Waters/Procedures for Salvage of Water Damaged Library Materials/July 1993

The Library of Congress

"Procedures for Salvage of Water Damaged Library Materials"
extracts from unpublished revised text, by Peter Waters, July
1993


Since the first publication in 1975 of ~Procedures for Salvage of
Water-Damaged Materials~ there has been no decrease in the
frequency of accidents or unexpected disasters which have result-
ed in extensive water damage to library materials but there are
many signs that we have begun to learn the immense value of
disaster preparedness planning.  Being familiar with the necessi-
ty of having to make a series of interrelated decisions promptly,
understanding the effects of any particular course of action on
subsequent ones -- this is the best kind of preparation needed in
the event of major water-damage problems.  A well-organized plan
can greatly reduce the costs of salvage and restoration as well
as the proportion of outright losses.  This preparedness can also
go a long way to lessen the emotional and stressful impact upon
human beings.

The various courses of action discussed in this revised edition
are designed to save the maximum amount of material with minimum
amounts of restoration on the one hand or replacement on the
other.  However, it cannot be emphasized too much that no general
instructions can take the place of an assessment of a given
situation on site by a qualified, experienced library or archive
specialist, who has proven experience in the reclamation of fire
and water-damaged collections.  It is strongly recommended that
such assistance and advice be sought at the earliest moment after
a disastrous event has occurred.  In addition, the Conservation
and Preservation Research and Testing Offices of the Library of
Congress stand ready to serve as a technical information center
and, if need be, a coordinating agency for emergency salvage
efforts.

Library and archive staffs are now generally better informed
about the mechanisms of drying cellulosic materials as well some
of the technologies developed for this purpose.  The use of
vacuum chambers for drying large quantities of books and paper
records has become an acceptable, almost common approach, but not
without some confusion as to the differences and relative merits
of vacuum drying and vacuum freeze-drying.  Both methods effec-
tively remove water but by quite different mechanisms and often
with quite different results.  An understanding of how these
technologies function is essential in planning for a recovery
operation, in order to make the best possible match between the
nature, condition and needs of the materials and the capabilities
of a particular drying system.

The use of fungicides to control the spread of mold growth has
become an increasingly controversial subject because they may
cause severe danger to workers and in some cases to the materials
treated.  Sterilizing by means of ethylene oxide and related
chemicals has come under close scrutiny by the EPA, to the extent
that we cannot recommend its use except by a commercial business
firm which is fully insured and licensed to perform this service.
Treatments involving the use of ethylene oxide (ETO), are best
carried out under controlled conditions, as in vacuum chambers at
the end of a drying cycle, and they must be guaranteed to leave
no residual toxicity in the material.  ETO remains the most
effective treatment for severe mold attack resulting from major
disasters, especially those exposed to river water.

The critical decisions that have to be made following water
damage require knowledge of available drying technologies and
their effects on a variety of composite materials.  Ideally,
materials removed from site, should be prepared and packed in a
manner most suitable for the drying method to be used.  Unfortu-
nately, what tends to happen, particularly when no emergency plan
exists, is that wet material is packed and shipped off to freez-
ing facilities without knowledge of how the material will be
dried.  This may result in the material having to be re-packed
before drying which adds considerably to the cost of drying and
the potential for further damage.

The complete restoration of water-soaked documents, particularly
bound items, can be a costly process even under the most favor-
able conditions.  In the majority of cases, the high costs in-
volved do not justify the salvage and restoration of books which
are in print and can be replaced.  However, decisions relating to
these factors are virtually impossible to make during a salvage
operation and even when a disaster plan exists.  On the other
hand it might be unwise not to attempt to salvage everything, if
an insurance assessment is required and a claim is to be made.

