Early Detection Systems
To minimize the damage of a disaster event, the team recommends that early detection measures be implemented into the existing building management system (when possible) or as a separate monitoring system. These early detection systems will speed response time to a disaster and relay accurate data of damaged locations to aid the recovery process.
Fire Sprinkler System
There is currently no effective way to restore collection materials that are charred, yet there is a high rate of success (95%) in restoring water damaged materials. The two modules in the facility are outfitted with 94 K-22 Early Suppression Fast Response (ESFR) Reliable sprinklers each which activate individually by heat detection (the sprinklers activate at heats that exceed 200°F). These sprinklers are designed to discharge 142 gallons per minute at 40 psi to prevent the fire plume early in its development, stopping the fire from spreading and reducing roof level temperatures quickly to prevent structural damage to the shelves.
According to the National Fire Protection Association (NFPA), when sprinklers operate but are ineffective, 71% of the time it is to due to insufficient water being applied to the fire, either because water did not reach the fire (42% of ineffective performances) or because not enough water was released (29%)5. To evaluate the effectiveness of the facilities fire sprinkler system the team is consulting and testing sprinklers in coordination with the Illinois Fire Services Institute (ISFI). The analysis of potential damage is directly related to the placement of the overhead sprinklers, and the team replicated the conditions in the facility where the greatest amount of damage would occur.
Using a NIST Fire Dynamic Simulator, the team was able to simulate the water flow and spray pattern of the facility’s sprinkler heads (Fig. 5.1) by specifying parameters such as pressure, velocity, flow, and sprinkler head size. The simulation showed that the top 5-7 feet of the shelves receive the majority of the water; spots below this are reached indirectly through cascading water. Along with this simulation, the team will perform testing with a 5 foot high shelf that replicates the top 5 feet of a 40 foot shelf in the facility, where the most damage may be expected.
Smoke detection was examined in addition to the fire detection provided by the sprinkler heads. The sprinkler heads only activate when the temperature at ceiling level reaches 200°F and this may only occur after a fire has spread extensively. The facility should be equipped with several ionized smoke detectors located in the return air ductwork or at intermediate heights in the facility. These detectors would provide early-warning smoke detection if materials were smoldering in the early stages of a fire. A fire is not expected to grow due to the low temperature and surface to mass ratio of the books in the facility. Thus, using ionized smoke detection is essential to recognizing fire at its earliest stage. These detectors would not be tied into the existing sprinkler system and would not cause the sprinklers to activate.
Controls (Temperature and Relative Humidity)
Approximately 80% of the collection items are paper, and deterioration is directly affected by temperature and relative humidity since paper is a hygroscopic material that has the ability to attract moisture from the surrounding environment. The lower the temperature where paper based items are stored, the slower the material will deteriorate since heat accelerates the chemical reaction that degrades papers’ cellulose fibers (Figure 5.2). Recent research shows an increase in temperature from 68 to 70°F will increase the deterioration rate by 2.5 times. Relative humidity can also contribute to acidic damage from increased moisture and encourage mold growth when the humidity level in the air exceeds 60%.6
The environment in the storage facility is maintained at 50°F and 30% humidity by a Harris Environmental HVAC system. Two hygrothermographs measure the temperature and humidity of the storage area and ensure the facility is within an acceptable tolerance of +/- 2.5°F and +/- 1.5% humidity. The sensors provide an average of the relative humidity and temperature throughout the shelving area and do not give information regarding specific locations. Relative humidity and temperature measurements taken at different locations within the shelving units would provide data on various microclimates that exist. Additional humidity sensors were researched by the team for this application. These sensors would be manufactured and installed by Harris Environmental Systems because of an existing contract with the facility. Humidity sensors were also examined to determine their suitability for use in detecting water. Research has indicated that the sensors will only detect significant water events (i.e. widespread flooding of the facility) unless the water is touching or within 2-3 inches of the humidity sensor.
Water sensing technology is another method of early disaster detection. There is currently no water detection system located in the stacks and it is recommended that a system either be implemented in order to monitor the presence of water that could damage the collection items. These water sensors and alarms should be installed strategically in areas where leaks are reasonably expected to occur such as under the wet pipe sprinkler system and locations where leaks are possible in the roof.
A Series 2100 Dorlen Water Detection System is recommended for use along the top of these shelves (under the wet pipe system). Dorlen Water Detection includes 6 monitors and water sensing cable that would run along the top of each shelf. The cable has sensors every three feet, and it is desirable that the top shelf be slightly angled to one side, where the cable can be located, to funnel water onto it. The Series 2100 with SM-6(T) monitors and sensing cable provides a maximum coverage area of 3,300 sq. ft, which is sufficient for the 3,000 sq. ft. of shelving and is priced at $6,190.
Individual water sensors that sound an alert when detecting water will also be recommended to use throughout the ground level of the facility. These devices would be used to detect any flooding that may occur in the facility. These sensors would be placed at the end of the aisles along the floor, near the exterior walls of the building. Sensors cannot be placed in the aisles because they would obstruct the Raymond lift’s movement during normal facility operations.
