D.1 Laboratory Furniture and Equipment
D.2 Architectural Finishes and Materials
D.3 Structural
D.4 Heating, Ventilation, and Air Conditioning
D.5 Plumbing
D.6 Electrical
D.7 General Health and Safety
D.8 Biological Safety
D.9 Radiation Safety
D.10 Laboratory Fire Protection
D.11 Laboratory Pest Management

D.1 Laboratory Furniture and Equipment

D.1.1 Physical Hazards: Furniture and cabinets/counters shall be designed to be as vertically flush as possible. Kneehole space shall be provided for waste containers. Both these approaches allow for better movement in the laboratory and increase safety.

D.1.2 Casework: Laboratory casework shall be easily cleanable, and finishes shall be compatible with materials used for cleaning and disinfection. Metal casework systems shall be utilized in the NIH’s laboratories. Minimum level of quality of casework is outlined in NIH Laboratory Casework Specifications, which are available from the NIH Project Officer. Long runs of fixed casework should be minimized. Racked equipment, mobile casework on wheels, or other options that minimize cost and maximize flexibility shall be considered. The casework selected should be interchangeable and readily available so reconfigurations can easily occur. Shelving height is not to exceed 2 200 mm. For additional information on
shelving layout and height, see General Design Guidelines, Section: Fire Protection. Fixed casework and countertops shall be sealed to walls and floors during installation to minimize harborage of pests and provide a cleanable joint. Architects/engineers (A/E) shall also review caulking and sealing requirements with the Division of Safety, Integrated Pest Management Section, when designing NIH laboratory facilities.

Countertop materials will vary depending on usage. Traditional materials such as chemicalresistant plastic laminates may be appropriate for some applications. Epoxy resin will apply to most applications where corrosive chemicals are used or where sinks or heavy water usage occurs. Other new materials should be investigated for cost-effectiveness and durability. Stainless steel shall be used for glassware wash areas, cold rooms, and other areas as the program requires.

D.1.3 Chemical Fume Hoods: All containment devices shall be located in the laboratory to avoid entrapment, blocking of egress, or safety hazard to the lab occupant. For correct positioning of the fume hood, the designer shall follow the design methodologies in the NIH publication Methodology for Optimization of Laboratory Hood Containment to evaluate containment performance.

D.1.4 Placement of Biological Safety Cabinets (BSCs) in Lab Module: Personnel traffic results in air pattern disruption in BSCs. Therefore, BSCs shall be placed out of the direct traffic pattern of the laboratory. Air supply diffusers or exhaust vents shall not be placed directly over or in front of BSCs where the movement of air can affect the airflow of the cabinet.

D.1.5 Equipment: A wide variety of laboratory equipment is used in NIH laboratories. The NIH’s goal is to create adaptability in laboratory space so that instruments can be relocated within the laboratory without altering the space or attendant utility systems and without compromising the operation of the instruments or safety of the users. Some instrumentation rooms, electron microscopy suites, MRI spectroscopy suites, x-ray crystallography suites, and mass spectrometry rooms require special utilities and environmental controls. For requirements, see individual technical discipline sections within the General Design Guidelines volume.

D.1.5.1 Autoclaves: For maximum flexibility, autoclave space shall be provided on each floor where microbiological research is performed. Actual installation of autoclaves and their use are an operational decision. Since quality control considerations may require separate autoclaves for clean and dirty procedures, space shall be considered for both clean autoclaves (for sterilization of microbiological media and clean instruments, etc.) and dirty autoclaves (for decontamination purposes). The A/E shall review the requirements of the building personnel when designing and specifying autoclave space.

Autoclave space shall be finished with epoxy coatings and shall not have a suspended, acoustical ceiling. This area shall be thoroughly caulked and sealed to promote cleanliness and reduce pest harborage.

The space shall have adequate exhaust capacity to remove heat, steam, and odors generated by the use of the autoclave(s). A canopy hood shall be provided over the door of the autoclave. The autoclave space shall operate at negative pressure to the surrounding areas.

D.1.6 Gas Cylinders: Commonly used gases such as CO2 should be supplied from a centralized manifolded or bulk storage tank and piped throughout the facility. All applicable warning gauges and valves with protective fusible links or the equivalent shall be included in the design. Note: Some gases (flammable gases) may not be stored outside the laboratory. The A/E shall consult with safety personnel regarding placement requirements for specific gases.

If cylinders are to be placed in the lab, they shall be properly secured to a vertical surface or counter out of the way of traffic in the space. Appropriate space for such cylinders shall be provided within the laboratory to minimize potential hazards associated with the use of these cylinders and to maximize usable laboratory space.

D.1.7 Flammable and Waste Storage: Flammable-chemical storage cabinets shall be placed in each laboratory and meet applicable fire safety requirements. Space shall be allocated in each laboratory for waste box storage.

D.2 Architectural Finishes and Materials

Design features and materials selected for the construction of laboratories shall be durable, smooth, and cleanable, provide ease of maintenance and minimize pest access, and contribute to the creation of a comfortable, productive, and safe work environment. Materials for laboratory finishes shall be as resistant as possible to the corrosive chemical activity of disinfectants and other chemicals used in the laboratory. Selection of materials
and design of penetrations through walls and floors have an impact on fire safety in buildings. For additional requirements, see General Design Guidelines, Section: Fire Protection.

D.2.1 Floor and Base Materials: Floor materials shall be nonabsorbent, skid-proof, resistant to wear, and resistant to the adverse effects of acids, solvents, and detergents. Materials may be monolithic (sheet flooring) or have a minimal number of joints such as vinyl composition tile (VCT) or rubber tile. Floor materials shall be installed to allow for decontamination with liquid disinfectants and to minimize the potential spread of spills. The
base for VCT or rubber tile may be a 100 mm-high readily cleanable vinyl or rubber material. When monolithic flooring is used, either a 100 mm-high integrally coved sheet flooring base or a readily cleanable 100 mm-high vinyl or rubber base may be used.

D.2.2 Walls: Wall surfaces shall be free from cracks, unsealed penetrations, and imperfect junctions with ceiling and floors. Materials shall be capable of withstanding washing with strong detergents and disinfectants and be capable of withstanding the impact of normal traffic.

D.2.3 Ceilings: Ceilings such as washable lay-in acoustical tiles (Mylar face with smooth surface or equivalent) shall be provided for most laboratory spaces. Ceiling heights shall be 2 850 mm in laboratory and laboratory support spaces and a minimum of 2 440 mm in administrative spaces. Gypsum board with epoxy paint ceilings, equipped with access panels, will be provided in glassware washing and autoclave rooms, where the potential for a high moisture level exists. Access panels shall be fitted with gaskets that seal the door when closed and also the flange around the panel lip where it meets the ceiling. Open ceilings are acceptable provided minimal ducting and piping are present and all exposed surfaces are smooth and cleanable. The A/E shall consult with Division of Safety personnel in establishing the final design criteria for ceiling finish in any renovation or new construction project.

D.2.4 Windows and Window Treatment: Windows shall be nonoperable and shall be sealed and caulked. Window systems shall use energy-efficient glass. Treatments shall meet all functional and aesthetic needs and standards. All window treatment selections shall be coordinated with other interior finishes. Light-tight treatments will be provided in conference rooms, laboratories, and other spaces that may need to be darkened. Consistent visual appearance on the exterior of the building shall be maintained by the type of window treatment selected.

D.2.5 Doors: Doors into laboratories along a service corridor shall be 1 200 mm wide with 900 mm active leaf and 300 mm inactive leaf. The door along the personnel corridor shall be a single-leaf 900 mm door. In the event no service corridor is planned, a double-leaf door along the personnel corridor is strongly recommended. Vision panels shall be provided in the active leaf of all laboratory doors. Doors shall be at least 2 100 mm high. In laboratories where the use of larger equipment is anticipated, wider/higher doors shall be considered. Laboratory doors shall be recessed and swing outward in the direction of egress. Door assemblies shall comply with all appropriate codes. Fiberglass-reinforced polyester (FRP) doors should be considered for areas subject to impact or abuse.

