Disaster Planning 101: Collections Specific Salvage

Bradley Wiles, Department Head, Special Collections and Archives, Northern Illinois University
Bonnie Parr, Historical Documents Conservator, Abraham Lincoln Presidential Library and Museum

Outside of normal wear and tear through regular usage, water damage is probably the most common preservation and conservation issue facing library materials. It is especially problematic for rare, valuable, and irreplaceable special collections and archives, which tend to reside in closed spaces where leaks, spills, and excessive humidity can go unnoticed and untreated for long periods of time. What's most troubling is that water damage usually is not related to natural disasters or human error, but rather the inherent problems with plumbing, drainage, and climate control systems that can fail unexpectedly, often in combination with inadequate or aging storage facilities. I've witnessed firsthand numerous instances of this in the course of my career: collections stored on bottom floors that sit below sea level; heavy A/C units placed on rooftops that cause unnatural bends on the surface; stormwater flowing through an elevator shaft that shorts out the electrical system and pools in hidden corners. At my current place of employment, thousands of dollars have been spent in the last few years to remediate rare books and replace shelving due to a condensation leak of mysterious origin.

In other words, water damage can happen any time and it can be catastrophic--a reality only aggravated by rapid climate change. Given the likelihood of water-based event--as well as the difficulty in predicting them--the best policy is to have an effective response plan to mitigate the damage. But that can be tricky because different materials require different mitigation methods when a water event strikes, and this may not be immediately clear to those responding.

To this end, Bonnie Parr, Historical Documents Conservator at the Abraham Lincoln Presidential Library and Museum, has created a resource that offers clear instruction on salvaging wet materials based on the type of object--whether books, documents, artifacts, and other collections affected by water damage. The initial triage and treatment are crucial to save what is salvageable, but it also helps address any lingering effects of water events like mold, infestation, and structural damage.

GUIDELINES FOR SALVAGING WET MATERIALS

The following guidelines are based on instructions taken from the Disaster Preparedness and Emergency Response Plan of the Abraham Lincoln Presidential Library and Museum.

General Guidelines

Inspect the collection as soon as it is safe to enter the building and before any salvage is attempted. Document the damage with photos, written documentation, and video.

Keep the following in mind when creating a salvage plan:

• Safety of staff
• Size and scope of damage
• Type of materials affected
• How much time has passed
• Supplies and personnel available
• Available workspace

Items to be aware of with any salvage plan:

Health and safety implications

• Be aware of potential health and safety issues (e.g., contact with potentially contaminated materials, if personnel have cuts or scratches)
• Know how to protect personnel from these dangers – don’t enter disaster area until cleared by first responders, use personal protective equipment (gloves, goggles, respirators)
• Consider source of water (clean, sewage, from flooding)
• Consider type of materials to be salvaged – made heavier and less stable from water absorption, hazardous materials in collection or in contact with hazardous materials

48 Hours

• Mold growth can occur in 48 hours, sometimes in less time with conditions of high humidity and heat
• Maximum time most, but not all, items remain reasonably stable when wet
• Important to keep immersion time at a minimum – more chance of a successful recovery

Stabilize the environment

• Lower the humidity
• Lower the temperature
• Provide air circulation – fans, but direct air away from items, so they don’t blow away

Weight / dimensional change

• Made heavier from water absorbed
• Susceptible to dimension changes when wet – easily torn, stretched, or broken apart

Fragility of support and media

• Water makes items more fragile by changing chemistry of components (like dissolving adhesive)
• Structure of items affected by expansion when wet
• Always be careful when handling wet items
• Provide support whenever possible

Drying Options

Air drying

• Small quantities of items to dry
• Best for damp or slightly wet items (water damage confined to edges)
• Effective for most types of collection materials
• Requires:  supplies, space, people
• Labor intensive
• Damaged collections still accessible – usually done in-house

Freezing

• Moderate to large quantities of wet items to dry
• Buys time when there is a delay in organizing salvage resources
• Prevents (but doesn’t kill) mold
• Allows control in how much to dry at a time
• Requires: access to freezer space, packing/interleaving supplies
• Materials not accessible until they’re thawed and dried

Freeze drying/vacuum freeze drying

• Most efficient method for drying large quantities of material
• Requires: prior arrangement with vendor, arrangement for transport of collection to vendor, packing/interleaving supplies
• Cost for service offset by savings in staff time and resources to salvage, less need for follow-up conservation treatment after drying
• No access to collections until treatment finished

