1、23.1CHAPTER 23MUSEUMS, GALLERIES, ARCHIVES, AND LIBRARIESENVIRONMENTAL EFFECTS ON COLLECTIONS . 23.2Determining Performance Targets . 23.2Airborne Pollutants. 23.5DESIGN PARAMETERS. 23.12Performance Target Specifications. 23.12System Selection and Design. 23.16NDERSTANDING and appreciating humanitys
2、 diverse cul-Utures and history dictates preserving objects including booksand documents, works of art, historical artifacts, specimens ofnational history, examples of popular culture, once-common tradegoods, technological accomplishments, the products of various tech-nologies, as well as historic b
3、uildings and sites. Museums, galleries,libraries, and archives may be purpose-built buildings or existingbuildings of historic significance; in some instances, the building isas (or more) important as the collection it houses. The importance ofcultural heritage ranges from national to regional or ev
4、en local, butall have symbolic, aesthetic, cultural, social, historical, and mone-tary values that are frequently impossible to estimate. Thus, theirpreservation is important, worthwhile, and may even be legally man-dated. The loss of any one of these artifacts is a loss to all individuals.Collectio
5、ns are vulnerable to many threats. Because they must bepreserved indefinitely, the steps taken to protect them are sometimesextraordinary. Most threats can be addressed by properly maintainedhousing and professional support. The level of acceptable risk is acompromise between the theoretically ideal
6、 environment and thepractical. It is possible to slow deterioration drastically, but doingso may conflict with the ultimate functions of museums, libraries,and archives: not only to preserve, but also to allow public and schol-arly access. Additionally, extremely high control over all environ-mental
7、 parameters can help to ensure an objects survival, but at aprice no cultural institution can justify or is willing to pay. Managingrisk, not avoiding it altogether, is the objective.This chapter addresses threats to collections that are mitigated bya properly designed HVAC system that provides stab
8、ility for low-access storage environments and also serves high-traffic visitorsareas.Theoretically, many systems (including passive building solu-tions) can successfully provide appropriate environmental control, ifproperly applied. From project inception, both the design objectiveand realistically
9、available operation and maintenance resources mustbe considered.Communication with the client is especially critical when design-ing systems for museums, galleries, archives, and libraries because ofthe uniqueness of the criteria: the inherent risk associated with envi-ronmental conditions. The desi
10、gn team must include not only mu-seum administrators but also collections managers, curators,conservators, and security. Administrators are responsible for fiscaldecisions, whereas the collection managers are responsible for careof the collection. Curators build the collection and design exhibitions
11、.Conservators are charged with preservation of the collection. Secu-rity staff is critical to safekeeping of the collection. Many HVAC sys-tem design decisions are based on the needs of the collection and theuse of the various spaces. To design the most appropriate system, allrelevant parties must b
12、e part of the process. This chapter can only ex-plain why temperature, humidity, light, and indoor air quality (IAQ)requirements are important; the team must decide the exact specifi-cations. To the conservator: Climate-induced risks should be seen incontext and relation to other risks to the preser
13、vation of cultural her-itage, such as natural and human-caused disasters. In some cases, itmay not be the greatest risk to a collection, and available funds maybe spent more effectively elsewhere. A climate-control strategyshould complement mitigation strategies for other risks and shouldnot in itse
14、lf create a greater hazard (e.g., when an energy supplyfails).This chapter focuses on relative humidity, temperature, and airpollution design for HVAC systems, and describes various systemsthat are applicable for these spaces. The goal is to illustrate specialneeds of collection spaces in museums, g
15、alleries, archives, andlibraries. See the References and Bibliography for additionalresources.Note that this chapter does not apply to libraries designed for pub-lic access, with collections that are not intended for archival preser-vation. These facilities may include collections designed for gener
16、alpublic use or school-aged children, and may have significant quan-tities of electronic documents in disk format or tape. The types ofcontrols (humidity, thermal, or particulate and molecular phase fil-tration) required for collections of archival preservation are not prac-tical for these facilitie
17、s (see Chapter 3 for additional information).In nonarchival libraries, there may be no HVAC system, or theHVAC systems may be designed specifically for human comfortduring occupied hours. In this application, the HVAC systems mayshut off during unoccupied or low-occupancy times for energy sav-ings.T
