Page |1 Susan Richardson Art Conservation 301 Dr. Vicki Cassman October 15, 2009 HOBO 13, University Archives Overall Situation HOBO 13 is located at the final of several cabinets in the University Archives. It is in a basement, outside of the vaults, and is thus no more climate controlled than the rest of the building. The cabinet is made of wood and chipboard, is raised several inches above the ground, and its top is made of chicken wire. It contains many paintings, mostly framed in wood or metal, as well as a few cardboard boxes containing artwork and documents. The presence of cardboard, chipboard and wood in close proximity to objects could be problematic. In this case, the potential damage is fairly minimal because the surfaces of the paintings do not come in contact with the wood. The frames are generally made of wood, and contact with lignins should not cause any damage to the frames. However, if the surface of the paintings were to come into contact with the wood, it could cause damage. Several pipes run directly above the cabinet, including chilled water pipes. Within the climate-controlled vault, there has been no problem with condensation on the pipes. The hall is more prone to fluctuations in temperature and relative humidity than a climate-controlled vault would be, so this does not mean there is no risk for the collections in HOBO 13. The presence of Page |2 the pipes also creates the potential for an emergency situation: leakage, or even bursting, are possible and would be disastrous for the contents beneath. Although the cabinet is raised off the ground, this doesn't provide any protection from water coming from above. There are some dust bunnies and insect husks outside the cabinet, and there is a known cricket problem in the archives. There are several glue traps laid around the archives for monitoring, but there are none in proximity to HOBO 13. Strategies Switch out the interleaving cardboard with acid free mat board or blue board. Line the shelves with some form of archival material such as cotton muslin or tyvek. Cover the top of the cabinet with waterproof plastic, preferably an archival polyethylene. Place a glue trap near or inside the cabinet to test for insect presence. Temperature and Relative Humidity Since HOBO 13 is located outside of the climate controlled vault, it is unsurprising that it exhibits great variation of climate. On the whole, it detected wide swings in humidity throughout the year. It was wettest in the summer and early autumn months, and driest in late autumn and early winter. Although a certain amount of fluctuation is acceptable, in this case the detected relative humidity percent went from 15% or lower up very near to 80%. A 65% or greater swing in humidity is dangerous. Such a dramatic change in relative humidity, even over the span of several months, has potential for severe damage to collections. Temperature fluctuated seasonally, ranging from the low 70s to the low 80s. Page |3 The Archives are located in a heavy masonry building with double-glazed windows, an ASHRAE class IV building. Thus, a control level of B (50% ±10% RH, and 77±9 degrees Fahrenheit) should be possible with the building envelope, but may not be practical without an overhaul of the HVAC system to provide a more nuanced response during the highly variable spring and autumn months. At the moment, temperature is within a very reasonable range, but relative humidity is wildly variable, placing the current control level at D (<75% RH). With the current HVAC system, it should be possible to improve the situation to C (25-85% RH, temperatures usually below 77). Although C is not ideal, any improvement is good. For the sake of ease, the relevant charts and conclusions will be presented by season. Page |4 Autumn Temperature Mean Range Minimum Maximum Relative Humidity 77.2950016 6.819 74.271 81.09 Mean Range Minimum Maximum 40.99982143 61.53 15 76.53 Autumn was the season with the greatest fluctuation in Relative Humidity. During Autumn, both the highest and the lowest percent relative humidity were recorded. There is an overall range of 61.53 between the highest and lowest reading, which is astounding. Highest Humidity The highest relative humidity on record for Autumn was 76.53% on September 6th at 5:15 PM. The temperature at that time was 80.029 degrees Fahrenheit. Page |5 Looking at the Dewpoint calculator, it becomes immediately clear how harmful such a high level of humidity can be. Every category is in the red. At this level of humidity, all objects are at risk. Metal objects may corrode, and organic objects may grow mold in a manner of days. Objects sensitive to humidity, such as wood or fabrics, may expand, and chemical aging will occur in ten years. Fortunately, this level of humidity only really occurred on a single day. Unfortunately, such a rapid and dramatic spike in humidity has its own associated risks. Rapidly changing humidity can cause wood to warp, splinter or crack and can cause paint cracking due to Page |6 expanding and contracting canvas. Since many of the paintings around HOBO 13 are framed in wood, have wooden stretchers or are painted on canvas, this is an area of concern. Lowest Humidity The lowest relative humidity recorded in Autumn was 15%, on November 22th 2008 at 1:00 PM. The temperature at the time was 76.703 degrees Fahrenheit. At first blush, humidity this low appears to be relatively harmess. Two of the four indicators are in the green. There