Face masks for use when vaporising OA

[Erichalfbee]

 

[Repwoc]

Oxalic acid has a Short term exposure limit ( STEL) of 2 mg/m3 ,( ref EH40/2005 workplace exposure limits- Page 17 list of work place exposure chemicals.)

Purely as a matter of interest, do you know how this concentration was deduced?

 

[Poly Hive]

I would think it comes from the MSDS from the manufacturer.

PH

 

[Repwoc]

I would think it comes from the MSDS from the manufacturer.

PH

OK, how does the manufacturer work it out?

 

[Camey]

Purely as a matter of interest, do you know how this concentration was deduced?

Hi Paul, as you can imagine, same as most chemicals, mostly in the labs, testing toxicity levels and using the results to determine comparable effects on humans.

 

[charlievictorbravo]

Just thought I’d give a “quick” comment regarding beards and face masks. I am a new first year bee keeper and have realised by taking a very non scientific straw poll, namely looking around at the bee keepers in my area and local group and on line that there are a reasonable number of beeks who like the bearded bee keeper look.
My “exciting” day job is an offshore Health and safety advisor and Medic, one task involves the responsibility with Respiratory protective equipment ( RPE), including workforce teaching/ training of hazards and controls related to RPE protection. This included carrying out face fit testing. Which legally in the UK requires the person to be clean shaven. I also noted a comment re positive pressure being more of an issue for bearded bee keepers, although a reasonable thought process it’s incorrect. The reverse of that is true. If you were well off enough to have a positive pressure RPE mask, that is the pressure within the mask is higher than the outside environment E.G 3m Versaflo TR-300 Powered Air Respirator then the wearing of beard is not as bad an issue due to the positive pressure keeping any external gases from being breathed in. However if wearing any of the “standard” negative pressure masks I/.E. air pressure inside the mask during inhalation is negative in respect to air pressure outside the respirator. For example (3m 4255 half mask with P3 filter) anything that can disturb the seal will prevent the mask from doing its job and leakage will occur at the seal.
Sublimation of Oxalic acid has been discussed frequently. Oxalic acid has a Short term exposure limit ( STEL) of 2 mg/m3 ,( ref EH40/2005 workplace exposure limits- Page 17 list of work place exposure chemicals.) The usual vaporised dose quoted to use per colony is around the 1.5 to 2 grams mark. Obviously not all of that would vaporise and it is usually carried out in a well ventilated area however it can be seen that it is possible to be well over the exposure limit.
In summary – it’s your choice, my advice is if vaporising oxalic acid and using face masks, use a P3 filter and also ensure you also have a good seal on the mask around your face, having facial growth or a beard will not give an adequate seal. Or splash out for a positive pressure set up if you like the beard.

Thanks for the helpful post - it's good to have posts from people with knowledge rather than suppositions. In a work environment, how would your company deal with RPE for people who wear spectacles - a full face mask would not make a seal around the arms of the glasses. That leaves an option of half-face mask and coverall goggles. As there's no negative air pressure inside the goggles, Oxalic Acid vapour would not enter - or is that just wishful thinking?

They other issue I'm struggling with is what filter to use. A P3 particulate filter would work provided that we were sure that all the vaporized gas had condensed into OA crystals. If there's any true vapour there then you would also need a organic acid filter. With the 3M mask, there's an option of combining filters to cover both eventualities - particulate and organic acid.

The situation is that I vapourise 2 gm of treatment (OA is the active ingredient) and I suspect that less than 5% emerges from the hive as a white cloud via the entrance or the mesh floor and roof. It leaves the heating equipment at a temperature just over 157°C (the vapourising/sublimating temperature) and, I suspect, it immediately starts to cool and condense into micro-crystals of OA, suspended in the air until it sticks to something - a bee, a frame, a lung, an eyeball, etc. Trouble is, it's beekeepers who are leading the way on this - no academics have done practical research into how to do vapourising, how to stay safe while doing it and how OA vapour kills mites, etc. It all pretty basic stuff that we are finding out as we go along. My view, for what it's worth, is that the P3 filter is PROBABLY good enough, but I don't know whether there's any true vapour in the white cloud of vapourised OA.

Sorry about the above essay but we need to try to get some clarity on this and it's not often we get an expert on here.

 

[Poly Hive]

Repwoc I would imagine that the maker unless they have labs able to work out the lethal dose would use a contract lab.

PH

 

[Buzzlodge]

Hi Paul, as you can imagine, same as most chemicals, mostly in the labs, testing toxicity levels and using the results to determine comparable effects on humans.

The acceptable limit is never set at the toxicity level (where first effects are seen). I think 1% of it might be typical.

 

[Nige.Coll]

A simple paper mask is supplied with a varrox.
If your using the varrox correctly their should be very little leakage.
The hive is sealed so no vapour should really escape and the pan is cooled between applications.

If your using a sublimox then a full face mask with protection from organic acids is sufficient.

 

[Camey]

Thanks for the helpful post - it's good to have posts from people with knowledge rather than suppositions. In a work environment, how would your company deal with RPE for people who wear spectacles - a full face mask would not make a seal around the arms of the glasses. That leaves an option of half-face mask and coverall goggles. As there's no negative air pressure inside the goggles, Oxalic Acid vapour would not enter - or is that just wishful thinking?

