Page 27 - OHS, October 2024

Th e next consideration will be the factors that might infl uence
the selection of which specifi c kind of respirator is required. Th ese
factors include:
■ Physical constraints of the jobsite. Th is typically won’t be
an issue if a simple mask or cartridge fi lter-type respirators are to
be used, but if the environment calls for an independent supply
of breathing air, hose fed breathing masks may be needed in tight
quarters. Consequently, the use of respirators with air hoses could
be limited if there are obstructions in the area and could be down-
right dangerous around moving machinery. In those cases, a self-
contained breathing apparatus will be the better option.
■ Certain medical conditions. Many common respirators are
classifi ed as negative pressure devices. Th is means that the wearer
has to draw air in through a restriction (like fi ltration media or
chemical cartridges), which means it takes more eff ort than just
“normal” breathing. Th ese aren’t suitable for everyone. For exam-
ple, they present a very real risk of undue pressure to the heart for
someone suff ering from lung diseases such as asthma or emphy-
sema. Positive pressure respirators provide a restriction-free fl ow
of breathing air and need to be used in those cases.
■ User comfort. It’s not good for anyone to burden workers
with awkward or unwieldy PPE of any kind. Th at can lead to lost
productivity, high turnover, and possibly legal action for the em-
ployer and a myriad of mental and physical stresses for the em-
ployee. Fortunately, technical and material improvements continue
to make safety equipment lighter, easier to don, soft er on the skin
and, many times, even more eff ective than before.
■ Required level of protection. Sanding drywall and clean-
ing up aft er an accident at a chemical plant present vastly diff erent
breathing hazards and, hence, need vastly diff erent levels of protec-
tion. Agencies like the aforementioned NIOSH & OSHA, as well as
the American National Standards Institute (ANSI) all have a num-
ber of standards and publications on this subject.
Once the appropriate level of protection is determined, select a
suitable respirator from two basic categories: air-purifying respira-
tors and atmosphere-supplying respirators.
Air-purifying respirators are self-contained devices, which re-
move contaminants from the air to make it safe to breathe. Dif-
ferent kinds can remove particulates, vapors or both. Th ey are all
classifi ed as negative pressure devices. So they may not be suitable
for use by someone with medical conditions as noted above.
■ Particulate respirators capture airborne particles in small
spaces between the fi bers that make up their construction. Th ese in-
clude simple masks that cover the mouth and nose and are typically
considered to be disposable. Th ey also come in a rigid frame with
replaceable fi lter elements. As particulate accumulates in the fi ber,
these actually become more eff ective aft er some use, but take care to
replace them when any resistance or breathing diffi culty is noted.
■ Vapor respirators use chemical fi lters (usually in a cartridge or
canister), which absorb the vapor. Th ere are diff erent specifi c types
for diff erent vapors; in fact, NIOSH has a color coding chart for them:
■ Combination respirators have both particulate and vapor
fi lters. Th ese are especially popular when working with pesticides,
as well as other chemical or biological agents that create airborne
particulate AND vapor contaminants.
Atmosphere-supplying respirators provide clean breathing air
from an outside source, usually an air tank or compressed air system.
Th ey’re used when a high concentration of contaminants could foul
www.ohsonline.com particulate elements, or expend a vapor cartridge quickly. Th ey may
also be needed in areas where the oxygen level could drop below safe
levels, such as confi ned spaces that cannot be adequately ventilated
with fresh air. Th ey’re also used for emergency situations to allow
personnel to safely evacuate an area where the atmosphere is unex-
pectedly fouled with smoke or other pollutants. All atmosphere-sup-
plying respirators provide protection against particulate and vapor
contaminants and come in three confi gurations:
■ Air-supplied respirators consist of a mask (usually full face
with straps to cinch it up for an airtight seal), with a short, low-
pressure hose connected to a regulator (usually made to clip on
the wearer’s clothing, belt, etc.) which is fed with a hose rated for
the supply pressure that has a quick connect for use with breath-
ing air manifolds. Th ese manifolds will normally be strategically
located in facilities where contaminated atmospheres require their
use. Advantages include their light weight and ability to provide
clean breathing air for long periods of time. Disadvantages are lim-
ited mobility (the wearer can’t go any further than the supply hose
length from a supply manifold) and failure due to hose damage.
■ Self-contained breathing apparatuses have the same masks
designed for an airtight seal, but are fed with breathing air from a
pressurized tank. Th e wearer has greater freedom of movement –
they’re not restricted to the supply hose length of an air-supplied
respirator – but they do have fi nite time limits.
Open-circuit types provide breathing air that the wearer
breathes right back out to the atmosphere. Th ese are typically good
for 30 to 60 minutes because the larger the tank gets, the more
cumbersome it is for the wearer to carry around.
Closed-circuit types recirculate exhaled air through a chemi-
cal-activated “scrubber” that removes carbon dioxide and gener-
ates oxygen. Th ese are also called “re-breathers” and some are good
for up to four hours.
■ Combination atmosphere-supplying respirators combine
features of the other two types. Th e primary supply comes from an
external source (like the air-supplied ones), but they also include an
air tank (like the self-contained ones). Th e tank is generally smaller
on these, as its main purpose is to provide air while the user exits the
area. Th ey’re commonly used in confi ned spaces without adequate
ventilation and when working for extended periods in atmospheres
that could be immediately dangerous to life and health.
Proper selection and use of respiratory protection is critical to
health and safety. Additionally, it’s important to the company’s bot-
tom line. In 2021, OSHA recorded 2,521 violations of respiratory
protection standards. Th is was second only to fall protection viola-
tions for that year. Th e associated fi nes are commonly compound-
ed per person and per day. Know and understand the hazards you
(and/or your employees) will be exposed to. Familiarize yourself
with all the diff erent respirator options. Conduct regular training
so everyone knows how to protect themselves and others. Fit test-
ing of respirators should be an integral part of that training.
Now take a deep breath. Right now. See how good that feels? It’s
certainly worth protecting, right?
Russ Bowman is an Application Engineer at EXAIR LLC (exair.com).
REFERENCE
1. OSHA 1910.134(d)(1)(iii): tinyurl.com/y74k86z9
OCTOBER 2024 | Occupational Health & Safety 27