Resporators

QUOTE: amyl nitrate (banana oil) was used for fitting.

If I'm not mistaken, amyl nitrate is a vaso-dilator used in the treatment of acute exposures to some toxic substances....but you were close!! ( I think all that chem-bio training is getting to you) I don't believe a pharmacist is going to hand this stuff out

I think what you were trying to say is n-amyl acetate. One small bottle will last almost a lifetime...unless you leave the top off.

BTW, testing with banana oil, or any other chemical discussed above is not absolutely necessary. If a positive and negative seal check is performed with each donning, that procedure is completely satisfactory, and no further testing is necessary. Qualitative fit testing using chemical substances is only required in occupational settings annually--or as local policies dictate. It's probably a good thing to try at home when first fitting a brand new respirator, or when changes have occurred in the individual such as major weight gain or loss, or after a change in facial conformity, such as major dental work or plastic surgery, to name just a couple examples. Just another reason to grab the fingernail polish remover. No need to lay out money for something rarely, if ever, utilized.

Gip

Having spent a bunch of years as a Bn NBC NCO, I got pretty well versed in the fitting of protective masks (which is pretty much what your resporator is). With the old M-17 or M-24 masks, amyl nitrate (banana oil) was used for fitting. The subject donned his mask, and a q-tip which had been dipped in banana oil was rubbed around the edges of the mask. If the subject smelled the banana oil, then an attempt to adjust the mask by using the straps was made. This usually cured the problem, but on occasion it wouldn't so a change of mask size was required.
If you can find banana oil, you can do the same thing. Check your local pharmacy as they often stock it.

QUOTE: If you have a narrow bridge to your nose slipping some rolls of modelling clay behind the seal flap can help seal a leak...trust me I have to do this on mine. Another trick is to wipe Vaseline around the seal if you have leaks elsewhere. Remember not shaving for a day or two is bad, three days unshaved is better because the hairs will lay flat then....but you should shave before using one.

PLEASE do NOT follow the above advice.

1. The new silicone facepieces are designed to follow the contours of your face without having to resort secondary means of trying to get a good seal, provided you get the right size. The new MSA masks going into many Home Depot stores have an improved nosepiece design to improve both fit and comfort. Even the simple act of lowering or raising the facepiece on the bridge of the nose can go a long way toward providing a satisfactory seal. Make sure to adjust the neck and head straps accordingly.

2. Wiping Vaseline on your face only enhances the destruction of your silicone facepiece, and does nothing to enhance a good face-to-facepiece seal. The petroleum products in Vaseline will attack the silicone and cause it to harden and become brittle--then it will become impossible to get a good fit. For that same reason, when cleaning one of the new facepieces, use warm soap and water; stay away from products containing alcohol.

Smearing Vaseline on the face also has the ability to attract particulates that otherwise would not adhere to the skin. Depending on the particulate, localized irritation including redness, itching and possible burning may now occur.

3. The OSHA respirator standard requires those who wear respiratory protective devices to be "clean shaven", meaning there is no facial hair between the respirator seal and the skin. Since this is a home hobby, occupational standards simply don't apply, since most hobbyists are not performing tasks requiring the use of respirators 8 hours a day, 40 hours a week. While being clean shaven certainly provides the best possible seal, I have seen and performed quantitative tests on those with 2 or 3 days of growth, and the protection factor of the respirator wasn't significantly decreased; however, being clean shaven is still the best way to go.

QUOTE: Most places now use liquid saccharine because you will be gagging from any leak.

Actually, I haven't personally seen saccharine used for fit testing in quite a few years. For most respirators, irritant smoke seems to be the preferred method since the biological response to a leak is involuntary; other methods can be faked or disregarded in the interest of expediency. Saccharine is also not indicated for organic cartridges, since that media will not capture the saccharin aerosol. Failure will occur 100% of the time. Saccharin will work on particulate filters, but the test assumes the ability of the one being tested to taste the substance at the test concentration. Not everyone can.

