WEBVTT 00:00:01.333 --> 00:00:08.933 [This tape was duplicated from 16mm original by Colorlab for the National Library of Medicine, July 2004, NLM call number HF 1079] 00:00:08.933 --> 00:00:15.733 [The U.S. Department of Health, Education, and Welfare Public Health Service Presents] 00:00:15.733 --> 00:00:21.166 [Laboratory Design for Microbiological Safety] 00:00:21.166 --> 00:00:27.832 [Produced for National Institutes of Health, National Cancer Institute, Special Virus Leukemia Program] 00:00:27.833 --> 00:00:33.199 [In Cooperation with The Ohio State University Department of Veterinary Pathology, The National Drug Company 00:00:33.200 --> 00:00:48.100 Biological Research Laboratories, The Brooks Air Force Base School of Aerospace Medicine, The Naval Biological Laboratory, 00:00:48.100 --> 00:00:57.366 The U.S. Army Biological Laboratories, The Public Health Service Taft Sanitary Engineering Center, 00:00:57.366 --> 00:01:03.666 The U.S. Department of Agriculture National Animal Disease Laboratory, The Virus Laboratories California Dept. of Public Health, 00:01:03.666 --> 00:01:07.332 The Medical Research Laboratory, University of Illinois 00:01:07.333 --> 00:01:12.499 [A Public Health Service Audiovisual Facility Production] 00:01:12.500 --> 00:01:21.700 [Dr. A.G. Wedum:] Every year approximately 175 million dollars are spent on constructing and remodeling biomedical research facilities 00:01:21.700 --> 00:01:23.266 in the United States. 00:01:23.266 --> 00:01:29.866 Of this amount, a significant portion is directed to laboratories handling infectious microorganisms. 00:01:29.866 --> 00:01:39.666 Because of the magnitude of this investment and the hazards to laboratory personnel, it is important that microbiological safety measures 00:01:39.666 --> 00:01:43.532 be incorporated in the design of infectious disease laboratories. 00:01:43.533 --> 00:01:51.899 These measures are needed to prevent accidental occupational infections among laboratory workers, to safeguard the health 00:01:51.900 --> 00:01:59.666 of the surrounding community, and to prevent false laboratory results due to cross-infection of animals or cultures. 00:01:59.666 --> 00:02:08.766 The purpose of this film is to describe and illustrate some of the principle building features and devices 00:02:08.766 --> 00:02:12.299 used to provide effective microbial containment. 00:02:12.300 --> 00:02:18.900 In determining what safety measures to incorporate in the design of infectious disease laboratories, 00:02:18.900 --> 00:02:21.166 much research and study was necessary. 00:02:21.166 --> 00:02:30.199 For instance, we needed to understand how laboratory workers become infected and how microorganisms might escape and spread 00:02:30.200 --> 00:02:33.833 within the building or escape to the surrounding community. 00:02:33.833 --> 00:02:43.199 During the study it was found that infectious agents are let loose into a laboratory worker's environment 00:02:43.200 --> 00:02:45.400 in a manner and in quantities that cannot always be detected. 00:02:45.400 --> 00:02:52.500 However, these infectious agents can be contained by establishing a system of enclosures or barriers within the building. 00:02:52.500 --> 00:02:59.700 Thus, from research and study the concept of primary and secondary barriers evolved. 00:02:59.700 --> 00:03:05.200 The enclosures immediately surrounding infectious agents are the primary barriers. 00:03:05.200 --> 00:03:08.633 The most important are the ventilated safety cabinets. 00:03:08.633 --> 00:03:18.666 Other primary barriers include such items as closed, ventilated animal cages, safety centrifuge cups, and safety blendor bowls. 00:03:18.666 --> 00:03:25.399 All serve as the first line of defense against the escape and possible spread of infectious microorganisms. 00:03:25.400 --> 00:03:32.733 The secondary barriers in a laboratory are the features of the building that surround the primary barriers. 00:03:32.733 --> 00:03:41.399 These provide a separation between infectious areas in the building and the outside community, 00:03:41.400 --> 00:03:43.766 and between individual infectious areas within the same building. 00:03:43.766 --> 00:03:52.432 Such features as walls, floors, and ceilings, ultraviolet airlocks and door barriers, 00:03:52.433 --> 00:03:58.899 and properly arranged personnel change rooms and showers are considered secondary barriers. 