18、his chapter may not apply and should be bypassed if one or moreof the following conditions exist with the scope of design for alibrary (see Chapter 3 for additional information):HVAC system is cycled off during unoccupied periodsHVAC system is turned off seasonallyHVAC system is designed to cycle on
19、/off with thermal satisfactionaloneNatural ventilation is the only method of air circulationGeneral Factors Influencing DamageIn designing HVAC systems for collections, a good working re-lationship among the mechanical engineer, architect, interior de-signer, and owner/operator, especially client pe
20、rsonnel responsiblefor preserving the collection, is critical. All expectations and limita-tions must be defined at the beginning of the design.Artifacts and collections can be made of one main material (e.g.,an archive of antique books), which simplifies target specifications,or combinations of mat
21、erials with different levels of instability (e.g.,The preparation of this chapter is assigned to TC 9.8, Large Building Air-Conditioning Applications.23.2 2015 ASHRAE HandbookHVAC Applicationsa multimedia library that includes books, film, and paintings); in thelatter case, target conditions are usu
22、ally a compromise, or speciallocalized environments may be required for some parts of a collec-tion. For more details, see Michalski (1996a).The buildings architecture and mechanical systems mustaddress eight types of threats to collections; mechanical engineersneed to appreciate and respect these c
23、oncerns even if they do notappear to relate directly to a buildings mechanical systems.Respecting all the risks gives the client an increased comfort zonefor threats the HVAC system is designed specifically to control. Thefollowing threats, in decreasing order of seriousness, affect all typesof coll
24、ections.Light damage presents perhaps the most extensive threat tomuseum collections. Most materials undergo some form of undesir-able, permanent photochemical or photophysical change from over-exposure to light. Damage is relatively easy to control if the problemis addressed at the architectural, d
25、esign, and operational levels byeliminating ultraviolet light, minimizing infrared radiation, limitingillumination intensity, and restricting total illumination duration.Relative humidity also presents a risk. For each material, thereis a level of environmental moisture content (EMC) consistent with
26、maximum chemical, physical, or biological stability. When the EMCis significantly too low or too high, the associated relative humiditybecomes a risk factor. Recent literature often calls humidity-relateddamage “incorrect relative humidity” to emphasize the concept ofranges of acceptable moisture co
27、ntent rather than absolute limits.Unstable relative humidity with large variation in levels can also bedamaging to certain types of objects.Temperature ranges for materials should also be controlled.Some polymers become brittle and are more easily fractured whenthe temperature is too low. At tempera
28、tures that are too high, dam-aging chemical processes accelerate. Thermal energy not only accel-erates aging, but also can magnify the effects of incorrect relativehumidity. Therefore, incorrect relative humidity and temperature areoften taken together when deciding ideal parameters for importantcla
29、sses of materials such as for paper and photography. Any temper-ature change also changes the relative humidity. Therefore, carefuland close control of relative humidity requires temperature control inthe same magnitude of importance. Air pollution (or contami-nants) includes outdoor-generated gaseo
30、us and particulate con-taminants that infiltrate the building and indoor-generated gaseouspollutants. Even very low levels of pollutants can adversely affectthe condition of collections. Particulate filtration to control bothcoarse and fine particles and gaseous filtration are discussed in theSystem
31、 Selection and Design section.Pest infestation primarily includes insects consuming collec-tions for food; mold, fungi, and bacteria also qualify as pests, butthey can be limited by controlling relative humidity, temperature,indoor air quality, and ventilation.Shock and vibration can cause long-term
32、 damage to sensitiveobjects. Vibration can be transmitted to objects by service vehiclesduring packing and shipping. Usually, HVAC design only needs toconsider this risk if vibration is transmitted through ductwork toworks hung on adjacent walls or in particularly active air drafts.Additionally, exc
33、ess vibration could potentially lead to objectsvibrating off of exhibit and/or storage shelves.Natural emergencies are, fortunately, rare, and most institutionshave (or should have) emergency response policies.Building and mechanical design malfunctions are usuallyavoidable emergencies and include w