Freezing, followed by vacuum freeze drying has been shown to be
one of the most effective methods for removing water from large
numbers of books and other paper records, but drying is not the
final step in the reclamation process.  In some cases, volumes
which are only damp or which have suffered minor physical damage
before freezing may come from a drying chamber in such good
condition that they can be returned to the shelves.  It is
preferable that, where possible, the packing on site should be
carried out in such a manner as to segregate very wet material
from that which is partially wet and those that are damp from
exposure to high humidity conditions  This will not only result
in cost savings during the drying operation but will help to
avoid over drying of the least wet material.  In the majority of
instances, drying must be followed by restoration and rebinding,
and therefore the technique and success of the drying method
chosen will directly affect the final cost of restoration.  This
can be very expensive.

Thus, librarians and others faced with decisions which follow
serious flooding and water damage from the aftermath of fire, and
related water-damaged exposure, need to be reminded that replace-
ment is nearly always much less costly than salvage and restora-
tion.  The necessity for making sound, on-the- spot, cost--
effective judgments is the best reason for being prepared in
advance by developing a pre-disaster preparedness plan.  There
are a number of such plans that have been drawn up, which can be
found in the literature, to serve as models.

We encourage all of our colleagues who care about the integrity
of library collections, including those who are difficult to
persuade that a disaster could ever occur, to formulate disaster
preparedness plans without delay so that it may never be neces-
sary to refer to this document in times of distress!

HOW WATER EFFECTS BOOKS AND UNBOUND MATERIALS
Paper absorbs water at different rates depending on the age,
condition, and composition of the material.  Thus, some under-
standing of the mechanism of swelling action, as well as the
development of mold, is essential to planning a successful
salvage operation.  In addition, when large collections are at
stake, it is useful to be able to calculate in advance the
approximate amount of water which will have to be extracted in a
drying process.  This will provide helpful data when selecting an
appropriate drying method.  Of equal importance is some knowledge
of the length of time each type of material can be submerged in
water before serious deterioration occurs.

ESTIMATING WATER ABSORPTION
Generally speaking, manuscripts and books dated earlier than 1840
will absorb water to an average of 80 percent of their original
weight.  Some may absorb as much as 200% of their original
weight.  Since there is a greater concentration of proteinaceous
material and receptivity to water in such early books and papers,
they are especially vulnerable to mold when damp.  Modern books,
other than those with the most brittle paper, will absorb an
average of up to 60 percent of their original weight.  Thus, in
estimating the original weight of a collection, if one assumes an
average of four pounds per book when dry for 20,000 books in each
category, drying techniques must be capable of removing approxi-
mately 64,000 pounds of water from the earlier materials and
48,000 pounds from the latter.

The major part of all damage to bound volumes caused by swelling
from the effects of water will take place within the first four
hours or so after they have been immersed.  Since the paper in
the text block and the cardboard cores of book bindings have a
greater capacity for swelling than the covering materials used
for the bindings, the text-block of a soaked book usually expands
so much that the spine assumes a concave shape and the fore-edge
a convex shape, thus forcing the text block to become partially
or completely detached from its binding.  The board cores of
bindings absorb a great amount of water in such circumstances and
are usually the source of mold development between the board
papers and fly leaves.  This is especially apparent when the area
in which water damage has occurred begins to dry out and the
relative humidity falls below 70%.  Although it is obviously
important to remove as much moisture as possible from the envi-
ronment, it is essential that the water content of the material
be monitored because this will remain dangerously high, long
after the area is apparently ~safe~.  Action taken to salvage the
material should therefore be governed by the water content of the
material and not by the relative humidity of the area.  A water
moisture meter, such as an Aqua Boy can be used to measure the
water content inside books and box files.  If such an instrument
is unavailable a crude but quite effective way is to use a mirror
within but not touching the text block. Condensation will cloud
the mirror.  A water content measuring less that 7% is considered
dry.

Leather and vellum books, especially those of the 15th, 16th, and
17th centuries, can usually be restored successfully if they are
dried under very carefully controlled procedures.  Such materials
are usually classified as rare and should be treated accordingly
by not mixing them with less rare materials during preparations
for salvage, stabilization and drying.  The advice of a certified
book conservator may be essential in order to safely carry out
the most appropriate methods.  If the material is frozen, freezer
paper should be used between each volume to prevent sticking.
(Refer to the section on freeze-drying for the special require-
ments needed for drying this type of material).