is little risk of mold growth or metal corrosion, and chemical Page |7 aging of objects is reduced. However, at such a low humidity level, organic objects grow weak and brittle. It wouldn't be good for a collection to remain at such a low humidity level for long. Strategies Increase interleaving material between paintings to buffer against humidity swings. o Cardboard works fine for this, so long as it remains in contact with only the wooden frame of a painting and not the painted surface. Otherwise, use archival blue board or acid-free mat board. Run a dehumidifier in early Autumn. o Any dehumidifier used should have a humidistat set to 50% relative humidity. If not, since early Autumn runs from moderately humid to very humid, there is little risk of overdrying the air. Run a humidifier in late Autumn. o Any humidifier used must have a humidistat set to 50% relative humidity. Otherwise, it is not worthwhile, as humidity fluctuates so much throughout late Autumn. Trading risk of mechanical damage for risk of mold growth isn't much of an improvement. Lower temperature in area to raise Relative Humidity in late Autumn. Page |8 Winter Temperature Mean Range Minimum Maximum Relative Humidity 76.60718009 6.264 73.062 79.326 Mean Range Minimum Maximum 24.39085764 31.2 15 46.2 Winter was a fairly stable season in terms of humidity. Although there was much variance from day to day, the overall range between high and low was 31.2: less than half that of Autumn. Humidity was never riskily high, although it did dip riskily low at several points during the winter, and in fact spent a large portion of the time at or below the sensitivity level of the hobo (15% RH). Highest Humidity The highest humidity recorded in Winter was 46.2% on February 17th, 2008 at 10:30 AM. The temperature at the time was 76.876 degrees Fahrenheit. Page |9 The humidity was sufficiently high to be a slight risk to organic objects, with a PI of 27 years. There was little risk of wood cracking or splitting, and there was no chance at all of mold growth. Humidity never spiked above 50% during the winter. However, there were rapid shifts of around 20% in a single day, which is dangerous in and of itself. Lowest Humidity The lowest humidity recorded in Winter was 15%, several times throughout the season. This is the lowest that this particular type of HOBO can detect, so it might well have been lower. The average temperature for the season was 76.61 degrees Fahrenheit. P a g e | 10 See Lowest Humidity analysis for Autumn, as the results are the same. Strategies Increase interleaving material between paintings to buffer against humidity swings. Run a humidifier throughout the winter. Lower heat in archives area, to increase relative humidity. P a g e | 11 Spring Temperature Mean Range Minimum Maximum Relative Humidity 75.21550521 7.488 72.718 80.206 Mean Range Minimum Maximum 37.09192482 50 15 65 Spring was almost as bad as Autumn in terms of fluctuating humidity. It had a large range of 50 between high and low, and there were significant changes in humidity over the span of a few days. Highest Humidity The highest humidity recorded in Spring was 65% on May 25th, 2009 at 8:30 AM. The temperature at that time was 77.749 degrees Fahrenheit. P a g e | 12 Although there is no risk of mold growth, metal and organic objects are both at risk of damage at this humidity. Worse yet, the humidity is significantly lower earlier in the day. Temporary spikes in humidity can be extremely damaging. Lowest Humidity The lowest humidity in Spring was 15% or lower, and was recorded on several occasions. The average temperature was 75.22 degrees Fahrenheit. P a g e | 13 The risks are identical to those of Winter and Autumn's lowest humidity days. Strategies Increase interleaving material between paintings to buffer against humidity swings. Run a humidifier in early Spring. Lower heat in early Spring to raise Relative Humidity. P a g e | 14 Summer Temperature Mean Range Minimum Maximum Relative Humidity 76.49599502 9.189 70.137 79.326 Mean Range Minimum Maximum 56.69838315 31.13 42.03 73.16 Summer had a fairly stable level of humidity. However, overall the humidity level was quite high. It was the only season not to have dangerously low humidity levels, but all but a handful of days had relative humidity over 50%. Highest Humidity The highest humidity recorded during the summer was 73.16%, on June 13, 2009 at 3:30 PM. At that time, the temperature was 70.651 degrees Fahrenheit. P a g e | 15 The potential for damage to all collection objects is high at this temperature and relative humidity. All of the indicators are in the red. There is a significant chance of metal eroding, of organic objects experiencing chemical aging, and mold growing. Although most days in summer weren't as humid, the overall humidity during summer merits concern. Lowest Humidity The lowest humidity recorded during the Summer was 42.09% on June 1st, 2009 at 3:45 AM. The temperature at that time was 74.619 degrees Fahrenheit. P a g e | 16 This temperature and relative humidity are decent. There is still some risk of chemical aging, but the risks of mechanical damage and metal corrosion are low, and the risk of mold growth is nonexistent. Ideally, humidity during the summer should remain at around this level. Unfortunately, there is only one day where the area around HOBO 13 is this dry. Strategies Run a dehumidifier throughout the Summer. Check collections for signs of mold growth.