34、ater pipe failure, especiallyover collections and storage facilities. The infrequency of these fail-ures leads many to forget that just one failure, however rare, couldruin a significant portion of a collection. Every effort should bemade to route water lines and other utilities away from areas that
35、house irreplaceable objects. Building systems also rely on the infra-structure to provide utilities and communications. Where the infra-structure is not reliable or of adequate capacity, provisions should bemade for temporary or alternative supply.Theft and vandalism can be addressed by limiting acc
36、ess tomechanical systems to improve security.This chapter focuses on relative humidity, temperature, and airpollutant control design for HVAC systems. Many excellent bookstreat the subject of environmental management in museums andlibraries extensively; consult the References and Bibliography forinf
37、ormation not contained in this chapter.1.ENVIRONMENTAL EFFECTS ON COLLECTIONS1.1 DETERMINING PERFORMANCE TARGETSMuseums, archives, and libraries have two categories of indoorair requirements: general health and safety, comfort, and economyof operation as listed in ASHRAE Standards 55 and 62.1; and t
38、hecollections requirements, which are not yet completely understood,and often conflict across material collection types. The risk of com-promising on relative humidity and temperature specifications mustbe assessed. The following sections summarize current informationon these issues.In terms of heal
39、th and safety and the collections requirements,building spaces can be categorized as shown in Table 1: (1) collec-tion versus noncollection, (2) public versus nonpublic, and(3) “dirty” versus “clean.” These subdivisions distinguish betweenareas that have very different thermal and indoor air quality
40、 require-ments, outdoor ventilation rates, air supply strategies, etc. Theseareas often require separate HVAC systems. See Chapters 16, 31,and 32 for more information on dirty rooms. Noncollection rooms(rooms that do not contain collections) are not considered in thisTable 1 Classification of Rooms
41、for Museums and LibrariesHigh Internal Source of Contaminants (Dirty) Low Internal Source of Contaminants (Clean)Collection Non-public access Conservation laboratories, museum workshops (VOCs, fumes, dusts)“Wet” collections (alcohol or formaldehyde evaporation from poorly sealed jars in natural hist
42、ory collections)Photographic collections (“vinegar syndrome” produces acetic acid vapors)Quarantine areas (potentially pest-infested objectsMost storage areas, vaults, library stacks Public access Displays of conservation work in progress (unusual and temporary)Galleries, exhibition spaces, reading
43、roomsNoncollection Non-public access Smoking offices (unusual) Offices (nonsmoking)Public access Cafeterias, rest rooms, spaces where smoking permittedPublic spaces without food preparation or smokingSome public and school library stacks and reading roomsMuseums, Galleries, Archives, and Libraries 2
44、3.3chapter because their HVAC requirements are similar to those inother public buildings, as discussed in Chapter 3.The following sections provide a framework for developingappropriate climate and indoor air quality (IAQ) parameters fordifferent types of museums, libraries, and archives. A single ta
45、rgetis a compromise among large numbers of different, often contradic-tory requirements. However, many collections are uniform enoughto allow useful generalizations to be made about their HVACrequirements. In this chapter, the term “effective” includes institu-tional value judgments as well as the s
46、cience of deterioration(Michalski 1996b).Temperature and HumidityCurrent Standards. The classic reference for conservation pro-fessionals is Thomsons (1994) The Museum Environment. Setpoints of 50% rh and 68F were listed as an example for temperateclimates and unfortunately taken as ideal (in the Un
47、ited States, 68Fwas frequently rounded up to 70F). Misuse is a danger associatedwith listing standards or settings: numbers in a table can beextracted or used without understanding the associated text. This iswhy the parameters in this chapter are presented for different clas-sifications of collecti
48、ons or building types. Environmental settingsshould be determined for collection types and must consider the cli-mate zone where building is located. The history of various objectsin the collection, as well as needs of especially vulnerable individualobjects, may also influence design. Housing for p
49、hotographic col-lections in a coastal, temperate climate may have different controlneeds than wooden furniture or porcelain in equatorial regions. Thedesign engineer cannot be expected to know the needs of the collec-tion, but can consult the other members of the team, especially theconservators, collection managers, and curators. Ideal set points area compromise between comfort for museum visitors and staff andthe appropriate preservation minimum temperature and relativehumidity for the collection.Davis (2006) reports that decreasing temperature from 70 to65F and relative humi
