Transcript RESPIRATORY PROTECTION

RESPIRATORY PROTECTION
…examination of the appropriate role
of personal protection against
inhalation hazards
Some History
first century: men wore animal bladders
1907: apparatus for breathing oxygen
1917: canister gas masks in military
1930s: effective dust respirators
US Bureau of Mines: tested/certified
NIOSH: research, testing, certification
Use of Respirators
When engineering controls are not
practical
#1 priority: keep contaminant controlled
For short, infrequent exposures
special cleaning; maintenance operations
In emergency situations
Types of Respirators
Air-purifying
Air-supplied
self-contained
breathing
apparatus (SCBA)
air-line
Mask
integral feature of
all respirators
varying amount of
protection
types
quarter
half
full
hood, helmet, etc.
Air-Supplied Respirators
Type A: full mask; body harness, tube up
to 300 ft.; blower; OK in IDLH areas
Type B: similar to Type A; no blower; not
for use in IDLH areas
Type C: “air-line respirator”; compressed
air supply; need for air quality; not for
use in IDLH areas
Abrasive Blasting Respirators
Types of Flow Control
constant flow
demand
pressure-demand
Self-Contained Breathing
Apparatus
Air supply is
independent of
surrounding
OK in toxic & low-O2
environments
Basic types
Non-recirculated (open
circuit)
Recirculated (closed
circuit)
rebreather
Air-Purifying Respirators
extract contaminant from
the air
must be specific for
contaminant
cannot be used in oxygen
deficient atmospheres
types:
aerosol removing
respirators/mechanical
filters
gas/vapor removing
respirators
combination (aerosols
and gases/vapors)
Mechanical Filter Respirators
for dusts, fumes, mists, smokes
half- or full-facepiece; replaceable
filter
one or more fibrous filters
no good for gases, vapors or low O2
make sure it is designed for the job
problems: limited life; clogging;
“hot”; uncomfortable
Gases & Vapors
Respirators
objective: remove contaminant
from air
design: via adsorption or
absorption
usually specific for a group or
type of contaminant; should not
be used for any other
respirator contains granular
chemicals either in a cartridge
(small) or canister (large
capacity)
Respirator Adsorbents
work on surface attraction forces
materials with high affinity for
certain types of chemical
some examples
activated charcoal
silica gel
Hopcalite
Respirator Absorbents
granular material with chemical to
react with toxic contaminant
most common application: “soda
lime” for use against acid gases
a few other chemicals with
reaction-specific applications
Chemical Cartridge Units
for use against toxic
gas/vapor
acceptable conditions for
use
construction: half-mask
+ cartridge(s)
cartridge replacement
regularly
when indication of pass
through
often combined with
filter
Gas Masks
for use against toxic
gas/vapor
acceptable conditions
for use
construction: full facepiece, canister,
harness
identification of type
on canister label
color coded
canister replacement
“Universal” Canister
Type “N”
contains several sorbents
in layers
provides protection
against most
contaminants; useful for
emergencies
protection against acid
gases, organic vapors,
ammonia, carbon
monoxide and particulates
Respirator Selection
identity and nature of contaminant
amount of employee exposure
atmosphere
physical configuration of job site
worker medical condition
worker comfort
capabilities of respirator
protection factors
Protection Factors
& Fit Testing
Protection factor
respirators efficiency in removing air contaminants
Purpose of fit testing
assuring that the respirator is the correct one and that it is
working
negative and positive pressure tests
Qualitative fit testing
irritant smoke
odorous vapor
taste
Quantitative fit testing
Respirator Limitations
poor means of worker protection
leakage problems (poor fit)
broken seals (facial hair, improper use)
communication interference
vision problems (fogging of lenses)
discomfort
difficult to enforce proper usage
Respiratory Protection Program
selection of respirators
medical surveillance/fit testing
issuance and use
training
supervision
storage & maintenance
recordkeeping