Appropriate design and flow of the laboratory facility is critical in assuring a safe work environment for laboratory employees. In the following section, several considerations for facility design are discussed with regard to their contribution in helping to reduce the potential of accidental chemical or biological exposure and accidental injury in the laboratory. This information is useful to those designing a new laboratory or to those renovating or updating an existing one.
A. Lighting
• Adequate, glare-free lighting is necessary throughout the laboratory facility. Unshielded lighting, the presence of harsh shadows and annoying reflections, and insufficient illumination are to be avoided in the design of the laboratory. Shielded fluorescent lights are particularly effective in providing sufficient lighting without direct glare. Placement of work stations facing windows or reflective walls tend to produce visual fatigue.
• The Illumination Engineering Society recommends illumination levels for different types of work. For regular office work (including chemist or laboratory technician offices) and most typical laboratory work, 70-100 foot-candles of illumination are recommended. For more intensive visual applications such as drafting, designing, and some accounting activities, 150-200 foot-candles are recommended.
• Each laboratory facility should anticipate the need for emergency lighting or power in the event of a power failure. The use of a backup generator or similar system may be required for sensitive equipment or procedures. Most OU buildings do not have such backup power, therefore, each location should determine the need and availability of such power.
B. Egress
The following procedures are required either by OSHA and/or by local building codes.
• Passageways should not be obstructed in any fashion such as from storage, equipment, telephone lines or other wiring, and should be a minimum of forty-four (44) inches wide.
• Both regular exits and emergency exits should be clearly marked.
• Locations of emergency exits should be identified in each work area, such as in a posted floor plan.
• Fire doors must be kept closed unless on a magnetic system which releases them in the event of a fire. Nothing shall be placed in front of such doors to prevent proper closure in the event of a fire.
• Non-exit doors and storage rooms should be marked as such to avoid confusion with exits in the event of an emergency.
• If possible, there should be two exits from each laboratory area.
C. Hallways
• Non-suite Areas
No storage or laboratory work of any kind is allowed in a non-suite hallway.
• Laboratory Suite Areas with Recirculating Ventilation
1. Hallway use for laboratory support in a laboratory suite area is limited to the establishment of desk work and storage areas. Laboratory work or storage involving chemicals or biological material biosafety level 2 (BSL2) or above (including human cells/blood/tissue) is not allowed in laboratory suites with recirculating ventilation. For a description of biosafety levels, see Section VI., Biological Safety.
2. Neither chemicals nor flammable storage cabinets are allowed in hallway areas.
3. Storage of biological material must be limited to biosafety level 1 (BSL1) materials only and must be placed in refrigerators, freezers, incubators, etc. that have locks and are locked after business hours and on weekends. BSL1 material may not be left unattended in shakers, evaporators, water baths, etc.
4. Compressed gas cylinders containing non-flammable gases may be stored in hallway areas if anchored to the wall (not to a table).
5. No eating, drinking, or applying cosmetics is allowed in the hallway if BSL1 material or compressed gas cylinders are stored or used in those areas. If the hallway contains on work stations and/or storage of supplies, books, reference material, etc., a break area can be allowed.
6. Nothing shall be placed within 16 inches of an emergency shower.
7. Egress of forty-four (44) inches must be maintained.
• Laboratory Suite Areas with Laboratory-Designed Ventilation
Normal laboratory operations and storage may occur in an appropriately designed laboratory suite. However, the following still apply:
1. No eating, drinking, smoking or applying cosmetics is permitted in areas where hazardous or biological materials are stored or used.
2. Nothing shall be placed within 16 inches of an emergency shower.
3. Egress of forty-four (44) inches must be maintained.
D. Electrical
The typical laboratory requires a large quantity of electrical power. Consequently, the likelihood of electrically-related problems and hazards is increased. One must address both the electrical shock hazard to the facility occupants and the fire hazard potential. The following recommendations are basic to a sound electrical safety program in the laboratory.
• Extension cords should not be used under any circumstance unless its use is temporary only. Contact OU Physical Plant for permanent wiring solutions.
• All electrical equipment must be properly grounded.
• Flexible cords and cables may not be run through holes in walls, ceilings, or floors; attached to building surfaces; or concealed behind building walls, ceilings, or floors.
• Do not route cords over metal objects such as metal racks, overhead pipes or frames, etc.
• All electrical repairs, splices, and wiring should be performed only by a Physical Plant electrician.
• Electrical receptacles, switches, and controls should not be located so as to be subject to liquid spills.
Source: NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals
E. Ventilation, Heating, Cooling, and Indoor Air Quality
Areas where laboratory work is performed should have all air exhausted with no recirculation of air to a common distribution system allowed. The American Society of Heating, Refrigeration, and Air Condition Engineers (ASHRAE) addresses ventilation rates of buildings by offering recommendations for maximum indoor air contaminant concentrations as well as volumes of fresh air expected to provide air test results lower than those concentrations.
