Respirator Selection & APF

Chris CaronAmerican Safety &

Supply, Inc.

Why So Important???In 2017 The International Agency for researchon Cancer (IARC) – Part of the World Health

Orgaization (WHO) reclassified welding fumes andUV radiation as a Known Group 1 carcinogen. As aClass I carcinogen, welding fumes are now in thesame category as smoking for a cancer risk. In

addition the IARC states that up to 1-percent of theworld’s workforce may be exposed to welding

fumes while on the job.

Respirator Selectionl Measure Employee Exposure

lOSHA’s Air Contamination Standardstates that…” A competent industrialhygienist or other technically qualifiedperson”…shall conduct exposuremonitoring.

Respirator Selection

l Implement Control Measures“The use of respirators is appropriate only after you

have determined and implemented feasibleadministrative and/or engineering controls.”

lEnclose or confine a processlEmploy improved local ventilationlSubstitute for a less toxic

chemical/Process

Respirator Selectionl Review APFs and MUCs to Ensure Proper

SelectionlAPF = Assigned Protection Factor:

– The level of Protection a Class ofRespirator is expected to provide

lMUC = Maximum Use Concentration– Maximum concentration of atmospheric

pollutants that an employee will be protectedfrom when using a specific class of respirator.

APF Notes

l The assigned protection factors are onlyeffective when the employer implements acontinuing, effective respirator program(1910.134) including training, fit testingmaintenance and use requirements.

l APF May also include Filtering Face Pieces.l These APFs do not apply to respirators used

solely for escape.

Assigned Protection FactorsType of Respirator Half Mask Full FaceAir Purifying Respirator 10 50Filtering Face-Piece 10 NAHood or Loose-Fitting PAPR NA 25Tight-Fitting PAPR 50 1,000Supplied-Air Respirator – CF 50 1,000Supplied-Air Respirator – PD 50 1,000Self-Contained Breathing NA 10,000Apparatus (SCBA)

Respirator SelectionExample – A Full Face APR has an APF of 50.The chemical Dimethylthingamabob has a PEL

(Permissible Exposure Limit) of 10 ppm.Multiplying the APF(50) by the PEL(10) givesus an MUC of 500 ppm. In our workplaceexample, the exposure level (MCU) of theDimethylthingamabob is expected to reach30ppm. In this example, the full face APR willoffer more than sufficient protection.

Respiratory Protection

Powered-Air-Purifying-Respirator –PAPR - Welding

Studies show that full-time welders are at

increased risk ofbronchitis, airway

irritation, lung functionchanges, pulmonary

infections (pneumonia),and lung cancer.

Respiratory Hazards - Fumes

l Welding Fumes:Welding fume is a complex

mixture of very smallparticles of metal oxides.The specific components

depend on the compositionof the welding electrode(stick, wire or filler rod),

base metal, surfacecoatings and the type of

shielding gas or flux.

Respiratory hazards – Gas andVapor

l Gases and Vapors:When electrode coatings,

fluxes, shielding gases andsurface coatings areburned or exposed to

ultraviolet arc rays, theycan generate potentiallyharmful gases such as

carbon monoxide, ozone,nitrogen oxides, gaseousfluoride and phosgene.

PAPR – Tight-Fitting

l Powered respirators, or PAPRs,use a battery-powered blower topull air through filters and/orcartridges providing the user with“Purified” or “Filtered Air.

l Because filtered air is constantlyflowing into the headpiece underpressure, leakage ofcontaminants into the helmet isgreatly reduced, increasing thelevel of protection for theserespirators.

More PAPR Applications

Some PAPRs willonly accept a P-

100 other willaccept OrganicVapor cartridgesto protect fromthose hazards

Other Safety Concerns for Welders

l Harmful Lightl High Noise Levelsl Combustion/Ignitionl Dehydration/Heat

Stressl Others

Respirator Selection in Review

1. Identify the hazard including exposure.2. Attempt to control or eliminate the

hazard.3. Select a respirator with an appropriate

APF.4. Continually review your program to

ensure effectiveness.