ANSWERS TO FREQUENT QUESTIONS REGARDING THE WEI T’O® NONAQUEOUS MASS DEACIDIFICATION SYSTEM

Richard D. Smith, Ph. D., P. Eng., C. Chem.

Answers to the following frequently asked questions are provided below.

What is the optimum amount and kind of space required for a medium size Wei T’o mass deacidification System for a research library? 

The optimum amount of space will be between 4,000 and 5,000 square feet, depending upon the deacidification capacity and services desired from the system. A medium size Wei T’o Nonaqueous Deacidification System that can be expanded is appropriate as a regional center for a group of research archives and libraries. Several kinds of space are required: (a) Processing area: preparation of books, deacidification and inspection space; (b) Mechanical room: noisy pumps and motors, solution tank, recovered solvent tanks, etc.; (c) Storage for supplies; (d) Book Storage: incoming acid books and outgoing deacidified books; (e) Office and testing area.

How should the major components of the System be arranged for efficient and safe use?

Ideally, the equipment should be arranged on two floors with the vacuum dryers and deacidification process tank located directly above the vacuum pumps and liquefied gas pumps, storage tanks, and other mechanical room items.

What equipment is needed to treat 75 to 100 books per hour?

 
The major items required are one Deacidification Process Tank, four Vacuum Dryers, three Vacuum Pumps, one High Pressure Recovery Solvent Vapor Compressor, one Low Pressure Solvent Recovery System for 100 percent Solvent Recovery, one Liquefied Gas Deacidification Solution Tank, one Recovered Solvent Tank, and one Preparation of Make-up Solution component. Although this medium size System theoretically treats approximately 90 books per hour, the actual production is 480 books per 7.5 hour shift per day or 960 books per 12 hour “flexi” shift. These rates are correct because time for other tasks: starting, stopping, reloading the dryer, etc., must be allowed. Output could be increased to 1,920 books per 24 hour (two “flexi” shifts) day, if some modifications are made and larger solvent and solution tanks are installed.

A book is defined as being 6″ x 9″ x 1″ thick with approximately 150 leaves. The actual numerical book treatment capacity will be higher because most books are less than 1″ thick. Books and documents up to 12″ x 15″ (any thickness) can be treated. Larger books and documents make up a very small proportion of an archive or library collection and are more economically deacidified by manually spraying them rather than by treating them in a mass deacidification system designed for books over 12″ x 15″. Documents and records in archival boxes may also be treated.

Are there vacuum dryers (dehumidifying chambers) available that hold 200 to 400 books at one time? 

The Vacuum Dryers used by Wei T’o (a minimum of 4 may be required) are standard industrial units with especially modified shelves for the particular purpose of drying books for deacidification. Each Vacuum Dryer would contain approximately 480 books, a number sufficient for one 7.5 hour shift.

Is there a Process Tank (pressure chamber) available to treat 200 to 300 books at one time? 

As above, our Process Tanks are especially designed and built. Each will deacidify approximately 60 books per 40 minute cycle.

The sizes of the Process Tank and Vacuum Dryers are matched so the output of one Vacuum Dryer can be deacidified every 7.5 hour shift. Our operating experience with existing equipment indicates two days are required for each drying (dehumidifying) cycle. In the future, we foresee drying rates improving so only one Vacuum Dryer will be required for one Process Tank for each 7.5 hour shift operation, rather than the two Vacuum Dryers that are required today. The 17 years of production experience to date indicate it is not labor or capital efficient to design the Vacuum Dryer and the Process Tank capacities larger than the capacities specified above. Moreover, safety is compromised in larger designs. We believe the low capital costs involved justify replication of the entire System when production over 645,000 books per year is desired.

What requirements exist for the room itself, i.e., air conditioning, electrical power, plumbing, venting? 

Depending upon the design and capacity selected, additional air-conditioning may be needed to maintain comfortable working conditions and to remove the heat produced by the various motors and mechanical operations. It may not be practical to provide additional air-conditioning from the library’s system because the extra air flow required would upset the air-conditioning balance of the building. Our recommendation is to mount one or more modest sized air-conditioners above a false ceiling in the appropriate locations.

