IACUC

Evaluation of Environmental Chambers

Criteria for Evaluation of Environmental Chambers Used for Rodent Housing (>24 hours)

Animal research may require the use of unconventional housing (e.g., use of environmental chambers) to facilitate the experimental design. The term “unconventional” is used in the context of not readily available commercially for animal husbandry (i.e., must be fabricated) or not routinely used in the practice of standard laboratory husbandry. This document outlines criteria that must be met for IACUC approval of unconventional environmental chamber housing for rodents. The criteria listed meet the minimum requirements as cited in the Guide1 for animal housing environments. Additional conditions may be required to support the experimental design, and will potentially necessitate additional performance documentation.

Environmental Chamber Housing Criteria

Chambers must be constructed of non-porous materials (e.g., resins, plastics, coated galvanized steel, or stainless steel).
All surfaces must be readily sanitized by either an automated cage washing method or by hand. Sanitization methods should be compatible with chamber materials. Frequency of sanitation is dependent upon the caging system used to house animals within the chamber. Documentation of sanitization effectiveness must be done at minimum of once every six months – consult with the ULAR QA laboratory for assistance on this.
Chambers must meet air quality standards (i.e., number of air changes, ammonia levels, and uniform air circulation within the chamber). Gross analysis of air quality can be done by smelling the air within the chamber. Quantitative analysis of ammonia levels should be done within 12 hours prior to a scheduled cage change, and must be maintained at less than 25ppm. Environmental Health and Safety can provide testing and documentation of ammonia levels.
Chambers must be capable of maintaining the following environmental parameters as listed in the Guide:

temperature,
relative humidity, and
lighting controlled by a timer.

An environmental monitoring system should be present and alarm if critical set point parameters (primarily temperature) are exceeded within the chamber.

Methods for Evaluating Air Quality

Number of air changes will be determined by one of the following methods:

Calculation of air exchange rate based on fan speed and volume of environmental chamber.
Measurement of air exhaust or supply volume and determination of air exchange rate.

Uniform air circulation will be validated by smoke testing of the chamber to observe mixing rates and identify potential dead spots.
Ammonia levels will be measured by either passive or active method.