3. Properties
◦ Flammable
◦ Small molecule - will leak
◦ Diffuses quickly
◦ Low spark ignition energy
◦ Not easily detectable (Colourless, odourless, tasteless)
◦ Asphyxiant
4. LEL 4% ; UEL 74.5%
◦ flammable at wide range
◦ eliminate ignition sources (0.000019 J)
◦ ventilate well to avoid LEL
Flames are invisible
◦ train workers
◦ check for leaks
5. Use your vendor
◦ safety information and training
Design your system well
◦ Outside!
◦ Eliminate ignition sources
◦ Follow piping and vessel industry standards
◦ Barricades against explosion
7. O2 % N2 % Consequence
21 % 79 % Normal air
14 % 86 % Loss of ability to keep attention, to think clearly, some loss
of muscular co-ordination. Pulse and respiration increase.
10 % 90 % Faulty judgement; no pain nor serious injury; rapid fatigue;
very short temper, etc.
6 % 94 % Nausea; vomiting; legs give way. This may be the first and
only warning and it is too late. No pain. Resuscitation, even
if possible, may give permanent brain damage
< 6 % > 94 % Respiration by gasps, etc. RAPID DEATH.
8. Do not:
◦ enter enclosed spaces
◦ assume atmosphere in any tank, drain or other enclosed
space is safe to breath until it has been tested
◦ follow a fallen/distressed colleague into such a space
◦ even take a look!
9. Well trained and alert personnel
Well designed systems
Adequate ventilation
Leak Prevention & Detection
Elimination of Ignition sources
Proper maintenance and inspection
Proper process control
ref; A. Stout, CFPA
10. National Fire Protection Association, NFPA
Chemical Engineering Institutes (AIChE,
IChemE, etc)
American Petroleum Institute (API)
Occupational Safety and Health Authority
DIN, BSI, etc.
