Carbon filter replacement in a salon extractor or purifier is due when the activated carbon has held as much vapour and odour as it can - and that moment depends on how many hours the unit runs, how much monomer and product is used in front of it, and how much carbon it holds. There is no honest single interval. Ravair supplies extraction and the carbon refills that keep it working, and this guide explains why the answer varies, how to tell a spent filter, and how to build a schedule for your own salon rather than someone else's.
The rule that does not vary: HSE's nail bar sheet asks salons to maintain equipment "as advised by the manufacturer, supplier or installer" and to keep a log of "checking, maintenance or parts replacement." Whatever your interval is, write it down and follow it.
Source: HSE COSHH Essentials SR13, Nail bars and other beauty services.
Why is there no single answer?
Because activated carbon works by holding vapour molecules on its surface, and it stops working when that surface is full. How fast it fills depends on three things that differ from salon to salon: how many hours a day the unit runs, how much vapour reaches it - a monomer station used all day loads carbon far faster than a manicure table - and how much carbon is in the filter to begin with. A thin impregnated pad and a kilogram of granular carbon are both "carbon filters"; they do not last the same time.
That is why we sell our refills by weight - 0.5kg for the desktop extractor, 1kg for the desktop Pro unit, 3.5kg for the Home Pro and Salon Pro units - and why any interval printed on a box is a starting point, not a promise. A manufacturer's schedule assumes a typical load; your salon's load is the one that matters.
What are the signs a carbon filter is spent?
The first is smell. Carbon holds odour as well as vapour, so when the monomer smell that used to disappear starts lingering, or the room smells of the last treatment by mid-afternoon, the carbon is no longer holding it. Do not wait for that sign to schedule a change - by then it has been letting vapour through for a while - but treat it as the signal that your interval is too long.
The second is the calendar against your hours. If the unit runs full salon days at a busy enhancement station, the carbon is loading every one of those hours whether or not you can smell it yet. The third is what you find when you open the unit: carbon that has gone from dry and free-running to clumped or discoloured has been working hard. None of these replaces a schedule; together they tell you whether the schedule is right.
How do you build a schedule for your own salon?
Start with the manufacturer's advice for the unit, as SR13 asks, then adjust it to your load. Note the date of a fresh filter and the hours the unit runs each week. Note the first day the smell comes back. The interval between those two dates, shortened a little so that you change before the smell rather than after, is your real-world interval for that station. A quiet manicure table and a busy acrylic desk in the same salon will end up with different dates; that is correct, not inconsistent.
Then put it in the log. SR13 says a user manual or log book "is helpful in setting out the frequency of checking, maintenance or parts replacement," and the same log is what shows an inspector that a control is being maintained rather than merely owned. Extraction is also LEV, which SR13 says needs a statutory thorough examination and test by a competent person at least once every 14 months, with records kept at least five years - the filter log sits alongside that report.
Does the particulate filter follow the same rule?
No - it loads differently. A particulate filter fills with dust, and in a nail bar that is visible: the surface greys and airflow drops. It is changed when it is loaded, on the manufacturer's schedule, and in a busy filing station that can be sooner than the carbon. A station using monomer generally needs both stages, and they rarely fall due on the same day. Our buying guide explains which stages each format of nail dust extractor carries.
What does a change cost, and can you get the refills?
The running cost is the filters, and it belongs in the buying decision. We keep replacement filters and carbon refills for every unit we supply in stock, listed with their prices on the filters and carbon refills page - at the time of writing the 0.5kg desktop refill is £9.99, the 1kg Desktop Pro refill £19.99 and the 3.5kg Home Pro and Salon Pro refills £39.99, though prices change and the listing is authoritative. A unit whose filters you cannot source in a year is a control that stops working, however good it was on day one.
Ravair has been developing practical clean-air and energy products in the UK since 2015. We supply the equipment and the refills and can explain what the guidance asks of them; the COSHH assessment and the thorough examination are the salon owner's duties.
Frequently asked questions
How often should a salon change its carbon filter?
There is no single interval: it depends on the unit's hours, the vapour load at that station and the weight of carbon in the filter. Start from the manufacturer's advice, watch for the smell returning, and set the date for that station a little before it does.
Can I refresh or wash activated carbon?
Spent carbon is replaced, not washed. We sell refills by weight - 0.5kg, 1kg and 3.5kg depending on the unit - so a change means fresh carbon, not a rinsed pad.
Why does my extractor smell of monomer again?
The carbon has held as much vapour as it can and is letting it through. Change it, and shorten the interval for that station in your log.
Do I have to record filter changes?
HSE's SR13 asks salons to maintain equipment as the manufacturer advises and recommends a log of checking, maintenance and parts replacement; it is the evidence an inspector looks for alongside the LEV thorough examination report.
This guide is general information, not health and safety advice. Follow the manufacturer's instructions for your unit and current HSE guidance.
Refills and filters for every unit we supply are on the filters and carbon refills page; call 01892 750777 if you are not sure which fits yours.
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Prices are on the site, delivery is UK-wide, and the team will say when something is not the right fit.