A guide for selecting disposable respirators that you can use for your next do it yourself project to ensure proper safety and health.
There are several types of disposal respirators that are used for varying do it yourself projects from demolition, carpentry, drywall finishing, and painting. These respirators come in three different classifications— N, R, and P—and with three different NIOSH (National Institute for Occupational Safety and Health) efficiency ratings. For most tasks, the use of an N-rated respirator is appropriate. In certain environments, though, R- or P-rated respirators should be used.
Disposable respirators which have two straps are much more effective than single-strap nuisance dust masks in filtering particulate out of the air.
The term particulate encompasses matter in the form of dust, mist, and fumes. Dust is created by breaking down solid material: cutting wood or sanding drywall are two examples. Mists are generated by spraying, mixing, or boiling liquids. Fumes are condensed vapor particles from solid materials that have been vaporized at high temperatures, like when metal is cut or welded; such as brazing and soldering copper pipe.
Always read and follow the manufacturer's directions for your respirator. The respirator must cover both the nose and mouth to guard the wearer from particulates in the air. If the respirator does not have a tight fit it will not work properly. Correct fit of the respirator requires contact with smooth skin. It will not work properly for people with beards or facial hair. Even one-day beard growth has been shown to let air leak in.
Disposable respirators have limitations where working with some materials can generate particulate as well as uncondensed vapor and gas. These are two substances a disposable respirator cannot filter. If particulate concentration levels are too high a different type of respirator must be used. In commercial and industrial work extensive air-sampling must be done to determine the concentration levels.
As a do it yourselfer, you can check with NIOSH (www.cdc.gov/niosh), a respirator’s manufacturer, and a product’s material safety data sheet (MSDS) to be sure you’re working within the limits of the respirator.
As the respirator becomes clogged, resistance to air flow increases and it becomes more difficult to breathe. When this occurs the respirator should be discarded and a new one used. Also discard the respirator if it gets wet; is deformed, which affects the fit, is dirty on the inside part next to your nose; or the filter is torn and will not filter the air. Disposable respirators cannot be cleaned or disinfected.
N-, R-, and P-rated respirators have different levels of resistance to airborne oil particles, which can degrade the filtration efficiency of a respirator.
N-rated respirators are not rated for use in environments that contain airborne oil particles. Removing mold ridden building materials and sanding spackle are examples are jobs where an N-rated respirator can be worn. When oil is in the air from sprayed lubricants or finishes, such as spray painting, or applying polyurethane finishes, an R- or P-rated respirator should be worn.
Disposable respirators are assigned a 95, 99, or 100 efficiency rating. Respirators filter the same-size particulate, but varying amounts of it. The efficiency rating signifies the percentage of particulate that a respirator is designed to filter. More important than ratings, though, is selecting a respirator that fits correctly. A mask that doesn’t seal properly to the face leaks and offers little protection.
Class - Description
N95 - Filters at least 95% of airborne particles. Not resistant to oil.
N99 - Filters at least 99% of airborne particles. Not resistant to oil.
N100 - Filters at least 99.97% of airborne particles. Not resistant to oil.
R95 - Filters at least 95% of airborne particles. Somewhat resistant to oil.
P95 - Filters at least 95% of airborne particles. Strongly resistant to oil.
P99 - Filters at least 99% of airborne particles. Strongly resistant to oil.
P100 - Filters at least 99.97% of airborne particles. Strongly resistant to oil