00:03:58.900 --> 00:04:05.066 Increasingly negative air pressure as one moves from a clean area to one of greater infectious risk 00:04:05.066 --> 00:04:08.799 can also be classified as a secondary barrier. 00:04:08.800 --> 00:04:17.266 Furthermore, the equipment for filtering air exhausted from laboratory rooms comes under this classification, 00:04:17.266 --> 00:04:22.399 as well as the facilities for treatment of potentially contaminated liquid waste. 00:04:22.400 --> 00:04:31.766 These and other secondary barriers generally are thought of as providing supplementary biological containment, 00:04:31.766 --> 00:04:39.032 serving mainly to prevent the escape of infectious agents if and when a failure occurs in the primary barriers. 00:04:39.033 --> 00:04:47.333 Actually, the more effective the primary barriers are, the less need there is for emphasis on secondary barriers. 00:04:47.333 --> 00:04:57.899 Therefore, during the design phase of any infectious disease laboratory, it is both important and economically necessary 00:04:57.900 --> 00:05:05.633 to first determine and select the primary containment devices to be used. 00:05:05.633 --> 00:05:12.833 [Narrator:] Early in the design of any new infectious disease building, definitions should be made of the five functional zones 00:05:12.833 --> 00:05:15.366 and their relationship to each other. 00:05:15.366 --> 00:05:18.399 There can be numerous physical arrangements of these zones. 00:05:18.400 --> 00:05:25.000 However, in this film we will consider one standardized floor plan as being typical, 00:05:25.000 --> 00:05:27.533 and showing most of the recommended containment features. 00:05:27.533 --> 00:05:31.799 The first functional zone we shall consider is the clean area. 00:05:31.800 --> 00:05:40.000 Here are located the main entrance to the building, offices, conference rooms, and library where administrative work, meetings, 00:05:40.000 --> 00:05:42.566 and similar activities are carried on. 00:05:42.566 --> 00:05:50.666 Also within this area are transitional rooms through which lab personnel enter and exit from the infectious areas of the facility. 00:05:50.666 --> 00:05:59.566 These consist of a clean change room equipped with toilets, storage space for laboratory clothing, and lockers. 00:05:59.566 --> 00:06:09.966 A non-ventilated airlock with UV lights, a shower room, and a contaminated change room equipped with toilets, 00:06:09.966 --> 00:06:14.666 storage racks for shoes, and a UV-shielded bag for discard clothing. 00:06:14.666 --> 00:06:20.332 In the rear of the facility is also a clean area with a transitional airlock. 00:06:20.333 --> 00:06:27.933 This serves to handle the inward flow of laboratory supplies into the building and the outward flow of materials from the building. 00:06:27.933 --> 00:06:33.399 Supplies entering the infectious areas are passed in through the UV airlock. 00:06:33.400 --> 00:06:41.033 Potentially infectious material leaving the building is treated in a double-doored steam or ethylene oxide sterilizer. 00:06:41.033 --> 00:06:47.533 Let's now observe some of the design features that one might see in the clean zone. 00:06:47.533 --> 00:06:54.699 Personnel usually enter the facility into a clean area in the front of the building, including the offices and other support areas 00:06:54.700 --> 00:06:57.366 pertinent to the operation of a laboratory. 00:06:57.366 --> 00:07:04.766 Clean offices, when located adjacent to the contaminated zone, make possible easy visual communication 00:07:04.766 --> 00:07:10.166 through a large viewing window and minimize personnel traffic between the two zones. 00:07:10.166 --> 00:07:18.599 Oral communication between the clean and infectious areas of some laboratories is often provided by means of speaking diaphragms. 00:07:18.600 --> 00:07:26.966 A tightly sealed plastic membrane provides the medium through which the sound passes. 00:07:26.966 --> 00:07:33.632 Treatment of data sheets and other papers sent from the contaminated to the clean zones is accomplished 00:07:33.633 --> 00:07:36.033 by passing them through an ultraviolet apparatus. 00:07:36.033 --> 00:07:41.233 Lever-driven rollers push the paper through at a constant rate. 00:07:41.233 --> 00:07:45.966 This assures adequate decontamination of each sheet. 00:07:45.966 --> 00:07:53.332 For treatment of envelopes, folders, and books, equipment pass-in locks utilizing cold sterilization 00:07:53.333 --> 00:07:55.399 with ethylene oxide are recommended. 