D.2.6 Door Hardware: Laboratory doors are considered high-use doors. All hardware shall be appropriately specified to withstand this type of use. Light commercial grade hardware will not be specified. All appropriate hardware to meet security, accessibility, and life safety requirements shall be provided. Doors should be fitted with kick plates. Laboratory door hardware and keying shall comply with requirements outlined in General Design Guidelines, Section: Architecture.

D.2.7 Wall Protection: Corner guards and bumper rails shall be provided to protect wall surfaces in high traffic/impact areas.

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D.3 Structural

D.3.1 Vibration: An analysis of vibration response of the structure shall be made. Consideration shall be given to vibration of floor-framing systems caused by mechanical and electrical equipment such as pumps, chillers, fans, emergency generators, and transformers and other sources such as foot traffic, parking garage traffic, and movement of heavy equipment.

Because vibration can interfere significantly with sensitive laboratory instruments, designers shall take every opportunity to control vibration and to locate vibration sources away from activities sensitive to vibration. An experienced vibration consultant shall make specific vibration recommendations. Steel structures shall not be precluded for use in structural design relative to vibration without analysis.

To control vibration transmitted into laboratory space, the A/E shall consider the following items during the early design phases:

• The structural system shall be relatively stiff so that any vibration that is transmitted occurs at high frequencies.
• Vibrations occurring at higher frequencies are more easily dampened with instrumentation vibration dampening systems and isolation tables than vibrations occurring at lower frequencies.
• The structural system shall have relatively short column spacing.
• Laboratory spaces shall be isolated from sources of vibration.
• Vibration-sensitive equipment shall be located on grade-supported slabs.
• On framed floors, vibration-sensitive equipment shall be located near columns.
• On framed floors, combining corridors and laboratory spans in the same structural bay shall be avoided.

D.3.2 Module/Bay Size: The dimension of the structural bay, both vertical and horizontal, shall be carefully evaluated with respect to the laboratory planning module, mechanical distribution, and future expansion plans. Because of the importance of the laboratoryplanning module to functional and safety issues, the laboratory planning module shall be considered as the primary building module in multi-use facilities.

The horizontal dimension of the structural bay shall be a multiple of the laboratory-planning module dimension to provide for maximum flexibility and regular fenestration and to allow uniform points of connection for laboratory services with respect to the laboratory-planning module. Columns shall not fall within the laboratory-planning module to prevent interference with laboratory layouts and inefficient use of valuable laboratory space. Close coordination between structural and mechanical disciplines is critical to minimize interference of piping and ventilating systems with the structural framing.

D.3.3 Floor Slab Depressions: Floor depressions and/or topping slabs will be evaluated for use in special-finish areas or areas exposed to materials that may cause the structural floor slab to deteriorate. Floor depressions shall be reviewed for equipment requirements to allow for ease of movement of equipment.

D.3.4 Equipment Pathway: The potential routing or pathway for the addition or relocation of heavy equipment shall be reviewed and identified during the design phase.

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D.4 Heating, Ventilation, and Air Conditioning

HVAC systems shall be responsive to research laboratory demands. Temperature and humidity shall be carefully controlled. Systems shall have adequate ventilation capacity to control fumes, odors, and airborne contaminants, permit safe operation of fume hoods, and cool the significant heat loads that can be generated in the lab.

HVAC systems shall be both reliable and redundant and operate without interruption. Fume hoods will operate continuously. HVAC systems shall be designed to maintain relative pressure differentials between spaces and shall be efficient to operate, both in terms of energy consumption and from a maintenance perspective. Federal energy standards shall be achieved. An energy monitoring control system shall be provided. Studies shall be conducted during the design phase to determine the feasibility of utilizing heat-recovery systems in research laboratory buildings.

Laboratory noise, much of it generated by HVAC systems, shall be maintained at an NC between 40 and 45 dB. Refer to General Design Guidelines, Section: Mechanical, for systems design, preparing a basis of design report, and energy conservation requirements.

D.4.1 Outdoor Design Conditions for the NIH, Bethesda, Maryland: For facilities whose purpose is laboratory research and for HVAC systems requiring 100 percent outside air, outdoor design conditions shall be as follows:

Table D.4.1.a Outdoor Design Conditions for the NIH, Bethesda, Maryland (Facilities With 100 Percent Outside Air)

Latitude, 39 N; daily temperature range, -8 °C.

All other facilities such as office buildings, administrative facilities, and noncritical HVAC systems not requiring 100 percent outdoor air will use the values recommended by the current ASHRAE Handbook of Fundamentals to conform with the following:

Table D.4.1.b Indoor Design Conditions for the NIH, Bethesda, Maryland (Facilities That Do Not Require 100 Percent Outside Air)

The design wet-bulb temperature for sizing cooling towers shall be 1° higher than the ASHRAE 1 percent outdoor design wet-bulb temperature. All outdoor air-cooled condensing equipment shall be designed and selected on the basis of a 41 °C ambient temperature.

D.4.2 Indoor Design Conditions: The following indoor design conditions shall be used in the design of research laboratories except as explained below. Laboratory areas shall be maintained at the design conditions at all times.

Table D.4.2 Indoor Design Conditions

In some special cases, certain NIH laboratories require special temperature and humidity control. The design engineer shall review and check the Program of Requirements for each laboratory room with the NIH Project Officer and the researchers prior to the initial design. Refer to General Design Guidelines.

D.4.3 Air Quality: HVAC systems shall maintain a safe and comfortable working environment and be capable of adapting to new research initiatives. In addition, they shall be easy to maintain, energy efficient, and reliable to minimize lost research time. Laboratory HVAC systems shall utilize 100 percent outdoor air, conditioned by central station airhandling systems to offset exhaust air requirements. Laboratory supply air shall not be recirculated or reused for other ventilation needs. Refer to General Design Guidelines. Laboratories containing harmful substances shall be designed and field balanced so that air flows into the laboratory from adjacent (clean) spaces, offices, and corridors. This requirement for directional airflow into the laboratory is to contain odors and toxic chemicals, i.e., negative pressurization. Air supplied to the corridor and adjacent clean spaces shall be exhausted through the laboratory to achieve effective negative pressurization. The A/E shall develop in the design phase a formal startup and commissioning plan and procedure that addresses indoor air quality requirements.

Supply air for all laboratory systems shall be filtered on the upstream side of fans with 30 percent efficient pre-filters and 95 percent efficient after-filters. High-efficiency particulate air (HEPA) filters shall be provided in special laboratories where research materials are particularly susceptible to contamination from external sources. HEPA filtration of the supply air is considered necessary in only the most critical applications. BSCs (which are HEPA filtered), rather than HEPA filtration for the entire room, are satisfactory. HEPA filtration shall be provided as required by the Basis of Design report for individual applications.

Exhaust air, in general, does not require filtration or scrubbing. However, in special laboratories using radioisotopes or certain hazardous chemicals and in biocontainment laboratories, exhaust air may require special scrubbing or filtration before entering the combined laboratory exhaust system or discharging to the atmosphere. The A/E shall consult with the NIH Division of Safety, Radiation Safety Branch, for specific requirements.

D.4.4 Air Distribution: Air supplied to a laboratory space shall keep temperature gradients and air turbulence to a minimum, especially near the face of the laboratory fume hoods and BSCs. Air outlets shall not discharge into the face of fume hoods. Large quantities of supply air can best be introduced through perforated plate air outlets or diffusers designed for large air volumes.

D.4.5 Relative Pressurization: Laboratories shall remain at a negative air pressure in relation to the corridors and other non-laboratory spaces. Laboratory air shall flow from lowhazard to high-hazard use areas. In general, laboratories shall be maintained at 47 L/s per module negative per door relative to non-laboratory spaces. Administrative areas in laboratory buildings shall always be positive with respect to corridors and laboratories.

Corridor supply air distribution shall be sized to offset transfer air to laboratories while maintaining an overall positive building pressure. Loading and receiving docks shall be maintained as positive to prevent the entrance of vehicle fumes.

