Table Of Content

T2AqI862: I Suge -ollection Storage— J291U 9 H9 7 aking a Case for Microenvironments Donald R. Cumberland, Jr. ecause of the wide range of climatic conditions and variety of buildings used for collection storage, the National Park Service (NPS) relies on the ability of museum cabinets and prefabricated modular structures to provide quality collection storage space for NPS museums. Specialized museum storage cabinets and prefabricated modular structures contribute to the preservation of museum collections by enclosing museum objects in a beneficial microenvironment—one free of ambient light, dust, insects, and rodents and, most importantly, having stable relative humidity (RH) and temperature conditions. Stabilized high quality conditions reduce physical and chemical stress on objects, slow deterioration and, thereby, lead to long-term preservation. Many museums, including NPS museums, use specialized museum storage cabinets as primary containment for museum objects in storage. These cabinets generally have double wall construction, locking doors and no glazing. They also have gasketing around the door jamb that reduces air exchanges, enabling a microenvironment to surround the objects. Prefabricated modular structures, such as those manufactured by Bally Engineered Structures in Bally, PA, are becoming increasingly popular for storing museum collections, either within an existing building or as a self- contained, stand-alone exteri- or building. (We will use the term “Bally” to describe this building system, although Bally is but one of a number of manufacturers. Bally products are the ones most frequently |n i used at NPS sites.) Bally ) buildings are similar in con- ! | struction to walk-in refrigera- | tors and are highly-effective in ! maintaining an appropriate LIK | | museum environment because ! of superior insulation and \‘r- - tually air-tight construction. Storage space is formed by . assembling foam-core (gener- 7 ally high-density polyurethane), metal clad (alu- minum or galvanized steel) panels. The paneis of most of the manufacturers have an NY insulation “R” value above 30; Bally panels are R-34. The panels are gasketed along the edges and, when fastened together form air-tight joints. The panels are light-weight and are quickly and easily assembled with ordinary hand tools. (In one instance at Harpers Ferry, WVA, an inexperienced NPS staff Exploded view of a museum storage facility showing the various prefabricated units that comprise the walls, put together a non-conditioned Bally building of 100 square feet in less corners, floor, ceiling, and sliding doors. Drawing by than one hour). Panels can be carried through the building’s doors and Christina Henry. assembled inside. Weatherproof roof panels are available to allow the building to be placed outside on a concrete slab. (continued on page 2) | COMPLETED (continued from page 1) The Harpers Ferry Project This project was conducted from February 23, 1987, to In order to justify this reliance on its storage equip- February 20, 1988, in the northwest corner room on the ment, the NPS tested these storage containers to deter- third floor of Building 33 at Harpers Ferry National mine their effectiveness in creating and maintaining sta- Historical Park. Building 33 is