RE: smoke sticks?

[Robert_A_Jones@RL.gov]

For qualitative door checks, we use the "Dangle-ometer" method (use a
strip of masselin or toilet paper on the cracks of doors.  This method
is extremely cheap and needs no MSDS-hazard control procedures and
training.  

For room airflow checks around immediate work environments (small area
application), I almost always use MSA smoke tubes.  These are made from
Tin Chloride sorbed on pumice in a breakable tube.  The product of
moisture from air blowing through it is a fine, white smoke (Tin
oxides).  By-product is HCl and a little SnCl4.  For normal use, no
respiratory equipment is needed because of the small amount applied.  I
usually get a slight sore throat after use.  You need to wear gloves
when using and definitely wash your hands after use - this stuff really
irritates your eyes and mucous membranes.  I usually send people out of
the room when I use it.  For small applications, I have not found
anything better so far.  NUREG 1400 has a table for technique and
application of airflow determinations.  

There are controllable-smoke generators on the Internet.  They are
usually a bit pricey, but some guarantee against particle size
stratification.  It should be worth trying.

Robert A. Jones			Robert_A_Jones@rl.gov
Health Physicist 			phone: (509)376-8528
PFP Radiological Control 		fax: (509)373-4274
Hanford, WA				Hanford Pager: 85-6559 


	-----Original Message-----
	From:	dsimpson@unlnotes01.unl.edu
[SMTP:dsimpson@unlnotes01.unl.edu]
	Sent:	Tuesday, November 17, 1998 7:31 AM
	To:	Multiple recipients of list
	Subject:	Re: smoke sticks?

	Having taught a lab in air sampling that included the
determination of air
	flow patterns, let me add a few comments:

	The dry ice is great in terms of expense and ease of production
of smoke,
	but my biggest complaint is that the smoke is so cold that it
tends to sink
	very rapidly, making it a little misleading if the air flow is
relatively
	slow.  Also, it tends to dissipate quickly once it warms up.

	The "sticks" that were mentioned are relatively inexpensive and
produce an
	almost neutral bouyancy smoke that is abundant enough  to
indicate even
	moderately fast air flows.  Also I never had a problem with
glass breakage
	since the ones we used were contained in tygon tubing material
But as
	previously indicated a residue can be left and the smoke can be
very
	irritating to some people.  I have had to excuse people from the
lab
	because of this at times.

	Another very cheap method we used was incense sticks.  They
don't produce
	much smoke but are very effective around door openings and for
determining
	relatively slow moving air currents (hoods with the fans turned
off, etc).
	The smoke rises at first due to temperature but seems to cool
quickly to
	ambient temperatures.  Again, I suspect some people will react
to the
	smoke, but I never had it happen.

	Finally, another method that I have seen suggested in the
literature is
	soap bubbles.  A little Karo syrup added to a soap solution
produces long
	lasting soap bubbles, but I strongly recommend against this
method.  When
	we have tried it, it leaves a slippery residue and the bubbles
tend to be
	heavier than air and sink to the ground when other methods
indicate no
	downward flow.

	Dave Simpson
	RSO, University of Nebraska - Lincoln
	dsimpson1@unl.edu



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