00:07:55.400 --> 00:08:02.700 This through-the-wall, double door chamber allows sterilization of items in about twelve hours, 00:08:02.700 --> 00:08:09.066 after which the items can be removed in the clean zone. 00:08:09.066 --> 00:08:16.399 The passage of personnel from clean to infectious zones should be through a clean change room. 00:08:16.400 --> 00:08:28.766 After changing into lab clothing, they pass through a non-ventilated ultraviolet airlock and then on into a contaminated change room. 00:08:28.766 --> 00:08:36.332 Personnel leaving infectious zones go through the same change rooms but in reverse order. 00:08:36.333 --> 00:08:44.366 After returning their shoes to the storage racks, their lab clothing is discarded into a bag screened with UV. 00:08:44.366 --> 00:08:51.532 They then take a shower using a germicidal soap. 00:08:51.533 --> 00:09:00.566 Finally, they return to the clean change room, passing first through the airlock. 00:09:00.566 --> 00:09:05.932 In the clean area at the back of the building there is another transitional airlock. 00:09:05.933 --> 00:09:10.199 Here supplies and equipment needed for lab operation are delivered. 00:09:10.200 --> 00:09:21.866 Once the outer door is closed, an electrical interlock allows personnel in the contaminated area access to the airlock to remove supplies. 00:09:21.866 --> 00:09:31.032 Returning to our floor plan, let's look at the second functional zone of a typical facility, the lab research area. 00:09:31.033 --> 00:09:37.133 Here, infectious microbiological operations exclusive of animal work are performed. 00:09:37.133 --> 00:09:42.366 Located in this area are the potentially infectious lab offices. 00:09:42.366 --> 00:09:48.532 The individual laboratory rooms are usually equipped with one partial barrier safety cabinet 00:09:48.533 --> 00:09:53.699 for work of low to medium risk and a free-standing, single-door autoclave. 00:09:53.700 --> 00:10:04.000 At least one room should contain a gas-tight, absolute barrier cabinet system for performing high hazard operations with a minimum hazard. 00:10:04.000 --> 00:10:11.966 The system should terminate in either a double-doored autoclave or a germicidal liquid bath. 00:10:11.966 --> 00:10:18.832 Other common features usually found in this research area are an instrument room for centrifuges and other apparatus, 00:10:18.833 --> 00:10:24.633 and constant temperature rooms for incubation and refrigeration. 00:10:24.633 --> 00:10:31.066 The hallway, with air pressure positive to the lab rooms, provides additional room-to-room separation. 00:10:31.066 --> 00:10:39.632 Let's examine some containment features found in this area, remembering that this is where the bulk of research and diagnostic work is done. 00:10:39.633 --> 00:10:45.066 The laboratory zone should be maintained at an air pressure negative to the clean zone. 00:10:45.066 --> 00:10:51.066 The lab rooms themselves should have an air pressure negative to the adjoining halls. 00:10:51.066 --> 00:10:54.599 And the ventilated cabinets should be negative to the rooms. 00:10:54.600 --> 00:11:04.133 Ultraviolet fixtures in the ceiling that are turned on when the room is vacant will aid in reducing nonspecific microbial flora. 00:11:04.133 --> 00:11:08.833 A special switch in the corridor indicates when the light is on. 00:11:08.833 --> 00:11:18.133 For accidents involving chemicals or fire, emergency showers may be installed convenient to the research area. 00:11:18.133 --> 00:11:25.466 Particular attention should be given to the selection of building materials and methods of construction. 00:11:25.466 --> 00:11:33.932 Due to the need for periodic decontamination, paints and coatings used on walls and other surfaces must be resistant to steam, 00:11:33.933 --> 00:11:37.066 disinfectants, and frequent washings. 00:11:37.066 --> 00:11:42.066 Walls, wall curbing, and ceilings should be free of cracks. 00:11:42.066 --> 00:11:46.699 Often a monolithic covering is used on the floors. 00:11:46.700 --> 00:11:56.000 In order to facilitate cleaning operations and to prevent leakage of organisms from the lab area, casework should be sealed to the wall. 00:11:56.000 --> 00:12:03.233 Equipment not sealed to the wall, such as cabinets, tables, and chairs, may be mounted on wheels 00:12:03.233 --> 00:12:06.333 to facilitate decontamination and cleaning. 