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I'm in the process of knocking up a mini airbrush booth to paint in my spare room with, that has a nice enclosed area to protect from overspray and a fan+filter system on the back of it. But I'm now wondering what the recommended airflow / pressure should be on the fan, so that I don't end up with something that simply isn't strong enough and I would have been better off not bothering haha.

Size of the booth is about 35cm x 35cm, so it's pretty compact. I was going to use a PC case fan, something like a 120mm or 140mm model.

I could use two fans, but that may end up meaning two separate filter assemblies. Which isn't a big deal, just rather avoid if not necessary

It will be pulling/pushing air through a standard paint filter (the normal screen you get in airbrush booths), as well as a second hepa/carbon filter, so may perhaps need to over estimate slightly.

My self made booth is 50x35cm and i am using a 140x140mm 12V pc fan. As you can see the airflow is sufficient to catch overspray. The filter pad i am using is one made for a kitchen hood, cut to fit the fan hole. Its held in place by the suction of the fan, no need for a holder. Its not pretty, but it works fine.

Spray booth design does not look so much at CFM as it does LFM. We care about how fast the air is moving through the aperture (fast enough to get the particulate and vapors out, but not so so fast that the paint is sucked out before it can hit the model). Based on that we calculate the CFM required to achieve it.

Its been discussed to death over at Fine Scale Model. The short hand is you want 80-100LFM....AFTER any any all resistance is taken into account. In other-words, you don't calculate your CFM and then get a fan rated at that. You need to add the resistance of the baffle, and every inch and curve in your output duct, and add that all up.

So lets say the aperture of your booth is 2 square feet (16x18" for example). You need 200 CFM "free air". But add a few feet of smooth duct and a couple curves and you might need 250+. Use flex-duct and your need could exceed 350CFM. There are tables you can use to calculate all this.

PC case fans dont come close to cutting it, even if you use several to get your target CFM: they are terrible at overcoming resistance (even the so called pressure optimized ones). You need a blower, and a fairly significant one IF you want to "do it right".

Not to mention the whole flamable thinners issue: forget "bathroom" fans, range hoods, and yes even PC fans. You really need a shaded pole blower which places the motor apart from the air-stream completely.

Dont be fooled by hobby spray booths either: most are horribly (and deceptively) inadequate.

 Sunsanvil wrote:
Spray booth design does not look so much at CFM as it does LFM. We care about how fast the air is moving through the aperture (fast enough to get the particulate and vapors out, but not so so fast that the paint is sucked out before it can hit the model). Based on that we calculate the CFM required to achieve it.

Its been discussed to death over at Fine Scale Model. The short hand is you want 80-100LFM....AFTER any any all resistance is taken into account. In other-words, you don't calculate your CFM and then get a fan rated at that. You need to add the resistance of the baffle, and every inch and curve in your output duct, and add that all up.

So lets say the aperture of your booth is 2 square feet (16x18" for example). You need 200 CFM "free air". But add a few feet of smooth duct and a couple curves and you might need 250+. Use flex-duct and your need could exceed 350CFM. There are tables you can use to calculate all this.

PC case fans dont come close to cutting it, even if you use several to get your target CFM: they are terrible at overcoming resistance (even the so called pressure optimized ones). You need a blower, and a fairly significant one IF you want to "do it right".

Not to mention the whole flamable thinners issue: forget "bathroom" fans, range hoods, and yes even PC fans. You really need a shaded pole blower which places the motor apart from the air-stream completely.

Dont be fooled by hobby spray booths either: most are horribly (and deceptively) inadequate.

What you're saying is what I thought was the case, however my understanding, though it's fairly rudimentary, is that the static pressure of the fan also plays a big part. If the fan is rated with a higher static pressure, then it will suffer from less loss of airflow due to filters/baffles/whatever.

What 'blower' style fan would you recommend for a 30x30 cm enclosure? The only ones I've seen seem to be designed for huge spray areas, apart from one or two 'miniature' ones with are multiple hundreds of pounds (and certainly not what any hobby painter is using).

Edit: Also I only paint in acrylics, so I suspect the chance of explosion is fairly slim.

Niiru wrote:
...the static pressure of the fan also plays a big part. If the fan is rated with a higher static pressure, then it will suffer from less loss of airflow due to filters/baffles/whatever.

Indeed. The key is knowing what the cfm of the fan is at a given static pressure. You calculate your duct resistance, then find a fan which will deliver the desired CFM at the corresponding pressure.

