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Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
This research agenda will ultimately provide scientifically based criteria for laboratory 
animal facility design and management, improve the scientific validity of research using 
laboratory animals, enable managers to adjust the animal facility systems and practices to 
conform to animal welfare guidelines, and develop a basis for reducing animal facility 
design and operational costs. It should be noted that meeting this challenge requires the 
following three other activities: 
• Adequate funding and support from both public and private organizations, 
• Conduct of research by multidisciplinary teams, and 
• Evaluation and utilization of research results. 
S. Frei: Facilities Approaches To Reducing Operating Costs, 1993, Affiliated Engineers, Inc. 
Frei noted that scientific justification for recommended ventilation rates is rather weak. 
The 1985 ILAR (Institute of Laboratory Animal Resources) Committee on Care and Use 
of Laboratory Animals recommendations can be traced back to Munkelf s (1938) work, in 
which he proposed a ventilation rate of 1.5 cfm/lb for rats or guinea pigs. A historical 
summary of the development of ventilation rates follows: 
• Munkelt (1938) developed a standard of 1.5 cfm/lb of animal or 11 air changes per 
hour while working with rats and guinea pigs. 
• Runkle (1964) extrapolated Munkelf s (1938) rates for mice through dogs. 
• In 1964, a laboratory extrapolated Runkle’s ( 1964) work to imply 10 to 20 air changes 
per hour (Frei 1993). 
• ILAR (1978) set the first standards at 10 to 15 air changes per hour. 
John J. Hasenau, Raymond B. Baggs, and Alan L. Kraus: Microenvironments In Microisolation 
Cages Using BALB/C And CD-I Mice, 1993, Contemp. Topics Lab. Anim. Sci., 32(1)1 1-16, 
32(2)58-61. 
Four different mouse caging systems were evaluated for microenvironmental temperature, 
humidity, and ammonia levels. All had polycarbonate bases and lids holding Reemay 
2024 filter material in three different designs or a control without filter. Comparisons 
were made of BALB/c and CRL: CD-I (ICR) BRV mice at four and two per cage under 
different macroenvironmental (room) conditions. All studies were conducted in an animal 
room measuring 11 ft. x 8.58 ft. x 8.0 ft. in an AAALAC accredited animal facility. 