Some laboratories, such as biohazard containment laboratories, genome DNA processing rooms, and tissue culture laboratories require control of relative pressurization. The HVAC system shall be capable of achieving these special relative pressure requirements. Refer to General Design Guidelines.

D.4.6 Air Balance: Control of airflow direction in research laboratories controls the spread of airborne contaminants, protects personnel from toxic and hazardous substances, and protects the integrity of experiments. In these facilities, the once-through principle of airflow is applied on the basis of (1) exhausting 100 percent of the supplied air, (2) maintaining the required airflow with all exhaust units operating at capacity, and (3) providing directional flow of air from areas of least contamination to those of greatest contamination.

For critical air-balance conditions, a personnel entry or exit airlock provides a positive means of air control. An airlock is an anteroom with airtight doors between controlled and uncontrolled spaces. The air pattern in the airlock suits the foregoing laboratory space airbalance requirements.

Supply air quantities are not fully established by the room-cooling requirements and load characteristics. Additional supply air required to make up the differences between room exhaust requirements and primary supply may be designated (1) infiltrated supply, if inducted indirectly from the corridors and other spaces, or (2) secondary supply, if inducted directly to the room.

D.4.7 Ventilation Rates: The ventilation rate for laboratory HVAC systems is driven by three factors: fume hood demand, cooling loads, and removal of fumes and odors from the general laboratory work area. The minimum air-change rate for laboratory space is six air changes per hour regardless of space cooling load. Some laboratories may require significantly higher rates to support fume hood demand or to cool high instrument heat loads in equipment laboratories. The design of the HVAC systems shall allow for the maximum exhaust capacity for all BSCs which may be required in the facility.

D.4.7.1 Ventilation in Laser Laboratories: Rooms where laser equipment is used shall be properly ventilated to avoid buildup of ozone generated from the laser and mercury lamps.

D.4.8 Heating and Cooling Load Calculations: Complete design load calculations and a moisture control study shall be prepared for each space within a design program and presented in a format similar to that outlined in the latest ASHRAE Handbook of Fundamentals. Heating and cooling load calculations are required for all projects to facilitate review and provide a reference for system modifications. Individual room calculations shall
be generated and summarized on a system basis and presented with a block load to define the peak system load. Load summary sheets shall indicate individual rooms with area, design air quantity, L/s per m2, air changes per hour, and corresponding return or exhaust air quantity. Calculations shall include but not be limited to indoor and outdoor design parameters, heat gains and heat losses, supply and exhaust requirements for central systems and for each area of the facility, humidification and dehumidification requirements, and heat recovery. As a reference, calculations for assessing heating and cooling loads may include but are not limited to the following:

All heating and cooling load calculations shall include a predetermined safety factor to compensate for load inaccuracies, future flexibility, infiltration, and air leakage. Safety factors shall be clearly defined in the Basis of Design report.

D.4.9 Lighting Loads: The HVAC system shall provide, at a minimum, the following heat loads generated by room and task lighting:

Table D.4.9 Lighting Loads

D.4.10 Occupancy Loads: In the absence of more specific program requirements, the following occupancy loads shall be used as a general guide for HVAC alculations during the facility design. The A/E shall review the actual occupancy load and these general loads with the NIH Project Officer prior to starting the HVAC design work.

Table D.4.10 Occupancy Loads

D.4.11 Ventilation Loads:

Table D.4.11 Ventilation Loads.

D.4.12 Laboratory Equipment Cooling Loads: The central HVAC system shall provide as a minimum cooling for 1 892 W of laboratory equipment per lab module or cooling for the actual calculated load, whichever is greater. NIH experience has shown that for a typical 22 nm² laboratory module, the equipment load is usually 1 892 W (sensible heat) or 86 W/nm². The A/E shall make a detailed and complete inventory of all laboratory equipment scheduled for installation in each design space and, using estimated utilization factors, determine the projected equipment load requirement. Equipment utilization factors shall be indicated in the Basis of Design report.

The A/E shall carefully evaluate the following rooms used for laboratory support, which often have higher than normal cooling loads, as well as evaluate the use of supplemental units to remove excessive sensible loads affecting these areas while maintaining minimum ventilation requirements:

• Common equipment rooms
• Autoclave rooms
• Glassware washing rooms
• Darkrooms
• Special function room

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D.5 Plumbing

The plumbing systems shall be coordinated with the laboratory-planning module. A piping distribution method, including mains, risers, and branch lines, shall be designed to accommodate easy service isolation and system maintenance while minimizing disruption to laboratory functions. Piping systems shall be designed for flexibility and have redundant components to provide reliable and continuous operation. Adequate fluid temperature, pressure, and volume shall be delivered to required laboratory functions through conservatively sized pipe mains. Future capacity allowances need to be considered in building designs. Emergency isolation valves shall be conveniently located on branch lines so that segments can be taken offline quickly in the advent of failures.

Building services needed by researchers (such as centralized bottled gases, compressed air) shall be considered in the design for modular systems and services for the facility. Manifolding gases and decentralizing some services can be evaluated. Refer to General Design Guidelines, Section: Plumbing.

Piping systems shall be designed for flexibility and have redundant components to provide reliable and continuous operation. Adequate fluid temperature, pressure, and volume shall be delivered to required laboratory functions through conservatively sized pipe mains. Future capacity allowances need to be considered in building designs.

Floor penetrations in laboratory areas shall be avoided. All required penetrations shall use raised sleeved openings that are sealed and caulked to prevent leakage and maintain the fire rating of the slab.

D.5.1 Emergency Shower/Eyewash Equipment: One emergency shower shall be available to each laboratory space containing a chemical fume hood. This shower shall be tapped to the laboratory water supply. Eyewash stations shall be available to each laboratory space. Eyewashes shall be no more than 22 m from any point in a laboratory. Eyewashes shall be tapped to the laboratory water source. See General Design Guidelines, Section: Plumbing, for additional information.

D.5.2 Vacuum Systems: Vacuum pump systems will have hydrophobic (water-resistant) filters on the suction side, with the exhaust to the outside of the facility. Vacuum system exhaust shall be vented to the outside of the building and not recirculated to the mechanical room. A sampling port may be needed to sample exhaust. Filter housing shall be designed for easy replacement of the filter, with maximum protection for maintenance employees from possible contamination.

Vacuum systems shall be protected with appropriate filtration (0.2 micron hydrophobic filter or equivalent) to minimize the potential contamination of vacuum pumps. Filters shall be located as close as possible to the laboratory in order to minimize potential contamination of vacuum lines. Some mechanism for the decontamination of filters shall be incorporated in the design of the vacuum system. The design of the vacuum system shall be reviewed by Division of Safety personnel prior to finalization.

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D.6 Electrical

D.6.1 Normal Power: The following load figures in W/m2 shall be used in calculating and sizing the overall building load. These figures are connected load and shall be used in the early design stages. Actual design loads shall be used in the later part of the design. The range provided allows for varying intensity of usage. The mechanical loads do not include chilled water or steam generation, which are produced centrally on the NIH campus. The engineer shall use sound judgment in applying these numbers.

Table D.6.1 Normal Power Load Figures

Laboratories shall have a surface metal raceway mounted above all benches and as otherwise required in the room. The power duct shall have a continuous 60 A, 120/208 V, 3 F, 4 wire plus ground circuit installed. Twenty ampere taps as needed shall serve receptacles via 20 A single pole circuit breakers mounted in the raceway. Receptacles connected to this circuit shall be ivory in color. Receptacles shall be mounted 600 mm on center in a continuous raceway above laboratory benches. Receptacles mounted within 1 m of water dispensing shall be the ground fault interrupter (GFI) type. One 60 A, 3 F, 4 wire circuit minimum shall serve a laboratory module.

Each lab module shall have two 20 A circuits for computers with a maximum of three duplex receptacles each. These computer receptacles shall be gray in color. Each lab module shall have one 20 A circuit for printers with a maximum of two duplex receptacles. The printer receptacles shall be blue in color.