Although the System could work on 230 volts, 3 phase, 60 Hertz and 115 volts, single phase, 60 Hertz, electrically; operating costs could be reduced if 360 volts, 3 phase, 60 Hertz were provided. The necessary 115 volt circuits would be taken from the 360 volt main circuit, if allowed, or supplied separately. Other normal voltages, e.g., 208 volts could be substituted, if desired. Approximately 200 to 300 amps of 230 volt electrical power are required for each basic System.

Both cold and hot water supply are necessary. The cold water is used for cooling the vacuum pumps and the condenser to recover and liquefy solvent vapors. Drains are needed for removal of the water, as well as, for removal of condensate produced when compressing air. The main use of hot water is for cleaning and personal sanitation. A supply of constant temperature hot water is needed for the Vacuum Dryers.

Fire regulations require the Deacidification Process, Storage, and Recovered Solvent Tanks be designed and installed with automatically vented pipe lines to provide protection against tank rupture caused by excessive pressure build-up in event of fire, etc.

The deacidification work areas should be vented continually to insure a supply of fresh air. Our opinion is the air pressure in the Deacidification Room and the Mechanical Room should be slightly lower than in other portions of the building. This differential insures air flows into, and is exhausted directly from the area. This air flow prevents spread of solvent vapors to the remainder of the building. The “Building Engineer” may choose to view the deacidification work areas as exhaust points for used air from the building.

What skills should the personnel have who are selected to operate the System’s equipment and what background would be useful? 

Several types and levels of staff competence are desirable. The Director, a working administrator, would most desirably have both library and conservation background. This individual would be capable of administering the System, communicating with library and university personnel and vendors, scheduling future operations, and training staff, as well as representing the institution to visitors. Administrative experience, a graduate degree, preservation knowledge, and library experience would be useful.

Two System Operators, presumably male due to lifting requirements, are needed to operate the Dryers, Process Tanks, and mechanical equipment. These men should have a feeling for chemical processing and machinery, and would be expected to understand and conduct the deacidification cycles, do routine maintenance, and keep appropriate records. Presumably, one of them will, when the Director is not present, explain the System to visitors. The Chief System Operator probably should also be the Assistant Director. An AAS degree and experience in industrial scale refrigeration or air-conditioning would be useful background for these technical persons.

The remaining two to three people in each 7.5 hour shift should be capable of maintaining records, preparing books for treatment, inspecting books following treatment, etc. Educational background from high school to an AAS degree are desirable. Training can be provided on the job.

How much training will be necessary to operate the Wei T’o System and where will our personnel acquire it? 

Our recommendation is key personnel, e.g. the Administrator and Chief System Operator should be trained by Wei T’o Associates. These senior staff persons can be expected to train the other personnel using their acquired knowledge and a detailed “Operation and Maintenance Manual” that Wei T’o Associates would supply. It is desirable, if at all possible, for additional “Hands on” training and experience to be obtained at an existing Wei T’o System. Much of the general experience and training can be provided during the start-up period when the System is being installed and tested.

Are the chemicals dangerous or toxic to handle? 

The chemicals will not endanger persons working with the System, persons handling or using deacidified books, or persons in the vicinity of the System when the System is operated properly. In essence, the System is no more dangerous than a large air-conditioning plant which uses present dry fluorocarbon refrigerants. Such air-conditioning systems have been routinely installed in large library buildings since the 1940s. The primary danger is an accidental “spill” of the liquefied gas deacidification solutions mixing with and diluting workroom air to reduce the amount of oxygen present to a life-threatening, i.e., asphyxiation level, an accident unknown in over 50 years of library air-conditioning. MSDS Sheets for the liquefied gas deacidification solution and deacidified paper and books are available elsewhere in this web site.

The personnel operating the System will be trained in proper working procedures and the System designed and operated with proven, well-known precautions. No difficulties are foreseen in establishing safe, efficient procedures for operating a Wei T’o System in a library building. The necessary knowledge and regulatory standards are known. Moreover, the existing System at the National Library of Canada has been operating over 17 years in a prominent location in a major Canadian government building. Actually, the Wei T’o System Room is located just under the main meeting room of the National Library and National Archives Building.

