Wednesday, September 14, 2011

Laboratory design and facilities

In designing a laboratory and assigning certain types of work to it, special attention should be paid to conditions that are known to pose safety problems. These include: 1. Formation of aerosols, 2. Work with large volumes and/or high concentrations of microorganisms, 3. Overcrowding and too much equipment, 4. Infestation with rodents and arthropods, 5. Unauthorized entrance and 6. Workflow: use of specific samples and reagents (Ionescu et al., 2007).
Design features:
For proper design, wide space must be provided for the safe conduct of laboratory work and for cleaning and maintenance. Walls, ceilings and floors should be smooth, easy to clean, impermeable to liquids and resistant to the chemicals and disinfectants normally used in the laboratory. Floors should be slip-resistant. Bench tops should be impervious to water and resistant to disinfectants, acids, alkalis, organic solvents and moderate heat (Stevens, 2003).
Laboratory illumination should be adequate for all activities. Undesirable reflections and glare should be avoided. Laboratory furniture should be sturdy. Open spaces between and under benches, cabinets and equipment should be accessible for cleaning. While Storage space must be adequate to hold supplies for immediate use and thus prevent clutter on bench tops and in aisles. Additional long-term storage space, conveniently located outside the laboratory working areas, should also be provided (Susan and Lauren, 2004).
For proper laboratory design, Space and facilities should be provided for the safe handling and storage of solvents, radioactive materials, and compressed and liquefied gases. Facilities for eating and drinking and for rest should be provided outside the laboratory working areas. Hand-washing basins, with running water if possible, should be provided in each laboratory room, preferably near the exit door. While safety systems should cover fire, electrical emergencies, emergency shower and eyewash facilities and first-aid areas or rooms suitably equipped and readily accessible should be available (Tjeerd et al., 2008).
In the planning of new facilities, consideration should be given to the provision of mechanical ventilation systems that provide an inward flow of air without recirculation. If there is no mechanical ventilation, windows should be able to be opened and should be fitted with arthropod-proof screens. At Biosafety Level 2, an autoclave or other means of decontamination should be available in appropriate proximity to the laboratory (Robert, 2007).
Code of practice
This code is a listing of the most essential laboratory practices and procedures that are basic to GMT. In many laboratories and national laboratory programmes, this code may be used to develop written practices and procedures for safe laboratory operations (Ezzelle, et al., 2008).

Personal protection
Laboratory personelles protection can be fulfilled by coveralls, gowns or uniforms must be worn at all times for work in the laboratory. Appropriate gloves must be worn for all procedures that may involve direct or accidental contact with blood, body fluids and other potentially infectious materials or infected animals. After use, gloves should be removed and hands must then be washed (David, 2003).
For proper safety, personnel must wash their hands after handling infectious materials and animals, and before they leave the laboratory working areas. Safety glasses, face shields (visors) or other protective devices must be worn when it is necessary to protect the eyes and face from splashes, impacting objects and sources of artificial ultraviolet radiation (Ezzelle, et al., 2008).
For GMT, Pipetting by mouth must be strictly forbidden. Materials must not be placed in the mouth. Labels must not be licked. All technical procedures should be performed in a way that minimizes the formation of aerosols and droplets. The use of hypodermic needles and syringes should be limited. They must not be used as substitutes for pipetting devices or for any purpose other than parenteral injection or aspiration of fluids from laboratory animals (Stevens, 2003).
Also, all spills, accidents and overt or potential exposures to infectious materials must be reported to the laboratory supervisor. A written record of such accidents and incidents should be maintained. A written procedure for the clean-up of all spills must be developed and followed. Contaminated liquids must be decontaminated (chemically or physically) before discharge to the sanitary sewer. An effluent treatment system may be required, depending on the risk assessment for the agent(s) being handled (Ionescu et al., 2007).
Laboratory working areas
The laboratory should be kept neat, clean and free of materials that are not pertinent to the work. Work surfaces must be decontaminated after any spill of potentially dangerous material and at the end of the working day. All contaminated materials, specimens and cultures must be decontaminated before disposal or cleaning for reuse. Packing and transportation must follow applicable national and/or international regulations. When windows can be opened, they should be fitted with arthropod-proof screens (Ricós et al., 2008).
Biosafety management
Biosafety management is the responsibility of the laboratory director (the person who has immediate responsibility for the laboratory) to ensure the development and adoption of a biosafety management plan and a safety or operations manual. The laboratory supervisor (reporting to the laboratory director) should ensure that regular training in laboratory safety is provided (Ionescu et al., 2007).
Laboratory equipment
Together with good procedures and practices, the use of safety equipment will help to reduce risks when dealing with biosafety hazards. This section deals with basic principles related to equipment suitable for laboratories of all biosafety levels.The laboratory director should, after consultation with the biosafety officer and safety committee (if designated), ensure that adequate equipment is provided and that it is used properly. Equipment should be selected to take account of certain general principles, i.e. it should be designed to prevent or limit contact between the operator and the infectious material. Also, it should be constructed of materials that are impermeable to liquids, resistant to corrosion and meet structural requirements and fabricated to be free of burrs, sharp edges and unguarded moving parts (Ezzelle, et al., 2008).
Essential biosafety equipment
Essential biosafety equipments include pipetting aids to avoid mouth pipetting. Many different designs are available. Also, biological safety cabinets should be used whenever infectious materials are handled specially with procedures with a high potential for producing aerosols; these may include centrifugation, grinding, blending, vigorous shaking or mixing, sonic disruption, opening of containers of infectious materials whose internal pressure may be different from the ambient pressure, intranasal inoculation of animals, and harvesting of infectious tissues from animals and eggs (Kimman et al., 2008a).
Plastic disposable transfer loops also should be available. Alternatively, electric transfer loop incinerators may be used inside the biological safety cabinet to reduce aerosol production. Screw-capped tubes and bottles, autoclaves or other appropriate means to decontaminate infectious materials are also required (Kimman et al., 2008b).
Waste handling
Waste is anything that is to be discarded. In laboratories, decontamination of wastes and their ultimate disposal are closely interrelated. In terms of daily use, few if any contaminated materials will require actual removal from the laboratory or destruction. Most glassware, instruments and laboratory clothing will be reused or recycled. The overriding principle is that all infectious materials should be decontaminated, autoclaved or incinerated within the laboratory (Shahangian and Snyder, 2009)

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