operating speeds. Do not run a rotor beyond its maximum rated speed.
• Check O-rings and grease the seals routinely with vacuum grease.
• Do not use harsh detergents to clean the rotors, especially aluminum rotors. Use a mild detergent and rinse with deionized water, if possible.
• Be sure to follow the manufacturer’s guidelines for when to retire a rotor.
• For flammable and/or hazardous materials, keep the centrifuge under negative pressure to a suitable exhaust system.
• Keep a usage and maintenance log.
• Always use the rotor specified by the manufacturer.
• Inspect the components of the centrifuge each time it is used:
ο Look for signs of corrosion of the rotors. Metal fatigue will eventually cause any rotor to fail.
ο Ensure that the coating on the rotor is not damaged.
ο Check the cone area for cracks, because this area is highly stressed during rotation.
ο Look for corrosion or cracks in the tube cavity.
7.C.7.3 Electrical Instruments
Most modern electronic instruments have a cord that contains a separate ground wire for the chassis and are supplied with a suitable fuse or other overload protection. Modify any existing instrument that lacks these features to incorporate them. As is true for any electrical equipment, take special precautions to avoid possibility of water or other chemical spills into these instruments.
Under most circumstances, any repairs to, adjustments to, or alterations of electrical instruments should be made only by a qualified individual. Laboratory personnel should not undertake such adjustments unless they have received certification as well as specific training for the particular instrument to be serviced. If trained laboratory personnel do undertake repairs, always unplug the cord before any disassembly begins. However, certain adjustments require connection to a power source, and appropriate protective measures and due diligence are required when working on energized devices. Extra precautions are particularly important for instruments that incorporate high-voltage circuitry.
Many electrical instruments, such as lasers and X-ray, electron-beam, radioactive, photochemical, and electrophoresis equipment, emit potentially harmful radiation, and, therefore, special precautions must be taken when they are used. Only trained laboratory personnel should use and service this equipment. (See section 7.C.1 and Chapter 6, section 6.E.)
7.C.8 Electromagnetic Radiation Hazards
Laboratory equipment that can produce hazardous amounts of electromagnetic radiation include ultraviolet lamps, arc lamps, heat lamps, lasers, microwave and radio-frequency sources, and X-ray and electron-beam sources.
7.C.8.1 Visible, Ultraviolet, and Infrared Laser Light Sources
Seal or enclose direct or reflected ultraviolet light, arc lamps, and infrared sources to minimize overexposure whenever possible. Wear appropriately rated safety glasses, chemical splash goggles, and face shields for eye protection. Wear long-sleeved clothing and gloves to protect arms and hands from exposure. When lasers or deep UV light sources are in use, lights or highly visible signage should be posted outside the room.
Control measures for the safe use of lasers have been established by the American National Standards Institute and presented in Safe Use of Lasers (ANSI Z136.1-2007; ANSI, 2007), which describes the different types of laser hazards and the appropriate measures to control each type. Operate Class IIIB and IV lasers only in posted laser-controlled areas. No one but the authorized operator of a laser system should ever enter a posted laser-controlled laboratory when the laser is in use. (See Chapter 4, section 4.E.5.)
7.C.8.2 Radio-Frequency and Microwave Sources
Section 7.C.5.7 provides guidelines for the safe use of microwave ovens in the laboratory. Other devices in the laboratory can also emit harmful microwave or radio-frequency emissions. Train personnel working with these types of devices in their proper operation as well as in measures to prevent exposure to harmful emissions. Position shields and protective covers properly when the equipment is operating. Post warning signs on or near these devices to protect people wearing heart pacemakers.
7.C.8.3 X-Rays, Electron Beams, and Sealed Sources
X-rays and electron beams (E-beams) are used in a variety of laboratory applications but most often for analytical operations. The equipment is government regulated, and usually registration and licensing are required. Train personnel operating or working in the vicinity of these types of equipment appropriately to minimize the risk of exposing themselves and others in the laboratory to harmful ionizing radiation.
The beam from a low-energy X-ray diffraction