If the system operated 12 hours per day and we have four Vacuum Dryers each holding 480 books, can we assume that capacity would allow us to process 1,920 books per day? If so, how many staff would be needed. 

As mentioned above, the envisioned System would have a capacity of 960 books per 12 hour flexible shift. This design would provide an output of approximately 1,920 books per day, if operated 24 hours per day. Production would exceed 645,000 books per year if the System were operated 24 hours per day, 48 weeks/year, or alternately, could be scaled down to only 115,000 books/year on a 7.5 hour 5 day/week schedule.

It is our understanding that is takes 36 hours to vacuum dry books but less than one hour to treat them in a mass deacidification process. How can one establish a work flow to treat 5 batches per day? 

The work flow procedure is to have one large Vacuum Dryer which contains all of the books that will be deacidified in a 7.5 hour shift by one Process Tank. The Process Tank deacidifies approximately 60 books in each 40-minute deacidification cycle. The Vacuum Dryer holds approximately 480 books (placed in baskets for handling convenience). The Dryers are used on alternate days or shifts, with a highly skilled staff. This schedule provides for vacuum drying to occur during the 40 hours of the unused 48 hour two-day period. This schedule is based on experience using equipment designed over 20 years ago; planned changes in design are expected to reduce drying time a minimum of 25 to 50 percent.

If we were to sell service to others, what issues should we be concerned with? 

In our opinion, the primary questions would be what are the benefits, losses, and problems in selling a deacidification service to other institutions. The basic problem is whether or not sufficient customers do exist, have funds, and are able to make a long-term commitment for a deacidification service.

Assuming that funding the customers exist, the problems change to the practical problems of operating a business. In this sense, no difference is seen between the operation of a well-managed not-for-profit business and a well-managed, traditional, for-profit business, with the exception that a not-for-profit organization does not distribute its profits. Profits in not-for-profit organizations are used for expansion, improvement of services, or reduction of charges, etc.

A peripheral, but important question is whether providing such a service would conflict with other businesses or jeopardize the tax status of your organization or its parent institution.

The records that are being kept and work actually involved should be closely reviewed to verify the costs of handling and treatment, maintenance and depreciation and product improvement are known and their costs are recovered in the charges to other institutions.

Is it practical to establish a mobile or transportable system which could be “knocked down,” loaded into a truck, and set up in the next location. We are considering the first phase of this preservation program to be the establishment of a pilot laboratory. The second phase, with statewide, support, would seek funds for a mobile laboratory. In either case, we would plan to provide preservation services to other smaller libraries in our region. Please comment on the various approaches, and resultant costs. 

With reference to the pilot laboratory, we assume it would not undertake mass deacidification, but rather the low-cost preservation services required by all libraries, e.g., (1) education of library and archive staff, (2) proper housing for library and archive materials, (3) proper environmental conditions, (4) mending broken books, (5) guidance in disaster services, and (6) deacidification of selected materials or portions of Special Collections. Excellent texts and articles exist that discuss the first five items.

Supplementing Item (6), deacidification, we suggest consideration be given to installing a Wei T’o “Soft Spray” System. Such a System could be supplied by Wei T’o for approximately $4,000.00. This funding would provide a basic spray booth, ready to plug in, spraying equipment, and sufficient deacidification solution to deacidify between 2,000 to 5,000 8 1/2″ x 11″ sheets. You would need to vent the Spray Booth, provide a 110 volt electrical outlet, a 30″ support table measuring 30″ by 48″, and retaining chains for the two cylinders of solutions used in “Soft Spray.”

Using student help, at $7.00, a typical 6″ x 9″ novel, having 150 leaves, could be spray deacidified every 15 to 20 minutes. This same type of equipment would be useful in a transportable laboratory, and continue to be useful for deacidification of books larger than 12″ x 15″ after your Wei T’o Mass Deacidification System was installed.

You may wish to offer disaster services in either facility. If so, a Wei T’o Book Dryer and Insect Exterminator could freeze-dry approximately 200 water-wetted volumes per month and exterminate the insects in approximately 1,000 books per week with none of the hazards involved in chemical fumigation.

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