Containment Standards for Facilities Handling Plant Pests
3.0 Physical requirements for containment facilities
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This chapter describes physical requirements for the containment of plant pests. The facility must be suitable for containing all pest organisms in use and it must be capable of containing the pest requiring the highest level of containment. New facilities must be constructed to meet applicable construction standards.
3.1 Primary containment
Primary containment devices (e.g. biological safety cabinets [BSCs]Footnote 8, insect cages etc.) and the use of good laboratory technique reduce the overall pest pressure inside the containment perimeter. Primary containment therefore reduces reliance on the secondary containment provided by the design of the facility.
Biological safety cabinets protect personnel, products and the environment from airborne or aerosolized microorganisms. Class II BSCs, Type A1, A2, B1 and B2, are appropriate for work carried out with plant pathogens. The exhaust air from these cabinets is HEPA filtered thus providing an extra level of protection against pest escape. Similarly, insect cages provide increased levels of containment by preventing the unrestricted movement of arthropods or by excluding potential arthropod vectors. Growth chambers and growth rooms can offer a cost-effective alternative to containment greenhouses while providing more precise levels of environmental control. Growth chambers and growth rooms can be located within a containment zone and thus provide primary containment or they can be sealed and modified to meet PPC-2 or PPC-3 containment requirements.
3.2 Secondary containment
Facility design and construction provides effective secondary containment to prevent the release of plant pests that have escaped from primary containment. The selection, design and installation of doors, windows, screening and air handling systems, along with the use of appropriate sealants, are factors that determine how well a facility can contain plant pests. Facility design and construction must be complemented with dedicated and trained staff who follow documented procedures and effectively utilize primary containment measures whenever feasible to minimize pest escape.
3.3 Risk mitigation
Risk mitigation measures should be applied within containment facilities, where feasible, to reduce the risk of pest escape and thereby effectively reduce the physical containment requirements needed for a particular plant pest. These measures may include providing adequate isolation between infected and uninfected hosts, providing a vector-free environment, caging insects and plants, and rendering all material non-viable at the end of experiments. Risks from plant pests can also be mitigated by locating containment facilities in areas where susceptible hosts are not present, and by conducting work during periods of the year when local hosts are not present or where, or when, local weather conditions would kill any pests that escape.
3.4 Design Considerations for new facilities
Facility design needs to address pest-specific issues in order to enhance the overall performance and operation of a containment laboratory, greenhouse or screenhouse. Designers, owners and operators should consider:
- Facility location - The site chosen for a containment facility should include an assessment of local agricultural and forestry programs as well as the local environment. A containment facility can be safely constructed in almost any location depending on available resources and construction methodologies. The risks to agriculture, forestry and the environment, including the impact of possible pest releases, should be considered before any work is begun with a particular pest. In areas prone to natural disasters, buildings and support systems should meet enhanced building code measures for the construction of containment facilities.
- Energy conservation - If energy conservation measures are envisaged (e.g. through the use of building automation controls, night air-change set-back [reductions], heat recovery and air recirculation), these measures must not compromise the level of containment provided by the facility.
- Inward directional airflow - Several standards (e.g. ANSI/AIHA Z-9.5-1992 and NFPA 45) recommend or require the use of inward directional airflow for new laboratory construction. Although it is advisable for new and existing facilities to have inward directional airflow, this is only a requirement for PPC-2 arthropod facilities and all PPC-3 facilities.
- Sealed PPC-3 containment zones should be located away from exterior walls to avoid pressure reversals associated with high winds. This cannot be done with greenhouses but their construction must be designed to prevent unplanned air infiltration.
- New facilities require storage space for supporting operations, cleaning, spill management, emergency safety response programs and tools and equipment. Providing dedicated equipment, washroom facilities, storage areas and clerical workstations inside the containment zone should be considered as a way to minimize traffic into and out of the containment facility.
- Containment facilities require frequent washdowns of surfaces and these surfaces need to be resistant to chemical attack and absorption. The underside of plastic laminated benches may contain absorptive organic materials which, in the case of PPC-3 facilities, must be sealed to facilitate cleaning and to prevent absorption of fumigants. Use of epoxy bench-top surfaces, stainless steel or other non-absorptive solid surfaces is recommended.
