From: Beltis.K**At_Symbol_Here**TIAXLLC.COM
Subject: Re: [DCHAS-L] Gas Cylinder Hydrostatic Testing
Date: Wed, 5 Feb 2014 17:05:21 -0500
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: OF7A50A567.E90EE826-ON85257C76.007821B8-85257C76.00795677**At_Symbol_Here**
In-Reply-To <852F486739ECB34484E384E1D009D97D0346EBA5**At_Symbol_Here**>

Prudent practice allows a cylinder filled before its hydrostatic test expiration to be used until emptied. This has long been the case in the use of SCBA and scuba tanks where tanks are actually worn and for fire extinguishers. As long as there has been no undue stress on the tank, all should be fine.

The hydrostatic test is conducted to safeguard the fill process where the gas, upon compression, becomes heated.The heat is transferred to the tank. In combination with the pressure stress and subsequent emptying over repeated cycles, the tank becomes fatigued and embrittled. So it is during the refilling process where the risk of stress and catastrophic failure may occur.  As a static system and in normal use of emptying, the risk of failure is extremely low.


Kevin J. Beltis
Director of Health, Safety and Environment

35 Hartwell Avenue
Lexington, MA 02421-3102

TIAX, "Powered by Innovation"


TIAX LLC is a privately held company at the intersection of business and technology. TIAX builds on a rich heritage based on creating business opportunities and growth through the power of science, technology, and innovation.

From:        Benjamin G Owens <bowens**At_Symbol_Here**UNR.EDU>
To:        DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Date:        02/05/2014 10:22 AM
Subject:        Re: [DCHAS-L] Gas Cylinder Hydrostatic Testing
Sent by:        DCHAS-L Discussion List <dchas-l**At_Symbol_Here**MED.CORNELL.EDU>

Just to summarize the responses, regulations allow a compressed gas cylinder that was filled before expiration of its hydrostatic test date to remain in service until it is emptied and such a cylinder with an expired test date can be transported (e.g., to be tested and refilled).  Of course prudent practice dictates that cylinders that have been damaged or subjected to extreme stress of any kind be inspected/tested sooner.  
Thank you to everyone who responded.
Ben Owens
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Dan Kuespert
Wednesday, February 05, 2014 3:45 AM
Re: [DCHAS-L] Gas Cylinder Hydrostatic Testing

While, as the fellow from Airgas (and others) pointed out, it is legal to transport and generally safe to continue to use the cylinder after its expiry date (probably—assuming the user hasn’t used it for target practice!), I still like to point to the need for recertification with our labs because it helps me encourage them to get rid of cylinders they’ve had since 1982 (really!) and consequently it reduces demurrage charges for cylinders kept for 32 years.
Daniel R. Kuespert, Ph.D.
Homewood Laboratory Safety Advocate
Krieger School of Arts & Sciences/G..W.C. Whiting School of Engineering
The Johns Hopkins University
Shaffer Hall 103G
3400 N. Charles St.
Baltimore, MD 21218
(410) 516-5525
On 2/4/14, 8:54 PM, "Benjamin G Owens" <bowens**At_Symbol_Here**UNR.EDU> wrote:
I understand that compressed gas cylinders must have a current hydrostatic test to be filled.  I have read a vendor site that indicates that a cylinder may be transported after the hydrostatic test expiration date if it was filled prior to the expiration date.  If cylinders that have exceeded the hydrostatic test date are considered safe to transport are they considered safe to continue using?  In other words, if a compressed gas cylinder is not empty but has exceeded the hydrostatic test expiration date is it required by regulation or prudent practice to be returned for testing or can it continue to be used?  
Ben Owens
Assistant Director, Laboratory Safety
University of Nevada, Reno
EH&S Dept., MS 328
Reno, NV 89557
775-327-5196 (office)
775-843-2113 (cell)

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