Date: Thu, 8 Jul 2010 12:54:11 -0700
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Eric Clark <erclark**At_Symbol_Here**PH.LACOUNTY.GOV>
In-Reply-To: <F5D83326DC77FD4EA138E9194D6B28883373765DC6**At_Symbol_Here**>
Thanks for the thorough email, Nick.  
I should probably comment on your implication that this lab might blindly 
jump to over-controlled solutions without regard to justification.  
Excellent point.  We considered many options but I only mentioned the end 
solution that worked for us:  Install the O2 sensor (Enmet Model ISA-40M). 
 I should also mention that the particular room is a terbuculosis lab with 
many biosafety regulations attached to its operation - e.g. you can't just 
vent the unfiltered TB lab air outside.  For this situation, if a CO2 line 
leaks and the oxygen level goes low, the horn honks; and you can easily 
test the unit by holding your breath for 10 seconds and exhaling on the 
sensor (codified on page 10 on the maintenance manual).  It's the same 
reason people put low-oxygen sensors in wine cellars - so when the butler 
goes down to get wine he'll come up again.  Of course for brevity's sake 
my email to Vic was only three lines long, and Vic's a professional 
engineer.  Thanks for the opportunity to clarify.  Eric 

>>> "Tsiakals, Nicholas John"  7/8/2010 8:55 AM >>>
This may be more than you're looking for, but here goes:

"Just install the detection system" might sound like a good / prudent 
thing to do, but there are some drawbacks.  With the information on the 
table, I would put "Just install it" under the "blindly over-controlled" 
column.  (By "blind" I mean "blind with respect to what is strictly 
necessary" or "blind w.r.t. how much control is enough control".)  Be 
aware that when bills come due and money gets tight, decision-makers can 
very easily cut the installation or maintenance costs on such systems - 
where's the justification?  

So the challenge is to develop a good understanding of what is an 
acceptable risk:  What control measures are necessary to sufficiently 
control the hazard?  Where is "the line", and how far beyond the line 
should we be?  A more robust rationale than "it's easy enough to do" is to 
run reasonable scenarios to describe the risk in the current scheme.  What 
would it take to develop an Oxygen Deficient Condition at any one of these 
utility stations?  At any neighboring offices?  How likely is such a 
scenario?  For instance, if you know it would require a very noticeable 
(think: loud) leak for 20 min in a busy hallway, then you may reasonably 
conclude a detection/alarm system would be overly redundant.  On the other 
hand, if a small bleed could result in an ODH at a desk, then the 
detection/alarm system would seem very justifiable.

Recognize that an alarm system is an administrative control.  What action 
does it call for someone to perform?  If the detection system is connected 
to emergency ventilation or shut-offs, now we are talking engineering 
controls.  So I would urge you to work forward through the hierarchy of 
controls:  elimination - substitution - engineering controls - administrati
ve controls - personal protective equipment.  Are there design phase 
(engineering control) solutions which make the administrative control 

A principal question here is, "If there were a problem, how would you 
know?" followed by, "How likely is it that a problem occurs?"

Hope this helps,

-----Original Message-----
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of 
Eric Clark
Sent: Thursday, July 08, 2010 10:02 AM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU 

Consider installing a low oxygen alarm; probably has what 
you need.  We have a similar situation using plumbed in CO2.  As far as 
regulatory backup to justify this very minor expense, OSHA's General Duty 
Clause 29 CFR 654, 5(a)1 likely covers that - especially since you've 
already identified the specific hazard.    

Eric Clark, MS, CCHO, CHMM 
Safety & Compliance Officer 
Los Angeles County Public Health Lab 

>>>  7/7/2010 8:44 AM >>>
We are constructing a two-story building approximately 168 ft x 32 ft x 14 
ft high on the lower floor. The building will be multi-use, with offices 
in one portion and maintenance facilities adjoining. There will be six 
utility stations in the building with nitrogen piped to each utility 
station along with other utilities. The nitrogen supply line at each 
utility station will be a one-inch diameter line with a ball valve, a 
check valve, and a globe valve.

Could you please alert us to any applicable codes and standards specificall
y regarding any risks associated nitrogen asphyxiation.

Thanks and best regards,

Victor H. Edwards, Ph. D., P. E.(TX)
Director of Process Safety
Aker Solutions

Tel: +1 (713) 270-2817
Mob: +1 (713) 724-0406
Fax:    +1 (713) 270-3195
e-mail: vic.edwards**At_Symbol_Here** 

Aker Solutions Americas Inc.
3600 Briarpark Drive, Houston, Texas 77042-5206

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