Unfortunately, modern manufacturing processes so degrade the
natural structure of leather that, once water soaked, book covers
are often impossible to restore.  Some leather bindings will be
reduced to a brown sludge, while others will severely shrink.
Swelling of covering materials, such as cloth, buckram, and
certain plastics is negligible, in some cases shrinkage occurs.
Book covers, however, which are made of a highly absorbent
cardboard, will absorb water to a greater degree than an equiva-
lent thickness of text block.  Some book covering materials which
have already deteriorated will absorb water at about the same
rate as the text block.

Once access to the collection is gained, the external appearance
of each volume and group of volumes is a useful indication of the
degree of water damage.  Those volumes found, usually in heaps,
in the aisles will naturally be the most damaged.  Not only will
they have sustained the shock of falling, as rapid swelling
caused them to burst from the shelves, but they will also have
been exposed to water for a longer period than the volumes on the
shelves above them.  These will need special, flat packing and
the most extensive restoration.  The appearance of such volumes
can be a devastating, emotional experience, but one must not
panic since every volume worth the cost of salvage and restora-
tion can be saved.

Above the floor levels there will be distinct signs among the
shelves of the locations of the wettest material.  Shelves which
have expanded under the pressure of swollen paper and bindings
will usually contain a mixture of evenly wet as well as unevenly
wet material.  The proportion of evenly wet material in these
situations is usually less than those that are unevenly wet.
This is because books, originally shelved closely packed togeth-
er, will not easily be completely saturated especially if the
paper is slow to absorb.  This is the major reason why so many
books become misshapen and distorted after water damage and also
after they have been frozen and dried.  If paper is unevenly wet,
it will not dry without distortion.  Misshapen volumes with
concave spines and convex fore-edges can be immediately identi-
fied as belonging to the category of very wet.  Others that have
severely swollen text blocks but that still retain some spine and
fore-edge shape may indicate that they were previously bound with
library binding oversewing techniques and may have sustained
irreversible sewing structure damage.  Others  may be relatively
sound in shape and these stand the best chance of drying with the
minimum of distortion.

COATED PAPERS
Coated papers are the most vulnerable to complete loss and should
not be permitted to begin drying until each volume can be dealt
with under carefully controlled conditions.  The period between
removal and freezing is critical.  It may be necessary to re-wet
them with clean cold water until they can be frozen.  During the
aftermath of the Corning Museum Library river flood of 1972, it
was found that the highest percentage of water damaged books were
printed on coated stock papers and that when they were frozen in
the wet state most were dried successfully by freeze-drying.

ARCHIVAL BOX FILES
Archival box files often fare better than book material because
their boxes are made of porous board stock which can be expected
to absorb most of the water, protecting the contents inside.
This would not be the case of course if they were completely
immersed under water for many hours.  During recovery, the
contents of each box should be carefully inspected and the box
replaced if it is water saturated.  Failure to do so will in-
crease the risk of physical damage as boxes collapse from pres-
sure during recovery, shipment and cold storage.

ACCESS
Where water damage has resulted from fire-fighting measures,
cooperation with the fire marshal, and health and safety offi-
cials is vital for a realistic appraisal of the feasibility of a
safe salvage effort.  Fire officers and safety personnel will
decide when a damaged building is safe to enter.  In some cases,
areas involved in a fire may require a week or longer before they
are cool and safe enough to enter.  Other areas may be under
investigation when arson is suspected.  There may be parts of a
collection that can be identified early in the salvage planning
effort as being especially vulnerable to destruction unless they
receive attention within a few hours after the fire has abated.
If the fire marshal appreciates such needs, he may be able to
provide means of special access to these areas even when other
parts of the building remain hazardous.