Since irritant smoke (or even banana oil, for that matter) is not readily available to everyone in the home hobby market, the next best substance (in my opinion) is fingernail polish remover. It has a relatively low toxicity at the concentrations used, a distinctive odor, and good evaporative characteristics, making it pretty good to test fit respirators at home. Make sure when testing, that you're in an area with little to no ventilation; the vapors need to linger around the facepiece seal long enough that the wearer can recognize the smell and discover a leak. In addition, make sure the bottle of test material is opened AFTER the respirator is in place, and positive/negative fit tests are conducted to assure a good fit.

Hope this helps some.

Gip Winecoff

QUOTE: If you still can't get a good fit, then you may have the wrong mask size. Masks come in S, M, and L.

If you have a narrow bridge to your nose slipping some rolls of modelling clay behind the seal flap can help seal a leak...trust me I have to do this on mine. Another trick is to wipe Vaseline around the seal if you have leaks elsewhere. Remember not shaving for a day or two is bad, three days unshaved is better because the hairs will lay flat then....but you should shave before using one.

QUOTE: the cartridges may need to be replaced. Normally, this check is done with n-amyl acetate, which can be found at some drug stores. I recommend trying it with nail polish remover because it's readily available, the acetone is dilute, and n-amyl acetate (banana oil) may not be available everywhere.

Most places now use liquid saccharine because you will be gagging from any leak.

Ditto what styrene said. I personally use the 3M half mask, It fits (me) well, is light weight, inexpensive, and cartridges are readily available.

Get yourself a good 1/2 mask respirator with organic vapor cartridges and paint mist prefilters. 3M, MSA, North, AO and others make very comfortable and affordable products. Check in your local hardware/home improvement store. Typically, these products are sold in kit form for $20-$25. Once you get it home, don't throw the bag away it came in. Use it to store your device when you're not using it.

Gip Winecoff

PS I posted this some time ago. Thought you might find it helpful for testing/fitting:

QUOTE: First, make sure the cartridges are seated well in the cartridge mounts, and that the rubber seat rings are properly installed. Run your finger around the ring and feel for any grit or other particulate matter that could be interfering with the seal. Next, check both the inhalation and exhalation valves to ensure they are properly seated and functioning on their mounts. The valves should be very flexible, and free of any tears or cracks. Now put the thing on. Attach the neck strap first, then bring the respirator up and over your face and put the head strap in place. Make sure you have a snug fit. If you have a beard or other facial hair that may interfere with the face-to-facepiece seal, you will probably get a little leakage in the mask and odors may be discernible. Facial hair will diminish the effectiveness of a respirator. OK, now that you have the respirator fit to your face like you want it, cover the cartridges with your hands, or a small plastic bag in each hand if your hands are too small, and breathe in. The respirator should collapse on your face. Hold your breath for 10 seconds. If you have a good fit, the respirator will remain collapsed. If not, you have a leak. This is called a negative pressure fit check. Next, cover the exhalation valve with your hand and breathe out slightly, but not enough to break the seal. The respirator should expand on your face. If air escapes, then you have a leak. This is called the positive pressure fit check. If you notice a leak while performing either test, readjust the respirator, and recheck. While it sounds involved, it really isn't, and should be done every time you put the respirator on. Otherwise, you spent $20 for a false sense of security. If you still can't get a good fit, then you may have the wrong mask size. Masks come in S, M, and L. Once you get it all together, try this: Get some fingernail polish remover and dip a q-tip in it. With your eyes closed and breathing through your nose, run the q-tip around the perimeter of the facepiece, paying special attention to the facepiece-to-face seal area. This is called a qualitative fit check. If you can detect the smell of dilute acetone, you have a leak. Re-fit and try again. Typically, if you have a good negative/positive fit check, you'll also have a good qualitative fit check. If you can smell the acetone and have a good fit check, the cartridges may need to be replaced. Normally, this check is done with n-amyl acetate, which can be found at some drug stores. I recommend trying it with nail polish remover because it's readily available, the acetone is dilute, and n-amyl acetate (banana oil) may not be available everywhere.