00:12:06.333 --> 00:12:14.799 Lighting units and other features that penetrate the barrier walls must be designed so as to assure adequate physical separation 00:12:14.800 --> 00:12:17.300 between the contaminated and clean zones. 00:12:17.300 --> 00:12:24.866 Fluorescent fixtures may be ceiling-mounted and serviced from within the room, or they may be installed above the ceiling 00:12:24.866 --> 00:12:29.699 encased in glass and serviced from a clean attic. 00:12:29.700 --> 00:12:35.300 A good gasket and seal is necessary to prevent the spread of contamination from the room into the attic. 00:12:35.300 --> 00:12:44.633 Where frequent wash-downs of the area are necessary, watertight units such as these should be employed. 00:12:44.633 --> 00:12:49.999 Also the electrical outlets in the room should be watertight to prevent water damage, 00:12:50.000 --> 00:12:54.966 and internally sealed to prevent leakage of contamination. 00:12:54.966 --> 00:13:01.999 To provide safe working conditions for maintenance personnel, electrical panels and utility spaces 00:13:02.000 --> 00:13:03.966 should be located in the clean area. 00:13:03.966 --> 00:13:11.666 Services penetrating the wall should be sealed airtight at the wall to preserve the secondary barrier. 00:13:11.666 --> 00:13:18.266 Particular attention should be given the safety features of walk-in refrigerators and incubators. 00:13:18.266 --> 00:13:22.632 Door should be equipped with viewing windows and speaking diaphragms 00:13:22.633 --> 00:13:36.033 so that personnel may observe operations before entering. 00:13:36.033 --> 00:13:44.133 Control switches for electrical outlets are usually located outside. 00:13:44.133 --> 00:13:51.633 The most important containment feature of the infectious disease laboratory is the ventilated safety cabinet. 00:13:51.633 --> 00:13:58.666 This primary barrier device isolates the laboratory worker's most potentially infectious environment. 00:13:58.666 --> 00:14:04.399 Although there are many different cabinet designs, there are only two basic types: 00:14:04.400 --> 00:14:13.033 the absolute barrier, represented by a gas-type modular system, and the partial barrier with its open panel. 00:14:13.033 --> 00:14:21.699 Both need to be resistant to a variety of physical and chemical materials and therefore are best constructed of stainless steel. 00:14:21.700 --> 00:14:25.733 Let's consider the partial barrier cabinet in detail. 00:14:25.733 --> 00:14:32.399 Here is an open-front type commonly used for low hazard manipulations. 00:14:32.400 --> 00:14:40.633 For slightly higher risk levels, glove panels without the gloves may be attached to the cabinet 00:14:40.633 --> 00:14:47.199 to increase the rate of air flow and reduce spilling and spattering of materials from the cabinet. 00:14:47.200 --> 00:14:52.466 The cabinet uses a high-efficiency microbial filter for air leaving the unit. 00:14:52.466 --> 00:14:55.766 The air is ducted to the nearest exhaust manifold. 00:14:55.766 --> 00:15:02.599 Some partial-barrier cabinets are equipped with front panels with attached arm-length rubber gloves 00:15:02.600 --> 00:15:05.733 to provide a greater degree of microbial control. 00:15:05.733 --> 00:15:11.866 With this cabinet there is a saving in operating cost, since it requires very little conditioned air 00:15:11.866 --> 00:15:15.666 as compared to that needed for the open-faced type. 00:15:15.666 --> 00:15:22.766 Steam is one of the desired services and is used with formaldehyde to decontaminate both the inside of the cabinet 00:15:22.766 --> 00:15:25.132 and its exhaust air filter. 00:15:25.133 --> 00:15:33.033 The other basic type of safety cabinet is the absolute barrier unit. 00:15:33.033 --> 00:15:39.566 It provides a total separation between the infectious working areas and the surrounding laboratory. 00:15:39.566 --> 00:15:46.866 This cabinet system can serve as a complete contained laboratory for the most hazardous microbiological procedures. 00:15:46.866 --> 00:15:54.099 It is modular in construction and the individual units may be fitted together in any desired configuration and length. 00:15:54.100 --> 00:16:00.033 These gas-type cabinet systems can vary widely in arrangement. 00:16:00.033 --> 00:16:06.899 Maximum utilization of floor area can be achieved by double stacking the cabinets and placing them around the walls. 00:16:06.900 --> 00:16:12.533 Others might be straight-line units that extend through a wall. 00:16:12.533 --> 00:16:17.033 This particular design speeds up workflow between two separate rooms. 