Perhaps the most important and difficult decision to make after
an assessment of damage has been made, is whether to remove the
wettest materials first or to concentrate on those that are only
partially wet or damp.  If the majority are in the latter catego-
ry the best course may be to recover these first since they may
develop mold if they are left in dank and humid conditions while
the wettest material is removed.  A balance must be struck
between the reduction of moisture content in the affected areas
and the time involved for the safe removal of the majority of the
collections in the best condition.  To remove the wettest materi-
al first will obviously lower the moisture content, but it is
often the case that this can be difficult and time consuming
owing to the fact that shelves become jammed with swollen wet
books and boxes that may require special equipment to free them.
The aim is always to recover the majority of the collection in
the best condition to avoid additional harm and costs brought
about by post-disaster environmental damage.

Once all entrances and aisles have been cleared, in addition to
the above considerations, the most important collections, includ-
ing rare materials and those of permanent research value, should
be given priority unless other material would be more severely
damaged by prolonged exposure to water.  Examples of the latter
are books printed on paper of types widely produced between 1880
and 1946, now brittle or semi-brittle.  However, materials in
this category which can be replaced should be left until last.

STABILIZING THE ENVIRONMENT
Salvage operations must be planned so that the environment of
water damaged areas can be stabilized and controlled both before
and during the removal of the materials.  In warm, humid weather,
mold growth may be expected to appear in a water-damaged area
within 48 hours.  In any weather, mold can be expected to appear
within 48 hours in poorly ventilated areas made warm and humid by
recent fire in adjacent parts of the building.  For this reason,
every effort should be made to reduce high humidities and temper-
atures and vent the areas as soon as the water has receded or
been pumped out.  Water-soaked materials must be kept as cool as
possible by every means available and be provided with good air
circulation until they can be stabilized.  To leave such materi-
als more than 48 hours in temperatures above 70 degrees Fahren-
heit and a relative humidity above 60 percent without good air
circulation will almost certainly result in heavy mold growth and
lead to high recovery and restoration costs.

Damaged most by these conditions are volumes printed on coated
stock and such highly proteinaceous materials as leather and
vellum bindings.  Starch-impregnated cloths, glues, adhesives,
and starch pastes are affected to a somewhat lesser degree.  As
long as books are tightly shelved, mold may develop only on the
outer edges of the bindings.  Thus no attempt should be made, in
these conditions, to separate books and fan them open.

As a general rule, damp books located in warm and humid areas
without ventilation will be subject to rapid mold growth.  As
they begin to dry, both the bindings and the edges of books will
be quickly attacked by mold.  Archival files which have not been
disturbed will not be attacked so quickly by mold.  A different
problem exists for damp books printed on coated stock, since if
they are allowed to begin to dry out in this condition, the
leaves will quickly become permanently fused together.

ASSESSMENT OF DAMAGE AND PLANNING FOR SALVAGE
Weather is often the critical factor in determining what course
of action to take after any flood or fire in which archive and
library materials are damaged.  When it is hot and humid, salvage
must be initiated with a minimum of delay to prevent or control
the growth of mold.  When the weather is cold, more time may be
taken to plan salvage operations and experiment with various
reclamation procedures.

The first step is to establish the nature and degree of damage.
Once an assessment of the damage has been made, firm plans and
priorities for salvage can be drawn up.  These plans should
include a determination of the special facilities, equipment and
personnel required.  Overcautious, unrealistic, or inadequate ap-
praisals of damage can result in the loss of valuable materials
as well as confusion during all phases of the recovery operation.
Speed is of the utmost importance, but not at the expense of
careful planning which must be aimed at carrying out the most
appropriate, safe and efficient salvage procedure within the
circumstances prevailing.  An efficient record keeping system is
a must.  Inventory of call numbers, shelf location and packing
box numbers will help make the task of receiving collections
returned after drying so that their original shelf locations can
be identified, as efficient as possible.

