Conservation DistList Archives [Date] [Subject] [Author] [SEARCH]

Subject: Ammonium hydroxide

Ammonium hydroxide

From: Doug Nishimura <dwnpph>
Date: Sunday, August 18, 1991
Ammonium hydroxide:  Yes, it is quite bad.  The concentrated acids and
bases are.  (I was entering a stairwell from the sixth floor when a 9 lb
(roughly a 2.2 L bottle) was dropped in the basement.  I don't know what
it reacted with but the cloud of fog made it all the way up to the sixth
floor.)  The problem with ammonia is that it is extremely soluble in
water (ie mucosa (lungs, throat), eyes).  My medical texts say that
pulmonary edema, glottic spasm or laryngeal edema are possible.  None of
these are exactly thrilling (laryngeal edema may result in cough, and a
feeling of suffocation among other things.)  I don't quite have all the
data I was looking for at my finger tips, but let me play anyway.

Assume that you have a lab that is 30 ft X 30 ft X 12 ft -- a total
volume of about 306 cu. meters.  1 ppm of ammonia is 0.71 mg/cu meter.
500 ppm then is 355 mg or 0.355 g./ cu meter. Our room needs about 108.5
g of gas to reach 500 ppm.  Let's look at a 4L bottle of ammonium
solution.  If we could get all of the gas out, we would get about 1.006
Kg.  It therefore only takes the evaporation of about 11% of the
available gas out of solution to reach 500 ppm in a fairly large room. I
might also add that it reacts very nicely with hypochlorites (such as in
Chlorox) to generate chlorine gas (very effective in WWI) and with
strong mineral acids to generate enough heat to boil.

Suggestions:  There are a number of companies that sell such chemicals
in plastic coated bottles for just this reason.  If the glass bottle
breaks, everything is contained in the outer plastic.  Good lab practice
also requires that an acid/solvent carrier be used whenever things like
ammonia are moved around (even from one table to another).  The intent
is 1) impact protection and 2) containment (if (1) fails.)  Although not
really cost effective, it may be better to buy small bottles of such
chemicals if safety is going to be a problem.  Lastly, if you rarely use
ammonia in full strength, you may find it better to buy pre-diluted
solutions.  Having looked in the catalog, I think I have most of the
common dilutions.

    **** Moderator's comments:   See the following message for an update
    to this table

Conc.                           w/w % (as NH3)

14.8 N (M)                      28%
 5   N (M)                       9.0%
 3   N (M)                       5.2%
 2   N (M)                       3.3%
 1   N (M)                       1.4%
 0.5 N (M)                       0.5%

Note that the density of the solution changes with concentration so you
just can't divide 2 N by 14.8 N and multiply by 28 % to get the w/w% for
2 N (The answer is 3.3%, but you'll get 3.8 % by this method.)

Remember that most negative pressure respirators would be swamped by
large quantities of fumes.  Also since the vapors are bad for the eyes,
a full-face positive pressure (air pack) respirator such as the Scott is
necessary for cleaning-up the spill.  (No beards, gentlemen.) One last
comment (I promise)-- the lower detectable limit to humans is about 40
mg/cu meter or about 53 ppm.


                  Conservation DistList Instance 5:16
                  Distributed: Monday, August 26, 1991
                        Message Id: cdl-5-16-001
Received on Sunday, 18 August, 1991

[Search all CoOL documents]