Volume 9, Number 3
May 1985

The Ideal Preservation Building

Reprinted with permission from American Libraries 15(11), Nov. 1984, p. 703, © American Library Association.

Large-scale preservation of the Newberry Library's treasures has taken the form of a 10-story bookstack building, windowless, of double-shell construction, and with computer-monitored environmental, security, and fire-detection systems, and a highly efficient air-filtration system.

The optimum conditions for preserving library materials are not the same as those for human comfort. Therefore, the library chose to separate its book storage areas from the reading areas and support functions. This allows us to maintain a storage environment that will reduce the rate of deterioration for all library materials.

Paul Banks, Conservator of the Newberry Library in 1964-1981, established the environmental standards for the book-stack building, which was completed in 1982. A system was designed to maintain the temperature at 60° ±5°F and the relative humidity (RH) at 50%, with a diurnal fluctuation of no more than ±3%, and a seasonal allowable fluctuation of ±6%. The Microtext Masters Storage Room is kept at 35% RH.

These conditions are monitored and controlled by a Johnson Controls JC/85/40 building automation system. Electronic sensing devices located on each level of the bookstack building and in the Microtext Masters Storage Room signal Field Processing Units. These, in turn, report the temperature and RH to the Central Processing Unit (CPU) in the Building Control Systems Room. There, a CRT and printer make it possible to "call up" this information as well as the status of all the individual components of the heating, ventilating, and air-conditioning system at any time.

At periodic intervals, a printout on the status of any of the field data points is run off. Presently the CPU produces a Trend Log for both temperature and RH, storing readings taken at two-hour intervals and printing them out in a specified format every 24 hours. [A portion of the printout, reproduced below, shows a 24-hour record of temperature.] Although the Trend Log has eliminated the need for manually rotating hygrothermographs throughout the bookstack areas, the Conservation staff still uses a Bendix psychrometer regularly to ascertain the accuracy of the thermostats and humidistats. It has been found that the humidistats need frequent recalibration.

Trend log indicating temperature variations over a 24-hour period. None of the readings is marked with an asterisk, indicating that all are within the allowed range (55°-65°F).

High- and low-level limits for all the temperature and RH points have been programmed into the system. If these are exceeded, an alarm is activated at the CRT and, when the library is closed, on a pager worn by the security personnel on duty 24 hours a day. This alarm will sound until it has been acknowledged at the CRT thus ensuring that the condition is responded to by a trained staff member. A printout of the alarm condition is produced simultaneously.

Clearing the Air

Banks' standards for air quality specified that levels of sulphur dioxide and oxides of nitrogen should not exceed 10 micrograms per cubic meter (m³) and that the ozone level should be no more than two micrograms/m³. To achieve this quality of air in a city like Chicago, we use a three-stage filtration system: an initial particle filter; a second-stage chemisorbant filter (Purafil) of pelletized activated alumina impregnated with potassium permanganate, capable of absorbing, adsorbing, and chemically oxidizing gases; and a final, high efficiency (90-95 percent) particle filter.

The performance of this filtration system will soon be monitored on a continuing basis by Meloy nitrogen oxides and sulphur analyzers. This equipment will sample outside air and air from a stack level to determine the effectiveness of the Purafil. The analyzers will also be tied into the JC/85/40 to signal alarms and provide permanent records.

Although the fire-detection system is not part of the JC/85/40 (it is a stand-alone system with its own auxiliary power source), it is interfaced with the computer to interlock with HVAC functions. If a fire alarm sounds, for example, the computer will automatically shut down the supply-fan units.

The bookstack building has no fire-suppression system (with one exception), relying instead on a high concentration of ionization smoke detectors. The exception is the Special Collections Vault, which has a Halon system, a chemical combustion suppressant. This arrangement eliminates the need for water in the bookstack building.

In fact, there is no vertical penetration between stack levels at all. The levels are self-contained "boxes" stacked one on top of another. The building is attached to the original library by a service link. All plumbing and electrical risers and the elevators are located in this service link.

Being able to prolong the useful life of library materials by maintaining a stable environment is terrific; but the current environmental conditions are actually a compromise. If economic and user constraints could be eliminated, it would be ideal to literally freeze most of the library's materials--theoretically extending their lives indefinitely. However, this would require "decompression" time and facilities, so that items could be brought gradually into equilibrium with the reading room environments. Also to be considered is the attrition rate of shelvers and pages working under those "ideal" conditions!