What 'blower' style fan would you recommend for a 30x30 cm enclosure? The only ones I've seen seem to be designed for huge spray areas, apart from one or two 'miniature' ones with are multiple hundreds of pounds (and certainly not what any hobby painter is using).

I dont think you need to be into "hundreds" of pounds/dollars, but if one wants to "do it right", one will need to spend some money. One brand/line which comes up frequently in discussions of airbrush paint booth building are the Dayton Shaded Pole Blowers. Models range from an almost worthless 50CFM up to a howling 500! Most important is the specs. Take the 6FHX9 just as an example: quoted as 265CFM..."free air". @ 0.500-In. SP it almost halves down to just 135CFM!

You need to start with a basic design, including aperture and amount of duct (size, length, and corners), figure out what you need for a blower, weight that against what you are willing to spend, and adjust your design accordingly.

I've seen too many DIY'ers who mistakenly think their $20 50CFM bathroom fan connected to miles of flexduct is doing them any good at all. lol.

If you are at all handy, and don't mind spending at least some money, its not hard to design and make something which far far exceeds what crappy "hobby" booths can do, and/or spend less than what the few "proper" airbrush booths cost. I used to have all the calc tables saved...somewhere. If you are really interested I'll dig them out again.

Also I only paint in acrylics, so I suspect the chance of explosion is fairly slim.

Perhaps, though do keep in mind some acrylics are based on glycol ether (a type of flammable alcohol) as are many thinners for acrlylics. Tamiya X-20, and Vallejo's Airbrush Thinner (the clear one) are examples.

In any event, always ware a decent respirator with cartridge appropriate to the material in question... even if you have a spray booth. Its awfully inexpensive protection for your lungs. Even solvent-free acrylic is not something you want to be ingesting in droplet form.

Sunsanvil is right on this. I've built a few booths over the years and always based them on "squirrel cage" type impellers. The amount of airflow needed is a lot more than you think and the outlet hose and vent system needs to be factored in. I usually use furnace air filters because they are very easy to get, and generally cut them in half. And I always add in a fluorescent light fixture as well. Simple to make really. Square box of thin plywood. Smaller box for the plenum and you're done. Caveat - Don't make it too small. You'll never know what you might end up modelling later.

Always clean my airbrushes with lacquer thinner and it doesn't stink up the house. But it probably might discolor slightly the screen of the window it vents through. So Caveat Emptor

 Sunsanvil wrote:
Snip

~Interesting, giving me a lot to think about. Those fans don't seem to exist in the uk (under that brand anyway), but they seem to work out at about £200 a fan.

I'm pretty sure that hardly any (if any) of the 40k / model sprayers that I know of are using anything like this. Going from the numbers, it seems designed to be used for industrial applications, where the booth is in the scale of cubic meters.

Not saying that this isn't what's required for a tiny model hobby booth... just concerned by the number of people on here who will be dead in a couple of years if this is true.

Seriously considering just returning the airbrush, as I can't afford to spend £300-£400 on a booth to spray little models in.


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 Grimoir wrote:
Sunsanvil is right on this. I've built a few booths over the years and always based them on "squirrel cage" type impellers. The amount of airflow needed is a lot more than you think and the outlet hose and vent system needs to be factored in. I usually use furnace air filters because they are very easy to get, and generally cut them in half. And I always add in a fluorescent light fixture as well. Simple to make really. Square box of thin plywood. Smaller box for the plenum and you're done. Caveat - Don't make it too small. You'll never know what you might end up modelling later.

Always clean my airbrushes with lacquer thinner and it doesn't stink up the house. But it probably might discolor slightly the screen of the window it vents through. So Caveat Emptor

Can't vent direct to a window, hence the plan was to filter the outflow. There's nothing in what I'm painting with that's not collectable by a filter. However it turns out I'd need to spend a fortune on a spray booth. I really don't know why this isn't more widespread information - most of the other spray booths I've seen people using on here (like 90% of the painters, if not more) are just using a small booth and normal fans.

Surprised those hobby booths can even be sold, they seem to be literally killing people.

 Sunsanvil wrote:

Niiru wrote:
...the static pressure of the fan also plays a big part. If the fan is rated with a higher static pressure, then it will suffer from less loss of airflow due to filters/baffles/whatever.