D.6.2 Emergency Power: The following load figures in W/m2 shall be used in sizing the generator. These figures are connected load and shall be used in the early design stages. Actual design loads shall be used in the later part of the design. The range allows for varying intensity of usage. The engineer shall use sound judgment in applying these numbers.

Table D.6.2 Emergency Power Load Figures

    * Minimum: One elevator per bank of elevators

The following loads are required to be connected to emergency power. These loads are in addition to any code-required emergency loads:

• A 20 A, 120 V circuit in a junction box mounted to the structural ceiling of each lab module
• One light fixture per module with one light switch per lab
• BSCs
• Supply and exhaust fans for BSL-3 and BSL-4 labs
• Lab equipment alarm-monitoring system
• Fume hood exhaust fans
• High-value specimen refrigerators, freezers, cold rooms, warm rooms, etc.
• Incubators

D.6.3 Lighting: Laboratory research requires high-quality lighting for close work, in terms of both brightness and uniformity. Fixtures shall be positioned to provide uniform, shadow-free and glare-free illumination of the laboratory benchtop.

General lighting for laboratories shall be fluorescent fixtures. Incandescent lamps may be required for special purposes. Fluorescent light fixtures should be directly above and parallel to the front edge of the laboratory bench to prevent shadows. Local wall switches shall control light fixtures. Fluorescent lighting shall be circuited to 277/480V panels located in electric closets. Electrical loads for laboratory lighting should be approximately 2.5 W/m². Fluorescent light fixtures should be equipped with RF suppression type ballasts in instrument laboratories, where RF may interfere with instrument operation or be cold cathode-type of ballast located remotely.

D.6.4 Alarm and Monitoring Systems: The increasing sophistication and fine control of laboratory instruments and the unique quality of many experiments demand closely monitored and alarmed systems that can be connected to individual pieces of equipment or temperature-controlled rooms. Several excellent monitoring systems are available for this purpose. They can be connected to a central monitoring facility at several levels of
observation or can be used internally within a laboratory setting. Wherever possible, all freezers (ultra-low and liquid nitrogen), refrigerators, refrigerated instruments such as centrifuges, environmental rooms, or any other piece of equipment with a variable temperature critical to sample preservation should be connected to the system. If the system is limited by capacity, then the user shall prioritize the units connected to the system.

If equipment in renovation work requires monitoring, the user or the designer shall receive approval from the Office of Research Facilities (ORF). If approval is granted, wiring and conduit shall be installed in accordance with ORF requirements.

D.6.5 Conduit: New buildings or major renovation of existing buildings shall have empty conduit with pull lines installed for monitoring lab equipment. A distribution system of raceways shall start at the building engineer’s office or another central location. The raceway shall connect with each lab module’s service corridor and other locations likely to have lab equipment requiring monitoring.

D.6.6 High-Voltage Equipment: Refer to the electrical design considerations for shunt trip breakers for labs with high-voltage electrical equipment in General Design Guidelines, Section: Electrical.

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D.7 General Health and Safety

The NIH, through the Division of Safety, has developed a comprehensive occupational safety and health program to protect the safety and health of all employees. This includes the occupational work setting found in laboratories, clinical settings, animal-handling activities, and mechanical support services. Safety and health regulations and guidelines require the use of engineering controls for worker protection, wherever possible, to minimize
the potential for occupational exposure to hazards in the workplace. To be most effective, engineering controls for protecting occupational safety and health shall be designed into facilities for both new construction and renovated space. This proactive approach can minimize numerous common health and safety concerns in laboratory facilities. Facilities shall be designed for ease of maintenance. This is particularly important with regard to the specific containment devices (e.g., HEPA filter housings, HVAC systems, vacuum systems, autoclaves, etc.) designed for the facility.

These health and safety guidelines are to be incorporated, as appropriate, in facility-specific construction documents by the A/E to ensure that health and safety protection is engineered into the design of any new or renovated facility and at the time of construction of the facilities.

While many of the requirements for health and safety engineering are incorporated in these guidelines, it is impossible to cover all possible concerns. The architectural/ engineering firm shall, whenever possible, have a health and safety specialist on staff and shall always consult with Division of Safety personnel with regard to specific health and safety engineering requirements in the design of new construction and renovation projects.

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D.8 Biological Safety

Additional biological safety regulations, codes, and standards that are required references for this section of the NIH Design Policy and Guidelines are located in the Appendix.

Work performed at the NIH involves the potential for occupational exposure to biohazardous materials. Biohazardous materials are defined as infectious agents, or materials produced by living organisms that may cause disease in other living organisms. While, generally speaking, the laboratory procedures identified as good microbiological techniques are helpful in minimizing potential occupational exposure to biohazardous materials, containment of these agents through the use of good facility design is also extremely important. The intent of this section is to provide A/Es with a working knowledge of the facility design parameters required for the construction of facilities, which shall provide for containment of biological hazards.

D.8.1 Background: The CDC/NIH guideline Biological Safety in Microbiological and Biomedical Laboratories provides guidance in the appropriate containment of biohazardous work. Biological safety levels 1-4 have been designated, with BLS-1 being the least hazardous. The biological safety levels are based on the probability of occupationally acquired infections resulting from the handling of specific agents in the laboratory. Containment facility design and laboratory practices have been developed for each biological safety level to minimize the potential for personnel exposure and release to the environment. All NIH laboratories at a minimum shall be designed to meet the requirements of biosafety level 2 (BSL-2) containment requirements.

D.8.2 Biological Safety Level 3: BSL-2 laboratory space is normally not easily convertible to BSL-3 containment space because of specific requirements for limiting access, airlocks, HVAC filter decontamination processes, autoclave space, and so on. Design considerations shall be given to designating a given amount of space in each facility as BSL-3 laboratory space or potential BSL-3 space. This space could be used as BSL-2 and easily upgraded or converted to BSL-3 as necessary. The space so designated shall be constructed using appropriate BSL-3 criteria.

D.8.2.1 Containment Requirements: BSL-3 laboratories require all of the design considerations for BSL-2 laboratories plus specific requirements for the additional containment of those biohazardous materials used in the laboratory. No compromise of the integrity of the containment of the BSL-3 laboratory is allowed.

D.8.2.1.1 Restricted Access: BSL-3 laboratories shall be separated from areas with unrestricted traffic flow by passage through two sets of self-closing doors. A ventilated airlock shall be designed to separate the common corridor(s) from the BSL-3 containment laboratory. The purpose of a BSL-3 laboratory facility is to ensure containment of agents used in this laboratory. It is recommended that airlock doors be interlocked to prevent
simultaneous opening of doors between the outside corridor and containment areas. Interlocks, when present, shall be provided with a manual override for use in case of emergency. Final determination on the design of airlocks for these facilities shall be made in consultation with Division of Safety personnel.

D.8.2.2 Sinks: A sink for hand-washing is to be located near the exit door in each BSL-3 laboratory (not in the airlock). Sink faucets shall be foot, elbow, or automatically operated.

D.8.2.3 Interior Surfaces: Interior surfaces of walls, floors, and ceilings shall be water resistant (e.g., epoxy paint, caulking, etc.), gas tight (i.e., capable of containing decontamination gas during decontamination process), and easily cleanable.

D.8.2.4 Ceilings: All BSL-3 facilities shall have a ceiling with a smooth, sealed finish. In new construction, all access to critical mechanical equipment (ventilation ducts, fans, piping, etc.) shall be provided outside the containment facility. See the HVAC System/Mechanical Equipment paragraph later in this section.

D.8.2.5 HVAC/Airflow: Ventilation shall be single-pass air, and all BSL-3 space shall be kept negative with respect to outside corridors and laboratories. Exhaust ducts shall be under negative pressure until the air is discharged outside the building, or until passed through HEPA filtration.

HEPA filtration of BSL-3 space may, in some cases, be required (see the HEPA Filtration of BSL-3 Laboratory Exhaust paragraph).

If the BSC cabinet exhaust system is connected to the building exhaust, it shall be connected in such a manner as to maintain the air balance of the cabinets and the building exhaust system. See the Biological Safety Cabinets paragraph later in this section.