00:16:17.033 --> 00:16:24.133 The possible internal features for absolute barrier systems are almost limitless. 00:16:24.133 --> 00:16:38.466 They include interconnecting gas-tight doors, back-mounted incubators, 00:16:38.466 --> 00:16:46.699 bottom-mounted, Lazy Susan refrigerators, 00:16:46.700 --> 00:16:54.666 bottom-mounted centrifuges, and other devices. 00:16:54.666 --> 00:17:02.566 The third functional zone in a standard facility is the research area for both small and large infected animals. 00:17:02.566 --> 00:17:10.366 This usually includes laboratories having appropriately ventilated cabinets for inoculation and autopsy, 00:17:10.366 --> 00:17:18.266 and animal rooms equipped with such isolation equipment as ventilated cages and UV cage racks. 00:17:18.266 --> 00:17:25.732 In some instances it may be desirable to locate,in a room adjoining the animal room, aerosol exposure equipment, 00:17:25.733 --> 00:17:29.233 such as the Henderson apparatus. 00:17:29.233 --> 00:17:35.499 Also, if not available elsewhere, the animal area should have an incinerator for disposing of animal carcasses 00:17:35.500 --> 00:17:41.866 and a large autoclave for sterilizing cages and passing them into a cage-washing room. 00:17:41.866 --> 00:17:48.199 In designing this research area, the type and degree of animal isolation should be considered early. 00:17:48.200 --> 00:17:56.766 It should always provide for safe working conditions for lab personnel and prevent undesired animal cross-infection. 00:17:56.766 --> 00:18:03.732 In rooms housing small infected animals the hazard level is sometimes high enough to require that protective clothing 00:18:03.733 --> 00:18:08.366 and respirators be worn by laboratory personnel. 00:18:08.366 --> 00:18:14.799 In the animal rooms, dust filters should be installed in the air exhaust ducts to prevent excessive loading 00:18:14.800 --> 00:18:18.766 of the downstream microbial filters with animal hair and dander. 00:18:18.766 --> 00:18:27.799 The recommended ventilation rate for the rooms is fifteen changes per hour of non-recirculated, draft-free air 00:18:27.800 --> 00:18:32.633 of the relative humidity and temperature appropriate to the animal species. 00:18:32.633 --> 00:18:39.833 Since the walls and floors of both large and small animal areas are washed frequently and exposed to urine 00:18:39.833 --> 00:18:45.499 and other wastes, careful selection should be made of wall paints and finishes. 00:18:45.500 --> 00:18:52.300 The nature of some disease agents in small animals is such that no special provisions are needed 00:18:52.300 --> 00:18:56.033 to prevent animal cross-infection or to protect animal handlers. 00:18:56.033 --> 00:19:02.266 However, there are some infectious agents that require animal isolation equipment for protecting personnel. 00:19:02.266 --> 00:19:08.266 One design is a ventilated cage rack compartment, similar to a fume hood. 00:19:08.266 --> 00:19:16.066 This unit has sliding doors, an inward flow of air, and filtration of exhaust air. 00:19:16.066 --> 00:19:25.499 By a design modification utilizing a bolted-on plastic panel, this compartment becomes a gas-tight, absolute barrier unit. 00:19:25.500 --> 00:19:30.166 It is maintained at a negative pressure and is supplied with filtered air. 00:19:30.166 --> 00:19:34.166 The exhaust air is also filtered. 00:19:34.166 --> 00:19:38.166 Here work with animals is done through attached rubber gloves. 00:19:38.166 --> 00:19:48.999 Infected animals in this system can be handled and then passed on to an adjoining cabinet for autopsy or another investigative procedure. 00:19:49.000 --> 00:19:57.100 In other situations where a high degree of isolation is required and where animal-to-animal separation is needed, 00:19:57.100 --> 00:20:00.966 infected animals are held in small, individually ventilated cages. 00:20:00.966 --> 00:20:11.499 In some instances instead of closed ventilated cages, animals may be housed in cages under an ultraviolet barrier. 00:20:11.500 --> 00:20:19.266 Non-portable, ventilated animal compartments have been found effective in some infectious disease laboratories. 00:20:19.266 --> 00:20:30.499 Each of these Horsfall units holds one or two animal cages and is equipped with a viewing window and inlet and outlet air filters. 00:20:30.500 --> 00:20:36.900 This particular version utilizes pads of spun glass for air inlet filters. 