They other issue I'm struggling with is what filter to use. A P3 particulate filter would work provided that we were sure that all the vaporized gas had condensed into OA crystals. If there's any true vapour there then you would also need a organic acid filter. With the 3M mask, there's an option of combining filters to cover both eventualities - particulate and organic acid.

The situation is that I vapourise 2 gm of treatment (OA is the active ingredient) and I suspect that less than 5% emerges from the hive as a white cloud via the entrance or the mesh floor and roof. It leaves the heating equipment at a temperature just over 157°C (the vapourising/sublimating temperature) and, I suspect, it immediately starts to cool and condense into micro-crystals of OA, suspended in the air until it sticks to something - a bee, a frame, a lung, an eyeball, etc. Trouble is, it's beekeepers who are leading the way on this - no academics have done practical research into how to do vapourising, how to stay safe while doing it and how OA vapour kills mites, etc. It all pretty basic stuff that we are finding out as we go along. My view, for what it's worth, is that the P3 filter is PROBABLY good enough, but I don't know whether there's any true vapour in the white cloud of vapourised OA.

Sorry about the above essay but we need to try to get some clarity on this and it's not often we get an expert on here.

Hi CVB,
your right " probably good enough" its like every task, needs to be taken in context. look at the hazards and likelihood of them happening and put relevant controls in place. So for sublimation the main hazard is breathing in the vapour cloud, less of a hazard is getting it in your eyes, and getting a hot finger.
Controls already in place are;
. block up the hive to minimize any residual gas escape.
. Work on a day where there is a light breeze and work upwind of the breeze.
. Ensure any escaped gas will not effect anyone else.
RPE and PPE are in reality the last line of defence, best to prevent the potential exposure to a person with other controls first.
As controls above are in place then the RPE and Goggles are a further control to ensure you have protected yourself against any escaped gas that drifts into your breathing zone.
As we are not talking about a work regulated environment then the onus is on the individual to protect themselves and significant others.
Personally I use a Sundstrom SR100 half mask with a combination filter SR229-2 ABEK1HgP3 and wear tight fitting goggles, as you say any residual gas wafting around is not under pressure and therefore not going to force into the goggles, you can buy protective goggles that will fit over your prescription glasses. PS- heat proof gloves are also a handy addition hope this helps.

 

[Poly Hive]

What is supplied with a bit of kit is frankly immaterial. Is it suitable is your decision not the manufacturers as they are looking at costs. Actually they could save a bomb by supplying an advice note quoting the right type of PPE for the buyer to use.

Would I trust a paper mask when dealing with fumes? NO, no and no.

PH

 

[madasafish]

What is supplied with a bit of kit is frankly immaterial. Is it suitable is your decision not the manufacturers as they are looking at costs. Actually they could save a bomb by supplying an advice note quoting the right type of PPE for the buyer to use.

Would I trust a paper mask when dealing with fumes? NO, no and no.

PH

As i wear glasses, I find paper masks (and any other mask without a breathing mechanism) impossible to use as breath from my nose ends up passing my glasses and depositing vapour on them... so I cannot see properly..

I HATE paper masks with a vengeance - and they are useless in dusty conditions I find as they clog up quickly...

 

[Poly Hive]

Yes we spend a lot of money offshore experimenting as we all HAD to wear safety glasses even when it created it's own hazards.

Try banking a crane in 35 knots with horizontal rain coming straight into your face for instance.

For dust we invested in Airstream helmets and they were excellent. Imagine a hopper in front of you and ten tones of chemicals to pour into said hopper one sack at a time over x minutes per sack and imagine the dust... so the Airstream was proven in pretty tough conditions.

I spotted on a Woodworking group a mask and goggles combo for dust. As a trifocal user I too have a keen interest in clear vision whilst working with powerful sharp machinery. It arrives tomorrow so I will test and report.

PH

 

[citrus]

Hi CVB,

....snip
Personally I use a Sundstrom SR100 half mask with a combination filter SR229-2 ABEK1HgP3 ...

so are you clean shaven then ?

I have two follow on questions:

Basically I bought one of these two years ago -> 3M 4255 Maintenance Free Half Mask FFA2P3

1. Do I need to shave the beard off (or certainly no hair around the neckline around the strap) ?

2. I have only used this mask twice for ~15mins when vaping around xmas time ... I keep it in a bag safe .. but at what point should I replace it (or the filter ?)

 

[Camey]

Hi Chris,
yes I'm clean shaven, a couple of days of stubble in practice is fine.
I've attached the technical datasheet for your series of mask.
Key points are-
page 1 item 3 -Do not use with beards or other facial hair that prevent
direct contact between face and edge of the respirator.

page 2 cleaning and storage info - also the mask should have a use by date stamped on it, either inside mask lip or on bottom.

 

[citrus]

Hi Chris,
yes I'm clean shaven, a couple of days of stubble in practice is fine.
I've attached the technical datasheet for your series of mask.
Key points are-
page 1 item 3 -Do not use with beards or other facial hair that prevent
direct contact between face and edge of the respirator.

page 2 cleaning and storage info - also the mask should have a use by date stamped on it, either inside mask lip or on bottom.

great thanks for that info ... will have a read of that info (that I should have read in the first place !) - and peform the FIT check !

 

[Poly Hive]

Some years ago now I arrived at the heliport to find a company rep there whith disposable razors. The rig was about to start a new hole on a new location and there was a risk of hydrogen sulphide gas.

All the beard wearers were told to shave or quit. Seriously.

PH