Continuous-flow centrifuges and other aerosol-producing equipment shall be contained in devices that exhaust air through HEPA filters prior to discharge into the laboratory. Where possible, such containment devices shall be discharged to the outside through the cabinet exhaust system.

D.8.2.6 HVAC System/Mechanical Equipment: When retrofitting existing laboratory space as BSL-3 containment, it may not be possible to keep access to critical mechanical equipment outside the laboratory space. In these cases, an access panel shall be supplied inside the laboratory. The access panel shall be hinged (piano-type hinge) and gasketed with gas-tight gaskets to ensure an appropriate seal for both containment and decontamination procedures.

D.8.2.7 Utility Distribution: All utilities (e.g., water, vacuum, gas, electrical conduit, etc.) shall be installed to minimize exposed surfaces and facilitate ease of cleaning.

D.8.2.8 Penetrations and Joints: All penetrations in walls, floors, and ceilings shall be sealed with a smooth finish to facilitate decontamination and cleaning. All joints between fixed cabinetry and equipment (e.g., shelves, cabinets, plumbing fixtures, etc.) and the floor or wall shall be smooth coved and sealed to ensure maximum cleanability. Supply and exhaust ducts shall be gasketed or sealed at the point of penetration into the laboratory to ensure containment and the capability of gas decontamination. Light fixtures in BSL-3 laboratories shall be surface or pendent mounted.

D.8.2.9 Laboratory Furniture: Laboratory furniture shall be designed and installed to facilitate cleaning around and under the furniture. Movable furniture with minimal wall and floor connections shall be considered for installation in BSL-3 laboratories. Such cabinetry lends itself to ease of cleaning and decontamination of the entire laboratory space.

D.8.2.10 Windows: BSL-3 laboratories should be designed without windows. However, laboratory windows, where present, shall be designed not to open. All interior windowsills shall be sloped, and the seams around the windows shall be sealed.

D.8.2.11 Autoclaves: Decontamination equipment (preferably autoclave) shall be available in the BSL-3 laboratory. Autoclave space shall meet the guidelines as provided in the Space Descriptions section of this volume.

D.8.2.12 Vacuum Systems: Vacuum systems in BSL-3 laboratories shall be protected by filtration. See General Design Guidelines, Section: Plumbing.

D.8.2.13 Alarms: BSL-3 facilities shall be designed to ensure notification of inappropriate directional airflow. Both visual (gauges) and audible local alarms are required. In addition, alarms indicating the potential failure of BSL-3 containment shall be tied to a central system at the building engineer’s office, where possible. Notification devices shall indicate the failure to maintain a negative pressure differential from a non-contaminated area to potentially contaminated areas. All designs shall meet CDC/NIH guidelines. All alarm systems shall be validated prior to occupancy of the containment space.

D.8.2.14 HEPA Filtration of BSL-3 Laboratory Exhaust: While HEPA filtration of room exhaust from BSL-3 laboratories is seldom necessary, an evaluation of the need for specific filtration shall be performed during the initial planning and design stages of the project. The need for HEPA filtration shall be determined on a case-by-case basis in consultation with NIH Division of Safety personnel and shall be based on a hazard assessment of the materials in use and the procedures to be performed.

D.8.2.15 Autoclave Exhaust Filtration: The exhaust from an autoclave contains a significant amount of moisture. Filtration of this exhaust, when necessary (as determined above in HEPA Filtration of BSL-3 Laboratory Exhaust), shall be through a moistureresistant (hydrophobic) filter such as a Pall 0.2 micron filter or equivalent. Filtration of moist exhaust through a cold filter housing containing a paper HEPA filter will result in destruction of the HEPA filter and a break in integrity.

D.8.2.16 HEPA Filter Housings: When installed, HEPA filter exhaust housings shall be constructed to allow for appropriate particulate testing (i.e., DOP or equivalent) and shall be capable of being isolated from the ventilation system for gas decontamination and testing (i.e., gas-tight dampers and housings).

NIH Division of Safety personnel shall be consulted with regard to the suitability of the decontamination mechanism designs and approve the system prior to the finalization of the design.

D.8.3 Biological Safety Level 4: BSL-4 is required for work with exotic agents that pose a high individual risk of aerosol-transmitted laboratory infection and life- threatening disease. Construction of BSL-4 laboratory facilities requires careful planning and unique design features. This type of containment laboratory shall be designed and constructed to specific containment requirements in order to minimize the potential for personnel exposure and to prevent dissemination of BSL-4 organisms to the environment. Specific requirements for the design and construction of BSL-4 containment labs shall be provided by the NIH Division of Safety, and no design or construction of such labs may proceed until the Division of Safety
has been contacted and approval given.

D.8.4 Biological Safety Cabinets: BSCs are safety devices used for primary containment of biohazardous materials. These units are uniquely different from other types of laboratory hoods, and installation involves specific design consideration. BSCs are classified as Class I, II, or III, although Class I cabinets are no longer being manufactured on a regular basis. The design of the HVAC systems shall allow for the maximum exhaust capacity for all BSCs, which may be required in the facility.

Where BSCs are needed, Class II cabinets are being installed in new and renovated laboratories. Class II cabinets include both Type A and Type B cabinets. The Type A cabinet recirculates 70 percent of the air in the cabinet and exhausts 30 percent to the room. Type B cabinets are further classified as Type B1 (exhausts 70 percent of the air of the cabinet directly out through the building exhaust system), B2 (exhausts 100 percent of
the air of the cabinet), and B3 (essentially a modified Type A that exhausts 30 percent of the air of the cabinet). Each type of cabinet has unique properties and specific uses.

Class III BSCs are totally enclosed glove boxes primarily used in BSL-4 laboratories, but they may also be used for work with hazardous chemicals. Note that Class III BSCs are negative-pressure cabinets not to be confused with positive-pressure glove boxes, which may, if they leak, release hazardous materials to the laboratory.

Modern BSCs are designed to minimize personnel, product (research), and environ-mental exposure to biohazardous agents and other particulate matter. In addition to specific requirements for placing and installing BSCs, absolute attention to procedural details by the user is necessary to ensure that these cabinets perform in the manner intended. BSCs are certified according to NSF Standard 49, which establishes the stringent cabinet performance requirements for both personnel and product protection.

D.8.4.1 Class II, Type A, Cabinets: Type A cabinets are suitable for routine microbiological research in the absence of volatile chemicals. These cabinets vent to the room in which they are housed. Although the exhaust is HEPA filtered, there is some small possibility of release of agents to the room if the filter is damaged. Volatile chemicals shall not be used in these cabinets since the recirculation of the air would result in concentration of the volatile chemical in the cabinet with potentially hazardous consequences. In addition, when these cabinets are vented to the laboratory, volatile chemicals would be released to the room with the potential for significant exposure to personnel in the laboratory and elsewhere in the building.

It shall be noted that Type A cabinets have a contaminated positive pressure plenum. A pressure test of this plenum to ensure that no leakage is occurring shall be performed on all new or relocated cabinets. Such tests shall also be performed following maintenance involving the removal of panels used to form the positive pressure plenum. At the NIH, Class II, Type A or Type B3, cabinets may not be exhausted to the outside through the building ventilation system.

If recirculation of exhaust to the laboratory space from an installed cabinet is not acceptable, a Class II, Type B1 cabinet, hard-duct exhausted to the outside, shall be considered. The final decision on the appropriate cabinet shall be made by personnel from the NIH Division of Safety.

D.8.4.2 Class II, Type B1, Cabinets: Type B1 cabinets are also used for routine microbiological research and for tissue cultures. Although these cabinets are recirculating (70 percent exhaust and 30 percent recirculating), it has been shown that small volumes of volatile chemicals may be used in them provided the work is performed past the middle of the work surface, toward the back of the cabinet. The exhaust from the work surface in Type B1 cabinets is to the back of the cabinet, and this exhaust is not recirculated in the cabinet. The HEPA-filtered exhaust from these cabinets is hard ducted through the facility ventilation system. All contaminated areas of these cabinets are under negative pressure. Potentially contaminated air from the work surface that is exhausted through the front vent of the cabinet is HEPA filtered below the work surface and then recirculated to the work surface.

