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Previous by Date: Subject: [DCHAS-L] Laboratory Gas Detection Date: Tuesday, March 12, 2019 at 9:37:31 AM Author: Stephen Beaton <Steve.Beaton**At_Symbol_Here**DAL.CA> |
Next by Date: Subject: [DCHAS-L] SO2 exposure Date: Tue, 12 Mar 2019 11:03:13 -0400 Author: David Roberts |
From our O2 alarm policy currently making its way through our policy committee:
1. Oxygen sensors/detectors with low and high-level alarms will be located in areas that present a potential asphyxiation hazard due to the presence of manifolded or central liquid nitrogen or other asphyxiant gases.
2. Before any large volume container of compressed gas or cryogenic liquid is used, Environmental Health and Safety must be consulted to determine the need for oxygen detectors and oxygen depletion alarms. Environmental Health and Safety will perform the worst-case scenario calculation assuming the entire volume of container contents are released. If the final oxygen concentration is lower than 18%, oxygen sensors and alarms should be placed.. The calculation to be used is:
Final O2 concentration = 20.9 - 20.9*(Vgas/Vroom)
where Vgas = volume gas released in cubic meters
Vroom = room volume in cubic meters
|
Liquid |
Gas |
|
1L Liquid Nitrogen |
0.694 m3 Nitrogen Gas |
|
1L Liquid Helium |
0.757 m3 Helium Gas |
|
1L Liquid Argon |
0.847 m3 Argon Gas |
3. Oxygen depletion alarms should not only sound locally. All alarms should be tied into the Facilities Operations building alarm system.
4. The placement of the sensors should also be determined by EH&S, depending on the nature of the gas.
|
Gases |
Gas Density |
Sensor Placement |
|
Argon, Heavy Hydrocarbons |
Greater than air |
Closer to the ground |
|
Hydrogen, Helium, Methane |
Less than air |
Near the ceiling |
|
Carbon Monoxide, Nitrogen |
Similar to air |
At or near breathing level (4 to 6 ft. from the floor) |
--- For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at membership**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchasHi all,
I am researching best practice for fixed gas detection in laboratories in the university setting.. There are certainly a number of variables to consider. Does anyone have guidelines/ standards/ decision-trees to establish whether detectors for flammable, oxygen-depleting and toxic gases are required in the laboratory?
Thanks in advance
Steve
Stephen Beaton, MSc, CHO, CRSP
Chemical Safety Manager
Environmental Health and Safety Office
902.494.1934 | steve.beaton**At_Symbol_Here**dal.ca
DALHOUSIE UNIVERSITY
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