Collection Storage: Guidelines by Material Type

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Lisa Elkin, American Museum of Natural History, New York, NY
Robert Waller, Protect Heritage Corp. and Canadian Museum of Nature, Ottawa, Queen’s University, Kingston, Ontario


Approaches to risk mitigation across all aspects of collection storage design and operation have been presented throughout this volume. Of course, not all guidelines will apply to all material types—they may not be practicable, or the resources for achieving them may not be available. It is also understood that various materials, structures, or formats respond differently and collections are often stored as “mixed media.” Educated decisions need to be made that weigh risks accordingly.

Storage at a Glance (SAG) segments provide capsule descriptions of broad material types and illustrate how these different material types vary in susceptibility to hazards. By recognizing and characterizing this variability (in susceptibility across hazards and within collections) priorities for risk management can begin to be appreciated from a broad perspective. Far from the last word, these SAGs are intended to be a first word in appreciating these variabilities.

The Vulnerability Fingerprint

A risk-informed approach involves learning how to transform uncertainty into understood variability. One of the key uncertainties is: will all parts of a collection be equally vulnerable to a hazard? Each of the collection/material types considered is subdivided into a more precisely defined material, structure, or format subset. The relative vulnerability of these subsets to hazards is depicted as a “vulnerability fingerprint.”

Of course, it’s impossible to include everything. If a portion (less than 10% of a typical collection) fits within a listed subset then that material, structure, or format may not appear as a subset and may only receive a mention in the text. In some cases, because of collection complexity and limited space, even a text mention is not possible. These SAG sections are meant to be broadly indicative rather than comprehensive in detail.

Simply identifying issues considered to be important cannot set priorities. Setting priorities requires an understanding of what is least important as well as what is most important. The vulnerability fingerprints are intended to give collection care professionals a snapshot appreciation of which parts of a collection are expected to be most, and least, vulnerable to each hazard. The color of a fingerprint entry is determined by the highest vulnerability within that category, so details of less vulnerable components within categories will not be reflected.

As was demonstrated and discussed in the chapter on risk management, responsible, comprehensive risk analysis requires significant effort and care in identification and definition of risks to collections. These simple vulnerability tables are in no way intended to replace that effort and care. Rather, they are intended to guide attention to preservation issues in a most general sense and to reinforce the understanding that vulnerability to hazards can vary greatly through most collections. As always, readers are encouraged to evaluate this information critically and in the context of their own situation.

Hazards and Effects

The Vulnerability Fingerprint summarizes and visually presents the more detailed information found in the Hazards and Effects section of each SAG. Potential hazards are broken down into 10 groupings based on 10 agents of change:

  1. Adverse Relative Humidity
  2. Adverse Temperature
  3. Criminals
  4. Dissociation
  5. Fire
  6. Light
  7. Pests
  8. Physical forces
  9. Pollutants
  10. Water

Where most relevant, these hazard groupings may be further broken down to represent various types of risks, such as those that may occur with low intensity but are ongoing versus those that have a more significant impact but occur sporadically or rarely. For example, when considering relative humidity for some organic materials, possible risks from ongoing higher than optimal relative humidity will be presented as distinct from risks resulting from brief excursions to high relative humidity. Table 1 presents parameters concerning the nature of the hazards that could impact collection items. Note that conditions known as inherent vice, such as radioactive decay or exuding of phases from mixtures within collection items, are not hazards to collections that can be mitigated through collection storage and, therefore, are not considered here. The vulnerability level of a collection subset to a hazard is defi ned as either low vulnerability, low vulnerability given moderate care, moderate vulnerability, or high vulnerability, and the levels are coded using colors depicted in table 2.

What do we mean by Moderate Care?

Moderate care implies that basic requirements for collection stewardship are met. For example, some materials may have high inherent vulnerability to UV radiation, but collections that are provided protection from exposure (i.e., stored indoors, inside cabinets, in the dark) would be considered “low vulnerability given moderate care.” In other words, generally accepted minimum precautions are met to avoid damaging exposures. Several resources provide preservation relevant performance areas or benchmarks that can help guide in determining how best to define moderate care (Collections Trust, 2018). In addition, the summary list that follows provides some direction.