Indeed. The key is knowing what the cfm of the fan is at a given static pressure. You calculate your duct resistance, then find a fan which will deliver the desired CFM at the corresponding pressure.

What 'blower' style fan would you recommend for a 30x30 cm enclosure? The only ones I've seen seem to be designed for huge spray areas, apart from one or two 'miniature' ones with are multiple hundreds of pounds (and certainly not what any hobby painter is using).

I dont think you need to be into "hundreds" of pounds/dollars, but if one wants to "do it right", one will need to spend some money. One brand/line which comes up frequently in discussions of airbrush paint booth building are the Dayton Shaded Pole Blowers. Models range from an almost worthless 50CFM up to a howling 500! Most important is the specs. Take the 6FHX9 just as an example: quoted as 265CFM..."free air". @ 0.500-In. SP it almost halves down to just 135CFM!

You need to start with a basic design, including aperture and amount of duct (size, length, and corners), figure out what you need for a blower, weight that against what you are willing to spend, and adjust your design accordingly.

I've seen too many DIY'ers who mistakenly think their $20 50CFM bathroom fan connected to miles of flexduct is doing them any good at all. lol.

If you are at all handy, and don't mind spending at least some money, its not hard to design and make something which far far exceeds what crappy "hobby" booths can do, and/or spend less than what the few "proper" airbrush booths cost. I used to have all the calc tables saved...somewhere. If you are really interested I'll dig them out again.

Also I only paint in acrylics, so I suspect the chance of explosion is fairly slim.

Perhaps, though do keep in mind some acrylics are based on glycol ether (a type of flammable alcohol) as are many thinners for acrlylics. Tamiya X-20, and Vallejo's Airbrush Thinner (the clear one) are examples.

In any event, always ware a decent respirator with cartridge appropriate to the material in question... even if you have a spray booth. Its awfully inexpensive protection for your lungs. Even solvent-free acrylic is not something you want to be ingesting in droplet form.

Got any examples of "proper" airbrush booths. Currently using one I got off amazon so I guess im running the cheapo budget version. Its better than nothing but once im looking to set up my paint/hobby area am happy to invest into a good set up.

Use an old vacuum cleaner with hepa filter

I used to use one on power tools in the garage stopped the saw dust going everywhere.

I also used to have in my PC, a 200cfm delta focus flow 120mm fan, it was so loud at 12v that I had to run it at 5v

Niiru wrote:
~Interesting, giving me a lot to think about. Those fans don't seem to exist in the uk (under that brand anyway), but they seem to work out at about £200 a fan. (...) Going from the numbers, it seems designed to be used for industrial applications, where the booth is in the scale of cubic meters.

Maybe you are doing the FX in the wrong direction? Something like the 6FHX9 is US$120...which is less than £100.

Seriously considering just returning the airbrush, as I can't afford to spend £300-£400 on a booth to spray little models in.

Well hang on, lets back up a bit. What are you wanting to achieve with a spray booth? While a spray booth is certainly nice to have, in some circumstances it is not absolutely necessary. Your primary concern is always your lungs, and a $40 3M 7000 series respirator (with appropriate cartridge!) satisfies that aptly. If the concentration of solvent fumes is low, a simple box fan in a window will do to keep the accumulation down low (and clear the room when you are done). The room in question WILL get VERY dirty/dusty over time of course so you wouldn't want to do this in a room with finished models on display, or TV/Stereo equipment, or fine furniture etc. Now, if your concern is primarily capturing paint dust, with no venting to the outside, the paradigm is completely different: now we need to talk about filters and how effective (or not) they are for the task at hand. In the case of something like acrylic paint, by the time its 18" away from the airbrush, it has turned into paint dust, just a few microns in size (I have data from Badger somewhere). There is still the question of what happens to solvent based cleaning fluids though.

 Grimoir wrote:
But it probably might discolor slightly the screen of the window it vents through. So Caveat Emptor

Indeed. A friend of mind had a lovely booth setup at his apartment (he was heavy into lacquers at the time). When he left, there was a streak down the side of the building below his window...a lovely shade of every color he had ever used. LOL.


Automatically Appended Next Post:

 Argive wrote:
Got any examples of "proper" airbrush booths. Currently using one I got off amazon so I guess im running the cheapo budget version. Its better than nothing but once im looking to set up my paint/hobby area am happy to invest into a good set up.