Type B1 cabinets are the most versatile of all the BSCs, and their installation results in more flexible laboratory space. However, since these cabinets require that they be hard ducted to the building exhaust system and such ducting is not always possible in retrofit projects,
Class II, Type A or B3, cabinets may be substituted when appropriate. The final decision on the type of cabinet to be used shall be made by the NIH Division of Safety.

D.8.4.3 Class II, Type B2, Cabinets: Type B2 (total exhaust) cabinets are useful when working with both biological and hazardous chemical materials, including volatile chemicals and carcinogens. The exhaust of these cabinets is HEPA-filtered, and additional filters may be added for special purposes (e.g., charcoal filters for radioactivity or volatile organics). Filters other than the HEPA filters shall be located downstream of the HEPA filter whenever possible since infectious agents could be present in the exhaust airstream and would be deposited in the HEPA filter without contaminating the extra filter.

Installation of Class II, Type B2, cabinets requires special ventilation engineering considerations. Type B2 cabinets are total exhaust cabinets that exhaust over 378 L/s of air. This air shall be supplied from either the room or the outside of the facility. At least 142 L/s shall be supplied from the room to satisfy the inflow air velocity across the front grill of the cabinet and to ensure containment of materials in the cabinet. It is important to evaluate the ventilation of the laboratory to ensure that sufficient air is supplied to the room to prevent robbing adjacent areas of air. Failure to adequately supply such cabinets could result in the failure of other containment devices (e.g., fume hoods, BSCs, etc.) in adjacent laboratories.

D.8.4.4 Class II, Type B3, Cabinets: Type B3 cabinets function in a manner similar to Type A cabinets but have been redesigned to provide a negative-pressure zone around all positive-pressure contaminated plenums. They have the same limitations as the Type A cabinets.

D.8.4.5 Requirements for BSC Installation: All BSCs to be installed at the NIH shall meet NSF Standard 49 requirements and be approved for purchase by NIH Division of Safety personnel. Selection of cabinets is to be based on an evaluation of the work to be performed and the specific safety requirements necessary to protect personnel, research, and the environment.

Air supply diffusers, or exhaust vents, shall not be placed directly over or in front of BSCs, where the movement of air can affect the airflow of the cabinet. The safe operation of BSCs depends on the air curtain formed by incoming and downflow air in the cabinet. Disruption of the air curtain will result in potential compromise of the operation of the cabinet and possible contamination of personnel or work. Personnel traffic results in air pattern disruption in BSCs. Therefore, these cabinets shall be placed toward the rear of the laboratory module, out of the direct traffic pattern of the laboratory. A gas-tight roll-valve (Baker Company, Sanford, Maine; Martin/ Peterson, Kenosha, Wisconsin; or the equivalent) shall be provided
on the Class II, Type B1, cabinet exhaust. This valve is required in order to facilitate decontamination and testing of the cabinets.

D.8.4.6 Natural Gas and Use of BSCs: Modern microbiological techniques, equipment, and materials have made the need for natural gas service to a BSC a thing of the past. Proper use of the BSC and sterile disposable supplies obviates the need for flame sterilization in most experimental procedures. There is no longer a need for natural gas to be supplied to the BSCs. In the event that the research protocol dictates a need for natural
gas, a Type B (ducted) BSC should be used. In areas that are already served by Type A (non-ducted) BSCs piped to receive natural gas, there is no need to replace them with a Type B BSC. A manual gas shutoff valve should be installed on the exterior of the cabinet, and gas shall be turned off when not in use. All future requests for natural gas supply to Type A BSCs will be considered on a case-by-case basis.

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D.9 Radiation Safety

Additional radiation safety regulations, codes, and standards that are required references for this section of the NIH Design Policy and Guidelines are located in the Appendix.

Work performed at NIH laboratories involves the potential for occupational exposure to radioactive materials and other sources of ionizing and non-ionizing radiation. While laboratory procedures identify good radiation safety practices and techniques essential to minimize potential exposure to radiation, the security, containment, and shielding of this material and equipment through the use of good facility design are other extremely important elements.
The intent of this section is to provide A/Es with a working knowledge of the facility design parameters required for the construction of facilities, which shall provide for the control and containment of these radiation hazards.

Not all sources of ionizing radiation are covered by NRC licensing. The nonlicensed sources are, however, controlled by regulations issued by the NIH Radiation Safety Committee upon recommendation by the radiation safety officer. Nonlicensed sources include x-ray machines, high-voltage accelerators, electron microscopes, and radioactive materials from sources other than reactor by-products.

In addition to the protection of occupationally exposed workers, the NIH Division of Safety, Radiation Safety Branch, must ensure that the general public and surrounding environs are also provided with an adequate and similar degree of protection.

D.9.1 Background: The NIH Radiation Safety Guide provides guidance and technical information concerning the use of radioactive materials as well as policies and procedures for radiation-producing machines and areas. Radiation safety control, containment, and shielding design and laboratory practices have been developed to minimize the potential for radiation exposure to workers as well as release to the environment.

D.9.2 Specific Areas of Concern: The following key radiation issues have been identified relative to laboratory activities:

• Radiation safety requirements for laboratories using radionuclides
• Radioactive airborne and liquid effluent sampling
• Radiation safety requirements for devices used in medical research, such as x-ray machines, accelerators, and irradiators
• Radiation safety requirements for non-ionizing radiation (only including MRI and highintensity lasers (e.g., CO₂)
• Security of radioactive materials

All radioactive materials stored at any NIH facility shall be secured. Unattended laboratories in which radionuclides are in use or stored shall be locked, or radioactive materials shall be locked in containers, refrigerators, or freezers. In addition, besides locked doors, other security options such as card key access, should be considered.

D.9.3 Radioactive Waste Storage:

D.9.3.1 On-Campus Buildings: Laboratory buildings on the NIH campus shall be designed with a separate area for the temporary staging of hazardous and radioactive waste. Mixed waste (hazardous waste that is also radioactive) shall be treated as radioactive waste in this temporary staging area. These staging areas are discussed in detail in General Design Guidelines, Section: Environmental. Only the specific issues that are directly related to radioactive waste are discussed here. Information on the carts and equipment for the transfer of radioactive waste currently in use can be obtained from the NIH Division of Safety, Radiation Safety Branch.

The staging area shall be large enough to provide for temporary storage of the radioactive waste and capacity for storage of specialized carts used to transport the radioactive waste from the laboratories. The staging area shall be designed to contain any spills of radioactive waste that may occur during handling of the waste materials. It is anticipated that this will be accomplished using specialized carts; however, the designer may propose alternate means for spill containment. Special consideration shall be given to this area in the fire protection design as indicated in NRC Information Notice 90-09, which specifies the description of the fire protection and suppression system to minimize the likelihood and extent of fire.

Coolers and/or walk-in freezers used to store MPW will also be used to store animal carcasses, tissues, and bedding contaminated with radioactive materials. Coolers and/or walk-in freezers shall be located in each building with laboratories conducting biomedical research with radioactive materials.

D.9.3.2 Off-Campus Facilities: Laboratory facilities not located on the NIH campus shall be designed with a room for use in processing and staging hazardous and radioactive waste. Mixed waste shall be treated as radioactive waste in this room. Only specific issues directly related to radioactive waste are discussed here. A 2 hour-rated wall shall be designed to separate radioactive waste and hazardous waste storage areas.

The waste will be transported to the NIH campus for additional processing and shipping to the long-term radioactive waste storage facility. Since this waste will be transported over public roads, this room shall be used to prepare the radioactive waste for shipment. Processing conducted in this room shall include bulking of waste into large containers, lab packing of individual waste containers, and labeling and manifesting the containers for
shipment. There will be a need for a bulking hood to perform these activities.

Consideration shall also be given to providing a service elevator on the premises that can be used to transport the radioactive waste to the appropriate marshalling area in the building. If a service elevator is not available, the use of a passenger elevator may be appropriate; however, dedicated times will be required to transport the radioactive waste.