Maintaining a detailed photographic and written record of all
stages in the recovery operation is an essential, but often
overlooked task which will aid the process of insurance claims
and demonstrate the condition of the material before it is frozen
and dried.  We have found that on receiving materials back from a
drying process, some administrators are shocked by the appearance
of distorted material, believing perhaps that the condition
should be much better, or be somewhat restored!  The photographic
record can be a very helpful reminder that distortion is mostly
the result of the initial water damage and not necessarily the
result of the drying process.  The photographic record should
provide key evidence for the reasons and nature of additional
damage resulting from any part of the recovery process.

THE RECOVERY TEAM
Conducting a successful and efficient recovery operation after a
major flood or similar disaster requires, in addition to a good
supply of dedicated labor, a team of experts who should be
assembled before practical work begins.

The leader should be a person who has had practical experience
and understands the effects of different environmental conditions
on water-soaked materials of all types, conditions, and ages.
The team leader should to be assisted by custodians who know the
collection intimately; conservators who can provide additional
advice and guidance as well as help in training workers in safe
removal procedures; procurement specialists; building maintenance
engineers; electricians; carpenters; plumbers; a chemist if
available, and health and safety experts.

One or more persons familiar with national and local resources
are highly desirable to assist in locating and procuring the
special facilities, equipment and supplies needed during the
operation.  They should be familiar with using the Yellow Pages
to track down materials and equipment, able to seek out the key
chemical supply companies in the country, if necessary, and
generally have the authority to cut through administrative red
tape.

The assembled team should be carefully briefed on the recovery
plan and procedures to be followed as well as various contingency
alternatives which might have to be adopted, priorities to be
observed, and their own specific responsibilities.

Team leaders need to be identified and instructed in the details
of the recovery plan and its main aims and goals.  They in turn
should brief all workers so that they too will understand the
purpose of the plan and what is expected of each of them.  A well
briefed and dedicated team works much better than enthusiastic
individuals who are allowed to carry out actions which may be
disruptive to the main purpose of the team plan.

The major objectives of this team should be:

To stabilize the condition of the materials before removal by
creating the environment necessary to prevent further damage.

To recover the maximum number of material from the damaged
collections in a manner which will minimize future restoration
and its costs.

PRIMARY CONSIDERATIONS FOR RECOVERY OF WATER-DAMAGED COLLECTIONS
Seek the advice of specialists who can assist at the site of the
disaster.

Organize a disaster team and prepare a comprehensive plan of
action, as well as plans for different contingencies.

Do not attempt to remove materials from the area until an overall
plan with a schedule of priorities has been established and all
personnel thoroughly briefed and trained.

In winter, turn off all heat in the building.  In summer, reduce
temperatures as much as possible through air-conditioning.

Create maximum air flow through all affected areas by opening
doors and windows.  If electrical facilities are operational, use
as many fans as can be acquired to create a current of air so
directed as to expel humid air from the building.  Use de--
humidifiers together with air conditioning and a good air flow.
The objective is to avoid pockets of stagnant air and to reduce
moisture content.

If house electricity is not available, hire portable generators
to provide electricity for lights, fan, dehumidifiers, and other
electrical services.  For safety purposes, all electrical lines
should be waterproofed and grounded and be administered by health
and safety personnel.

Do not permit anyone to open wet books; to separate single
sheets; to remove covers when materials are water-soaked; or to
disturb wet file boxes, prints, drawings, and photographs.  Such
handling can result in extensive and often irreparable damage to
materials that otherwise might be salvaged.  Reducing the cost of
future restoration must be one of the top priorities of the
salvage operation.

Canvass the community to locate freezing and storage space.

Locate sources of one cubic foot milk crates and corrugated board
boxes.

PRELIMINARY STEPS IN THE EVACUATION FROM WATER-DAMAGED AREAS
If the materials are to be frozen, prior arrangements should have
been made to ship the packed materials immediately to freezing
facilities.  Packed materials must not be allowed to remain on or
near the site for more than a few hours, since such delay will
further increase the possibility of mold development.  Before
actual removal of the water-soaked material begins, lighting,
fans, dehumidifiers, and all possible venting should be fully
operational.  All work surfaces should be covered with polyethyl-
ene sheeting.  Areas selected for packing or drying should be
prepared for the operation by emptying them of all unnecessary
equipment and furniture.