00:20:36.900 --> 00:20:41.100 The exhaust air, after filtration, goes to a common exhaust manifold. 00:20:41.100 --> 00:20:45.300 Cages of this type must be decontaminated in place. 00:20:45.300 --> 00:20:53.333 A pressurized, ventilated suit provides another form of personnel protection during the housing and handling of infected animals. 00:20:53.333 --> 00:20:58.799 Following its use, the attendant must decontaminate the outside 00:20:58.800 --> 00:21:07.800 with a solution of two percent peracetic acid or another liquid decontaminant. 00:21:07.800 --> 00:21:14.933 It is convenient to locate small animal holding rooms close to rooms where inoculation and autopsy are done. 00:21:14.933 --> 00:21:20.666 With disease agents of low hazard, tabletop autopsy is permitted. 00:21:20.666 --> 00:21:26.166 In this case the operator should wear a respirator. 00:21:26.166 --> 00:21:31.899 For higher hazard work, animal autopsy should be done in ventilated safety cabinets 00:21:31.900 --> 00:21:37.400 where an inward sweep of air prevents the accidental escape of infectious aerosol. 00:21:37.400 --> 00:21:45.500 Where maximum protection is required, an absolute barrier cabinet system with attached rubber gloves must be used. 00:21:45.500 --> 00:21:54.000 This cabinet is equipped with an autoclave for sterilizing animal carcasses and other materials removed from the system. 00:21:54.000 --> 00:22:00.266 Large animals usually are housed and studied in facilities separate from those for small animals. 00:22:00.266 --> 00:22:06.066 In this suite the animals are infected with epizootic diseases not transmissible to man. 00:22:06.066 --> 00:22:17.466 Here are located a series of adjacent rooms and stalls for housing, inoculation, surgery, autopsy, and incineration of carcasses. 00:22:17.466 --> 00:22:26.599 Laboratory personnel entering the area should pass through a change room and dress in proper clothing. 00:22:26.600 --> 00:22:33.133 Necessary supplies, such as food and equipment, should be brought in through properly designed airlocks, 00:22:33.133 --> 00:22:43.666 and stored temporarily in adjacent storage rooms and feed vestibules. 00:22:43.666 --> 00:22:50.399 In the design of holding rooms, attention should be given to their flexibility so as to accommodate 00:22:50.400 --> 00:22:53.500 various sizes and species of animals. 00:22:53.500 --> 00:23:02.200 This may be accomplished by using a room equipped with removal stanchions and partitions. 00:23:02.200 --> 00:23:09.800 The room should be constructed to withstand frequent washing and cleaning. 00:23:09.800 --> 00:23:19.066 Furthermore, it should be provided with vestibules for storage of feed. 00:23:19.066 --> 00:23:30.866 Not only must the individual rooms be cleaned, but the corridors serving them must be hosed down frequently. 00:23:30.866 --> 00:23:37.966 In some large animal research areas it is desirable to have a hydraulically operated tilt table for surgery. 00:23:37.966 --> 00:23:45.099 Occasionally animal monitoring equipment also is provided. 00:23:45.100 --> 00:23:50.733 After an autopsy, provisions should be made for transporting the carcass. 00:23:50.733 --> 00:23:59.299 Here a large pan, supported from a monorail is used to carry the carcass through an airlock to the incinerator. 00:23:59.300 --> 00:24:07.333 When the incinerator is part of the infectious area, the firebox should be maintained at negative air pressure to the room, 00:24:07.333 --> 00:24:11.566 in order to prevent blowback of contaminated materials. 00:24:11.566 --> 00:24:17.666 The fourth zone in a lab facility is designated as laboratory support. 00:24:17.666 --> 00:24:21.866 This is best located outside the contaminated research areas, 00:24:21.866 --> 00:24:26.099 and includes rooms for washing and sterilizing glassware and animal cages, 00:24:26.100 --> 00:24:36.066 preparing culture media, storing glassware and animal cages, and repairing various laboratory items. 00:24:36.066 --> 00:24:43.166 A more detailed look suggests that due to the many heat-generating devices and odor-producing procedures 00:24:43.166 --> 00:24:48.899 in this area, careful attention should be given to the design of a ventilation system. 00:24:48.900 --> 00:24:54.833 Also, because of the great amount of water involved in washing operations, 00:24:54.833 --> 00:24:59.099 doors, walls, and other surfaces should be resistant to moisture. 