming — poor airflow, odours, unexplained energy use, damper faults — we carry out targeted investigations to trace the cause, mapping the system as we go and flagging anything that doesn’t match the building’s drawings.
Using calibrated deposit thickness gauges across representative sample points, we measure the mean thickness of dust deposits on internal duct surfaces in microns — the recognised benchmark method for deciding whether a system needs cleaning under TR19®.
Formerly known as Preferred Vacuum Testing (PVT), EVT is the laboratory-verified method recommended by BS EN 15780 and TR19®. We vacuum-sample measured areas of internal duct surface into sealed cassettes, independently lab-weighed to determine deposit levels in grams per square metre — an objective, third-party-verified cleanliness classification.
Wet Film Thickness Testing measures grease deposits inside kitchen extract ductwork in microns — the TR19® Grease benchmark that insurers and fire risk assessors ask for. We test at representative points across the system and report against the compliance thresholds, so you know exactly when a clean is due — and can prove it afterwards. Kitchen extract grease testing in depth →
Every survey concludes with a full report: annotated video and photographic records referenced to your building drawings, test results against BS EN 15780 cleanliness classes, and clear prioritised recommendations. If cleaning or remedial work is needed, we carry out before-and-after verification — so you hold proof of the outcome, not just an invoice.
Surveys and testing are carried out in line with BESA TR19® (Internal Cleanliness of Ventilation Systems), TR19® Grease for kitchen extract, and BS EN 15780 (Ventilation for buildings — Ductwork — Cleanliness of ventilation systems), reported against the standards’ cleanliness quality classes.
And because we’re fire and security specialists first, duct surveys are assessed through a fire-risk lens, not just a hygiene one — damper condition, compartmentation breaches and fire-stopping issues get flagged, not filmed past. Combine a CCTV survey with fire damper testing, ventilation hygiene or pressure testing on the same visit and get a single consolidated compliance picture across commercial kitchens, healthcare estates, data centres and commercial buildings.
A high-resolution camera is fed through your ductwork from existing access points, recording video of the internal condition. Our engineers review the footage live, then provide a report with annotated video, photographs and prioritised recommendations.
Typically up to around 35 metres of duct per access point, depending on system layout. Robotic crawlers and drop cameras let us cover rectangular, circular and vertical ducts, keeping access works and making-good to a minimum.
European Vacuum Testing (formerly known as Preferred Vacuum Testing, PVT) measures the weight of dust deposits inside your ductwork. Samples are vacuumed from measured internal areas into sealed cassettes and weighed by an independent laboratory, giving a grams-per-square-metre result compared against BS EN 15780 thresholds. Because the analysis is independent, the result is objective evidence — not a contractor marking their own homework.
The survey itself isn’t mandated, but under the Regulatory Reform (Fire Safety) Order 2005 the responsible person must manage fire risks — including grease and dust accumulation in ductwork — and BESA TR19® and BS EN 15780 set the recognised benchmarks. A survey with quantified testing is how that compliance is evidenced.
It depends on system type and use. Kitchen extract systems in heavy use should be checked as often as every 3–6 months, while low-risk supply systems may only need inspection every 1–2 years. We recommend an interval based on your survey results and the guidance in TR19® and BS EN 15780.
Yes — through our ventilation hygiene service. Crucially, we verify with before-and-after testing, so you hold proof that the cleaning achieved the required standard — not just an invoice.
A named engineer, not a call centre, comes back within 24 hours. Tell us the building and the system, and we’ll scope the right survey.