45th Annual Meeting – Collection Care Session, “Evaluation of climate control in Yale Peabody Museum of Natural History–energy consumption and risk assessment” by Lukasz Bratasz et al


Lukasz Bratasz et al presented about a risk assessment and recommendations made for storage of the collections at Yale’s Peabody Museum of Natural History.  Trying to get away from flat-lined standards, they are taking a risk management approach to most effectively spend their preservation resources in a pragmatic and sustainable way.  By doing a risk analysis and gathering data on current energy use across the campus (and comparing with some far-flung peers), a pretty stark result was revealed.  What struck me most about the presentation, the active question and answer period notwithstanding, was the confirmation of my gut feeling that chemical degradation is the most serious preservation risk that many collections face.  Yes, fires can be catastrophic and leaks happen frequently, but chemical degradation happens constantly and quietly at human-comfort temperature storage with extreme relative humidity swings, until one does an analysis like this and bring it to everyone’s attention.

In their relatively quickly assembled risk assessment, the notion of item value was disregarded and every item was assumed to have the same value.  This is appropriate for collections that are of value in the aggregate.  Some audience members found this to unrealistically skew the data, but I don’t have a problem with it.  It is always possible to add on the variable of value later, when one is ready to address multiple risks of similar likelihood and severity.  But to get the big picture, I think this kind of assessment is a good first step.  The most significant risks identified included mold growth, pest damage, chemical degradation, and mechanical damage.

The scope of the project was to analyze energy consumption and current environmental conditions, assess the preservation condition of the collections and determine the risks.  The risk assessment revealed that chemical degradation was two orders of magnitude above any of the other risks.  They found they could both address the most significant risk and save energy at the same time, so they prioritized on improving the climate for the collections.

Some of the comparisons for energy use seemed like apples and oranges (i.e. comparing a multi-use, aging building in New Haven with a relatively new passive-environment storage facility in Denmark).  However, it was clear that the aging building was wasting money and energy compared to other buildings at Yale.  This was due primarily to a high ventilation rate and constricted set points that did not allow for any floating.  In other words, they were bringing in too much fresh air, and keeping such a tight set point that they were constantly running the equipment to either heat or cool.  The rigid temperature set point combined with the uncontrolled humidity brought in by unnecessary fresh air meant that the indoor humidity ranged from 10-80%, extremes which cannot be safely tolerated by natural history collections without risk of mechanical damage.

They made the point that the collections had weathered temperature and humidity changes for years before the current flat-lined temperature was implemented, and thus the collections have been “proofed” and don’t require the flatlining.  Among my library conservation colleagues the proofing concept is not fully embraced…just because the mechanical damage hasn’t happened in the past, once chemical degradation has progressed to a certain point, mechanical damage due to the shock of a temperature or RH spike could still happen even to an aged object.  However, within a moderate range I suspect the Yale authors are right that some variation of temperature and humidity is not likely to cause damage.

The recommendations made were to move the most vulnerable ethnographic collections to cool storage, reduce the ventilation rate, adopt dual set point control (i.e. minimum and maximum rather than single point) for both temperature and relative humidity, control the relative humidity to eliminate the extremes, and evaluate the conditions according to long term temperature and relative humidity values.  While the recommendations at the end of this presentation did not emphasize energy savings, I’m guessing this was a selling point and was part of the bargain with facilities and administration, who juggle multiple priorities and are more likely to embrace a win-win solution.