- To facilitate decontamination and maintenance, systems such as liquid effluent treatment systems and HEPA filter housing systems must be located as close to the containment perimeter as possible, and consideration should be given to installing valves to isolate sections of ductwork and drains. Appropriately sized screens or filters need to be used to protect all openings that may provide routes for incoming or escaping arthropods.
- Circuit breakers and shut-off valves should be located outside of the containment perimeter to facilitate maintenance.
3.5 Greenhouse design considerations
All requirements for ventilating and controlling containment laboratories need to be considered when designing ventilation requirements for greenhouses. Typically, greenhouses have high humidity, high heat production, significant cold weather influences and increased risks of ingress or egress of flying vectors. Ventilation strategies need to include screening of all forced-air and natural air venting systems. Air conditioning may include a combination of cooling/heating (temperature control), humidity control, CO2 control and air circulation patterns. In greenhouses that rely on screened natural air venting, it will be difficult to maintain negative pressure in areas prone to high winds. Greenhouses that are designed to be tight require verification of their as-constructed performance and regular testing for leaks.
A control system that integrates lights, ventilation requirements, temperature control and shading systems should be envisaged when constructing a containment greenhouse.
Where it is necessary to collect and treat waste water, greenhouse floors should be sloped toward drains and have curbs to contain water.
To increase physical security, consideration should be given to locating greenhouses away from public walkways and other amenities. Consideration should also be given to the use of kneewalls, windbreaks and physical barriers to reduce the probability of loss of containment through mechanical damage to the greenhouse caused by things such as machinery and carts.
Screenhouses may be constructed to provide BASIC or PPC-1 containment.
3.7 Physical containment requirements
The following tables describe physical containment requirements for facilities (e.g. laboratories, greenhouses, screenhouses) working with plant pests. The following symbols are used:
The absence of a symbol in the tables indicates that an item is either not required or not applicable. Where or are followed by an "A" suffix, the item applies only to arthropod facilities. Where the "A" suffix is not present, the item applies to all facilities, including those working with arthropods.
3.7.1 Structure, location and access
|3.7.1||Structure, Location and Access||PPC-1||PPC-2||PPC-3|
|1||Appropriate security to be provided for the building (e.g. fencing, motion sensors, physical barriers, patrols).|
|2||Signage to be installed on entry doors within the containment zone indicating containment level, contact information, and entry requirements.|
|3||Entry to the containment zone is via self-closing and lockable doors.|
|4||Restricted access to the containment zone is to be ensured through a controlled access system (e.g. electronic access card, code or equivalent).|
|5||Entry and exit is to be via an anteroom. Where stipulated by building codes anterooms that permit rapid emergency egress are to be placed at emergency exits. Corridors are acceptable as anterooms for non-arthropod PPC-2 areas.|
|6||If separate from a containment facility greenhouse and screenhouse entry and exit to be via an anteroom. Corridors and headerhouses are acceptable for PPC-1 and PPC-2 facilities.|
|7||Anteroom doors are to be self-closing and shall not open simultaneously (interlocking doors, and audible or visual alarms are acceptable).|
|8||Anteroom to be provided with windowless self-closing doors and lights that automatically switch off when either door is opened, and switch on only when both doors are closed, to avoid attracting phototropic arthropods.||A||A|
|9||Entry is to allow for separation of personal clothing from dedicated facility clothing (i.e. "clean" change area separated from "dirty" change area).||A|
|10||Anterooms can be considered as a change room, and a single change room can include both a clean and a dirty change area with a line demarcating the two areas.||A|
|11||Insect traps (e.g. sticky, pheromone, visible or ultraviolet light) to be provided in the anteroom of the containment zone.||A||A||A|
|12||Tight-fitting doors (e.g. with weather stripping, magnetic seals, brush barriers or flexible flanges) and, preferably, a raised threshold to be provided to deter ingress or egress of arthropods.||A||A|
|13||Inner anteroom door to be fitted with a forced-air curtain, as required, to deter arthropods from exiting the containment zone.||A||A|
|14||Mirrors to be installed within the containment zone and immediately inside the anteroom to permit self-inspection for hitchhiking arthropods.||A||A|
|15||Emergency exits are to be provided, where required, that open only from the inside, are alarmed and display "Emergency Exit Only" signage to deter unauthorized access.|
|16||Dedicated laboratory clothing and personal protective equipment are to be stored separately from street clothing.|
|17||Lowered ceilings to be provided in arthropod rearing rooms to facilitate arthropod recapture.||A||A|
|18||Facilities, including greenhouses and screenhouses, are to be designed to withstand extremes of local weather and anticipated maximum snow and ice loads, as well as wind, windborne debris and hail.|
|19||Greenhouses are to be constructed with a rigid reinforced frame with walls, floors and glazing forming a shell. All perforations and joints in greenhouses and between the greenhouse and other contained structures are to be sealed to provide a continuous containment barrier.|
3.7.2 Surface finishes and casework
Surface finishes should be scratch and stain resistant, easy to clean and durable enough to withstand repeated disinfection, while offering minimal opportunity for pests to persist and cross-contaminate samples. Appropriate surface coloration is important for facilities working with arthropods, to facilitate the detection of escaped individuals.