00:24:59.100 --> 00:25:07.166 In glass washing, non-contaminated glassware may be processed either in a tunnel-type machine that allows for an automatic 00:25:07.166 --> 00:25:15.399 continuous flow of items, or a batch-type washing unit for small amounts. 00:25:15.400 --> 00:25:26.800 The sterilization equipment needed in lab support consists principally of dry heat ovens and steam sterilizers. 00:25:26.800 --> 00:25:38.166 In the cage-washing room, small animal cages may be processed in a continuous flow tunnel-type machine. 00:25:38.166 --> 00:25:50.232 Where larger units are processed, a batch-type washer with multiple or rotating spray heads often is used. 00:25:50.233 --> 00:25:57.899 When the cage debris contains highly infectious organisms, the cage with its debris should always be sterilized 00:25:57.900 --> 00:26:04.333 before it enters the lab support area. 00:26:04.333 --> 00:26:08.966 Another lab support activity is the preparation of culture media. 00:26:08.966 --> 00:26:13.932 The room for this should have a controlled movement of filtered supply air during the 00:26:13.933 --> 00:26:18.199 pouring of the plates and the preparation of other sterile media. 00:26:18.200 --> 00:26:24.033 To limit the ingress of microorganisms, air in the room always should be maintained 00:26:24.033 --> 00:26:28.999 at positive pressure to the other lab support rooms. 00:26:29.000 --> 00:26:34.200 An adequate storage room should be provided for glassware, animal cages, and other equipment, 00:26:34.200 --> 00:26:45.900 as well as a small machine and glass repair shop. 00:26:45.900 --> 00:26:52.000 The fifth functional zone in the lab facility provides engineering support. 00:26:52.000 --> 00:27:00.000 Included here are the necessary pipes, ducts, pumps, blowers, and filters, as well as the liquid waste treatment system, 00:27:00.000 --> 00:27:03.666 and the bulk of the air-handling system. 00:27:03.666 --> 00:27:10.999 Special engineering arrangements should maintain the integrity of the secondary barrier when penetration of the wall is made by pipes, 00:27:11.000 --> 00:27:20.333 wires, and ducts regardless of whether the engineering zone is located on the same or a different level from the other functional zones. 00:27:20.333 --> 00:27:27.233 As much of the engineering support area as possible should be located outside the contaminated zone, 00:27:27.233 --> 00:27:33.399 possibly on the grounds adjacent to the building, or in the basement, or attic of the facility. 00:27:33.400 --> 00:27:42.466 Because of the large amount of engineering equipment needed, more than half of total building area is sometimes required. 00:27:42.466 --> 00:27:48.532 The most important engineering functions are air handling and ventilation, often involving nearly 50 percent 00:27:48.533 --> 00:27:51.299 of the cost of the laboratory building. 00:27:51.300 --> 00:28:00.566 One vital consideration is the need to locate the air intake grill upwind to the exhaust stack. 00:28:00.566 --> 00:28:07.799 There should be adequate physical separation between both to prevent cross-contamination. 00:28:07.800 --> 00:28:17.633 In engineering support, air ducts going to each room in the infectious zone should deliver nonrecirculating, filtered, and conditioned air. 00:28:17.633 --> 00:28:23.833 In virus labs, inlet air is often passed through ultra high efficiency filters. 00:28:23.833 --> 00:28:26.933 These ducts need not be of airtight construction. 00:28:26.933 --> 00:28:34.566 Exhaust air ducts coming from the infectious zone must be airtight, however, to assure no leakage 00:28:34.566 --> 00:28:40.132 infectious microorganisms before air reaches the exhaust filter plenum. 00:28:40.133 --> 00:28:47.533 Galvanized ducts with taped, epoxy-coated joints have been found satisfactory. 00:28:47.533 --> 00:28:54.699 The exhaust air plenums in the building are often designed to serve several laboratory rooms of about the same hazard level. 00:28:54.700 --> 00:29:01.233 They may be equipped either with high efficiency spun glass mats or with ultra high efficiency units 00:29:01.233 --> 00:29:04.166 for filtering air discharged from the rooms. 00:29:04.166 --> 00:29:11.499 Since the filters in the plenum must be changed periodically, provisions must be made 00:29:11.500 --> 00:29:16.366 for decontaminating both the filters and the plenum itself before opening the unit. 00:29:16.366 --> 00:29:21.199 A mixture of steam and formaldehyde is used as the decontaminating material. 