Second, the observations on buildings systems are limited to the Smithsonian experience and not generally applicable to typical museums. Mechanical vs. Chemical Degradation From the two CAL papers I have seen presented at AIC, and from discussion with others, the emphasis of the CAL research highlighted in the press release is on how material samples mechanically tolerate temperature and humidity changes. The primary conclusion that might be drawn from their research is that test materials are not mechanically as sensitive to fluctuations in conditions as some believe. This also implies that conditions may be maintained at the extremes of these ranges. This is simply not the case for many if not most collections, and is not necessarily supported by the research.
Field observations correlating object damage with humidity problems are overwhelming.
While some materials in almost any collection can tolerate extremes, the conditions in a museum must be maintained for the most sensitive objects, unless they are housed under separate conditions. In summary, CAL research plays an important part as another piece in the puzzle of understanding how objects behave and how their life under museum, library and archival care can be extended. However, the acceptable conclusions do not support the sweeping changes suggested in the press release. A reduced humidity set point in winter has been a viable, published and exercised option for decades. Where appropriate, it is common to consider and use this option for modern projects.