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BIOSAFETY


Djalma da Silva Lima – Member of the Brazilian Association for the Development of Hospital Building (ABDEH) and a teacher


Biosafety design for laboratories


Biosafety is the science-oriented control and minimisation of risks arising from practices undertaken in a laboratory, or when applied to the environment. This article looks at the process of architectural planning of laboratory buildings, particularly specialised environments for research purposes, where the physical space contributes to the reliability of experiments and to the protection of human health and the environment. It is essential in these environments to observe the security methods used for handling risk agents, to reduce or eliminate exposure to humans and the environment.


Biosafety in a laboratory is a set of practices, equipment and facilities with the aim of preventing, minimising or eliminating risks inherent to the activities of service, research, production and teaching. According to Bicalho (2010),1


the technician responsible


for the laboratory should assess the level of biosafety, based on the procedures, equipment and microorganisms involved, adopting compatible security measures. The laboratory design will be guided by the need for protection from the biological hazards it may present. These are defined by four biosafety levels – BL-1, BL-2, BL-3 and BL-4 – increasing in complexity and the degree of containment protection, using the criteria for risk assessment of the Center for Disease Control (CDC). Suitable for work with agents known to


involve minimal risk to humans and the environment, Biosafety Level 1 (BL-1) establishes a basic level of containment that relies on standard microbiological practices with no indication for primary or secondary barriers, except for a sink for handwashing. Biosafety Level 2 (BL-2) practices, equipment, design and construction applicable to laboratories that develop research with a larger number of native agents of moderate risk, associated with human disease of varying severity. Secondary barriers, such as sinks for hand hygiene and decontamination facilities for garbage need to be installed to reduce contamination of


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the environment. For Biosafety Level 3 (BL-3) practices,


safety equipment, planning and construction of the dependencies are applicable to clinical laboratories, diagnostic, laboratory and research school. Working with indigenous or exotic agents has the potential for transmission via respiratory infections and can be potentially fatal. In these areas primary and secondary barriers are necessary, such as controlled access and ventilation systems that minimise the release of infectious aerosols. For Biosafety Level 4 (BL-4) practices,


safety equipment, planning and construction of the premises apply for tasks involving dangerous exotic agents. The complete isolation of laboratory researchers is conducted, primarily in biological safety cabinets, or Class III using individual jumpsuits with positive air pressure. These areas represent a geographical unit that is functionally independent from other areas, with supply system vacuum and decontamination.


Containment in BL-3 laboratories The analysis procedures developed in BL-3 laboratories must be made with the adoption of containment measures. Security methods are used for handling risk agents, to reduce or eliminate exposure of researchers and environment. The containment can be both primary and


secondary. Primary containment procedures and equipment includes personal protective equipment (PPE) such as surgical gloves, masks, goggles, laboratory coats and boots, and collective protective equipment such as sink, biological safety cabinet, safety shower and eye wash. Secondary containment protection occurs through architectural elements and facilities such as anteroom pass, unidirectional flow of air, air filters and wastewater treatment. According to Vieira (2008),2


the principles


of primary and secondary containment are a triad of key elements – good practices and laboratory techniques (ducts), the provision and use of appropriate PPE and collective equipment and architecture design laboratory (installations).


‘The laboratory design will be guided by the need for protection from the biological hazards it may present.’


Biological safety cabinets The objective of a biosafety cabinet is to protect the operator, product and environment. They are used to prevent leakage of aerosol into the local environment. Different cabin types are defined by the


work area (open or closed), air flow, filtration equipment and types of exhaust. Silva (1996)3 highlights the importance given to the exhaust duct for the cabin air. The cabins are divided into classes I, II and III. Cabin class I has exhaust duct with high


efficiency particulate air (HEPA). The air velocity is 75 feet/min. Class II cabinets will have laminar flow cabin air, with a front opening that allows access to the working surface and HEPA supply and exhaust air. Cabin class III is for maximum


containment. It is fully enclosed with proper ventilation, built in stainless steel gas-tight, and operates with negative pressure. Work in the chamber is carried out via rubber gloves attached to the cabin. To filter the contaminated air leaving the cabin, two HEPA filters are installed in series and a HEPA filter or an incinerator. The introduction and removal of materials to the cabin is made through autoclaves, double door air lock, double door or immersion tank chemistry.


Djalma da Silva Lima


Djalma da Silva Lima graduated in Architecture and Urbanism from the Federal University of Piauí, Brazil in 2006. He is a member of the Brazilian Association for the Development of Hospital Building (ABDEH) and a teacher.


IFHE DIGEST 2014


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