|3.7.2||Surface Finishes and Casework||PPC-1||PPC-2||PPC-3|
|1||Surfaces are to be continuous and compatible with adjacent and overlapping materials (to maintain adhesion and a continuous perimeter). For PPC-3 containment, walls and floors with welded seams are acceptable.
A continuous 100mm (minimum) cove floor finish up the wall is recommended.
|2||Floors to be slip-resistant in wet areas.|
|3||Interior coatings are to be easy to clean and resistant to gas and chemicals, as well as to repeated disinfection in accordance with function (e.g. will withstand disinfection, fumigation).|
|4||Bench tops to be non-absorptive, impervious to water, and resistant to acids, alkalis, organic solvents and moderate heat. Backsplashes to be installed tight to wall and sealed at wall-bench junction.|
|5||Greenhouse floors to be impervious to water and easy to clean (e.g. concrete).|
3.7.3 Containment perimeter
The containment perimeter is the continuous floor, ceiling and wall surfaces that form a barrier against the ingress or egress of plant pests, including all windows, doors and service penetrations into the area.
|1||Autoclave or other validated and acceptable means of waste treatment/disposal are to be located within the containment zone or, if not available in the containment zone, then procedures must be in place to safely transport waste for treatment/disposal elsewhere.|
|2||Dedicated double-door barrier autoclave with bio-seal flange is to be located on the containment barrier; equipped with interlocking doors (recommended) or audible or visual alarms, to prevent the simultaneous opening of both doors. Body of autoclave should be located outside of containment for ease of maintenance.|
|3||Autoclave to be equipped with a cycle log recorder to record time, temperature, and pressure.|
|4||For materials that require removal from the containment zone and cannot be autoclaved (e.g. heat sensitive equipment, samples, film) other proven and validated treatment technologies (e.g. irradiation, chemicals, gas) are to be provided at the containment barrier.|
|5||All penetrations of the containment perimeter, including all conduits and wiring, are to be sealed with an appropriate sealant to facilitate cleaning and fumigation and to prevent arthropod escape.||A|
|6||Windows positioned on containment barrier are to be non-opening and sealed to suit local climactic conditions; window glazing material must provide the required level of security.||A|
|7||Containment zone to be screened or sealed for PPC-1 and PPC-2, and sealed for PPC-3 and PPC-2 arthropod containment zones|
|8||Spare greenhouse window panels, emergency glazing and screening to be stored nearby for emergency repairs.|
|9||Greenhouse glazing must be break-resistant (e.g. double glazing, laminated or tempered glass, polycarbonate) and provide the required level of security.||A|
|10||Greenhouse glazing must be sealed to the greenhouse framework with a sealant that provides a tight, flexible and continuous seal resistant to degradation by chemical disinfectants, UV radiation and temperature changes.|
3.7.4 Heating, ventilation and air conditioning (HVAC)
Systems must be capable of providing a comfortable environment for laboratory staff that is also suitable for the organisms with which they work.
