then translate that information into a facility that meets the expectations of the users.

The Guide allows for interpretation or modification in the event that acceptable alternative methods are available, or unusual circumstances arise when deviating from the Guide. For example, ventilation rates that exceed 10 to 15 air changes per hour (ac/h) would be allowable, given appropriate justification. When deviating from the Guide, thought should be given to other environmental factors that may be affected by the deviation. In the case of air change rates, it is possible that air movement, diffusion pattern influence on the animal’s microenvironment, and the relation of the type and location of supply-air diffusers and exhaust vents would warrant further consideration.

Environmental criteria topics that have been discussed include the following: temperature and humidity, ventilation rate, lighting, containment, and air quality. Each of these topics is briefly described below.

The most common source of data for temperature and humidity is ASHRAE; however, most data are outdated and date back to the 1950s or 1960s. Some researchers believe that the measurements concluded from past heat and moisture data are too low for today’s animals. Recent rodent data have provided evidence that rodents have higher metabolisms and heat generation (Riskowski and Mermazedeh 2000).

Ventilation rates have historically followed the 10 to 15 ac/h (fresh air) recommendation from the Guide. This range has proven to be a good range although different approaches allow lower ventilation rates while maintaining a stable animal room environment (i.e., ventilated caging systems). Some applications, species, and rooms require more than 15 ac/h. It should be emphasized that 10 to 15 ac/h has historically proven successful in managing most animal thermal and respiration loads and equipment loads. However, the Guide is clear that calculations must be performed to determine the air change rates required to remove the thermal and moisture loads and provide any additional make-up air exhaust devices (i.e., fume hoods or biosafety cabinets).

Front Matter (R1-R14)

Introduction (1-6)

Plenary Lecture (7-14)

Session 1: Current Status: Identifying the Issues (15-62)

Session 2: Assessment of Animal Housing Needs in the Research Setting--Peer Reviewed Literature Approach (63-90)

Session 3: Approaches to Current Guidelines--US and Europe (91-130)

Session 4: Environmental Control for Animal Housing (131-166)

Dinner Speaker: Kay E. Holekamp (167-174)

Session 5: Environmental Enrichment Issues (175-198)

Point/Counterpoint: The Cases For and Against Harmonization (199-224)

Appendix A: International Workshop on Development of Science-based Guidelines for Laboratory Animal Care (225-231)

Appendix B: Workshop Faculty (232-237)

Appendix C: Committee Bios (238-239)

Appendix D: International Guiding Principles for Biomedical Research Involving Animals (1985) (240-248)