3D Systems, Inc.
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NITROGEN/OXYGEN SAFETY
The SLS system uses nitrogen to create an inert atmosphere in the print chamber . The nitrogen inhibits any potential rapid combustion
of particulate matter during the SLS process .
The oxygen content of air is approximately 21 percent . Displacement of the normal atmosphere with an inert gas, such as nitrogen, can
reduce the oxygen content in a room . In the remote chance that nitrogen leaks into the room during the sintering process, the situation
can be hazardous .
Your site must have an oxygen alarm monitor installed in the room containing the SLS system . This monitor will alert you if the oxygen
level drops below a designated point . It must be wired to trigger an immediate shutdown of the SLS system and nitrogen generator (if in
use) .
CAUTION: Exposure to an atmosphere containing 12 percent or less oxygen causes unconsciousness without any
warning symptoms . This happens so quickly that you cannot help or protect yourself .
The table of
Oxygen Deprivation Effects and Symptoms
explains the potential effects and symptoms that can occur at different
concentrations of oxygen in the atmosphere .
When you work in an environment that may become oxygen-deficient, make sure you comply with the following items
:
•
If, at any time, you feel you are experiencing symptoms of oxygen deprivation, leave the area immediately .
•
You have received oxygen/nitrogen safety training .
•
The room is well-ventilated; at least 4 air exchanges per hour .
•
Self-contained breathing apparatus is available and easily accessible .
•
The room oxygen alarm monitor is functioning and audible .
•
Leave the SLS system room/area immediately when you hear the oxygen alarm .
Oxygen Deprivation Effects and Symptoms
OXYGEN CONTENT
(% BY VOLUME)
EFFECTS AND SYMPTOMS AT ATMOSPHERIC PRESSURE
a
15 – 19 %
Decreased ability to work strenuously . May impair your coordination or may induce early
symptoms in persons with coronary, pulmonary, or circulatory problems .
12 – 14 %
Increases respiration during exertion . Pulse rate goes up . May experience impaired
coordination, perception, and judgment .
10 – 12 %
Respiration continues to increase in rate and depth . Lips become blue . May lose
consciousness at this point .
8 – 10 %
Mental failure . Fainting and unconsciousness . Face becomes ashen, lips become blue .
Nausea and vomiting may occur .
6 – 8 %
100% fatal after 8 minutes of exposure .
50% fatal within 6 minutes .
Recovery with treatment within 4 to 5 minutes .
4 – 6 %
Coma within 40 seconds; convulsions, respiration ceases, death occurs .
a . From Safety Bulletin SB-2 - 1983—”1983 by the Compressed Gas Association, Inc . 1235 Jefferson Davis Highway, Arlington, VA
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