a three-story stone and ble RH and temperature conditions both with and with- stucco structure with no climate control on the third out the influence of environmental conditioning equipment. floor. Unconditioned space was necessary to more accu- The test consisted of monitoring projects at two sites in rately determine the buffering effects of each layer of which cond*t'ons were recorded in several locations with microenvironment. The first and second floors of each location experiencing different environmental con- Building 33 are used as ranger offices and are heated and ditions and having different environmental require- air-conditioned. The joists supporting the second story ments. Each monitoring location or “station” indicates ceiling and the third storv floor are uninsulated and may either the ambient weather conditions or a sequential have allowed some heat transfer from the lower stories to layer of microenvironment. the third floor. Conditions were monitored for each of the following The purpose of this project was to determine the effec- functions: ¢ maximum 24-hour RH change, which compares tiveness of NPS equipment in maintaining microenvironments within virtually unconditioned space within a his- ambient RH conditions with the RH stabilizing toric structure. This situation is representative of what is effects of each layer of microenvirorument; found in many parks: collection storage in a dedicated ¢ maximum/minimum RH levels, which indicate the space that has no active environmental controls. range of RH conaitions; Hygrothermographs were placed in six monitoring sta- ¢ maximum 24-hour temperature change, which com - tions as indicated below and on Figure 1. pares ambient temperatures with the temperature Station 1. Recorded conditions within a museum cabi- stabilizing effects of each layer of microenvironment; net in the unconditioned Bally building. ¢ maximum/minimum temperature levels, which indi- Station 2. On top of a cabinet (Station 1 in the Bally cate the range of temperature conditions. building) to record conditions within the Bally building Both projects involved assembling a Bally building, itself. installing museum cabinets and hygrothermographs, and recording conditions over an extended period of time. 4 \ patty STRUCTURE STATION 1 - IN MUSEUM CABINET WITHIN BALLY STRUCTURE STATION 2 - IN UNCONDITIONED BALLY STRUCTURE STATION 3 - IN UNCONDITIONED HISTORIC STRUCTURE ROOM STATION 4 - AMBIENT OUTSIDE CONDITIONS AS RECORDED AT PARK WEATHER STATION CY STATION 5 - WITHIN INTERIOR STEEL MANUFACTURED sae T — Wil T ENFVIXIT RUNMENUNFATCTUARELD - CAMBIUNEN ITORING _>ROJECT HARPERS FERRY NATIONAL HISTORICAL PARK BUILDING 33 - THIRD FLOCR - NORTHWEST CORNER ROOM pawn 5" _D, CUMBERLAND JUNE_1991 L SaE 1/4" = 1'0" Figure1 CURATORIAL SERVICES DIVISION , WASO 1992 No. 4 Station 3. Exposed in the unconditioned northwest cor- cabinet in the Bally building) as depicted in the drawing ner room on the third floor of Building 33 to record room in Figure 6. Stations were designated as follows: conditions. Station 1. Recorded conditions within a cabinet in the Station 4. In the park’s weather station to record ambi- conditioned Bally building; ent weather conditions. Station 2. On top of the cabinet (Station 1) to record con- During the test