Phoenix Journal · Ductwork
A ventilation survey is only as good as the provider behind it. Here is how to judge competence, accreditation and report quality before you book.
Choosing a provider
A ventilation survey is only as useful as the person holding the camera and writing the report - so the choice of provider matters more than the price on the quote.
If you run a commercial kitchen, you already know that your extract system is a fire-safety asset, an insurance condition and a compliance obligation all at once. A survey is how you find out what state it is really in: how much grease has built up inside the ductwork, where the access is, how the fan and canopy are performing, and what it will take to bring the system back to a defensible standard. Get the survey right and everything downstream - the clean, the certificate, the insurer conversation - becomes straightforward. Get it wrong and you are paying for a document that tells you very little and protects you even less.
The trouble is that "ventilation survey" is not a protected term. Anyone can offer one, and the quality varies enormously. This guide walks you through what a competent provider actually looks like in the UK, what standards and qualifications to insist on, and the questions that quickly separate a genuine specialist from someone with a torch and an invoice.
Start with the standard the work is measured against. For kitchen extract systems the reference point in the UK is BESA's TR19® Grease specification - the stand-alone document focused specifically on the fire risk created by grease accumulation inside extraction ductwork. It sets out how systems should be inspected, how cleanliness is measured, and what a verification report needs to contain. A credible provider will talk fluently about TR19® Grease without prompting, and their paperwork will map to it. If a company cannot tell you which standard they survey against, that is your answer.
Accreditation is the next filter. BESA operates the Vent Hygiene Register (VHR), and VHR-approved contractors are independently audited to confirm they genuinely work to TR19®. That third-party audit is the difference between a firm that says it follows the standard and one that has been checked doing so. Membership is not a marketing badge - it is a verifiable route to competence, and for many insurers and facilities teams it is now the baseline expectation rather than a nice-to-have.
Then look at what the survey physically covers. A thorough kitchen extract survey should follow the system from the canopy and grease filters, through every accessible run of ductwork, to the fan and the discharge point. The surveyor should be recording grease-deposit thickness readings at representative points, noting where access panels exist and, crucially, where they are missing, and photographing the internal condition rather than describing it in the abstract. Deposit measurement matters because TR19® Grease ties recommended cleaning frequency to how heavily the system is used and how quickly grease accumulates - a fact-based reading, not a guess.
Access is where inexperience shows most. In older or awkward premises the ductwork often disappears above ceilings, behind boxing or through voids, and a real specialist plans for that: they know they may need to recommend additional access panels so the whole system can actually be reached and cleaned, not just the easy first few metres. If your kitchen sits below ground or has an unusual layout, this becomes even more important - the airflow and access challenges of ventilation in basement and windowless kitchens are exactly the sort of thing a weak survey glosses over and a good one flags early.
Check before you book
Before you accept any quote, hold the provider against a few hard reference points. These are the numbers and names that a genuine UK specialist will recognise instantly.
If a provider can speak to all three without hesitation, you are dealing with a specialist. If any one of them draws a blank, treat the quote with caution - the shortfall will show up later in the report you are handed and the questions your insurer asks.
The deliverable is where a survey earns its keep. A weak report is a page of reassurance; a strong one is evidence you can hand to an insurer, a fire risk assessor or an environmental health officer and have it stand up. Look for measured grease-deposit readings against the TR19® Grease thresholds, a clear pre-clean and post-clean comparison where cleaning is carried out, dated photographs of the internal ductwork, a recommended cleaning frequency justified by the system's usage, and a certificate on completion that states plainly what was cleaned and to what standard. Vague wording and stock images are red flags - real evidence is specific to your building.
If your site also runs local exhaust ventilation - fume or dust control beyond the kitchen canopy - the competence bar is set by law rather than good practice. Under COSHH Regulation 9 every LEV system must undergo a thorough examination and test at least every 14 months, and the HSE expects that work to be done by a competent person. The recognised qualification is BOHS P601, and the technical benchmark is the HSE's HSG258 guidance. If a provider is offering LEV testing, ask directly whether their testers hold P601 and whether their reports follow HSG258. A capable firm answers without pausing.
A few practical questions cut through the sales talk quickly. Ask who actually attends site and what they are qualified to do - not the company's credentials in general, but the individual's. Ask to see a sample report so you can judge the evidence quality before you commit. Ask how they handle systems where access is limited, and whether the quote includes fitting the access panels the clean will need. And ask how they arrive at a recommended frequency - the honest answer references usage and measured deposits, not a flat annual default. General ventilation is commonly inspected every 12 months, but a heavily used kitchen extract may need attention far more often, and only a survey grounded in real readings can tell you which applies to you.
Older and unusual buildings deserve extra scrutiny. Duct routes drawn decades ago rarely match what is on site now, and the survey needs to account for that reality rather than assume a tidy layout - our guide on how to spec a ventilation survey for an older building goes into the detail worth building into your brief. The theme running through all of it is the same: insist on evidence, insist on named competence, and insist on a report you could defend to a third party. A provider who welcomes those questions is one worth booking.
Questions
For kitchen extract work, look for membership of BESA's Vent Hygiene Register (VHR), which independently audits contractors to confirm they work to the TR19 Grease standard. If the provider also offers LEV testing, their testers should hold the BOHS P601 qualification and follow HSE guidance HSG258. These are verifiable credentials rather than marketing badges, so it is fair to ask for evidence.
A defensible report includes measured grease-deposit readings taken against the TR19 Grease thresholds, dated photographs of the internal ductwork, and a clear before-and-after comparison where cleaning is carried out. It should also give a recommended cleaning frequency justified by how heavily your system is used, plus a completion certificate stating what was cleaned and to what standard. Vague wording and stock images are warning signs.
There is no single fixed interval - TR19 Grease ties frequency to how much grease your system accumulates, which depends on usage. General ventilation is commonly inspected around every 12 months, but a heavily used kitchen extract may need attention far more often. A survey based on real deposit readings is the only reliable way to set the right frequency for your kitchen.
No. Local exhaust ventilation (LEV) testing covers fume and dust control systems and is a legal duty under COSHH Regulation 9, which requires a thorough examination and test at least every 14 months by a competent person. A kitchen grease extract survey is assessed against TR19 Grease instead. Some providers offer both, but they are distinct pieces of work with different standards and qualifications behind them.
Phoenix Duct Clean · by the numbers
Phoenix surveys and cleans kitchen and building ductwork to the TR19 standard - measured, cleaned and certificated, UK-wide.