REMOVAL AND PACKING OF WATER-DAMAGED MATERIALS -- THE WORK FORCE
Safety of the materials and future restoration costs will depend
largely on the competence and dedication of the salvage crews.
The work will be arduous, dirty, and often frustrating.  Team
leaders should not hesitate to dismiss careless and thoughtless
workers.  Experience has shown that well-disciplined crews having
brief rest periods with refreshments about every hour and a half
are the most efficient.  Working salvage crews to exhaustion pays
no dividends.

REMOVAL FROM WATER-DAMAGED AREA -- THE CATALOG AND OTHER RECORDS
OF THE COLLECTION
High priority should be given to salvaging the catalog and other
records of the collection.  Salvage operations should avoid any
action that might remove or deface identifying marks and labels.

During the pre-recovery planning stage a decision needs to be
made on whether or not to use a location number identification
system which could be used after the material is returned from
the drying operation to reassemble the collection in similar
shelf order.  There will be a need to identify and segregate
materials which are very wet from partially wet; mold contaminat-
ed from uncontaminated; rare and sensitive items from the less
rare and sensitive etc.  If an orderly, efficient and safe
recovery is to be achieved, together with a control over the
choice of drying and other special measures needed to save rare
and sensitive materials, a box coding system is indispensable.

At least one person should be assigned specific responsibility
for making an ~inventory~ at each location where the materials
are taken from the shelves and boxed.  This person might also be
given charge of supervising the boxing and box coding process.

Conveyor belts and ~human chains~ are normally used  to remove
large numbers of material from each shelf, pack them in corrugat-
ed boxes or plastic milk crates and to move them to the loading
site for shipment to cold storage facilities.  It is at this time
that a great deal of additional damage and confusion can occur.
The number of people involved in this operation and their behav-
ior needs to be closely supervised.  Try to initiate a rhythm
when using human chains that keeps everyone busy without being
over taxed.  Too many helpers will hamper progress, encourage
~loafing~ and generally reduce the efficiency of the operation.
It is highly desirable to instruct the team daily on the tasks to
be carried out and to keep them informed as to the major objec-
tives of the recovery operation and as to any changes that have
been made to the master plan.

An efficient and dedicated work force needs to be provided with
all the accouterments of human survival, such as regular rest
periods, a place to eat, a convenience to wash and clean up and a
immediate access to medical attention.

Manuscripts and other materials in single sheets create particu-
larly difficult problems if they have been scattered.  An indica-
tion of the approximate location in which they are found during
the salvage operation may be extremely helpful at a later date.
Materials should never be moved from the site in large batches or
left piled on top of each other, either at the site or in adja-
cent temporary housing, since the excessive weight of water-af-
fected books and paper records can lead to severe physical
damage.

When flood-damaged books were removed from the Biblioteca Nazion-
ale in Florence following the river flood disaster of 1966
substantial numbers were piled high outside the library building
while awaiting shipment to drying facilities.  This action caused
significant damage to the books from the weight of water saturat-
ed volumes and lead to very high costs of post disaster restora-
tion.

REMOVAL AND PACKING
The aisles between stacks and main passageways will probably be
strewn with sodden materials.  These must be removed first, sepa-
rately, by human chain, in the exact condition in which they are
found.  Open books will be greatly swollen, but no attempt should
be made to close them.  Closing them will cause further damage by
tearing the leaves, since paper will not slide when wet.  In-
stead, books should be passed undisturbed to an adjacent dry area
where an awaiting team may pack them without disturbing their
shape.  This particular type of material must not be packed
tightly but should be packed flat in boxes and separated with at
least one layer of freezer paper and one sheet of 1/2" polysty-
rene between each open book.