of the Lally building a comparison of ditions within the Bally building; the buffering effectiveness was made between cabinets of Station 3. Exposed in the minimally conditioned case- two different manufacturers. This cabinet test took place mate to record conditions there; in the same northwest corner room of Building 33, but Station 4. In the park’s weather station to record ambi- not within the Bally building. The unconditioned third- ent conditions. story room allowed sufficient fluctuation of conditions to A second test to compare cabinets by manufacturer was make possible a determination of whether one brand of considered unnecessary and was not undertaken. Con- cabinet was superior to the other in maintaining a stable sequently, this project did not require Stations 5 and 6. internal microenvironment. Hygrothermographs were recorded on a 7-day (weekly) Station 5. Within a museum cabinet manufactured by basis. Four or five charts were analyzed to organize the Interior Steel Equipment Company, Cleveland, Ohio. information in approximately 30-day increments that Station 6. Within a museum cabinet manufactured by the roughly corresponded to the calendar months. This Steel Fixture Manufacturing Company, Topeka, Kansas. information was used to produce the data in Figure 7 The hygrothermographs at all stations recorded for 31- and the graphs in Figures 8 and 9. day intervals. The charts were changed at the end of each interval. Accurate information regarding station Test Results number and dates were entered on the charts. The The following two parameters were incorporated into hygrothermographs were calibrated using an electronic the findings: hygrometer on February 23, June 1, and October 21, 1987, First, the fluctuation rate of 24 hours was selected as or approximately once every four months. representative of the diurnal (day/night) cycle. The An analysis of the records resulted in the information in diurnal cycle generally experiences the greatest tempera- Figure 2. Salient information on the chart was organized ture and RH differential and is the time span when most in graph form to produce Figure 3, which represents the physical and chemical damage to objects occurs. highest and lowest temperatures and humidities record- However, because of the buffering effects of the museum ed during the test period, and Figure 4, which represents storage equipment, fluctuations in sequential layers of the greatest 24-hour change of RH and temperature. microenvironment were delayed and did not exactly cor- Figure 5 gives results of the test comparing the two respond to the day/night cycle. Because of this phenom- brands of museum storage cabinets ability to maintain enon it is felt a 24-hour rather than a true day/night stable interior RH conditions. The test also allows the cycle indicated changes more realistically. performance of the cabinets to be compared against the Secondly, infrequent fluctuations of durations of two Bally building. hours or less were not accounted for on the data sheets and diagrams because the hysteresis (i.e. the time lag Fort Pulaski Project exhibited by an object in reacting to changes in the From January 2, 1988 to January 4, 1989, a monitoring forces, in this instance the RH and temperature, affecting project was conducted in