Breathing apparatus for working with methanol
Methanol vapour is poisonous, it is a nerve poison.
It doesn't have a strong smell, which is bad, because by the time you can smell it, it is sufficiently concentrated to be above the safe working level.
Breathing filters must NOT be used for methanol, because they do not work well enough to protect you.
The only safe solution is to breath fresh air. This can carry risks of its own...
For example, don't use a compressor to feed air into a breathing mask, because most compressors are oiled, and they introduce a fine oily mist into the compressed air which is bad news for your lungs.
The ideal solution is to invest in breathing apparatus, but this can be expensive and may be enough reason to put most people off the whole idea - they may just prefer to take a chance.
Here is a low cost, low tech, reliable way for you to breath fresh air, whilst working in an environment with methanol vapour. How well it works will depend on how well you build and maintain it, of course, but it is easy to do right, and can be made safer with a 'telltale' feature I developed for it.
First, lets look at the picture of me in my reaction shed, which can become heavy with methanol fumes when decanting byproduct. Hover your mouse over the picture for descriptions...
It is nothing more complex than a snorkel mouthpiece connected to a length of garden hosepipe which goes about 20 feet or 7 metres away from the shed, to pick up fresh air. You may want to fit a gauze bag over the far end of the tube to prevent insects from climbing in.
There is a correct and a wrong technique. First, the correct technique...
- Breathe in through your mouth - ONLY in thru your mouth
- Breathe out thru your nose - ONLY out thru your nose
The wrong technique is to try and breathe in AND out thru the tube, using only your mouth, or, breathing in half with your mouth, half with your nose.. This will soon make you faint and collapse in a heap on the floor, as you keep re-using the same old air until all the oxygen has been exhausted.
So, never breathe out into the tube or you will fill it with CO2. And never breathe in with your nose, or you will breathe in methanol vapours.
With the correct method, you will only draw fresh air in along the tube, through your mouth. You will quickly find it is easy to breathe in through your mouth without breathing in through your nose, but if you feel uneasy about this, I have a very quick training method which will have you using the correct method in a minute or 2.
Here's how you do it, look at the picture below...
The aroma pad immediately lets you know if you are breathing in thru your nose - you quickly learn not to do that. Before long, you can do away with the aroma pad, but it is useful to start with it, to be sure your technique is good. With correct technique, you should never notice the aroma pad. This pad is the 'TellTale' feature I mentioned.
The snorkel mouthpiece is easy to find at any swimming sports supply shop.
The tubing I used is professional multi-layer garden hose pipe - called Hozelock-Professional here in the UK. It won't kink, so you'll always have an open line to breathe thru.
You'll also need some pipe clamps to tighten the pipe onto the snorkel mouthpiece.
Keep the mouthpiece inside when not in use, I keep mine in a sealable sandwich box, after washing it.
Have the pipe suspended from above you - bungee cords are useful because they give you good freedom of movement. The higher the support point, the more freedom of movement you will have.
Always remember to give the pipe a good blow-though before you start processing, to make sure nothing is hiding in there! It may be a good idea to seal the ends with a cork when it is not in use.
You'll be amazed how much momentum air can have - with a length of 20 feet or 7 metres, you will notice a definite inertia in the air's movement at the beginning and end of your inward breath. For this reason, you'll want to keep the pipe to no more than 30 feet or 10 metres, because beyond that the momentum makes breathing rather a strain. The longer the pipe, the greater the diameter you should use, to reduce the air velocity, which will reduce the momentum effect.
Don't inhale methanol fumes!
Hope it helps, good luck.
You can email me at grahamlaming at hotmail dot com
Posted January 7 2006
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