|3.7.4||Heating, Ventilation and Air Conditioning||PPC-1||PPC-2||PPC-3|
|1||Inward directional airflow to be provided such that air will always flow towards areas of higher containment (e.g. ± 12.5 to 25 Pa differential).||A|
|2||Supply and exhaust air to be appropriately filtered or screened in order to contain and exclude pests.||A|
|3||Supply and exhaust air systems are to be designed to prevent backdraft of contaminated air to other areas.||A|
|4||Supply and exhaust air ducts to be equipped with dampers to allow for screen or filter cleaning, removal and replacement.||A|
|5||Supply and exhaust air ducts to be equipped with bubble-tight dampers to permit gaseous or fumigant decontamination (the bubble-tight dampers can also be used to provide backdraft protection and isolation of the HEPA filters).|
|6||Exhaust air is to be HEPA-filtered. HEPA filters to be installed in a certifiable housing.|
|7||Bubble-tight dampers should be installed as close as possible to the containment perimeter.|
|8||Pre-filters or screens should be installed to protect and extend the life of the HEPA filters.|
|9||Filter housings and ductwork must be able to withstand pressure changes due to air supply and/or exhaust fan failures.|
|10||HEPA filter efficiency is to be demonstrable with the filter in place.|
|11||Airflow control devices and duct sensors to be located downstream of the exhaust HEPA filter and upstream of the supply bubble-tight damper or HEPA filter.|
|12||Supply and exhaust air systems to be interlocked to prevent sustained laboratory positive pressurization.||A|
|13||Supply and exhaust air ductwork to be sealed airtight between the room perimeter and HEPA filter or bubble-tight damper(s) in accordance with SMACNA Seal Class A 1985.||A|
|14||Alarms (audible or visible) to be provided both inside and outside the containment zone to signal air handling systems failure.||A|
|15||Visual pressure-monitoring devices to be provided at the entry to the containment zone.||A|
|16||Greenhouse vents and greenhouse HVAC penetrations to be screened with appropriate mesh screening to prevent pest escape.|
|17||Greenhouses constructed to meet PPC-3 level must undergo and pass the following tests: (a) an air infiltration test conducted according to ASTM E 283-91: the test pressure difference will be 6.24 pounds per square foot positive static pressure, and the allowable leakage rate is 0.03 cfm per square foot; (b) a static pressure water resistance test conducted according to ASTM E 331-93: the minimum test pressure will be 10 pounds per square foot, and the passing standard is no water penetration to the interior surface; and (c) a dynamic pressure water resistance test conducted according to AAMA 501.1-94: the minimum test pressure will be 10 pounds per square foot, and the passing standard is no water penetration to the interior surface.|
|18||Greenhouse ventilation system to be designed to allow for greenhouse fumigation and pesticide applications.|
3.7.5 Facility services
Facility services include all plumbing, electrical, gas, oil and safety equipment, etc. related to the operation of the facility. All such systems must be installed in a manner that does not compromise the containment required for the plant pests that will be used in the facility.
|1||A handwashing sink (or, if required, a sink and a shower) to be located within the containment zone and near the point of exit.|
|2||Handwashing sinks to be provided with "hands-free" capability.|
|3||Appropriate primary containment devices to be available (e.g. BSCs), as required, to minimize the potential contamination of the containment zone.|
|4||Emergency eyewash facilities to be provided in the laboratory containment zone in accordance with activities and applicable regulations (i.e. ANSI Z358.1-1998).|
|5||Emergency shower equipment to be provided in the laboratory containment zone in accordance with activities and applicable regulations (i.e. ANSI Z358.1-1998).|
|6||Facility service supply controls to be located both inside and outside of the containment zone, as required, to facilitate servicing.|
|7||All drains and associated piping to be connected to a validated effluent sterilization system consistent with laboratory activity and local regulations.|
|8||150-mm drain traps to be provided to avoid trap drying.||A|
|9||Soil traps to be installed in drains as required.|
|10||Plumbing vent lines (including effluent sterilization system) to be appropriately screened or filtered to prevent ingress and egress of arthropods.||A||A|
|11||Communication system (e.g. fax, LAN, modem) to be provided to allow the electronic transfer of information and data from the containment zone to other areas.||A|
|12||Intercom or telephone system to be provided to allow voice communication beyond the containment zone and to reduce traffic into and out of containment zones.||A|
|13||Laboratory to be adequately equipped (e.g. BSCs, thermocyclers, ELISA plate readers, centrifuges and microscopes) to avoid moving equipment into or out of the containment zone.|
|14||Alarm system to be installed to detect loss of containment due to unauthorized entry or mechanical or power failure.|
|15||Monitoring and security system to be installed to monitor critical containment systems. System monitoring to be available outside of the containment zone.|
|16||Emergency power system to be provided for HVAC, lighting, BSCs, essential equipment and other safety systems.|
|17||Vacuum pump contamination to be minimized by filtration of vacuum line and use of disinfectant traps.|
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