the 19th century masonry it) of most materials that make up museum objects does coastal fortification at Fort Pulaski National Monument not allow sufficient time for the objects to react. near Savannah, GA. Monitoring took place in a west side casemate two rooms south of the sally port. (See Harpers Ferry Project Findings Figure 6 for a diagram of the collection storage casement Hygrothermograph records reveal that over the course showing the Bally building.) Minimal conditioning (i.e. of the two-year testing period and without any energy to human comfort range) is provided by a heating, venti- input for heating, cooling and humidity control, the lation, and airconditioning (HVAC) system in the case- greatest 24-hour RH and temperature changes recorded mate. In addition, the Bally building is conditioned to on the interior of the Bally building were 6% and 6°F museum quality levels with a dedicated heat pump respectively (which were virtually the same changes HVAC system. recc“ded for inside the cabinet within the Bally building). The purpose of this project was to determine the effec- These findings are quite impressive when compared to tiveness of a Bally building and a cabinet within the Bally the maximum 24-hour fluctuation of 25% RH and 47°F building to maintain stable microenvironments within temperature recorded in the historic structure room itself space that has minimal controls (i.e. the casement) and and 63% RH and 46°F temperature recorded in the within a Bally structure having dedicated environmental weather station. controls. This situation at Fort Pulaski represents more Conditions within the cabinet inside the Bally building sophisticated and better quality control than what com- were essentially the same as those in the Bally building monly is found in most NPS museums and can be con- itself, indicating that the cabinets contributed little addi- side.ed optimum. tional climate control. Hygrothermographs were placed in four stations in Cabinets by both manufacturers were equal in main- order to monitor the ambient outdoor conditions and taining a stable microenvironment. conditions within three layers of microenvironment (i.e. the historic casemate, the Bally building, and within a (continued on last page) 1992 No. 4 r n u a a n a 28/02/>| 48/va/e}] 48/63/72}( S| fae £8/|8 I/S- £8|/ 02/- 48/+|¥ 2/E- g : =: EA | 4 jn Lu A saneanan>3i a l ar i: z= Ww atlctllaleol Aa fs Be rm x ke c Ee> AHAaKnidaN AnAuSaiac un launFE ee p iL = ku LJ & > i i oO co rm - LPL 2/v2|8 “e/ez/2|_Le/vere| [D2B|/8 I/S- |28/02/9—- L£8/v2/E- ATEC —=AB INE T Sare el. TTEAST-—--8~7—T *m™Is i —O_—N_6— . civs|] cevet/s| ree ZB/|E I/Z- £8/|S 1/9- |2 Sa}, |e 3 A| StIe «P|SIS E 4kK e d BF fA paP) WOD aa rsiv9|_zevewz| _zevers| /0L£8/E19/L-- 28|/S T/ an m49 Le/ eB A afo vdize 72 - BlI s IY - i e—S6_3 eevee] cevet/é| ; £B/E|/ 6- £8/|8/ 8 | A e| S ESE wb el at a Been < actolade sald bia cb 3NIavo NOSHt _zevere| E/e£-8 / £8/8/8 nn S L /E/A6|B —s Hesevere] I- t/oI£-8 / . T LNONSS_—LB/T/OI IWANVOdYWIOADN SOXDIW cerivol] £8/S/ I64 - = i 2 N vs/m| Z£e/iv e A z T iN a] |/ s/I- 4387 y GH a cev8e otye e A /s/t] eee 88/1/2- Perl sM Fle d Bol ABia1 es] 88/I/2- 767 _—8e/t/e 8888/|9 2/2- es > Cu alae aebt se4 3 eave e88|/ 92/2- olen 2 |B) 4 i/e STATION 1 - IN CABINET IN BALLY STRUCTURE