Its been a while since I went shopping, but the last time I had a critical look, the best bang for the buck was the Paasche HSSB-22-16. All steel construction, it has a 2.4sq.ft aperture and a 270CFM fan. If we quote on the low end and say 80LFM (assume we are doing fine work) then we only need 195CFM which leaves some capacity to overcome prefilter and some rigid duct work. Not inexpensive of course (street price usually around US$300), and it has gone through revisions over the years: at one time it employed a blower, now it looks like they've switched to an axial fan.

The other booth which has an decent reputation, but is similarly overpriced, is the ArtoGraph 1530. Lager aperture. Downdraft (as compared to the Paache's back/up draft), it uses axial fans totaling 370CFM ("free air"). While it has duct hookups, it is marketed as being a holistic filter design: Coarse filter, fine filter, and then charcoal filter (to capture OV). While 370CFM sounds like a lot, by the time you push through all that, I'd say it sounds about right.

EDIT: the 1530 is listed as discontinued, though replacement filter material is still being sold.

Quick side note: if anyone goes looking, they will notice that Paasche also has a cheaper plastic 16x13 which by all accounts comes off the same factory line as the ubiquitous made-in-china one sold under myriad generic brand names. This concerned me because those are categorically inadequate so I contacted Paasche a while back. At that time they asserted that they spec a higher CFM fan in theirs compared to the generics, but it was so long ago I cant recall the details (notice they dont say on their website, unlike all their other models). Seems to me I judged it to still be inadequate (else I would have bought one I think). If I can find the email exchange in my archive, I'll edit this post.

All this underscores the fact that A) Good PROPER hobby booths are not cheap and B) building something comparable on your own is substantially less expensive... but does require some education. There is a saying "it costs just as much to do it wrong as it does to do it right".

Any chance you could link a good source site I can look at these fancy booths? The links arent working, but it might be because of my work PC security BS..

I honestly have never bought one of the fan assemblies new. So I cannot speak to the cost. However, in the US they are commonly found at "Ham Radio" flea markets because Amateurs use them to pressurize their final amplifier. Which also explains why they work so good for a booth They can provide reasonable pressure and maintain good airflow.

 Argive wrote:
Any chance you could link a good source site I can look at these fancy booths? The links arent working, but it might be because of my work PC security BS..

Links are working from a couple different PCs/locations. They are the manufacturer websites. Try googling the model names I've given.

 Sunsanvil wrote:


Well hang on, lets back up a bit. What are you wanting to achieve with a spray booth? While a spray booth is certainly nice to have, in some circumstances it is not absolutely necessary. Your primary concern is always your lungs, and a $40 3M 7000 series respirator (with appropriate cartridge!) satisfies that aptly. If the concentration of solvent fumes is low, a simple box fan in a window will do to keep the accumulation down low (and clear the room when you are done). The room in question WILL get VERY dirty/dusty over time of course so you wouldn't want to do this in a room with finished models on display, or TV/Stereo equipment, or fine furniture etc. Now, if your concern is primarily capturing paint dust, with no venting to the outside, the paradigm is completely different: now we need to talk about filters and how effective (or not) they are for the task at hand. In the case of something like acrylic paint, by the time its 18" away from the airbrush, it has turned into paint dust, just a few microns in size (I have data from Badger somewhere). There is still the question of what happens to solvent based cleaning fluids though.

I'm based in the UK, so I'm not sure if my sources for respirators/masks would be any different. When I search for that 3M 7000 series I get options for dust masks, half masks, and full-face biohazard jobs..

My goal was to have a small paint booth that extracts overspray etc via a strong fan at the back and through a hepa filter (which seems to be a stronger filter than what is used in any of these booths).

I was still intending to use a mask, especially if I ever did spray something like a Tamina Clear paint. What mask would you recommend? I did a quick search on dakka, and the recommended masks (such as the 3M™ Particulate Respirator 8514, N95) were again in the £200 + range. They seem to be much cheaper in the US though, so I guess it's an import issue.

That seems a little much for a disposable mask

Reading the 3M sheet about the mask indicates that it is for welding so deals with metal vapours and organic vapour through activated charcoal layers.

I went for a £20 reusable filter mask from screwfix with P3 filter cartridges. It's actually pretty comfortable to.wear.



Automatically Appended Next Post:
To clarify, I just went for particulate filters and I deal with fumes through ventilation (I spray next to an open door to the outside).

Niiru wrote:
I'm based in the UK, so I'm not sure if my sources for respirators/masks would be any different. When I search for that 3M 7000 series I get options for dust masks, half masks, and full-face biohazard jobs.

