Dear Margaret,
As you assess your setup, you may want to begin by reviewing the local and state fire code requirements for storage and any limitations set by the fire and building codes to ensure compliance (max per sq ft,
20 ft from oxidizers, number per room, fire walls, etc.). Your fire marshall should be able to help you. Grounding may also be recommended, but it is important to do so carefully and ensure proper grounding paths. I once encountered a building where numerous
items were connected to the ground, rendering it essentially ineffective.
Use only stainless steel or copper for hydrogen handling on installations for compatibility and permeation reasons. They will both experience embrittlement over time, depending on pressure, temperature, and
the duration of exposure to hydrogen. From my understanding, whenever modifications are made to the setup, it is advisable to replace the copper and stainless-steel tubing/pipes to mitigate embrittlement concerns and prevent the formation of microfissures
during bending or movement. If feasible, flushing the system with an inert gas after use is always recommended.
Regarding material lifespan, a typical replacement period is around 20 years, with periodic inspections throughout the year to ensure continued integrity and safety.
Additionally, having a Lower Explosive Limit (LEL) detector in the room is a key safety measure.
Please feel free to reach out if you’d like to discuss any of these points further. I’d be happy to assist.
Tammy Rechtin, Ph.D.
Chemical Engineering Safety Coordinator
Ralph E. Martin, Department of Chemical Engineering
University of Arkansas
Email:
tlutzrec**At_Symbol_Here**uark.edu
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU>
On Behalf Of Margaret Rakas
Sent: Friday, February 21, 2025 9:18 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] Hydrogen Gas Safety
We have 3 different cylinders of hydrogen in use in one lab (different grades for different pieces of equipment ) and have the following questions (I've searched the web but am not sure what is done with relatively small amounts of hydrogen
versus a lab that has higher number in use or a 'tank farm' setup.
1) Do you routinely use excess flow shutoff valves? We do have flame arrestors in line with each regulator....
2) How long are regulators (for inert gases as well as hydrogen) used before refurbishing or replacement? Apparently hydrogen gas can embrittle metals...
3) If you send them out for refurbishment I would be interested in knowing where, and how you know their initial age?
thanks very much!
Margaret
--
Margaret A. Rakas, Ph.D.
Lab Safety & Compliance Director
Clark Science Center
Smith College
413-585-3877 (p)
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