STATION 2 - EXPOSED IN BALLY STRUCTURE STATION 3 - IN UNCONDITIONED ROOM WITHIN HISTORIC STONE BUILDING STATION 4 - AMBIENT OUTSIDE CONDITIONS STATION 5S - WITHIN INTERIOR STEEL MANUFACTURED CABINET IN UNCONDITIONED ROOM STATION 6 - WITHIN STEEL FIXTURE MANUFACTURED CABINET IN UNCONDITIONED ROOM m - STEEL FIXTURE CABINET UNAVAILABLE FOR TEST UNTIL APRIL, 1968. Figure 2 1992 No. 4 HARPERS FERRY PROJECT MONTHLY MAXIMUM/MINIMUM LEVELS RELATIVE HUMIDITY (RH) COMPARISONS 2723/87 | 3/84/67 | 4/e07e7 | 5/ia/e7 | 6715/07 | 7/13/07 | 070/07 | 973767 | 10/1707 | 4/5707 | itvve7 | sea | b/i7e0 DATES | -3724/87 |- 4/20/87 |- 5/18/87 | -6/15/87 |- 7/13/87 | -8/8/87 | -9/3/87 | -10/1/87 | -11/5787 | -12/1/87| -1/5788 | -2/17e8 | -2726/88 100 _——- | 1 90 : - 3 ' 80 t , ® 70 : : . ; | ts 60 [i ] t 1 < 7 Taal lid b]] "8, ri {yar Zz 50 ] r uJ ¢ | | 3 3 2 2 t 3 & 49 ae sstt* tT rf cs 2, 4“ 8>< 1 . : , . 44 d ‘‘ 4 3 q : i233, 12 30 7 20 : 4 4 10 ; 0 TEMPERATURE COMPARISONS DATES 2/23/87 | 3/24/87 | 4/20/87 | 5/18/87 6/13/87 7/13/87 8/8/87 9/3/87 10/1/87 11/3/87 12/1/87 1/3/88 2/1/88 -3/24/67 | -4/280/87 | -5/16/87 | -6/15/87 | -7/13/87 | -8/0/87 -9/3/87 | -10/1/87 | -11/5/87 | -12/1/87 | -1/5/66 -2/1/66 100 ? ? 30 eo? r 2 oltel 1} | +3 | rt re , 133 . *)]1e3]] 4s] ity se 60 ft? j , 1 f if‘ , { rer) || 123 4 4 3 | | | | || r 5% [reat [tes : Hess yyy te "50 I Te tT? tt oo ’ 4 d T ‘ 40 ” 4 , 1 | by 30 ¢ 2 4 3 a : i A 4 4 4 10 4 0 STATION 1 - IN CABINET IN BALLY STRUCTURE STATION 2 - IN UNCONDITIONED BALLY STRUCTURE STATION 3 - IN UNCONDITIONED ROOM WITHIN HISTORIC STRUCTURE STATION 4 -— AMBIENT OUTDOOR CONDITIONS Figure3 1992 No. 4 HARPERS FERRY PROJECT GREATEST 2@4-HR CHANGE N14o9 9.2 RELATIVE HUMIDITY (RH) COMPARISONS F4i gure 2/23/87 | 3/24/87 | 4720/87 | 5/1e/e7 | 6/15/87 | 7/13/87 | 9/8787 | 973787 | 10/1787 | u757e7 | 1271787 | 175788 | e717¢8 DATES -3/24/87 | -4/20/87 | -5/18/87 | -6/15/87 | -7/13/87 | -8/8/87 -9/3/87 | -10/1/87 -11/5/87 | -12/1/87 -1/5/88 -2/1/88 -2/26/88 PRHE RCENTAGE | ,tF J ,J EY | en: | | — | ul | ‘ul ‘ul wal La | ‘ul al Ti ‘ul al al G2C@RH4EA-NAHGTR EE ST 1234 ]}1234)i2es4]12a4}i234]1ea4)i1234]i2s4}i2ea4]iea4 | 1es4}i2ea4] 1234 STATION TEMPERATURE COMPARISONS 2/23/87 | 3/24/87 | 4/20/87 | 5/18/87 | 6715/e7 | 7713787 | @7e7e7 | 973787 | 10/17e7 | 175787 | 12/1787 | 1/5788 | 271788 o > =fm ”~ =3/24/87 |- 4/20/87 | -5/18/87 | -6/15/87 | -7/13/87 | -8/8/87 | -973/87 | -10/1/87 | -11/5787 | -12/1787 | -175/e68 | -e/1/e8 | -2726768 >oowOOs-oo loU WDllCUOD 20 10 D«TFEE>GM RPEEERSA TURE rit L ELLA Ess tL EDEL Es IE Eide east essa test tL Et Ep cot ELL G2C@RH4EA-NAHGTR0E E ST 1234]1234]/1234]/1234]/1234]/1234/1234]1234;1294]1234}1234/1234]1234 STATION STATION 1 - IN CABINET IN BALLY STRUCTURE STATION 2 - IN UNCONDITIONED BALLY STRUCTURE STATION 3 - IN UNCONDITIONED ROOM WITHIN HISTORIC STRUCTURE STATION 4 - AMBIENT OUTDOOR CONDITIONS U HARPERS FERRY PROJECT RELATIVE HUMIDITY (RH) COMPARISONS BETWEEN MUSEUM STORAGE CABINETS AND BALLY STRUCTURE | : MAXIMUM 24-HOUR CHANGE 4720/87 | 3/18/87 _| 6/13/67 _| 7/13/67 | 8/8/87 9/3/87 10/1/87_-| 11/35/67 _| 12/1/87 | 1/5/68 2/1/88 40 m 30 8 <= 20 =z @ 10 t L*E, | *E, pip bp PE, pe, Lica yp PE, pet ed eg Ea, tea | eséelesé6lese6leselese6leseles6lese 6leséelese6lese6lese MCavTHLY MAXIMUM/MINIMUM LEVELS DATES 