reducing costs through life-cycle cost analysis, innovation, and adaptation. It should be noted that many of the projected costs and cost savings are estimates made during the design phase. Actual results will be known several years after this project is completed. The detailed analysis is presented here to highlight the necessity for a comprehensive planning process and the need to define goals and set targets. The design team should include the facility director, facility manager, researchers, and representatives of the animal care staff who bring day-to-day front-line experience.

With direct labor representing 50-65% of operating costs, investment in technology that reduces staff or makes current staff more efficient is critical. The committee's recommendations are organized around physical and operational issues.

VENTILATED RACKS

Many institutions have used ventilated microisolator cage and rack systems to extend cage-changing intervals from twice a week to once a week or once every 2 weeks. This extension of the cage-changing interval could allow a doubling of the mouse-cage census without substantially increasing the number of staff involved. Lengthening cage-changing intervals also decreases the load for the cage-wash centers because each cage is washed less frequently. (However, since laboratory animal care technicians also clean rooms, take censuses, receive animals, and support area management, material transport, training, and meetings in addition to cage changing, it should not be expected that halving the cage-changing frequency will lead to a doubling of productivity.) The capital investment in ventilated micro-barrier cages and racks is substantially larger than in static microbarrier housing systems. For example, a 126-cage ventilated rack with water bottles costs 139% more than a double-sided static rack, and a ventilated rack with automatic watering costs 230% more. However, site-by-site comparison of these cage and rack systems, considering total operational costs (equipment, sanitation, personnel, and space), typically indicates, on the basis of committee experience, a payback period of under 5 years for the higher initial investment. Payback periods will vary considerably, depending on the current and projected cage-rack systems, cage-changing frequencies, use of water bottles or automatic watering, mechanical HVAC capacity, room size and configuration, and volume equipment discounts. For some large operations, the payback period is not an important consideration, because hiring and retaining sufficient staff are difficult during a tight labor market. Unless an institution plans to extend the cage-changing frequency substantially (for example, from once a week to once every 2 weeks) or increase the



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