The packing team should have approximately the same number of
people as the team which passes the damaged material to them.
This will avoid bottlenecks and stacking materials on the floor
awaiting packing.  If a sufficient number of people and conveyor
belts are available, the most efficient place to pack damaged
materials will be on site.  Teams will have to be organized to
assemble packing materials and supply them to the packers in a
smooth flow.  Use of a second human chain or conveyor will reduce
bottlenecks and the likelihood of incoming supplies interfering
with the flow of packed materials being passed out of the build-
ing.  After the isles have been completely cleared, the main work
of recovery can begin.  Hopefully, a decision will have been made
as to which material to remove first: the wettest or the ones in
the best condition.  As stated earlier, if the majority is only
damp and in relatively sound condition, these could be removed
first and more rapidly than other materials.  In these circum-
stances de-shelving and packing will be a relative quick opera-
tion and will help to establish a smooth worker flow.  As each
line of shelves is emptied, an assistant should code each box and
record the box number and its general contents in a notebook.
The contents of archival storage boxes are unlikely to be satu-
rated with water if they were previously positioned close togeth-
er.  However, since certain types of boxes have a corrugated
inside layer, they may be very wet, even though the major portion
of the contents is only damp.  In such cases, it is best to
repack the contents in new boxes or in plastic milk crates.  This
will not only make each unit lighter to lift and prevent the
collapse of a wet box but will also speed the drying process.
When repacking it is important that the new boxes be properly
identified.

DISPOSITION OF REMAINING MATERIALS AND CLEANING OF WATER-EXPOSED
AREAS
If the wettest materials were removed first the drier material
will usually be above the first four or five shelves and packed
closely together.  On no account should this third category be
separated or spaced out during the earlier salvage efforts.
Closely packed materials will not readily develop mold internal-
ly.

However, since these will have been in a very humid atmosphere
for, maybe several days, it is likely that some mold will have
developed on the outer edges of bindings and boxes.  This is less
like to occur if, during the evacuation of the wettest materials
every effort had been made to reduce temperatures and humidity
levels and establish a good air flow.

There may be books and box files in such good condition that they
need not be sent to freezing facilities but can be dried in
ambient conditions.  On no account however should the drying be
attempted in the location in which they were found because the
environment will be totally unsuitable. They should instead be
removed to a controlled environment while shelves, wall, floors,
and ceilings are sterilized and necessary maintenance work is
being done to return the site to its normal condition.  If moved,
materials should be stacked with air spaces between them provided
that the drying area has a good circulation of air, together with
airconditioning and dehumidification.  If air-conditioning is not
available, fans and dehumidifiers should be used to keep air
moving and to extract moisture from the area.  The relative
humidity of a drying area is no guide to the actual moisture
content of cellulose materials.  The normal water content of
paper is between 5 and 7 percent by weight.  Materials which feel
relatively dry to the touch as they come out of a humid, flood--
damaged area, may actually contain moisture from above 10 to 20
percent.

Heat is one of the best means of drying, but since it increases
the risk of mold development on humid books and documents, it
should be used only if a good circulation of air and dehumidifi-
cation can be established.  Hygrothermographs for recording
temperature and relative humidity should be installed to monitor
the general area, and moisture-content meters used to measure the
moisture in the materials themselves.

CLEANING AFTER A RIVER FLOOD
The safest time to clean materials is after they have been dried.
If water-damage is the result of a river flood then the following
might, under certain circumstances, be considered.  The Florence
experience demonstrated that the best time to remove mud was
after the books were dry.  However some books did benefit from
partial cleaning in the wet state.

If adequate assistance is available, mud deposits on books which
will not be further damaged by water may be washed off in clean,
running water.  Closed books may be held, one at a time, under
water and the excess mud removed with a hose connected to a fine
spray head.  Similar washing should not be attempted with opened
volumes, manuscripts, art on paper, or photographs.

