On 2 Feb 2006 04:08:50 -0800, "Bryan Martin"
wrote:

Were there any chemical fumes in that tank he might have inhaled along
with the nitrogen?

JJS wrote:
"Bryan Martin" wrote in message
oups.com...
snip

Releasing N2 in a sealed space will simply increase the pressure in the
room and cause no particular breathing problems because the room will
still have enough oxygen in it to breath. You won't have a problem

N2 will not mix unless there is air circulation. This is one of the
things we learned with vessel entry and permits. In industry, at least
in the states, a person is not allowed to enter a closed vessel,
container, or even hole in the ground much over waist deep without a
safety harness, rope to the outside world, and enough muscle on the
outside to pull them out should they become responsive.

Even when entering underground pump rooms we had to be tied to the
outside world unless there was forced ventilation and even then some
one had to be present on the outside.

until the pressure gets high enough for the toxic effects of N2 to show
up (nitrogen narcosis). This takes several atmospheres of pressure.

Although part of what you say is true, I disagree with the above paragraph. In particular the part insinuating that
the nitrogen has to be pressurized to be toxic. I had a job related experience in which a contractor working under
supplied breathing air respirator had a near fatal incident. The catalyst vessel he was working in was under
nitrogen atmosphere to prevent the catalyst from going pyrophoric. There was no pressure on the vessel and the

This completely misses the most dangerous aspect of N2 in a closed
space (vessel entry). Narcosis is not a problem at normal atmospheric
pressure. N2 will not mix with the air unless there is some form of
forced circulation. The N2 will displace the O2 and lighter gasses
causing the person suffocate. N2 gives no warning either.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Joe Schneider
8437R