00:29:21.200 --> 00:29:27.733 The facility's ventilation system should provide an interlock between the exhaust and supply blowers. 00:29:27.733 --> 00:29:33.999 This is to prevent pressurization of the infectious zones in case the exhaust blower fails. 00:29:34.000 --> 00:29:44.300 A pneumatic control system senses the air pressure in each room and assures correct air balance throughout the laboratory. 00:29:44.300 --> 00:29:53.200 Exhaust air from aerosol chambers and other high-hazard equipment should pass through welded pipelines to an incinerator. 00:29:53.200 --> 00:29:59.266 Electrically operated units are both practical and efficient for quantities of up to 100 cubic feet a minute. 00:29:59.266 --> 00:30:07.366 This unit and the ones that follow should be preceded by a microbial filter as a failsafe device. 00:30:07.366 --> 00:30:17.966 For larger volumes of air, gas or oil-fired incinerators may be used. 00:30:17.966 --> 00:30:32.966 With this oil-fired unit a tall stack serves to discharge the air at a substantial distance above the building. 00:30:32.966 --> 00:30:38.166 An important part of an engineering support zone is the central control board. 00:30:38.166 --> 00:30:43.699 Here readouts of all systems in the area can be readily monitored by engineering personnel. 00:30:43.700 --> 00:30:51.600 Such boards should have visual and audible alarms that will automatically signal the failure of any part of the system. 00:30:51.600 --> 00:30:55.600 Another important item is the standby electrical generator. 00:30:55.600 --> 00:31:00.133 It is used in the event commercial power supply is interrupted. 00:31:00.133 --> 00:31:05.433 Sometimes the units are mounted in trailers to provide easy portability. 00:31:05.433 --> 00:31:12.933 In some laboratories facilities must be provided for treating contaminated liquid waste. 00:31:12.933 --> 00:31:18.233 Two basic systems are employed, the batch and the continuous flow. 00:31:18.233 --> 00:31:25.099 The batch system, shown here, is used to collect waste from infected animal areas. 00:31:25.100 --> 00:31:32.666 Liquids flow by gravity to the tank where they are sterilized by adding steam and holding for a period of time. 00:31:32.666 --> 00:31:39.399 The piping should have welded joints to assure no possibility of leakage. 00:31:39.400 --> 00:31:47.800 Note that a concrete curb has been provided to contain the liquid in the event of a rupture in the system. 00:31:47.800 --> 00:31:54.500 Where larger volumes of waste are produced multiple batch treatment tanks are used. 00:31:54.500 --> 00:32:00.800 Here is a continuous flow arrangement which utilizes steam to raise the liquid to a proper temperature. 00:32:00.800 --> 00:32:09.500 The waste flows through a series of retention tubes and is cooled through a heat exchanger before being discharged. 00:32:09.500 --> 00:32:15.666 All such systems can be monitored and controlled from a central board where floor arrangements, 00:32:15.666 --> 00:32:23.732 waste volumes, treatment times and temperatures are visually indicated. 00:32:23.733 --> 00:32:29.366 [Dr. A.G. Wedum:] This film has emphasized the concepts of the primary barrier and the secondary barrier 00:32:29.366 --> 00:32:34.232 in designing a laboratory for the study of infectious disease. 00:32:34.233 --> 00:32:38.299 These concepts apply to the five functional zones, namely: 00:32:38.300 --> 00:32:46.366 the clean, the laboratory research, the animal research, the laboratory support, and the engineering zones. 00:32:46.366 --> 00:32:52.466 The film has given examples of how various operating laboratories have used these concepts. 00:32:52.466 --> 00:32:59.032 Although there is no complete substitute for careful training and good microbiological technique 00:32:59.033 --> 00:33:05.499 by a knowledgeable laboratory supervisor, sooner or later a point may be reached in the experimentation 00:33:05.500 --> 00:33:12.600 when there's need for a building and equipment with emphasis upon protection for the investigator, 00:33:12.600 --> 00:33:15.533 the experiment, and the public. 00:33:15.533 --> 00:33:22.733 The film has served its purpose if it provides significant assistance to those persons responsible 00:33:22.733 --> 00:33:31.999 for the design, construction, and operation of laboratories for the study of infectious disease. 00:33:32.000 --> 00:33:36.600 [The End M-1091] 00:33:36.600 --> 00:33:43.700 [Director Durward R. Thayer, Technical Advisors A.G. Wedum, M.D. G Briggs, Ph.D.]