Hypertherm THC ArcGlide - Manual (Page 21)

Safety and Compliance SC-21
Safety
DRY DUST COLLECTION INFORMATION
At some sites, dry dust can represent a potential
explosion hazard.
The U.S. National Fire Protection Association’s 2007
edition of 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 68 has been
“adopted by reference” in your local building codes.
Refer to NFPA68 for definitions and explanations of
regulatory terms such as deflagration, AHJ, adopted by
reference, the Kst value, deflagration index, and other
terms.
Note 1 – Hypertherm’s interpretation of these new
requirements is that unless a site-specific evaluation
has been completed to determine that all dust
generated is not combustible, the 2007 edition of
NFPA 68 requires the use of explosion vents designed
to the worst-case Kst value (see annex F) that could be
generated from dust so that the explosion vent size and
type can be designed. NFPA 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 of Hypertherm manuals should consult
and comply with all applicable federal, state, and local
laws and regulations. Hypertherm does not, by the
publication of any Hypertherm manual, 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.