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Unattended Operations

• Experiments that are left unattended must have overriding controls with automatic shutdown devices to prevent system failure that could result in fire or explosion, for example, the loss of cooling water, overheating, flooding, and pressure buildup. Permanent piping, and shields or barriers if necessary, should be provided.
• Warning signs must be used if radiation, toxic fumes, or other hazardous conditions are present. Custodians, utility, or security personnel need to be warned of them.
• The laboratory entrance door should display an Emergency Notification sign naming the people to contact in case of trouble.
• All unattended electrical heating equipment must be provided with fail safe oven temperature shutoff controls, as overheating can result in a fire hazard.
• Burners, induction heaters, ovens, and furnaces must be located away from areas where temperature-sensitive and flammable materials are handled.
• Fan-cooled heating equipment must be equipped with an interlock arranged to disconnect current to the heating elements when the fan is inoperative.
• If your equipment is potentially dangerous and must be left on overnight, consult with your supervisor to see whether it is permissible to do so. Ensure that persons who may have to check the room can re-enter exterior doors (check with campus police). Notify the facilities manager (as some repair work and janitorial services are often performed during the night hours).
• Post a notice on your equipment describing possible malfunctions, emergency shutoff procedures, and the nature of the hazards.
• Bunsen and other gas burners without approved flame-failure devices must not be left on overnight. Gas pressure often fluctuates; an increase in pressure will cause a taller, hotter flame, overheating equipment and perhaps causing a fire. If the pressure decreases the flame may go out. Upon resumption of gas flow unburned gas will accumulate to create a fire or explosion hazard.
• Over-temperature cutoff devices should be used on heated oil baths.
• Use permanent piping if you must supply water to an overnight experiment. A sudden rise in pressure due to water fluctuations may rupture plastic or rubber experimental apparatus and cause flooding of lower floors. Floor flooding also takes place when water is left running into sinks to maintain a desired level and the drain becomes blocked or plugged. Consideration should be given to the use of standing overflow devices, which make drain plugging less likely.
• Electrical extension cords shall never be left plugged in while unattended (they are for temporary use while working with portable equipment in rooms where receptacles are not available).
• Protect the cords of electrical devices that must operate unattended. Prevent chemical or physical damage to the cords, by draping cords away from foreseeable hazards and heat sources.

Monitoring Instruments

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