INTRODUCTION |
This
chapter explains the procedures and requirements for using toxic gases in the laboratory.
The discussion includes the use of gas cabinets, gas cylinder safety, and security. |
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According to the
TGO, toxic gases must be stored and used in an exhausted gas cabinet, exhausted enclosure,
or a separated ventilation room. |
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6.1
Gas Cabinets, Fume Hoods and Ventilated Enclosures |
If an exhausted
gas cabinet, fume hood or ventilated enclosure is used, the following requirements must be
met: |
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1. An individual using the toxic gas must
obtain thorough training from the gas cabinet and equipment vendor or a person designated
by the faculty advisor.
2. A toxic gas cylinder and its dedicated inert gas purge cylinder should be stored in
the same gas cabinet or exhausted enclosure.
3. Cylinders in the cabinet shall be secured with chains at 1/3 and 2/3 their height.
4. All gas cabinets, in accordance with provisions of the current Uniform Building Code
(UBC), shall be seismically braced.
5. The exterior of the gas cabinet shall be labeled with the full chemical name(s) of
the toxic gas(es) including concentration(s).
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6.2
Cylinders |
Follow these
procedures when using gas cylinders: |
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• Investigate and thoroughly
understand the physical and chemical characteristics of the gas to be used.
• Verify that the DOT label is legible and that
the full chemical name (including mixture components and concentrations) is clearly
visible on the cylinder.
• Label all cylinders with their maximum flow rate. The maximum flow rate for
cylinders with reduced flow or excess flow valves will be determined by the valve
manufacturer or the gas supplier.
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Toxic Gas "Don'ts"
Do Not:
- Purchase Gases in non-returnable "lecture bottle"
containers.
- Deface or remove the contents identification label.
- Strike an electric arc on a cylinder.
- Use lasers near the cylinders.
- Use a cylinder without a regulator.
- Refill a cylinder.
- Smoke around a cylinder.
- Store near heat or ignition source.
- Tamper with any part of a valve such as the safety or
packing nuts.
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• Keep cylinders, valves, regulators
free from oily or greasy substances.
• Close cylinder or lecture bottle valves when not in use.
• Secure lecture bottles in a stand or similar device.
• Close valves on all cylinders that are being returned to the vendor and indicate
that the cylinder is "empty" by labeling it with the initials "MT".
• Regularly check cylinder for obvious signs of defects, deep rusting, or leakage.
• Ensure that Material Safety Data
Sheets (MSDS) are available to personnel.
• If there is an accidental release of toxic gas, dial 9-911 and/or pull
the nearest fire alarm (See Chapter 9 Emergency
Preparedness and Response). If there is a non-health threatening, minor leak that is
contained in a ventilated enclosure or gas cabinet, report the leak to EH&S (725-9999)
and to Praxair (1-800-660-2066) to arrange for an exchange of cylinders.
• Use experimental equipment suitable for the contents of the cylinder. Materials
of construction for experimental equipment should be able to withstand the physical force
of the pressure and the reactive properties of the gas. Toxic gas vendors have specific
information regarding appropriate materials to be used with specific toxic gases.
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6.3
Security |
Any laboratory
that uses toxic gases must be secured against unauthorized entry. Basic security measures
can be accomplished by having the laboratory building remain locked in the evening and on
weekends, or having the individual laboratories locked when no one is working inside them. |
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6.4
Fire Extinguishing Systems |
Any interior or
exterior area in which regulated toxic gases are used and/or stored must have an automatic
fire sprinkler system. Sprinkler systems need to be designed to specifications no less
than those required in UBC 38-1 for Ordinary Hazard Group 3. If you have any questions
regarding your fire extinguishing system, contact the Stanford Fire Marshal at 723-0609. |
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6.5
Self-Contained Breathing Apparatus |
The TGO mandates
that facilities with Class I or corrosive materials must provide a minimum of two (2)
Self-Contained Breathing Apparatus (SCBA) for use by fire fighters and other emergency
response personnel. The SCBAs, suitable for the materials in the laboratories, are
maintained on University emergency response vehicles. |
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At Stanford,
Emergency Responders are equipped with their own SCBAs. However, in some instances,
additional SCBAs are needed to be provided on site. It is dangerous and prohibited for an
untrained individual to use an SCBA. Individuals should only use an SCBA after receiving
medical approval, attending Stanford University's Respiratory Protection Program (723-0448),
and receiving SCBA training. |