i use 3m ffp3 filters i replace them when it become hard to breathe i think,you can maybe get more life out of them by blowing compressed air to clean the filters

Funny you should ask this as I just did a safety review for our 3M P100 filters (2091 model) at work about a month ago. We have a monthly PM to replace filters on our full and half-face respirators every month due to company policy. Obviously, our plant has a corporate safety budget so we can afford to do that. At the home shop, that can be a bit expensive. There are two things to consider, using these filters and since you said 3M P95, I assume you are using the 2071 model. Use with aerosols oils, use with particulates.

The P-series is made to handle oil vapors and particulates, N-series are particulate only.

Direct from 3M's packaging:

P-SERIES TIME USE LIMITATION

In response to NIOSH’s request, the following time use limitation is recommended for all 3M P-

series filters:

If filter becomes damaged, soiled, or breathing becomes difficult, leave the contaminated area

and dispose of the filter. If used in environments containing only oil aerosols, dispose of filter

after 40 hours of use or 30 days, whichever is first.

As discussed above, if a filter is used in environments containing non-oil aerosols, the filter will

cake and efficiency will increase. This increase in efficiency is accompanied by an increase in

breathing resistance which can help signal the wearer to change the filter. Atmospheres that

contain both oil and non-oil aerosols will most likely result in filter caking from the non-oil

aerosol. Therefore, the P-series time use limitation reverts to dispose of the filter when it

becomes damaged, soiled, or difficult to breathe through if the filter is used in environments that

contain no oil aerosols, or if the filter is used in environments that contain a mixture of oil and

non-oil aerosols. Only if a P-series filter is used in an environment that contains only oil

aerosols does the full time use limitation apply.

Basically, after a cumulative 40 hours of oil vapor use or 30 continuous days, replace the filter. If no oil vapor use, replace when its hard to breath. In either case, replace when it is visibly damaged, wet or extremely dirty.

Please, do not clean them with compressed air. It has been shown that this will damage the filter by ripping holes that reduce its filtering ability or, at the very least, embed particles in a way that binds the interior fibers together and reduce the life of the filter. Also, if you don't have a dryer on the outlet of your air compressor, you will be blowing moisture into the filter which will also reduce its filtering ability. 3M specifically says not to clean the filters in the insert with every new filter.

I keep two half faces in my home shop, one in my grinding room that is closed off from everything else. I change those filters when its hard to breath.

The other I keep for oil quenching and working with any aerosols. I change that one the 1st of each month.

I don't often wear my respirator when oil quenching, however i also mainly use a horizontal steel feeding trough a quench tank unless i am making a sword...so should i be wearing a respirator well quenching? I do not think at this time i would need a separate respirator for quenching as I tend to quench one in many 20 blades...I think I lost count of how many i got to near quench and found some flaw that caused me to toss it into the scrap bin.

Maybe someone else would be better to reply to that question. I wear it anytime I work with anything that could be potentially in the air that I dont want in my lungs. Same reason hoods at restaurants over oil fryers need to be cleaned, they get a build up of oil over time. To me, the smoke while quenching is either vaporized oil or burnt hydrocarbons. Neither of which I want to breathe.

But again, someone else might know better. I take the better safe than sorry approach, plus I look like I might know what I'm doing!

Yes, you should wear a respirator while quenching. As Andy said, that smoke coming off is vaporized oil. Not good to breathe in.

Brion

So, P95 or P100? If I understand correctly they both filter the same size particles, just the P95 lets more particles slip through. Is it a significant difference? And what size particles should we be concerned with in a knife shop anyway?

Yes Jesse, you are correct. The number in the rating is the percent of filting of air particles. The 95 is 95%, there is also a P/N99 which is 99%. The 100 is actually 99.97% since they (NIOSH) cannot say that the filters are 100% effective. As far as particle size, these numbers are based on filtering of 0.3 microns (0.000013 inches). That's not to say they're not capable of filtering smaller, just not as effective.

I've read that on average dust from an angle grinder is around 10 microns but I've also seen that a surface grinder can throw 0.5 microns. It really depends on the type of equipment you are using and how good your ventilation is. Regardless, wearing breathing protection of some sort is a necessity. I like to think of it as a tool that is needed in every aspect of every project.

For comparison, a human hair is about 40-50 microns. Also, in keeping with world events, a virus 0.004 to 0.1 microns.

|quoted:

Yes, you should wear a respirator while quenching. As Andy said, that smoke coming off is vaporized oil. Not good to breathe in.

Brion

thanks for answering I will start wearing it when quenching from now on.

has anyone been able to get p95, n95, p100 or n100 filters for their half face respirators?