Respiratory Protection and You

[Fuelrush]

I've had difficulty looking for an exact answer for respiratory protection for what we do. It appears that typically a N95 Filter is sufficient for most metal fumes. 3M also suggest this. But it really depends on the concentration of what your trying to protect yourself from is the determining factor. Large concentrations require venting and/or supplied air. My best guess is were dealing with a low volume and open air environment not requiring either. Also it appears N95 is used frequently by welders.


United States NIOSH standards define the following categories of particulate filters:

Not oil resistant
N95 Filters at least 95% of airborne particles
N99 Filters at least 99% of airborne particles
N100 Filters at least 99.97% of airborne particles

Oil Resistant
R95 Filters at least 95% of airborne particles
R99* Filters at least 99% of airborne particles
R100* Filters at least 99.97% of airborne particles

Oil Proof
P95 Filters at least 95% of airborne particles
P99* Filters at least 99% of airborne particles
P100 Filters at least 99.97% of airborne particles

NIOSHA/OSHA in reguard to zinc oxide (a cause of "Metal Fume Fever") says:
"Up to 50 mg/m3: (APF = 10) Any particulate respirator equipped with an N95, R95, or P95 filter (including N95, R95, and P95 filtering facepieces) except quarter-mask respirators. The following filters may also be used: N99, R99, P99, N100, R100, P100."

The above information I've collected from various sources. The best way to protect yourself is research what you are working with and the related hazards. Keep in mind that the dangers involved can be from more than the metal your working with. Other dangers can be from working with scrap that contains impurities such as paints that release additional fumes.

I've done a little research on Respirator Filters and how to protect myself. You are responsible for your own research and your own protection. If anyone who has more expertise in this field I would love to know your thoughts and recommendation.

I'll probably end up with a 100 series filter and half mask. I believe this will protect me from all I'll be doing, and then some. I also can use this in many other areas of my workshop. This can also protect you when working with your molding sand (especially if its dried out). Silica sand when inhaled can cause many problems, often series problems.

I've found NIOSHA's Pocket Guide to Chemical Hazards a great reference.
http://www.cdc.gov/niosh/npg/default.html

 

[Artie]

Hi Fuel, I think your comment regarding low volume and open air is pretty accurate in my case. I use a 3 sided shed with ventilation for my burns. I do however hold my breath while doing the intial lift where the concentrations of gasses is highest and my head is nearest the open foundry. This is a concious thing and Its particularly important when dealing with molten brass (nasty zinc burn off).

I use a full face shield and simply cant get my canister filter under it. But if im in the area of the foundry for any length of time its on. Naturally Aus has differing designations for the filters over here so I thought the local guys might be interested in the cartridges I use. Its a Class P2 particulate filter designed for "for mechanically and thermally generated toxic particulates up to 10 times the exposure standard". These filters are also non oil resistant.

Cheers

Rob