The significant renovations and expansion currently in progress at the Royal Ontario Museum have provided the opportunity to take a fresh look at the provision of humidity-controlled air to display cases. The planning process began in 2002, and the first of the new galleries opened in December 2005. When the last of the galleries reopens, the building will comprise sections of architecture built at four different periods from the 1914 west wing to the new Michael J Lee-Chin Crystal. Though the four spaces are for the most part physically contiguous, each imposes its own constraints on the environmental conditions.
Arriving at the finished system has involved many steps, beginning with the assessment of the RH needs of the more than 19,000 objects destined for display in the new galleries. Planning the controlled cases and piping layouts has had to take into account the varying needs of the objects, the large volumes of some of the display enclosures, the power of the control systems in relation to the distance that the air must travel, and the leakage rate of the cases.
Achieving the desired results to date has required compromise, flexibility, and the ability to re-think processes in view of the empirical evidence. This paper follows the course of the process from the ideals of the initial planning to the realities of the final implementation, and passes on some lessons learned the hard way, as phase two of the expansion continues.