Adverse relative humidity: Moderate care implies

Adverse temperature: Moderate care implies

  • avoiding higher than necessary temperature control set point
  • providing cool or cold storage for materials subject to rapid thermal degradation (see Low Temperature Storage)
  • avoiding storage against cool or cold floors and walls, or near heat sources

Criminals: Moderate care implies

  • maintaining effective security perimeters around collections
  • installing and maintaining security systems, as appropriate
  • avoiding unsupervised general access
  • conducting audits (see Security for details of these basic as well as more advanced measures)

Dissociation: Moderate care implies

  • maintaining relationships (through physical and inventory controls)
  • maintaining secure catalogs and transaction records, with offsite backups
  • clearly labeling items, including all disarticulated parts and/or their containers, shelves and cabinets using archival materials (see Labeling and Labeling Natural History Collections)

Fire: Moderate care implies

  • installing and maintaining automatic fire alarm and suppression systems
  • maintaining a good fire-prevention program
  • developing, practicing, and updating an emergency response plan and related staff training in emergency salvage
  • and response (see Fire Protection, Emergency Management and Disaster Planning for details of these basic as well as more advanced measures)

Light: Moderate care implies

  • avoiding all unnecessary exposure, including
  • avoiding windows in storage
  • using cabinets where possible
  • switching off lights when storage areas are unoccupied
  • using only low UV or UV-filtered lights (see Lighting for details of these basic as well as more advanced measures)

Pests: Moderate care implies

  • developing and maintaining an Integrated Pest Management Program, including regular cleaning and monitoring of collection storage space
  • excluding food items from collection storage areas
  • keeping vulnerable materials stored inside cabinets or pest resistant enclosures
  • raising cabinets and shelves at least 10 cm (4 in.) above the floor to allow for access for cleaning
  • sealing buildings and rooms as well as possible against pest entry (see Integrated Pest Management for details of these basic as well as more advanced measures)

Physical forces: Moderate care implies

  • ensuring seismic stability of building and storage hardware
  • not exceeding load-bearing capacity of floors, shelving, and cabinetry
  • providing adequate support for items while facilitating safe access
  • handling items carefully and only by unhurried, trained personnel with appropriate equipment
  • protecting highly susceptible items from routine or excessive handling while in storage (Rehousing for details of these basic as well as more advanced item-level precautions)

Pollutants: Moderate care implies

  • employing protective collection item enclosures made from nonreactive materials where appropriate (see Rehousing)
  • avoiding close association of interacting collection materials such as wool and silver, mercury and gold, etc.
  • ensuring filtration is adequate for the collection, where an HVAC system is in place (see Air Quality)

Water: Moderate care implies

  • avoiding locating collections below plumbing (excepting fire suppression systems) or within areas known to be vulnerable to water incursions
  • providing an additional level of protection with water-proof or -resistant cabinets or enclosures
  • raising cabinets and shelves at least 10 cm (4 in.) above the floor
  • ensuring floor drains are present and maintained
  • installing and monitoring water alarms where necessary
  • developing, practicing, and updating an emergency response plan and related staff training in emergency salvage and response


Each Storage at a Glance segment concludes with specific recommendations; added if the author feels an important concept is not covered and needs to be. Also, a short bibliography recommends publications providing more detailed information.


Collections Trust. 2018. Benchmarks in Collections Care 2.1, Accessed July 9, 2018.

Michalski, S. 2009. Agents of Deterioration: Incorrect Relative Humidity, Accessed July 7, 2018.

List of Materials

  • Bone, Antler, Ivory, Teeth - Christopher A. Norris and Robert Waller
  • Books - Alice Cannon, Jean Holland, and Belinda Gourley
  • Ceramics - Victoria Oakley and Fi Jordan
  • Chitin - Suzanne Ryder
  • Electronic Media - Sarah Stauderman
  • Film and Film Negatives - Andrew Robb
  • Fossils - Matthew Brown
  • Glass - Stephen Koob
  • Keratin - Julia Sybalsky and Lisa Elkin
  • Metals - Ian D. MacLeod and Shelley Sturman
  • Minerals, Gems, and Meteorites - Robert Waller
  • Paintings: Traditional - Sarah Spafford-Ricci and Emily Min
  • Paintings: Nontraditional - Sarah Spafford-Ricci and Emily Min
  • Paper - Alice Cannon, Elizabeth Melzer, and Belinda Gourley
  • Photographs: Positive Prints and Plates - Paul Messier
  • Plant Material - Victoria Purewal
  • Plastics - Mary Coughlin
  • Shells and Corals - Paul Callomon
  • Skin, Leather, and Parchment - Catharine A. Hawks and Robert Waller
  • Textiles - Patricia Ewer
  • Wood - Emily Williams