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Designer’s Notebook By Joseph V. Messina, CPD Plumbing Design for Arthropod Laboratories (Insectaries) Everyone should know what arthropods are from high school biology class, but if you cannot remember, they are invertebrate animals with segmented bodies and jointed limbs, such as mosquitoes, spiders, roaches, ticks, fleas, tsetse flies, black flies, and sand flies. The laboratories in which these types of animals are studied are called insectaries, and the person who studies arthropods is called an arachnologist. What will be discussed in this article is how plumbing designers and engineers design plumbing systems for an insectary. Insectaries where living arthropods are reared and maintained for research have been around for decades. The insects are infected with pathogens, which can be a risk to whomever comes into contact with them. Extreme precautions are taken within the plumbing, HVAC, and electrical systems to protect the public by ensuring the infected insects cannot escape. It is also important to take precautions against the escape of uninfected insects as well. Plumbing designers and engineers can help by designing certain precautions (discussed later) into the plumbing systems. Arthropod Containment Levels Insectaries are classified in different levels called Arthropod Containment Levels, similar to the Biological Safety Levels. (For more information on Biological Safety Levels, see “A Primer on Infectious and Biological Waste Drainage Systems,” PS&D March/April 2006, and “Designing Biosafety Laboratories,” PS&D July/August 2005.) These levels are recommended by the American Committee of Medical Entomology, a special committee of The American Society of Tropical Medicine and Hygiene, for work with a variety of uninfected arthropods and those that are carrying infectious agents. The classifications set requirements for the level of protection to be designed for the insectary. If the arthropod is infected with an agent, the containment level is increased to at least what is required for that particular agent. Arthropod Containment Level 1 (ACL-1). This level is suitable for working with arthropods that are not infected or those that are infected with a non-pathogen. Precaution should be taken from the arthropod escaping through the sanitary sewer by specifying screens over the sink drains. Even though floor drains are not highly recommended to be installed in an insectary, specifying screens to be placed between the drain strainer and drain body will prevent loose arthropods from escaping through or breeding in the floor drain. Arthropod Containment Level 2 (ACL-2). This level is practiced when working with indigenous arthropods infected with a BSL-2 agent associated with animal or human disease, or even suspected of being infected with such agents. BSL-2 agents are moderate-risk agents that are present in the community and associated with human disease, such as hepatitis, HIV, and salmonellae. As with ACL-1, screens specified for the sink drains are required to prevent any life stages of the arthropod being washed into the drainage system when personnel 26 Plumbing Systems & Design JANUARY/FEBRUARY 2007 wash their hands after handling cultures or infected arthropods. Moreover, before any infected or uninfected arthropods are disposed of they should be destroyed by heat or freezing. It is preferable for them to be autoclaved or incinerated. You also can destroy by heat by using an instantaneous hot water dispenser, such as used for making coffee, and very hot water (120°F to 140°F) may work as well. If a central vacuum system is installed for use under this containment level, each inlet is required to be fitted with a suitable filter to prevent an arthropod from escaping. HEPA-type filters are usually used. These filters can be attached to each inlet, or if the central vacuum system is strictly dedicated for the use of this insectary, the HEPA filter can be installed on the inlet side of the vacuum system or on the exhaust side of the system. If floor drains are installed in the insectary within this containment level, not only is the use of screens between the floor drain strainer and the floor drain body recommended, but a chemical treatment also should be applied in the floor drain trap. All penetrations through the walls, floors, and ceilings shall be sealed with caulking to prevent the chance of escape. Arthropod Containment Level 3 (ACL-3). Under this level, arthropods may be infected with BSL-3 agents associated with human disease. Arthropods that are infected or potentially infected with a BSL-3 pathogen can pose additional hazard when or if the insectary is located in an area where the arthropod is indigenous. The ACL-3 insectary has similar practices, procedures, and containment equipment and facility requirements as an ACL-2 insectary. The central vacuum system is treated the same way it is treated in an ACL-2 facility. Floor drains are not recommended; however, if installed, they should be treated as in an ACL-2 facility, or ideally, they should be plumbed to a holding tank where either heat or chemical treatment can be introduced to kill all stages of the arthropod prior to disposal into the building or public sanitary waste system. Access into an ACL-3 insectary is more restricted than that into an ACL-2 facility. Access into an ACL-3 facility is through a shower. Personnel are required to shower before going into the facility as well as when exiting the facility (sometimes referred to as a shower-in, shower-out facility). The way arthropods are handled is also different than in an ACL-2 facility. In an ACL3 insectary, the handling of arthropods is within a biological safety cabinet. The Centers for Disease Control’s Biosafety in Microbiological and Biomedical Laboratories states: “All procedures involving the manipulation of infectious material are conducted within biological safety cabinets or other physical containments devices, or by personnel wearing appropriate protective clothing and equipment.” These biological safety cabinets are equipped with a HEPA filter to prevent any possibility of insects escaping while being manipulated. Arthropod Containment Level 4 (ACL-4). This containment level is for the most dangerous pathogen-infected arthroPSDMAGAZINE.ORG The requirements depend on the arachnologist. It has been my experience that each has his own way of handling and disposing of arthropods. That is what makes it interesting because there is always the chance of learning different ways of designing. Resources Arthropod Containment Guidelines, Version 3.1. American Committee of Medical Entomology, American Society of Tropical Medicine and Hygiene. Biosafety in Microbiological and Biomedical Laboratories, 4th Edition. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, and National Institutes of Health. Joseph V. Messina, CPD, is the discipline director of plumbing engineering for CUH2A Inc., Architecture, Engineering, Planning in Atlanta. He has more than 30 years experience specializing in plumbing and fire protection design of instructional, research, and medical facilities. For more information or to comment on this article, e-mail [email protected]. NOVEMBER 2 - 4 pods and shall meet all the requirements of Arthropod Containment Levels previously mentioned as well as added procedures. An escape of the arthropods is absolutely not acceptable. BSL-4 agents are studied at this level and are associated with the highest risk of infection from aerosol exposure and life-threatening diseases. Of the 12 viruses requiring BSL-4 containment in the United States, five are transmitted by arthropods. These are central European encephalitis, Congo-Crimean hemorrhagic fever, Kyasanur forest disease, Omsk hemorrhagic fever, and Russian spring-summer encephalitis. Laboratories in this level are required to decontaminate all waste by means of autoclaving. All personnel entering and leaving the laboratory must wear the appropriate protective suit with breathing air. All work shall be preformed within a biological safety cabinet. If there is a central vacuum system, it can only be used within the biological safety cabinet and must be provided with an in-line HEPA filter on the inlet. Other liquids and gases used shall be provided with a backflow device. All sanitary waste coming from the ASL-4 space shall be plumbed to an approved heat treatment process, which includes floor drains and sinks. It is not recommended to install water closets or urinals for this containment level of insectary, but if these fixtures are installed, they too must be taken to the approved heat treatment process system. Designing plumbing systems for an insectary can be very interesting because not all insectary requirements are the same. JANUARY/FEBRUARY 2007 Plumbing Systems & Design 27