In design of the ventilation system, air intakes and exhausts should be located to avoid re-entry of contaminated air. Specific sources of laboratory-related emissions should be controlled with fume hoods and local exhaust ventilation. Fume hoods and biological safety cabinets should be located in low traffic areas and away from air supply locations. Also, additional general ventilation may be required for stockrooms and storerooms in the facility.
Proper heating and cooling of room air in the laboratory should be maintained in accordance with ASHRAE guidelines. In some cases, the addition of equipment can increase the heat load to a room which may require a modification of the ventilation system to maintain appropriate temperatures. Any significant modifications to the layout of a laboratory or location of laboratory equipment should be evaluated by OU Physical Plant or A&E Services.
F. Sanitation Facilities, Lunch and Break Areas
Eating, drinking, smoking, and applying cosmetics is not permitted in areas where hazardous or biological materials are stored or used, and/or where the potential for occupational exposure to blood or other potentially infectious materials is present. Cross contamination between food items and hazardous materials is an obvious hazard and should be avoided.
Lunch or break rooms and sanitation facilities such as rest rooms must be distinctly separated from the main laboratory areas. As a matter of routine, employees should perform any washing, cleaning, or any other decontamination required when passing from the laboratory to other areas. Any laboratory coats, gloves, or other protective equipment must be removed prior to leaving the laboratory.
G. Natural Gas Usage
Natural gas outlets are available in many laboratories for connection to equipment such as Bunsen burners. The following precautions should be taken.
• Any tubing used to connect the equipment to the gas outlet should be of minimum length and should not exceed 6 feet. Tubing should not be concealed and should not extend from one room to another nor pass through wall partitions, ceilings, or floors.
• If the natural gas outlet is located within a biological safety cabinet, do not assume that the use of a Bunsen burner inside the cabinet is appropriate. Such use may compromise the performance of the cabinet and may be dangerous. During operations, the flame of a burner is very disruptive to the airflow patterns of the cabinet, and may actually increase the dispersion of aerosols in the work area. In addition, if the flame of the burner is too large, the excessive heat may melt the adhesive holding the HEPA filter together or literally burn holes in the filter media. Alternative methods such as electric incinerators, or disposable inoculating hoops may be used. If a procedure absolutely requires the use of a flame in a biological safety cabinet, a burner that can be activated only when needed should be used. It should be placed to the rear of the work space where resulting air turbulence will have a minimal effect.
• Do not leave a burner unattended as it may blow out or tip over. Always ensure that the valve is turned completely to the off position when work is completed.
Source: NFPA 54, National Fuel Gas Code
H. UV Light
Ultraviolet (UV) radiation can be associated with adverse health effects depending on duration of exposure and the wavelength. Some effects include erythema (sunburn), photokeratitis (a feeling of sand in the eyes), skin cancer, melanoma, cataracts, and retinal burns. See Table II-1.
TABLE II-1
UV HEALTH EFFECTS
Band Wavelength Potential Hazards
UV-A 315-400 nm Cataracts of lens, skin cancer, retinal burns
UV-B 280-315 nm Corneal injuries, cataracts of lens, photokeratitis, erythema, skin cancer
UV-C 100-280 nm Corneal injuries, photokeratitis, erythema, skin cancer
Transilluminators and hand held UV units are frequently used in research laboratories for visualizing nucleic acids following gel electrophoresis and ethidium bromide staining. UV is also used in biological safety cabinets. Safety precautions are as follows:
• Access to rooms with this equipment should be controlled by closing the door and posting a warning sign on the door stating the instrument is in use. The warning sign should include: Caution: High Intensity Ultraviolet Energy. Protect Skin and Eyes.
• Personal protective equipment (PPE) should be worn which protects the eyes and skin by all individuals in the room while the UV is operating. Appropriate PPE would include gloves, lab coat with no gap between the cuff and the glove, and a UV resistant face shield.
I. House Vacuum System Protection
Aspiration of carcinogenic or infectious agents should not be performed with a house vacuum system unless protection of the vacuum system occurs.
• For infectious fluids or particulates, in-line overflow flask(s) and a HEPA filter should be used. The left suction flask (A) is used to collect the contaminated fluids into a suitable decontamination solution; the right flask serves as a fluid overflow collection vessel. A glass splarger in flask (B) minimizes splatter. An in-line HEPA filter (C) is used to protect the vacuum system (D) from aerosolized microorganisms. See Figure II-1.
1. For organic vapors, an in-line charcoal filter should be used.
Source: CDC/NIH: Primary Containment for Biohazards: Selection, Installation and Use of Biological Safety Cabinets
J. Unattended Operations
In accordance with the OSHA laboratory standard, when laboratory operations are unattended, laboratory personnel should leave lights on, place an appropriate sign on the door, and provide for containment of toxic substances in the event of failure of a utility service (such as cooling water).
Source: OSHA Occupational Exposure to Hazardous Chemicals in Laboratories Standard (29 CFR 1910.1450)
