Airbrush spray booth

[AlexBB]

That is an exceptionally well argued treatise by Alex’s. It’s much clearer and better focussed than mine. I wish he hadn’t brought up GAMP 5 though. That particular mares nest of a nightmare is behind me .

As further explanation of hazardous substance control, here is the associated hierarchy of control diagram…
[ATTACH=CONFIG]n1197208[/ATTACH]
This diagram reads from top to bottom, with the top tier being the most effective, and the lowest giving the least effective control.

In terms of spray control, if you substitute water based acrylics for lacquers you are performing (obviously) substitution . Using an inbuilt carbon filter or venting to outside is using engineering control. Lastly, if you wear a mask you are using PPE, which is the lowest form of control in an industrial setting.

I would suggest that if you spray for a couple of hours a day, every day, as part of your hobby, you should be looking at kit that gives you engineering control as a minimum, and seriously think about moving up a tier and employing a substitution strategy. If, like me, you spray maybe once or twice a month for perhaps half an hour at a time, then PPE and a well vented area will do you.

Nice explanation Tim Marlow

Yep GAMP 5 is a true nightmare especially when external validation consultants are involved!! :confounded::confounded::tired::rolling:

I remember many projects that never got beyond the URS and Initial Risk assessment stages lol.... Killed dead by estimates for Engineering Controls that made the sirens sound in the Accountants Offices lol.... Started using an intermediate stage with a broad Engineering Design for the FDS and then a broad scope RA and pricing submission to the steering group lol...

Now back to the Hobby Stuff lol....

[KarlW]

Agree with everything written regarding carbon filters. I operated ours in a clean room environment so atmospheric contamination would have been far better controlled, leading to better operational life cycles. I never took that into account.

I would also say that it’s your lungs, you protect them as you see fit. I’ve just typed this up as it may be of interest to some.

Those particulate filter change times are simply outrageous. To me that means one of two things. Either the filters are not correctly sized so they are quickly overloaded, or (cynical view) the company has decided that overselling consumables is a way to supplement income.

A HEPA filter is not a sieve (common misconception), it is a maze. I attended several (five I think) courses run by Pall filtration in the course of my Pharmaceutical production career, and they used very good graphics illustrating this concept.

To summarise, the depth of filtration material to be crossed is what makes a particulate filter effective. The particles drawn in by the air have to navigate labyrinthine pathways as the air crosses the matrix, and eventually, due to the many changes of direction they are subject to, become impacted on the filter wall and are removed from the airstream. As more particles are impacted, the “maze” becomes more involved, so removing particles more effectively.

There are three ways you can get particulate breakthrough in this type of application. The first is mechanical failure of the filter matrix. The second is by the contaminant challenge at one time being too great for the filtration matrix’s ability to remove particulates, and the third is that the challenge partials are too fine for the filter to remove them all so they are carried through on the airstream. The first is eliminated by use of quality components. The others are eliminated by utilising a HEPA filter that has been appropriately sized for the task in hand.

With use a HEPA filter becomes more effective at its primary task, removing particulates. However, as it becomes more efficient at removing particulates, the airflow velocity drops off until it is lower than an effective threshold so rendering the filtration device ineffective. This is when the filter needs to be replaced.

Here’s some background.……My reasons for attending these filtration courses was to enable me to fully understand the concepts involved in worker protection and the design, installation, testing, and maintenance of bio containment equipment. This equipment included protected powder discharge systems and biological laminar flow safety cabinets.

These systems were velocity airflow tested daily, and smoke tested (particulate challenge) at three monthly intervals. No HEPA in my experience had a life of less than two years, and most of these systems ran 24/7/365. I realise that nobody on this forum has the ability to do this at home, but it is the most reliable measurement of filtration efficacy. If you do want to investigate this further, airspeed velocity meters are cheaply available on Amazon…..

However, my experience and knowledge tells me that In infrequent home use a filter in this sort of application should have a much greater life than two months……the HEPA should easily outlast the carbon filter.