    
Choice of drying method depends on:

• Degree of water damage (damp, slightly wet around edges, wet/submerged)
• Format of material to be dried    
• Quantity of items to dry    
• Resources available (staff, supplies, space, time)

Drying Procedures by Item Type

BOOKS

Can be air dried, frozen-thawed-air dried, freeze dried, or vacuum freeze dried

Priority for salvage:

• Coated pages before uncoated pages
• Leather/vellum before cloth/paper covers

Tips:

• Be aware that wet books are heavier and can easily fall apart
• Wet books and books with coated paper are best frozen or sent to freeze drying/vacuum freeze drying facility
• Leather and vellum are vulnerable to distortion and disintegration in water and are susceptible to mold – freeze ASAP

How to prepare for drying:

• Remove book jackets and plastic covers to speed drying and prevent mold growth on the covers
• Generally, cleaning off dirt, mold, etc. after drying is easier, but if it must be cleaned, hold tightly closed, dip in water, gently squeeze excess water, let drain, place on absorbent material, wrap to freeze, or interleave to air dry
• To pack for freezing:  use wax paper or freezer paper to wrap around outside of covers, pack spine down in box, one layer of books

How to air dry:

• For damp books: stand/support upright on the drier of the top or bottom edges on absorbent material, fan pages, turn book over every 2-3 hours
• For slightly wet (around the edges) books: place blotting paper inside covers (prevents color transfer); interleave every 50 pages or so with absorbent material, starting in back; interleave no more than a third of the book thickness, otherwise will stress binding; interleaving material should be larger than pages; stand book on edge; change absorbent material as it becomes wet; turn over book at intervals
• Oversize, heavy, too wet to stand on edge: lay flat on absorbent materials, interleave as above
• Damp or slightly wet books with coated paper: must interleave every page
• Always check for mold growth during drying process
• When dry but still cool to the touch: lay book flat, gently reshape, and put under a light weight to prevent warping

DOCUMENTS

Can be air dried, frozen-thawed-air dried, freeze dried or vacuum freeze dried

Priority for salvage:

• Coated paper before uncoated
• Water soluble inks before more stable printed documents
• Parchment/vellum manuscripts

Tips:

• Paper easily tears when wet – use caution when handling and always provide support
• Watch for blurry inks – they are unstable or “bleeding” – freezing is best to halt solubility
• Don’t allow coated papers to dry in a clump – keep wet until treatment (air dry or freeze, best recovery if vacuum freeze dried)

How to prepare for drying:

• Remove from enclosures (especially enclosures in color), encapsulations, mats, or frames
• To pack for freezing:  use wax or freezer paper to cover/interleave intact manuscript boxes or stacks of folders or documents (limit stacks to 2 inches thick); sandwich parchment/vellum manuscripts between folders lined with freezer paper        

How to air dry:

• Lay flat on absorbent surface, change absorbent material when wet, turn over documents at intervals
• For items with water soluble media:  dry face up, don’t blot
• For items with coated (glossy) paper:  important to separate sheets, if possible – press sheet of polyester film on top of stack, peel off with first sheet attached, dry document on polyester film or sandwich between 2 sheets of spun-bonded polyester material (like Hollytex, Pellon, or Remay)
• Alternative air drying (for documents in good condition):  hang on a line to dry vertically, using plastic clothespins and, if needed, sandwiching document between 2 sheets of polyester material for extra support
• Expect papers will be distorted after drying, unless dried under weight
• Expect dried papers will take more storage space

PHOTOGRAPHIC MATERIALS

Can be air dried, some can be frozen-thawed-air-dried

Priority for salvage:

• Color before black and white
• Cased or mounted photographs and glass plates before paper or film
• Prints before negatives
• Acetate and nitrate film before polyester-based film

Tips:

• Don’t touch emulsion (image side) – hold by edges
• Cased photographs and glass plates should never be frozen     

How to prepare for drying:

• Remove items from enclosures including mats and frames, if possible – watch for sticking of emulsion onto enclosure material
• For framed items:  lay glass side down, remove backing materials, take item and glass out of frame, carefully remove item from glass; if sticking, leave on glass and air dry glass side down
• Keep stacks of photos wet in a container of clean water until they can be separated; air dry or freeze within 48 hours
• If no time to separate photos – freeze
• Do not freeze cased photographs or tintypes        

How to air dry:

• Air dry on absorbent material, emulsion (image) side up; also applicable for cased photographs (open case but don’t disassemble), tintypes, and glass plates
• Alternative for film/prints in good condition:  hang on a line to dry vertically, use plastic clothespins on edges only (not over image)
• Photo albums:  lay flat on absorbent material, interleave pages with polyester material covering absorbent material (to prevent items from sticking to each other), change at intervals

FILM (microfilm, movie film, negative strips and sheets)

Can be air dried, frozen-thawed-air-dried, some can be freeze dried

Priority for salvage:

• Acetate and nitrate film before polyester-based film
• Color before black and white

Tips:        

• Avoid touching emulsion (image side) – handle by edges
• If can’t air dry within 48 hours – freeze negative sheets/strips or keep film on reels wet until can get reprocessed
• Best to send reels wet to reprocesser for washing and drying

How to prepare for drying:

• Remove items from envelopes or sleeves, if possible – save enclosures for ID purposes
• Wipe cans/boxes before opening – contents may be dry, even though enclosures are wet
• Don’t unwind or remove film from reel
• For wet slides, if large quantity: remove from mounts to dry film chip

How to air dry:

• Prefer to dry sheets/strips vertically on a line
• Use plastic clothespins on margins, avoid pinning image
• Alternatively, lay sheets/strips flat on absorbent material, emulsion side up
• Prop reels vertically to dry – don’t weight or press flanges against film

CDs, DVDs

Can be air dried

Priority for salvage:

• Unmastered originals before masters
• Masters before reference copies
• Older before newer

Tips:

• Avoid scratching the surface of disks – always handle by outer edges
• Keep away from heat
• Never freeze

How to prepare for drying:

• Remove from enclosures – keep labels, enclosures for ID purposes
• If need to clean:  wipe from center outward in straight line (not circular) with dampened lintless cloth

How to air dry:

• Prefer to dry vertically on racks
• Alternatively, lay flat on absorbent material, label side down
• After dried:  make a copy

MAGNETIC MEDIA (cassette tapes, videotapes, reel-to-reel tapes)

Can be air dried

Priority for salvage:

• Unmastered originals before masters
• Masters before reference copies
• Older before newer
• Acetate before polyester-based tapes

Tips:

• Don’t touch tape – wet tape is easily stretched, handle by reel or cassette
• Keep away from heat
• Never freeze – tapes will stretch, lubricants in tape will migrate out

How to prepare for drying:

• Remove from boxes/cases, keep enclosures for ID purposes
• Don’t unwind or remove tape from reel
• To clean (if needed, but not always necessary):  pour distilled water over tape or cassette

How to air dry:

• Empty excess water from cassettes
• Prefer to dry vertically – with empty hub on bottom or reel supported on edge, so water can drain out
• Alternatively, lay flat to dry on blotting paper
• After dried:  make a copy or have duplicated onto newer format

PAINTINGS

Can be air dried

Priority for salvage:

• Most highly valued
• Least or slightly damaged before severely damaged

Tips:

• When using a cart to transport framed items, place cardboard between each frame
• When carrying paintings, move one at a time; hold the face side toward the body and use both palms to hold the sides of the frame/painting; avoid pressing any fingers into the painting surface or back
• Use multiple people to move large paintings

How to prepare for drying:

• If paintings are framed and time permits, remove paintings from their frames, but not from their stretchers  
• If paintings are framed and have glass or acrylic glazing, unframe immediately – start from the back by removing hardware and backing material first, then taking the painting and glazing together as a “package” out of the frame; carefully remove the painting from the glazing, watching for any paint sticking on the glazing
• If water is underneath the glazing, slide the glazing off in the direction where most of the water has collected to minimize moving moisture over other areas of the painting

How to air dry:

• Paintings should be laid flat, face (painted surface) up, to dry
• They should not be towel dried
• Don’t place anything across the front or rub the front of the paintings

TEXTILES

Can be air dried or frozen

Priority for salvage:

• Most highly valued
• Textiles with bleeding dyes

Tips:

• Wet textiles weigh more and can tear with careless handling; always provide support when moving
• Do not attempt to unfold delicate fabrics

How to prepare for drying:

• Separate textiles (if possible)
• If muddy, briefly rinse with clean water
• Gently press out excess water; avoid squeezing or wringing textiles and other soft materials
• If the textile is stable, bag for freezing if they cannot be air dried within 48 hours – pack flat, separated with freezer paper (if needed to prevent transfer of dyes)