The staging room shall be divided into two separate areas. The first area shall be large enough to provide for temporary storage of the radioactive waste as it is received from the laboratories and after it is packed for shipment. The second area shall be used for bulking and packaging the waste. Sufficient space shall also be provided for storing specialized carts used to transport the radioactive waste from the laboratory. The staging room shall be designed to contain any spills of radioactive waste that may occur during handling of the waste materials. Spill containment in the bulking and packaging area may be accomplished with a curb around the area, secondary containment bins, or a combination thereof. Spill containment in the staging area may be accomplished with a curb around the area, secondary containment bins, shelving designed to contain spills, or a combination thereof. These areas shall be thoroughly caulked and sealed to minimize pest harborage and exclude pests.

It is important to note that prior to contracting for leased space that will require remodeling, renovation, or other extensive architectural or engineering work, the NIH Division of Safety shall be informed and provide the necessary technical assistance.

D.9.3.3 Laboratory Module Requirements: All laboratory modules shall be designed for the safe storage of radioactive waste. The volume of radioactive waste generated by a laboratory is a function of the type of work being performed there. The designer will need to consider the function of the laboratory to determine the space necessary for radioactive waste storage. The designer shall also recognize that some types of radioactive waste will require segregation from other types and design the radioactive waste storage area to accommodate multiple containers.

All laboratories shall be designed to fit the appropriate low-level radioactive waste (LLRW) storage receptacles and/or containers. Contact the Radiation Safety Branch for specifications on these containers. Five LLRW streams have been identified from the NIH Waste Disposal Calendar, current edition:

• Liquids
  • aqueous waste
  • solvents/other hazardous chemical constituents (mixed waste)
• Dry or solid waste (dry active waste)
  • disposable labware
  • sharps (can also be categorized as MPW)
• Liquid scintillation vials and/or bulk liquid scintillation media
• Animal carcasses and/or tissues
• Animal bedding and/or solid excreta

The size of the space dedicated to each of the containers shall be based on the volume of radioactive materials generated and/or research activities performed in the laboratory. Standard-sized containers are available from both the Radiation Safety Branch and the radioactive waste contractor. Container placement locations shall be considered in the design. The location of the radioactive waste storage in laboratories shall be standardized to assist emergency response personnel. It is recommended that this storage be located near the laboratory door for convenient access by the technician collecting the radioactive waste. For laboratory modules with a service corridor, it is recommended that this storage be located near the service entrance rather than the hall entrance. This will avoid the need for moving radioactive waste through the main corridors of the laboratory building. The configuration of the radioactive waste storage area in the laboratory shall be designed to facilitate radioactive material spill cleanup and decontamination. Interior surfaces of the storage area shall be readily cleanable for ease in decontamination.

The designer shall also include the following considerations in the design:

• All laboratories shall have the ability to be locked against unauthorized access.
• All radioactive materials in laboratories shall be secured when unattended.
• Space required for shielding waste containers shall be considered.
• Laboratories and marshalling areas shall be sized appropriately to reduce accumulation.
• Appropriate spill containment shall be included in all storage areas.
• Potential shielding requirements shall be considered between adjoining or adjacent lab bench areas for high-energy beta emitter radionuclides.
• If the laboratory is to be used for high-energy gamma emitter radionuclides, then the design of the countertops and hoods shall take into account and compensate for the additional weight required for the appropriate lead shielding.
• Secure equipment alcoves shall be considered for storage of radioactive materials and/or irradiator equipment.
• If there is a need to store radioactive materials in refrigerators and/or freezers, the design specifications shall include security provisions, e.g., locks as part of the integrated system, to secure this equipment.
• Corridors and public space shall not be designated and used for storage, and equipment such as refrigerators and freezers shall not be designated to store this material in these areas.

D.9.4 Module Requirements: Beta barriers for shielding energetic beta emitters (P-32), often transparent plastic (Lucite) sheets, 0.95 to 1.27 cm thick, shall be considered to protect personnel working in adjacent and close work areas.

D.9.5 Ventilation Systems: Ventilation systems used for controlling airborne radioactive discharges require design considerations. Laboratory exhausts shall be manifolded into the regular building exhaust. Hoods used for bulking radioactive materials shall have the capability for sampling. In addition, the design shall accommodate space in the mechanical room to provide for any future additional filtration capability.

If the facility requires additional hoods, specifically for the use of iodination techniques, then the exhaust from these installations shall be equipped with the capability for HEPA or charcoal filtration. A distinct installation shall be considered separate from the main exhaust system.

D.9.6 Radioactive Airborne and Liquid Effluent Discharges: The NIH Division of Safety, Radiation Safety Branch, prohibits discharge of radioactive material into laboratory sinks. Provision shall be made in the design for installation of appropriate sampling probes for sampling capability to assess airborne and liquid effluent discharge streams, including main exhaust systems, sufficient to demonstrate compliance with the requirements of 10 CFR 20.1302. Liquid effluent monitoring can be accomplished by batch, composite, or continuous sampling prior to discharge into the sanitary sewer system.

Design and construction considerations for airborne radioactive effluent monitoring shall also include the following:

• All systems for use with radioactive materials shall have the capacity to sample the airborne effluent being discharged, primarily gases and vapors.
• Sufficient capacity shall be provided for sampling the combined discharge, specifically gases and vapors, at a common point located inside the mechanical room downstream of the filters and fans.
• Where iodination is performed in specific laboratories, those hoods shall be equipped to accept appropriate HEPA and charcoal filters.
• Airborne radioactive effluent monitoring systems shall be designed in accordance with ANSI Standard N13.1, Guide to Sampling Airborne Radioactive Materials in Nuclear Facilities (1969), specifically Appendix A, Guides for Sampling from Ducts and Stacks.
• A single-nozzle sample probe shall be designed inside the airstream for sampling gas and vapors, as specified in ANSI Standard N13.1.

Laboratory design considerations shall also include state-of-the-art design considerations, as specified by ANSI, and other acceptable industry standards, such as the following:

• National Council on Radiation Protection and Measurements (NCRP), Report No. 59, Operational Radiation Safety Program, Chapter 3, November 1, 1980.
• Hanson and Blatz, Radiation Hygiene Handbook, Section 9, Facility Design, 1959.
• Epoxy coatings, laminates, floor coverings, and protective coatings shall be utilized for ease of decontamination and to provide a protective coating that can be readily removed without extensive damage to the existing facility and surfaces.
• Sinks shall be either plastic composite or coated with epoxy or the equivalent to ease decontamination of surfaces. Stainless steel is also an option for sinks. Soapstone shall not be used.

Air filtration systems (activated charcoal/HEPA filtration) shall be installed and tested in accordance with ANSI/American Society of Mechanical Engineers Standard N510- 1980, Testing of Nuclear Air Cleaning Systems. The activated charcoal and HEPA filters shall be tested with current state-of-the-art methods and techniques for filter efficiency and compliance with technical specifications at the factory and after installation at NIH facilities. Chemical fume hoods for radionuclide use shall be designed in accordance with the following industry criteria and technical specifications:

• Landis and GYR Powers, Inc., Laboratory Control and Safety Solutions Application Guide, 1993.
• ACGIH, Industrial Ventilation: A Manual of Recommended Practice (current edition).
• Hoods shall have a minimum face velocity of 100 m/s.

A typical chemical fume hood designed for hazardous materials is acceptable as a radioisotope fume hood. The hood design shall include smooth, nonporous surfaces for ease of decontamination. In addition, the fume hood shall be constructed of materials that will not generate mixed waste if the surfaces and the construction materials interact with the radioactive materials.

D.9.7 Vacuum Systems: Vacuum systems shall be protected with appropriate filtration (0.3 micron hydrophobic filter or the equivalent) to minimize the potential for contamination of vacuum pumps. Filters shall be on the suction side of the pumps, with exhaust to the outside of the facility and not recirculated into the mechanical spaces. Filters shall be located as close as possible to the laboratory in order to minimize the potential contamination of vacuum lines and to preclude and minimize decontamination and decommissioning costs. Filter housings shall be designed for easy filter replacement in order to minimize the possibility of maintenance worker contamination and to provide for easy disposal.