It's the same in the aquarium world, filter manufacturers recommend changing the filter media every X months. But this is where the bio-filter that actually does the work lives, so you're basically resetting the aquarium each time.
Best practice is to rinse the media, in aquarium water, to remove solid waste. And only replace once it's broken down too far, and never the whole lot at once.

The bio-filter is a bacteria that eats ammonia (Toxic to fish, but in their waste.) to produce nitrite (Still toxic) which is eaten by other bacteria in the bio-filter to produce nitrate. (Not as toxic, but lots safer.) We remove the nitrate when doing water changes.

[Jim R]

This is the reply to my query from Graphicair.

Thank you for your email,

Correct, the carbon filters are to capture fumes and odours so that we can filter the air and recirculate it back in the room.
You’d spend a lot more on filter replacements for these units.

Ducted ones – all the fumes and odours are extracted straight to atmosphere so less filtration is needed.
We do always try to suggest if suitable a ducted unit over a recirculating one.

I think we are all of one mind now and I feel I have a better understanding than I did 24hours ago :smiling:

[dave]

The Hierachy of Controls takes me back to my lab days, when I was on the units COSHH Committee and reviewing safety controls for the various chemicals in use.

[KarlW]

The Hierachy of Controls takes me back to my lab days, when I was on the units COSHH Committee and reviewing safety controls for the various chemicals in use.

Takes me back to today, currently PPEd up in a biohazard lab, lone working, looking at the diphoterine cabinet wondering what's in here that requires it to be present and why it wasn't mentioned during my walk through earlier. (It was mentioned when I done the clean rooms here.)
Do daily Dynamic Risk assessments here and is sometimes too easy just to tick boxes.

[Tim Marlow]

Takes me back to today, currently PPEd up in a biohazard lab, lone working, looking at the diphoterine cabinet wondering what's in here that requires it to be present and why it wasn't mentioned during my walk through earlier. (It was mentioned when I done the clean rooms here.)
Do daily Dynamic Risk assessments here and is sometimes too easy just to tick boxes.

Probably just for acid or alkali spills Karl. Pretty much standard kit in a lab handling corrosive chemicals these days because it’s much more effective than just rinsing with water.

[KarlW]

Probably just for acid or alkali spills Karl. Pretty much standard kit in a lab handling corrosive chemicals these days because it’s much more effective than just rinsing with water.

Oh it's great stuff, just on lab walk throughs I'm told where it is and where the relevant nasties are stored so I can make a note on my DRA, though to be fair when I'm the only person in the lab and there are no proceses running the risks drop away. I did throw an unlabelled beaker of IPA over myself once, a quick "What's this?" and an equally quick answer saved me jumping under a shower.......
I've got a higher risk lab this morning.......must be accompanied as there's no lone working allowed, even with everything shut down. Infact this is the lab with a recirculating fume cabinet that inspired me to add activated carbon to my spray booth, which recirculates. And allowed me to do more than prime with lacquers.
(I knew there was a point to my posts.)

[stillp]

Thanks Karl and Tim . I hadn't heard of Diphoterine so I went down the rabbit hole of looking it up, then looking up the terms used to describe it...
My experience of risk assessment is mainly about electrical and machinery safety. I kept well away from the process side of things!
Pete

[Waspie]

Too much for moi!! I'll revisit this when I get past elementary airbrushing 101!!!

[Jim R]

You're right Doug. All sounds very complicated and dangerous :rolling:
I'll stick to something easier - bomb disposal or lion taming. Sounds safer :thumb2::tongue-out::tongue-out3:

Just love this forum :thumb2:

[Mark1]

I just stick on my ppe and good to go!

[Tim Marlow]

I just stick on my ppe and good to go![ATTACH=CONFIG]n1197255[/ATTACH]

Don’t forget to stick the hose out of the window Mark

[Jim R]

Don’t forget to stick the hose out of the window Mark

Sticking your hose out of the window can upset the neighbours and get your name on a special register!! :rolling:

[Mark1]

Sticking your hose out of the window can upset the neighbours and get your name on a special register!! :rolling:

Nice to feel special though :tears-of-joy:

[dave]

Somewhere I have a photograph of myself doing a dive in that gear, weighs a ton when you are on the surface