The half -face respirator is what I like (#7503). Shouldnt be any more than equivalent of C$40. Super comfortable! Please understand that reusable respirators like these are adapted to a wide array of tasks by virtue of the filter choice. For example, if you are working with lacquers and lacquer thinners, you'll need the organic Vapor cartridge (#6001). If there is dust involved as well, we add the N95 particulate on a retainer over the OV cart (#5N11+#501). If on the other hand you were just sanding resin, an N95 or N99 would do. Personally, I use a P100 with "nuisance ov relief" (#2097). Its the highest level of particulate protection you can get (great for sanding work!). Not enough OV protection for things like lacquers though (its just for "nuisance" levels of OV, which is to say levels not exceeding OSHA exposure limits).

My goal was to have a small paint booth that extracts overspray etc via a strong fan at the back and through a hepa filter (which seems to be a stronger filter than what is used in any of these booths).

Although this sounds like a reasonable and tenable goal, I dont believe its going to be practical. A true HEPA filter will be completely clogged after just one painting session! You'd have to design and implement a multistage filter (coarse, medium, fine). Is there no window at all in the room you plan to work in?

I did a quick search on dakka, and the recommended masks (such as the 3M™ Particulate Respirator 8514, N95) were again in the £200 + range. They seem to be much cheaper in the US though, so I guess it's an import issue.

I'm almost certain what you priced was a carton full of them. A lot of safety equipment like this is sold in bulk for workshops, factories etc. A box of 10 8514s is around C$100... and IMO a waste of money. Although they do at least have an exhale valve (cheaper disposables dont even have that), you will just throw them out in short order....and you dont even have the option of ov protection.

In case anyone is interested, when a filter/mask is quoted as "N95", the N means it is only for Non-oil substances. The 95 means it captures at least 95 % of particles down to 0.3 microns. N99 would be the same thing but capturing 99%. P100 by comparison is oil proof capturing at least 99.97% of particles down to 0.3 micro. Neither does anything for organic vapors. If a filter doesn't explicitly state OV/organic vapor protection, then it does NOTHING to filter them (and I do mean nothing...they go right through!). There are a butt load of other filter classifications but these are the most common in our hobby.

I'd be remiss if I didnt also mention: beards/facial hair is pretty much out. The half-face respirators dont work if the seal is resting on whiskers. lol

 Sunsanvil wrote:

Niiru wrote:
I'm based in the UK, so I'm not sure if my sources for respirators/masks would be any different. When I search for that 3M 7000 series I get options for dust masks, half masks, and full-face biohazard jobs.

The half -face respirator is what I like (#7503). Shouldnt be any more than equivalent of C$40. Super comfortable! Please understand that reusable respirators like these are adapted to a wide array of tasks by virtue of the filter choice. For example, if you are working with lacquers and lacquer thinners, you'll need the organic Vapor cartridge (#6001). If there is dust involved as well, we add the N95 particulate on a retainer over the OV cart (#5N11+#501). If on the other hand you were just sanding resin, an N95 or N99 would do. Personally, I use a P100 with "nuisance ov relief" (#2097). Its the highest level of particulate protection you can get (great for sanding work!). Not enough OV protection for things like lacquers though (its just for "nuisance" levels of OV, which is to say levels not exceeding OSHA exposure limits).

My goal was to have a small paint booth that extracts overspray etc via a strong fan at the back and through a hepa filter (which seems to be a stronger filter than what is used in any of these booths).

Although this sounds like a reasonable and tenable goal, I dont believe its going to be practical. A true HEPA filter will be completely clogged after just one painting session! You'd have to design and implement a multistage filter (coarse, medium, fine). Is there no window at all in the room you plan to work in?

I did a quick search on dakka, and the recommended masks (such as the 3M™ Particulate Respirator 8514, N95) were again in the £200 + range. They seem to be much cheaper in the US though, so I guess it's an import issue.

I'm almost certain what you priced was a carton full of them. A lot of safety equipment like this is sold in bulk for workshops, factories etc. A box of 10 8514s is around C$100... and IMO a waste of money. Although they do at least have an exhale valve (cheaper disposables dont even have that), you will just throw them out in short order....and you dont even have the option of ov protection.