How to air dry:

• Lay flat on drying surfaces covered with absorbent material
• When the textile is partially dry, shape and/or pad it to its approximate shape
• Synthetic batting or netting can be used to shape textiles to support them in the correct position while they dry

THREE-DIMENSIONAL OBJECTS

Can be air-dried

General tips:

• Start by surveying objects and identifying material types
• Watch for personal hazards (sharp edges, hazardous materials) while also looking out for potential problems (e.g., if there are objects that have collected water, empty these; if dyes on textiles are clearly running onto other objects, separate these)
• The immediate and long-term goal is to remove moisture by getting the moisture out of the objects, removing moisture from the room, and, if necessary, moving the objects to a drier environment
• Dry the object surface, if the object allows:  always “pat” with a towel or soft cloth, never rub; use soft sponges, old towels, or paper towels; all of this material needs to be changed during the drying process at least once a day, but quite possibly more
• Raise large objects off the floor to allow air to circulate underneath the items
• To remove moisture from the room:  run dehumidifiers, set HVAC systems to remove humidity and lower temperature; if fans are set up, direct them so they are not aimed toward the objects
• Generally, objects must be air dried slowly and naturally; avoid quick-drying methods/solutions
• Always make sure that provenance information is kept intact and with the objects throughout the drying process

FURNITURE

Can be air dried

Priority for salvage:

• Most highly valued
• Metal before wood
• Wood before other materials

Tips: 

• Begin drying within 48 hours

How to prepare for drying:

• Leave dirt in place; remove after drying
• Leave drawers in place after removing contents
• Remove cushions and other removeable pieces, to dry separately    
• Blot excess water with soft cloths, sponges, or paper towels
• Avoid wiping painted surfaces, especially if they are blistered or flaking; allow to air dry as is

How to air dry:

• Dry wood furniture slowly
• Hold veneers in place with padded weight or clamps
• Wrap cushions and other upholstery pieces in cloth (sheets or towels) to air dry; replace cloths as they become damp
• Varnished surfaces may become hazy; after drying, send to a furniture conservator for treatment

METALS

Can be air dried

Priority for salvage:

• Because metal will quickly corrode if it is wet, it has high priority for salvage

Tips:

• Separate from other materials to prevent staining from corrosion
• Coated metals are susceptible to damage from standing water (can penetrate cracks in the coating and cause corrosion under the coating)

How to prepare for drying:

• If muddy, rinse with clean water
• Use soft towels or absorbent paper to blot dry, as soon as possible

How to air dry:

• Air dry as soon as possible
• Keep flaking surfaces horizontal as objects air dry

INORGANIC MATERIALS (ceramics, glass, glazed ceramics, stone)

Can be air dried

Priority for salvage:

• Porous materials before solid materials
• Glazed ceramics before unglazed
• Objects with an applied finish

Tips:

• Always provide proper support when lifting vessels; lift around the body of the object rather than the handles, rims, or spouts
• The most serious threats to ceramic or glass objects are scratching and breakage
• If a vessel has been reconstructed, the joins will be very compromised; take care when lifting, as it will be very unstable
• Items that can hold water make them more of a priority to salvage, because they will raise the relative humidity in the room

How to prepare for drying:

• If objects are muddy, rinse them quickly in clean, cool water
• Blot objects dry – do not rub
• If an object has a rough surface or an applied finish, do not blot

How to air dry:

• Air dry on a plastic screen or a clean towel; change towels frequently as they become damp

ORGANIC MATERIALS (bone, horn, ivory, leather, shell, wood)

Can be air dried

Priority for salvage:

• Composite objects before single-material type objects
• Painted objects before unpainted

Tips:

• Watch out for bleeding dyes from painted surfaces – separate such items to avoid transfer of the dye to other artifacts
• Organic materials will be very fragile when wet; handle carefully

How to prepare for drying:

• Surface dry (blot, don’t rub) with sponges or towels
• If objects are muddy, rinse them quickly in clean water or wipe with a damp cloth; blot with a soft cloth to remove excess water

How to air dry:

• Set out to dry on towels or other absorbent material; change out absorbent material frequently  
• Bone, ivory, and shell artifacts need to dry slowly; closely monitor them during the drying process; if necessary, place them under a polyethylene sheet to slow drying
• Synthetic batting or netting can be used to pad and shape leather items to support them in the correct position while they dry

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