precautions while using centrifuge

High speed centrifuges pose additional hazards due to the higher stress and force applied to their rotors and tubes. In addition to the safety guidelines outlined above, follow these guidelines for high speed centrifuges: 1 Filter the air exhausted from the vacuum lines. 2 Keep a record of rotor usage, in order to avoid the hazard of metal fatigue. 3 Frequently inspect, clean, and dry rotors to prevent corrosion or other damage. 4 Follow the manufacturer s operating instructions exactly.

Centrifuge tubes or centrifuge tips are tubes of various sizes made of glass or plastic. They may vary in capacity from tens of millilitres, to much smaller capacities used in microcentrifuges used extensively in molecular biology laboratories. The most commonly encountered tubes are of about the size and shape of a normal test tube (~ 10 cm long). Microcentrifuges typically accommodate microcentrifuge tubes with capacities from 250 ?l to 2.0 ml. These are exclusively made of plastic.

Glass centrifuge tubes can be used with most solvents, but tend to be more expensive. They can be cleaned like other laboratory glassware, and can be sterilized by autoclaving. Plastic centrifuge tubes, especially tend to be less expensive. Water is preferred when plastic centrifuge tubes are used. They are more difficult to clean thoroughly, and are usually inexpensive enough to be considered disposable.

The load in a laboratory centrifuge must be carefully balanced. This is achieved by using a combination of samples and balance tubes which all have the same weight or by using various balancing patterns without balance tubes. Small differences in mass of the load can result in a large force imbalance when the rotor is at high speed. This force imbalance strains the spindle and may result in damage to the centrifuge or personal injury. Some centrifuges have an automatic rotor imbalance detection feature that immediately discontinues the run when an imbalance is detected.

Centrifuge rotors have tremendous kinetic energy during high speed rotation. Rotor failure, caused by mechanical stress from the high forces imparted by the motor, can occur due to manufacturing defects, routine wear and tear, or improper use and maintenance. Such a failure can be catastrophic failure, especially with larger centrifuges, and generally results in total destruction of the centrifuge. While centrifuges generally have safety shielding to contain these failures, such shielding may be inadequate, especially in older models, or the entire centrifuge unit may be propelled from its position, resulting in damage to nearby personnel and equipment. Uncontained rotor failures have shattered laboratory windows and destroyed refrigerators and cabinetry. To reduce the risk of rotor failures, centrifuge manufactures specify operating and maintenance procedures to ensure that rotors are regularly inspected and removed from service or derated (only operated at lower speeds) when they are past their expected lifetime.

Protocols for centrifugation typically specify the amount of acceleration to be applied to the sample, rather than specifying a rotational speed such as revolutions per minute. The acceleration is often quoted in multiples of g, the acceleration due to gravity at the Earth s surface. This distinction is important because two rotors with different diameters running at the same rotational speed will subject samples to different accelerations.

Centrifuges are instruments with strong potential for harming users due to the high speed at which they operate: mechanical failure of the rotor can result in injury, even death; and sample container breakage can generate aerosols that are harmful to inhale. Thus, it is very important to act safely when using and maintaining these instruments.

It is the responsibility of the user to: attend a mandatory training session on centrifuge lab safety, use, care and maintenance before being allowed to operate a centrifuge,operate and maintain all centrifuges in accordance with NIEHS policy and good safe laboratory procedures, safety procedures as required),Read and follow all instructions for safe usage and maintenance of the centrifuge.

All centrifuge maintenance must be clearly documented in the log book provided in the lab for each unit. This includes record of service history, warranties and warranty expiration dates as well as details of maintenance carried out by laboratory users.2. If no reliable record of centrifuge history is found, or records are inadequate or not up to date, the unit concerned must be immediately taken out of service. A service representative from the centrifuge manufacturer must be contacted and the unit completely inspected and parts requiring replacement ordered and replaced by the service representative. Proper records must be kept thereafter.