Temperature sensors integrated with the current fire suppression system would alert the facility to the presence of a fire. Although individual sprinkler heads are temperature sensitive and activate at 200°F, there is no way to distinguish between an inadvertent activation and an intentional one. Temperature sensors independent of the sprinkler heads would allow the facility to differentiate between the two. When used in conjunction with water sensors, temperature sensors could allow for an automatic shut off of the water supply. If water is detected and the temperature sensors indicate the absence of fire, water would be prohibited from entering the wet pipe system by activating a water shut-off valve. If the temperature sensors indicate the presence of fire, water flow would be allowed.
Temperature sensors integrated with a fire suppression system in this manner are known as “smart” systems, and are a major developmental research area within fire protection. When these systems are better developed, damage from accidental sprinkler activation could be minimized, reducing water damage to seconds rather than minutes. It is recommended that the facility integrate temperature sensors with the current wet pipe system, and use a wet or dry pipe system with a smart system in future modules as. If a dry pipe system were used with a smart system, water damage would be completely eliminated in the case of sprinkler malfunction.
Recovery of Critical Items
Critical items that are to be recovered first after a disaster include:
- Content that is irreplaceable or essential
- Valuable/permanent papers with legal/fiduciary/evidentiary value such as vital records or materials essential to the functioning of the library
- Irreplaceable materials that must be retained in their original format (e.g., manuscripts or rare books with intrinsic or artifactual value)
- Content with high economic value
- Materials with significant research value that are expensive to replace or repair
The safe recovery of the special collections materials is the highest priority in the event of a disaster. Currently, there is no way to identify special collections other than visual inspection (special collection trays are white instead of the standard brown). An operator would drive the Raymond lift to the section that was deemed most critical and load to capacity (approximately 16 trays); subsequently the operator would return the books to a repository and continue. No plan exists for specifying the exact aisle or shelf to retrieve from and possible retrieval paths must be analyzed to determine which route will obtain the highest value of materials in the shortest time. The first objective addressed in improving this process is discovering the location of high priority materials.
Although all special collections materials are “high priority”, the team has further segregated items (See Appendix A) into three levels of importance according to the number of books at each location. The locations containing less than 10 special materials were labeled “green”, those containing between 10 and 50 materials were assigned “yellow”, while all locations containing more than 50 items were labeled ”red”. A greedy algorithm is being developed to analyze multiple retrieval tactics to determine which should be used. These tactics include:
- Recovering only “red” items first
- Recovering both “red” and “yellow” items. (“Green” items are not considered due to their low quantity and have been deemed equivalent to general collections in recovery priority)
- Recovering only locations that have more than a specified number of trays
The effectiveness of each method will be evaluated by both its recovery time and its economic impact (how much money has been saved in the form of special collections materials).
The algorithm’s main challenge lies in addressing the random placement of high priority items. Targeting these materials first for recovery is desired but there are locations that contain only partially filled trays or trays that house both special and general collection items, with no distinction between individual materials. Additional problems may arise because special collection items were not always placed in separate white trays when the facility first opened.
In designing the algorithm, the widths of the shelves are assumed to be 53.25”, though 3 shelves in each aisle are 38” to accommodate the return air ductwork. The assumption is also made that the lift’s velocity is constant at 2.73 mph horizontally and 1.28 mph vertically (speeds are an average taken while the Raymond lift was in normal operation) and that it has a 16 tray capacity regardless of tray type. An outline of the algorithm is given below:
While recovery is not complete
- Identify recovery location (x,y) using findNextLocation function
- Return the location if the number of trays at that location is greater than zero, else increase x until trays are found
Relocate to the next aisle when the wall of the current aisle is reached (x=maxX)
- Recovery trays from location (x,y) using getTray function
- Take trays from location and fill up the bookbag, If all trays at location are recovered, reassign location to have zero trays
- Recovery trays until bookbag is full (16), then empty. If all trays at location are not recovered, reassign the number of trays at location to reflect how many were put into the bookbag
- Compute recovery time using evalTime function
- Compute time it takes to drop off books and return
- Compute time it takes to move to new location if all books are recovered and bookbag is not full
- Return a matrix output or list of recovery locations along with the total time associated with the process
Obstacles to Recovery
Testing has shown that books swell significantly (a 17” row of books expanded to more than 21”) when exposed to water and may fall into the aisles after a disaster, blocking retrieval paths and posing a risk of falling objects. There are no procedures for safely recovering these items and solutions must be proposed to safely clear fallen books from retrieval paths before shelved items may be recovered. Moveable stair ladders that have storage underneath the steps are being considered for use in the facility (Figure 5.3). These ladders provide overhead protection from falling books, and would allow the staff to safely clear obstacles before the lift starts retrieval. The team has designed a moveable stair ladder with storage and given detailed specifications to the University of Illinois Ironworks shop so that they may assess the feasibility of building it and estimate the cost of fabrication.
Another impediment to the recovery process is standing water. The facility has one wet/dry vacuum, and additional cleaning supplies to remove water must be acquired in the case of a disaster. There is one drain in the entire storage area, and water will not be removed unless it is physically taken out with pumps, wet vacs, mops, or squeegees.
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