Love your lungs – what you need to know about respiratory protection devices
We’ve known for decades that exposure to fine dust and volatile organic compounds from solvents, finishes and paint can lead to all sorts of respiratory issues. In the short term it’s likely to be symptoms such as sneezing, coughing, eye irritations, throat infections and perhaps the worsening of pre-existing conditions such as asthma. In the longer term exposure can result in much more serious conditions, including respiratory infections, chronic obstructive pulmonary disease, lung cancer and heart disease. You can read more about the effects of dust on lungs at ccohs.ca.
It’s important to know the difference between the various types of respiratory protective devices (RPDs) on the market and what’s best to use for specific jobs in the shop or around the home.
There are five broad styles of RPDs of interest to woodworkers and DIYers: the ubiquitous one-strap disposable dust mask, disposable respirator masks, reusable respirator masks, half-mask cartridge respirators and full-face cartridge respirators. The first three styles are also technically “half-mask” respirators as they cover mouth and nose.
To provide optimal protection, any RPD has to form a tight seal around the mouth and nose. Fit is critical so air flows through the mask and doesn’t seep in through the sides. It’s good practice to check the fit of your mask every time you put it on. Facial hair can limit any RPD’s ability to work properly, sometimes severely.
Not a Respirator
Single-strap dust masks without a NIOSH number provide little protection from shop dust and none from the most dangerous fine dust. (Homedepot.ca)
Dual Straps
Dual-strap respirator masks will have a NIOSH number (N95 in this example) that can filter out 95% of dust particles down to 0.3 microns. Masks with a front-mounted exhaust valve make breathing somewhat easier, while a foam strip over the nose piece provides a better seal. (3M.com)
Gaskets
A mask with a large gasket creates a more secure seal on your face, helping to reduce dust infiltration. (Milwaukeetool.ca)
Rigid Shell
This mask has a high-resistant shell that resists collapsing from excessive humidity or heat and an active carbon filter for protection from organic vapours. (Moldex.com)
Flexible Masks
Flexible mesh fibre masks incorporate a replaceable filter and the mask itself can be washed. Some have exhaust valves. (Bcmask.com)
Added Eye Protection
Similar to a mesh fibre mask, this model has a rigid frame with a replaceable filter and a removable visor for eye protection. (Forgedair.co)
Hard Shell
Rather than a flexible mesh, this respirator has a hard shell with a replaceable P100 filter and a downward-pointing exhalation valve to keep glasses from fogging. (Trend-usa.com)
Replaceable Filters
The standard half-face elastomeric respirator has dual replaceable cartridges and filters. (Gvs-rpb.com)
Full-Face Protection
A full-face elastomeric respirator delivers greater respiratory protection and has the added benefit of covering your eyes. (Sps.honeywell.com)
Disposable dust masks
The first thing to know is that not all disposable dust masks are respirators. If the dust mask doesn’t have the word NIOSH printed on the mask or packaging (read more about NIOSH in the sidebar) it isn’t a respirator. It’s better to think of them as nuisance masks. Usually these masks have a single strap. They’re made of a single thin layer of nonwoven fabric or tissue paper and designed to prevent respiratory emissions, such as coughs and sneezes, from entering the air. They provide only minimal protection from larger particulate matter and none from fine wood dust. Medical and surgical masks fit into this category as well (unless they’re labelled as NIOSH rated). They’re typically very inexpensive and can be had for as little as 80 cents apiece. It’s fine to wear one of these masks while mowing the lawn, sweeping the driveway or cutting up firewood (tasks that result in larger particles), or if you have a cold or flu, but not in the workshop.
Disposable respirator masks
A disposable respirator mask, which looks similar to a dust mask, is a true respirator. Unfortunately, most manufacturers still label them as dust masks. But it’s easy to tell the difference. Respirator masks will always be labelled “NIOSH” and have a number – either N95 or P100 – printed on the mask. They almost always have dual straps, which provide a more secure fit than single-strap masks. Some look like domes, others like duck bills. These masks will usually consist of an outer pre-filter (generally of a nonwoven polypropylene fibre) and a softer inner filter. The fibres carry an electrostatic charge that attracts passing particles – 95% of the particles down to 0.3 microns – and keeps them from entering your lungs. Some have an active carbon filter that reduces harmful fumes and vapours. Others have an exhalation valve that directs warm, moist air out the front of the mask, which can make breathing easier, help reduce heat buildup and keep glasses from fogging. Others include a foam gasket under the nose piece that enhances the seal against your face to reduce dust infiltration. An N95 mask will not protect you from organic vapour (unless it has an active carbon filter), but the P100 mask will (if it contains an active carbon filter). Respirators with an activated carbon filter layer provide protection from nuisance level organic vapors. However these respirators are not designed for environments that are deemed “Immediately Dangerous to Life or Health”. For these environments you do need a cartridge respirator (the correct cartridge color for organic vapors is black). Fortunately, it’s highly unlikely that hobbyist woodworkers or DIYers will find themselves in an IDLF environment. A P100 respirator with an activated carbon filter layer should provide ample protection for the organic vapours that they will encounter in a shop or home environment.