D.9.8 Irradiators Utilized in Medical Research: Irradiators are designed to contain significant amounts of radioactive material and therefore are designed with engineering controls as well as adequate shielding to perform the necessary functions utilized in medical research. However, the following facility design parameters are required for the construction to adequately house this equipment:

• Floor loads shall be assessed to ensure structural integrity given the amount of shielding, and associated weight, of this equipment.
• Consideration shall be given to the available means for moving this equipment to its location (e.g., loads on elevators).
• Because of the shielding requirements, this equipment is usually located on the lower floors of a facility (e.g., ground floor, basement, or subbasement).
• The room or facility housing the irradiator shall be secured or have the capability to be secured (locked).
• The NIH Division of Safety, Radiation Safety Branch, shall be contacted when the design and installation of an irradiator is considered.

D.9.9 Radiation-Producing Equipment and/or Machines: In accordance with the NIH Radiation Safety Guide, the NIH Division of Safety, Radiation Safety Branch, shall be notified when there is any change in the setup of radiation-producing equipment or machines. This includes purchase and installation of new equipment, changes in shielding, changes in the output of the radiation, or changes in usage of the unit. With respect to the use of radiation-producing equipment and/or machines, the following design guidance shall be used:

• National Council on Radiation Protection and Measurements (NCRP), Report No. 102, Medical X-Ray, Electron Beam and Gamma-Ray Protection for Energies up to 50 Mev (Equipment Design, Performance and Use, 1989).
• NCRP, Report No. 49, Structural Shielding Design and Evaluation for Medical Use of XRays and Gamma Rays of Energies up to 10 MeV, September 15, 1976.

The documents referenced above shall be used by the Radiation Safety Branch to:

• Implement an “as low as reasonably achievable” (ALARA) program to minimize radiation exposure to occupationally exposed individuals and the general public.
• Provide the appropriate design criteria as they relate to radiation-producing equipment and/or machines.
• Provide structural shielding requirements for any new installations or installations undergoing renovations or changes.

The following factors, such as W (workload), U (use factor), and T (occupancy factor), as defined in the appropriate NCRP handbooks, shall be utilized to calculate and design the necessary shielding requirements. The dose equivalent limit for design purposes shall be 10- mRem public exposure and 500 mRem occupational exposure.

D.9.10 Non-Ionizing Radiation: This section applies only to MRI and high-power intensity lasers. With respect to the use of MRI devices, the following regulations and design considerations apply:

• U.S. Food and Drug Administration (FDA) regulations 21 CFR 892.1000, Magnetic Resonance Imaging.
• Security requirements for housing and enclosing the equipment.
• Warning placards, signs, and postings, which may also include barriers.
• Warning requirements for cardiac pacemakers as well as other prosthetic devices and/or equipment.
• Shielding requirements to minimize radiation exposure to electric and magnetic fields.
• Posting concerning electrical hazards.

With respect to the use of lasers, specifically high-power intensity lasers, the following regulations and design considerations apply:

• FDA regulations 21 CFR 1040, Performance Standards for Light-Emitting Products.
• ANSI Standard for the Use of Lasers, ANSI Standard 2136.1, 1986.
• Conference of Radiation Control Program Directors, Frankfort, Kentucky. Suggested State Regulations for Control of Radiation, Volume II: Non-Ionizing Radiation (latest edition).
• Security requirements for housing and enclosing the equipment.
• Warning placards, signs, and postings, which may also include barriers.
• Appropriate personal protective equipment warnings prior to entering and/or working with the equipment to mitigate and prevent eye and skin exposure.

A Class III laser system is a medium-pulse system requiring control measures to prevent viewing of the direct beam. Design and control measures emphasize preventing direct access to the primary or reflected beam. Safety eyewear is necessary and required with this class of laser.

High-power intensity lasers (e.g., CO₂lasers) are classified as Class IV lasers in 21 CFR 1040. These lasers produce radiation so powerful that they can cause injury with a direct or reflected exposure, even when the beam is scattered or diffused by a rough surface or smoke screens. Class IV radiation lasers emit more than 0.5 W continuous output. Laser facilities shall be designed to minimize the use of reflective/refractive surfaces to provide additional protection to occupational personnel.

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D.10 Laboratory Fire Protection

This fire protection section includes specific requirements for laboratory facilities. The general fire protection requirements are found in General Design Guidelines, Section: Fire Protection. All laboratory areas are considered Class “B” per NFPA 45 definitions.

D.10.1 Fire-Resistant Materials and Construction: All laboratory corridor walls shall have a minimum 1 hour fire rating. All 1 hour fire-rated partitions shall have 45 minute opening protection. Each vision panel shall not exceed 0.84 m².

D.10.2 Fire Dampers: Fire dampers shall not be provided on any fume hood system. Fire dampers shall not be provided in any laboratory fume removal exhaust system or in laboratory hoods per NFPA 45. Alternative protection of the fire-rated assembly shall be provided by means of one of the following:

• Independent risers from each floor in a fire-rated shaft or
• Steel subducts at least 558 mm in length shall be used at each branch duct connection of exhaust risers in which the airflow moves upward and the riser is appropriately sized to accommodate the flow resistance created by the subduct.

D.10.3 Automatic Sprinkler Systems: All sprinkler system designs shall meet, at a minimum, NFPA 13 Ordinary Hazard Group II spacing and hydraulic requirements. Open storage in the laboratories shall not be permitted, on a horizontal plane, within 0.46 m of the sprinkler deflectors (as measured vertically from the bottom of the sprinkler deflector to the horizontal plane). Enclosed perimeter storage (i.e., within cabinets) to the underside of the ceiling is permitted. In areas that also have a pressure differential at the ceiling, which can affect the operation characteristics of the concealed heads, the gasketed concealed heads shall be specifically listed for use in ceilings with pressure differentials.

D.10.4 Fire-Protective Signaling Systems: All laboratory corridors shall be equipped with ionization-type smoke detectors if the constructed width of the corridor is greater than 1.5 m.

D.10.5 Duct Smoke Detection: Duct smoke detectors shall not be installed in air-handling units of less than 7 083 L/s, in air handling units that serve only one fire area, or in fully sprinklered buildings. Where duct smoke detectors are installed, they shall be of the photoelectric type, connected to the building fire alarm system, and cause shutdown of the associated air handler upon alarm.

D.10.6 Fire Extinguishers: Laboratory fire extinguishers shall be located in the corridors. The maximum travel distance to an extinguisher, from any point, shall be 15 m.

D.10.7 Means of Egress: A minimum 0.30 m clear aisle space shall be maintained around laboratory benches and furniture.

D.10.8 Flammable Storage Cabinets: A flammable storage cabinet (FSC) shall be provided in each laboratory. Additional FSCs shall be provided per NFPA 45 requirements. All FSCs shall be constructed of metal. The exterior of all FSCs shall be appropriately signed. The FSC shall be located as remote as possible from the exit doors of the laboratory. FSCs shall not be installed beneath fume hoods. FSCs shall not be located in corridors. The integrity of the FSC shall not be compromised by its mounting method. The FSC shall not be vented.

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D.11 Laboratory Pest Management

For general design considerations related to pest management, see General Design Guidelines, Section: Pest Management. Consideration of pest management shall be given to any function, finish, or detail contributing to pest infestation and harborage in or around a building. Design features shall promote cleaning and maintenance while minimizing pest ingress and harborage. Floor penetrations and void areas shall be minimized and completely sealed. The designer shall ensure that areas of pest ingress, such as doors, windows, loading docks, and so on, are fitted with appropriate pest-exclusion devices. Consideration shall be given to designs that minimize pest harborage and promote proper cleaning. Examples of harborages are inaccessible voids behind and under equipment and casework, unsealed cracks or joints between pieces of equipment or finish materials, or the use of unsealed foam or fiberglass insulation on pipes and equipment. The NIH Division of Safety, Integrated Pest Management Unit, shall be consulted to review and approve all plans for new construction or renovation of old space and to provide additional programspecific caulking and sealing information.