Safety and Compliance  SC-7
Safety
NOISE CAN DAMAGE HEARING
Cutting with a plasma arc can exceed acceptable noise levels as 
defined by local regulations in many applications. Prolonged exposure 
to excessive noise can damage hearing. Always wear proper ear 
protection when cutting or gouging, unless sound pressure level 
measurements taken at the site have verified personal hearing 
protection is not necessary per relevant international, regional, 
andlocal regulations.
Significant noise reduction can be obtained by adding simple 
engineering controls to cutting tables such as barriers or curtains 
positioned between the plasma arc and the workstation, and/
or locating the workstation away from the plasma arc. Implement 
administrative controls in the workplace to restrict access and limit 
operator exposure time, and screen off noisy areas and/or take 
measures to reduce reverberation in cutting areas by putting up 
noiseabsorbers.
Use ear protectors if the noise is disruptive or if there is a risk 
of hearing damage after all other engineering and administrative 
controls have been implemented. If hearing protection is required, 
wear only approved personal protective equipment such as ear 
muffs or ear plugs with a noise reduction rating appropriate for the 
situation. Warnothers near the cutting area of possible noise hazards. 
Inaddition, ear protection can prevent hot splatter from entering 
theear.
DRY DUST COLLECTION INFORMATION
In some workplaces, dry dust can represent a potential explosion 
hazard.
The U.S. National Fire Protection Association’s NFPA standard 68, 
“Explosion Protection by Deflagration Venting,” provides requirements 
for the design, location, installation, maintenance, and use of devices 
and systems to vent combustion gases and pressures after any 
deflagration event. Consult with the manufacturer or installer of any dry 
dust collection system for applicable requirements before you install 
a new dry dust collection system or make significant changes in the 
process or materials used with an existing dry dust collection system.
Consult your local “Authority Having Jurisdiction” (AHJ) to determine 
whether any edition of NFPA standard 68 has been “adopted by 
reference” in your local building codes.
Refer to NFPA standard 68 for definitions and explanations of 
regulatory terms such as deflagration, AHJ, adopted by reference, 
theKst value, deflagration index, and other terms.
Note 1 – Unless a site-specific evaluation has been completed that 
determines that none of the dust generated is combustible, then 
NFPA standard 68 requires the use of explosion vents. Design the 
explosion vent size and type to conform to the worst-case Kst value 
as described in Annex F of NFPA standard 68. NFPA standard 68 
does not specifically identify plasma cutting or other thermal cutting 
processes as requiring deflagration venting systems, but it does apply 
these new requirements to all dry dust collection systems.
Note 2 – Users should consult and comply with all applicable national, 
state, and local regulations. Publications do not intend to urge action 
that is not in compliance with all applicable regulations and standards, 
and this manual may never be construed as doing so.