2/23/67 | 3/24/87 | 4/20/67 | 5/18/67 | 6/15/67 | 7/13/67 | 8/8/67 9/3/67 | 10/1/87 | 11/5/87 | 12/1/67 | 1/5/68 2/1/88 ~3/84/87 | -4/80/87 | -3/18/87 | -6/15/87 | -7/13/87 | -8/6/87 | -9/3/87 | -10/1/87 | -11/5/87 | -12/1/87 | -1/5/88 | -2/1/88 EN S ia— tleo w—}h—+y—1»e —vu2 Uel- —oe or =oj— +—e eUlt e Om OVE STATION 2 - IN UNCONDITIONED BALLY STRUCTURE STATION 5 - WTTHIN A MUSEUM STORAGE CABINET MANUFACTURED BY INTERIOR STEEL EQUIPMENT CORP. IN AN UNCONDITIONED ROOM STATION 6 - WITHIN A MUSEUM STORAGE CABINET MANUFACTURED BY STEEL FIXTURE MFG, CO. IN AN UNCONDITIONED ROOM « - STEEL FIXTURE MANUFACTURED CABINET UNAVAILABLE FOR TEST UNTIL APRIL, 1988 Figure 5 1992 No. 4 EXTERIOR OF FORT , ENTRANCE , a SALLY PORT OFFICE Y SALLY STaucTURE” CO LECTION ROOM HISTORIC CASEMATE a i = gz & | : | PIAZZA ROOF LINE ” PARADE GROUND STATION 1 - IN MUSEUM CABINET WITHIN BALLY STRUCTURE STATION 2 - EXPOSED IN CONDITIONED BALLY STRUCTURE STATION 3 - WITHIN MINIMALLY CONDITIONED HISTORIC CASEMATE STATION 4 - AMBIENT OUTSIDE CONDITIONS AS RECORDED IN PARK WEATHER STATION MICROENVIRONMENT MONITORING TEST FURT PULASKI NATIONAL MONUMENT CONDITIONED BALLY STRUCTURE WITHIN HIS TORIC CASEMATE prawn DD. CUMBERLAND JUNE_1990 1/4" = 3’0’ agi n314 CURATORIAL SERVICES DIVISION , WASO P72O66N1 y FORT PULASKI PROJECT MICROENVIRONMENT TEST DATE CONDITION S**TION 1} STATION 2| STATION 3} STATION 4 63 76 8 4 32: 88/2/1 8/9/2- ES° 45 z— | E 8 8B 8/9/72 /S/E- ¢ ‘“44I 2 5 a2= — | 8 88 8/ /S/2/+ IF S44o ie 9 E- E O S $0 W E 7i ANSONSOSSITWa Vd 88/c|/Bb Br /0|BB/0E/r|- 8 8/7 5 a qa] 463756 2 _ =46 OSI E/¥ /9- 5 =ab N | W 8 NS 88/8/¥ + ie i L ¥/ /L 9 - + —-F Ss | i -| 8 BB/r8/0E/Z i 3 -2 /L 2- 5 | 8 E 88/0EB/Le/ |J e /8 Z- || 8 8/22/68 88/T1/0I- + i -e$3e- 1 = — 88/1/0/62/01 ¢ +0 1 - 3g || 8 88 8 x1 39 // # 6E a 2/ /012I- tea — 86 88 + // E¢ // 2T ve 1- STATION 1 —- IN MUSEUM CABINET WITHIN BALLY STRUCTURE STATION 2 - EXPOSED IN CONDITIONED BALLY STRUCTURE STATION 3 - WITHIN CONDITIONED HISTORIC CASEMATE CONTAINING BALLY STRUCTURE STATION 4 - AMBIENT OUTSIDE CONDITIONS Figure 7 1992 No. 4 FORT PULASKI PROJECT MONTHLY MAXIMUM/MINIMUM LEVELS RELATIVE HUMIDITY (RH) COMPARISONS eves | ev6ves | 375/68 | 472788 | 4730/88 | 674ves | 774/88 | 7730768 | @727/e0| wes | 10/29/68 | 12/3/68 DATES | -2767e8 | -3/57e8 | -47e788 | -4730708| -6/4/88 | -774768 | -7/30/68| -6727/68 | -10/1/88 | -10/29/68| -1273788 | -1/4769 100 - ) : 90 ; —) 80 70 4 5 | Vink uw 60 3 2 . 1 z . z t if t 1 as . E50 TT i 1 T] T7s/l11 ir [fit fyit ¢4ntritfil 11 ie 4 4 } 5 aril a e-4| & 4] @ 23||'21||'a! Oo 40 ; 3 3 td 3 4 ; 4 30 3 34 ~~ ~ 3 4 4 © 20 7 q 10 0 TEMPERATURE COMPARISONS 1/2768 /e8 | 375708 | 472700 | 4730/88 | 6/4/88 | 7/4/68 [7730768 | 8727700] wonves | 10/29/88 | 1273788 DATES | -276788 | -3/57e8 | -4/2/68 | -4/30/08| -6/4/98 | -7/4/88 | -7/30/88| -8/27/768 | -10/1/88 | -10/29/e0| -12737/e8 | -174789 100 j 90 ° 80 70 rhe tee LT \ f 4 l ? ? u 60 an bf tl. UJ 2 1231 “3. f2 lt - o Tiar {iar tie i E , < 4 3 Ww 50 ' az 31 1 40 4 4 4 3 | 4} 3 30 4 4 ‘ 4 20 10 0 STATION 1 - IN CABINET IN BALLY STRUCTURE STATION 2@ - IN CONDITIONED BALLY STRUCTURE STATION 3 - IN MINIMALLY CONDITIONED HISTORIC FORT CASEMATE STATION 4 - AMBIENT OUTDOOR CONDITIONS STATION 2 ANOMALY ,8/27/88-10/1/88, DUE TO HVAC MALFUNCTION - . igure 1992 No. 4