In case anyone is interested, when a filter/mask is quoted as "N95", the N means it is only for Non-oil substances. The 95 means it captures at least 95 % of particles down to 0.3 microns. N99 would be the same thing but capturing 99%. P100 by comparison is oil proof capturing at least 99.97% of particles down to 0.3 micro. Neither does anything for organic vapors. If a filter doesn't explicitly state OV/organic vapor protection, then it does NOTHING to filter them (and I do mean nothing...they go right through!). There are a butt load of other filter classifications but these are the most common in our hobby.

I'd be remiss if I didnt also mention: beards/facial hair is pretty much out. The half-face respirators dont work if the seal is resting on whiskers. lol

It was for a single mask. The actual price was a lot lower, but there was a large import cost involved. I'd have to source an option that's available in the UK (through mainstream channels).

So which mask / filters would I require for painting with Vallejo Game Color Acrylics? With occasional use of Tamiya Clear and ... that's probably about it really. I know you listed a lot of different options for a lot of use cases, but none of them seemed to be relevant to painting models.. The P100 you mentioned seemed like it might be the one you were recommending?

Also there is a window in my room, which will be open, but it's on the back wall opposite where the desk is. And the desk is huge, and only fits in the room on it's current wall (and moving it isn't really an option anyway). It would take about 3 or 4 meters of piping to pipe from the airbrush chamber, up the wall, round the walls to the window and out... and no, this is not an option lol. Maybe if I lived alone, but my setup needs to be something that can be easily and quickly folded down and stored away when not in use.

The Hepa filter is only the final filter before the fan, before that will be the normal filtering material (the... I forget the name, but the standard particle catching loose foam that normally lines the back of spray chambers). So the hepa should only be catching the very tiny overspray particles. I haven't tested this yet of course, but I'd expect it to last multiple painting sessions without too much issue. And they come in packs of two.

As far as masks go, these are what are available:
3M Half Mask

There also seems to be one that comes with weird P100 pads? - Pads+Mask

Otherwise theres the trapezoid filters which are about £40 for a pair.

Indeed the ArtoGraph 1530 was a tiered filter design. Media is still available so that might be a good design reference for you. In any event you'll want a fan in the window regardless.

For your lungs, the safest thing is of course to err on the side of caution: full OV cartridge + particulate. P100 with nuisance OV is not a substitute as it should only be used where concentrations are so low they dont constitute a hazard in the first place (hence the term "nuisance"). Also note that not all P100 filters have nuisance ov incorporated.

The 3M 6000 series you found on amazon is good, 7500 is better. The 6000's main material is plastic, the 7500's silicon (although that might be an allergy concern for some), and has a better exhale value. They both use the same filters. Both are available in 3 sizes. Do you have an industrial supply outlet, or workplace health and safety supply store you can call on? Ironically, such places ten to be dramatically less expensive than consumer hardware stores because they are accustomed to selling at bulk pricing, but usually dont mind selling to an individual. They might be able to point you to a comparable brand more common in the UK, advise on filter choice etc.

 Sunsanvil wrote:
P100 with nuisance OV is not a substitute as it should only be used where concentrations are so low they dont constitute a hazard in the first place (hence the term "nuisance"). Also note that not all P100 filters have nuisance ov incorporated.

OK now I'm really confused... you JUST SAID that the P100 is what you yourself use! If you use it anyway, but it's not good enough, then what's the point? You're telling me I need full hazmat gear or I'll die from paint fumes, while simultaneously telling me that you use normal stuff and are fine. I'm guessing it's a "I know the risks and decided to take them" but then that seems pretty weird.

What filter SHOULD I be looking for then, if the one you use is not up to the job?

This seems to be basically full hazmat particulates and volatiles.

The 3M 6000 series you found on amazon is good, 7500 is better. The 6000's main material is plastic, the 7500's silicon (although that might be an allergy concern for some), and has a better exhale value. They both use the same filters. Both are available in 3 sizes. Do you have an industrial supply outlet, or workplace health and safety supply store you can call on? Ironically, such places ten to be dramatically less expensive than consumer hardware stores because they are accustomed to selling at bulk pricing, but usually dont mind selling to an individual. They might be able to point you to a comparable brand more common in the UK, advise on filter choice etc.

I don't know of any local industrial supply outlets. I can look around, but any places around here would likely only sell via online orders or to suppliers. I'l look though.

The only person I vaguely know who's 'in the business', when I asked what kind of cartridges I would need for non-toxic child safe acrylic paints, told me he would just wear a painters dust mask and turn a fan on.