Environmental Monitoring, Preservation Department || Syracuse University Library

Environmental Monitoring
and Control

"The purpose of a library, archives or any other cultural institution is to preserve and provide access to information and artifacts from the past. The value and meaning of these collections are diminished if they have been embrittled, warped, stained by mold or soot, faded, or are too fragile to be handled. Such damage often comes from exposure to extremes in humidity, excessive light levels, gaseous and particulate pollutants, water damage, and other environmental offenses."

William Lull, Conservation Environment Guidelines for Libraries and Archives, Ottawa, Canadian Council of Archives, 1995, p. 6.

This web site has been developed to help libraries, archives and historical societies in Central and Upstate New York with the ever present problem of environmental control. The site offers a summary of the standard environmental guidelines, a list of available resources for more information, tips on environmental monitoring, and suppliers for equipment.

Environmental Guidelines

Click here for a summary of environmental guidelines. This summary is distilled from many different sources. It is meant to be a quick reference for what the average goal should be. The list of resources which follows this section will provide a good understanding of the topic and allow for better decision making.

There will be times when it will be difficult to maintain the optimal levels stated in the summary. Seasonal adjustments will be needed. Depending on the institution's system, this may involve adjusting the temperature to counteract the change in relative humidity or adding external equipment such as dehumidifiers.

Although maintaining conditions close to the ideal is preferred, it is most important to minimize daily fluctuations. Large swings in temperature or humidity can be very damaging to materials as they try to reach equilibrium with their surroundings. Daily fluctuations should be kept to ±5° F and ±3% relative humidity.

Along with temperature and relative humidity, it is important to keep light levels under control. Many works of art, textiles, photographs and works on paper are very sensitive to light and will fade or discolor over time if exposed to high levels. Light damage is cumulative, hence, the length of time that materials can be exposed is dependent upon brightness. Not only exhibit lighting levels should be considered but also levels in work areas so that materials are not damaged while waiting to be accessioned, catalogued or researched. In all areas, the ultraviolet(UV) levels should be kept low. One of the easiest ways to control UV levels is to close window shades when the light is pouring in (this also helps keep heat gain down in the summer). Another way is to have UV filters on fluorescent lights and windows with strong sunlight.

One last area of the environment to consider is the particulate level in the air. For sites with forced air systems, filters should be used that remove better than 50% of 0.5 micron particles. For sites that do not have that level of control, keeping windows closed when possible and good housekeeping are important.

Resources

The Chicora Foundation

Managing: The Museum Environment

Beth Doyle with Robert Herskovitz

Museum Environments

Richard L. Kerschner and Jennifer Baker

Practical Climate Control: A Selected, Annotated Bibliography

Thomson, Garry. The Museum Environment, 2nd ed. London, Butterworth-Heinemann, 1986.

** This book is available at the Syracuse University Library.

Lull, William P. with the assistance of Paul N. Banks. Conservation Environment Guidelines for Libraries and Archives, Ottawa, Canadian Council of Archives, 1995.

** This book is available through CLRC Interlibrary Loan.

Museum and Galleries Commission

Serving Food and Drink at Events in Museums

Using Cut Flowers and Potted Plants in Museums

National Archives and Records Administration (NARA)

The Realistic Preservation Environment

This paper talks about how small institutions can achieve proper environmental conditions for the storage of documents and books.

Northeast Document Conservation Center

Low Cost/No Cost Improvements in Climate Control

** The link to this leaflet is broken, please contact CLRC for a copy
The Environment (a group of technical leaflets in The Preservation of Library and Archival Materials: A Manual.)

Fergus Read

Preventative Conservation

Environmental Monitoring Tips

"An environmental monitoring program should gather meaningful data on humidity, temperature, light... A regular monitoring program is important not only when an environment is suspect, but when an institution believes a good environment is being maintained. Clear and reliable monitoring information can provide concrete evidence and lay the basis for convincing arguments for improving poor environmental conditions. Continuous monitoring can also identify transient or progressive problems with building systems to provide early warning of threats to the quality of the environment, and to the safety of the collection. For institutions that do not have the services of a trained conservator, it may be advisable to obtain the services of a consultant to set up and environmental monitoring program, helping determine the need for special testing and the scope of prudent continuous monitoring. The program could then be carried out by the regular institution staff."

William Lull, Conservation Environment Guidelines for Libraries and Archives, Ottawa, Canadian Council of Archives, 1995, p.22.

Before embarking on an environmental monitoring program, a collection and building survey should be done. The variety and condition of the collection will determine the conditions to aim for and the features and characteristics of the building will determine how best to achieve the environment desired. A step-by-step guide for completing a building audit can be found at the CLRC web site in the document "In the Face of Disaster" (see page 27 of the PDF document). Another good introduction to starting an environmental monitoring can be found in William Lull's publication Conservation Environment Guidelines for Libraries and Archives, Ottawa, Canadian Council of Archives, 1995, p. 15-19. This book can be borrowed through CLRC interlibrary loan.

For an institution setting up a monitoring program on a limited budget, equipment for spot measurements or that do not record information (max-min devices for example) are less expensive but would give a general idea of what is happening on a day-to-day basis. When beginning a monitoring program with spot measurement equipment, it is a good idea to record in several areas (near windows, doors, work and exhibit areas, storage areas, ideally on each floor of the building including basement and attic if used) at different times of the day to see the daily range. The drawback of using spot equipment is that the readings are never done at night when the greatest fluctuations in temperature and relative humidity usually occur. If using the max-min devices, check on a daily basis. A record can be kept (along with what the outdoor conditions were) to give an idea of how the current system works and what changes need to be made. Here are two sample charts to help record environmental conditions: for spot measurements and for using max/min recorders.

Dataloggers have come down in price so that almost every institution can own at least one. Dataloggers will continuously record temperature and humidity (and often more) throughout the day to allow for accurate charting of the changes. These are, at this time, the best means of getting continuous measurement. Traditional hygrothermographs are still expensive, need hand calibration, need a large, stable place to sit and need the pen and paper changed on a regular basis. The datalogger is the size of a deck of cards or smaller, attaches just about anywhere and only needs to be downloaded to a computer once a month. Max-min units used in conjunction with the datalogger will give a daily heads up if the environment is getting to the danger levels.

Light levels, unlike temperature and humidity, can be effectively measured with spot readings. In rooms with windows, readings should be taken when the daylight is brightest. The most direct sunlight may come in before or after opening hours or fluctuate with the season so these conditions should be taken into consideration when taking spot readings. Light levels can be measured with a moderately priced light meter or with a manual camera with a built in light meter. If using a camera, set the ASA to 400 and the lens to f/5.6. Point the camera at a white piece of paper in the area to be measured and, with the paper filling the field of view, read the shutter speed (1/8, 1/15, 1/20 etc.). The denominator (8, 15, 30...) will roughly indicate the light level in footcandles which is one tenth the level in lux (so 15 footcandles would be 150 lux). UV levels are more difficult and expensive to measure but most light sources have a typical UV measurement. William Lull's book gives a summary of common light source and their related UV levels.

Monitoring the levels of particulates in the air is best done by direct observation.

Suppliers

Gaylord Archival

Gaylord carries one type of datalogger, humidity monitors and controls, and light monitors and filters.

University Products

University Products carries dataloggers, hygrothermographs, digital temperature and relative humidity max/min readers, and light meters.

Talas

Talas carries humidity indicator cards, temperature and humidity cards, digital temperature and relative humidity max/min readers, hygrothermographs, digital light meters, UV absorbent film for windows and sleeves for fluorescent lights.

Conservation Resources