The leading brands are 3M (3mcanada.ca), Honeywell (sps.honeywell.com) and Moldex (moldex.com). Prices range from about $1.50 per unit up to about $10 per unit, when purchased in bulk.
It’s important to remember these dust masks are not designed for continuous reuse. They’re meant to be used a few times and then tossed away. Even though these masks are not recommended for the hirsute woodworker, they are still commonly used in workshops. Obviously, they provide some protection but not at an optimal level. Regardless of which mask you use, moisture accumulation from hours of breathing is going to degrade the electrostatic charge, which will reduce its filtering efficiency, while fine dust will saturate the fibres of the mask. With repeated use, the head straps are likely to stretch and the metal nose strip can come loose or bend out of shape. It’s good practice to check the seal of these masks every time you put them on.
Reusable respirator masks
This style of mask has been around for over a decade and is becoming increasingly popular among woodworkers. These masks have a reusable carrier that supports a replaceable filter. They’re lighter in weight than cartridge respirators and provide a better seal than a disposable mask. Two of the most popular brands – Base Camp (bcmask.com) and RZ mask (rzmask.com) – are made of a mesh fabric construction. These masks have single filters that provide 99% filtration down to 0.3 microns, active carbon filtration, dual exhalation valves, adjustable nose clips and are available in different strap options. Note that while these masks have been independently tested, neither of them is NIOSH rated.
The Canadian-made Forged Air (Forgedair.co) model is a bit of a cross between a mesh fibre mask and a cartridge respirator. It features a rigid frame with a soft medical grade silicone face gasket that provides a superior seal around mouth and nose and dual adjustable straps. It uses a large replaceable filter (available in either a 95% or 99% filtration efficiency) and a removable visor for eye protection. Forged Air is in the process of seeking NIOSH certification.
The Air Stealth mask (Trend-ca.com) has a hard shell with dual replaceable P100 filters, dual straps and a downward-pointing exhalation valve to keep glasses from fogging. It’s NIOSH certified.
Half-mask cartridge respirators
These are among the most common respirators used by professional woodworkers. If you do occasional spraying you’ll want to consider using this mask as well. They’re often called elastomeric masks because they’re made of a rubber-like polymer that provides a good seal around mouth and nose. They come in a range of styles but all have dual cartridges and / or filters. Respirator cartridges provide protection from gases and vapours while respirator filters protect against particulate matter. There is a range of cartridges to choose from and each is colour coded to indicate what it protects you from. There are also combo units, where the cartridge and filter are in one unit. The leading brands are from 3M (3mcanada.ca), GVS (gvs.com), Honeywell (sps.honeywell.com) and Moldex (moldex.com).
Full-face cartridge respirators
A full-face respirator is the same as a half-mask except it incorporates a visor that covers the face and eyes. For optimal filtration efficiency the visor has to have a gasket that creates a seal around the face. These respirators have an Assigned Protection Factor of 50 – five times that of a half-mask – and the added bonus of protection against liquid splashes. This is the mask to use if your work involves contaminants, such as removing asbestos from older dwellings, or if you do a lot of spray finishing. Top brands include 3M (3mcanada.ca), Honeywell (sps.honeywell.com) and Moldex (moldex.com).
NIOSH certification
The National Institute for Occupational Safety and Health (NIOSH) is a U.S. federal agency that conducts research and makes recommendations for the prevention of work-related injury and illness. Respirator manufacturers whose products meet specified criteria can have their products labelled as NIOSH rated for their efficiency. There are three categories of filters: N (Not resistant to oil), R (Resistant to oil), and P (oil Proof). Each of these filters can have one or more Particle Filtration Efficiency (PFE) ratings for removing dust down 0.3 microns: 95%, 99% or 99.97%.
Respirators also have an Assigned Protection Factor (APF) that is a measure of the level of protection that a respirator offers. Disposable respirator masks, reusable respirator masks and half-mask cartridge respirators have an APF of 10, while full-face cartridge respirators have an APF of 50.
For protection from shop dust, use a respirator with a N95 rating; you’ll get protection from 95% of particulate matter down to 0.3 microns. These respirators won’t protect you from organic compounds, so when using solvents or applying finishes you’ll want to switch to a P100 respirator, which protects you from 99.9% of airborne organic vapours as well as particulate matter.
Carl Duguay - [email protected]
Carl is a Victoria-based furniture maker and the web editor at Canadian Woodworking & Home Improvement.
This article incorrectly states that a P100 respirator will protect against organic vapour. This is FALSE. Only an OV cartridge will do so.
Thanks for the feedback Jim. I’ll add a note of clarification to the article. Our information from 3M was that respirators with an activated carbon filter layer (such as their Specialty Particulate Respirators #8000 series) provide protection from nuisance level organic vapors. However these respirators are not designed for environments that are deemed “Immediately Dangerous to Life or Health”. For these environments you do need a cartridge respirator – the correct cartridge color for organic vapors is black. Fortunately, it’s highly unlikely that hobbyist woodworkers or DIYers will find themselves in an IDLF environment. A P100 respirator with an activated carbon filter layer should provide ample protection for the organic vapours that they will encounter in a shop or home environment.