Rubbing and brushing should be avoided, and no effort  be made to
remove oil stains.  Anything which is hard to remove is better
left until after drying, when techniques for removal can be
worked out during the restoration stage.  In some cases, printed
books bound in cloth or paper can be left immersed in clean
running water for as long as two weeks.  Although this should be
avoided if possible, it is preferable when the only alternative
is leaving such books in warm, humid air while awaiting atten-
tion.

THOROUGH WASHING TO REMOVE HEAVY DEPOSITS OF MUD
A more thorough washing procedure, intended to remove as much mud
and slime as possible from books, requires six to eight tanks big
enough to accommodate the largest volumes in the collection.
This process is obviously wet and messy and needs to be set up
outdoors in fair weather or in an area fitted out to use and
remove large quantities of water.  Since large quantities of
water are required, the area will be wet and dirty throughout the
operation, and good drainage is therefore essential.

Any rustproof receptacles may be used if they are large enough,
but plastic garbage cans (20 or 30 gallons) are recommended.
Each can should be equipped with a hose to provide low-pressure,
continuous water flow to the bottom so that dirty water, as it
overflows the rim, will be constantly replaced by fresh.  Each
hose should be fastened securely to prevent damage to the books
being washed.  Wooden duck-boards, rubber boots, gloves and
aprons are recommended for the protection of workers.

Keeping a book tightly closed, a worker should immerse one book
at a time in the first can and remove as much mud as possible by
gentle agitation under the water.  Workers should not use brushes
and or any tool which would cause an aggressive rubbing action.
Books should be passed from one can to the next and the same
operations repeated until most of the mud has been removed.  At
the last can, books should be rinsed by spraying them gently with
a fine stream of water.  No effort should be made to remove mud
which continues to cling after sponging under water.  This is
much better done when the books are dry.

Finally, excess water can be squeezed from books with hands pres-
sure; mechanical presses should never be used.  It must be empha-
sized that the above procedure should be attempted only by a
carefully instructed team and in a properly fitted-out area.  If
there is any doubt about the ability of the team to follow direc-
tions, washing should not be attempted.  There are many classes
of books which should not be washed under any circumstances, and
it is therefore imperative to have the advice of an experienced
book conservator who can recognize such materials and who under-
stands their treatment requirements.

PRINCIPLES OF STABILIZATION BY FREEZING
The most generally accepted method of stabilizing water-damaged
library and archival materials before they are dried is by
freezing and storing at low temperatures.  This buys time in
which to plan and organize the steps needed to dry the material
and to prepare a rehabilitation site and the building for return
of the collections after drying.  Freezing provides the means for
storing water damaged material safely and for an indefinite
period of time in similar physical condition in which they were
found, preventing further deterioration by water and mold while
awaiting treatment.

Freezing is not a drying method, nor can it be expected to kill
mold spores, but it is highly effective in controlling mold
growth by inducing a dormant state in the spores.  If mold dam-
aged material is frozen it is important that the drying method
chosen must prevent mold spore activity during the drying pro-
cess.  For this reason it is important to segregate such material
during removal and packing operations.

Stabilization by freezing also provides important advantages when
it is not possible to immediately assess the value of the damaged
materials or to determine which items can or cannot be replaced.
In other words, stabilization gives time in which to estimate
recovery costs, to prepare adequate environmental storage condi-
tions, and to restore the building.  In some cases, it may be
necessary to restore or rebuild the original facilities - a
process which can require a long period of time.

Had freezing technique been used after the catastrophic Florence
flood in 1966, thousands of additional volumes could have been
saved completely or would have suffered significantly less
damage.  The Florentine libraries which sustained the greatest
losses contained mostly 19th and 20th-century materials.  In
these collections, losses were heaviest among books printed on
coated stock, whose leaves stuck together during drying and could
not be separated afterward.  These losses could have been largely
prevented if the materials had been frozen while wet, and if
drying methods now known had been used to prevent adhesion of the
leaves.

The effect upon freezing water soaked volumes which have lost
their shape or have had their binding structures damaged by
immersion, will be to slightly increase the thickness of volumes
by the physical action of ice crystals, but this additional
increase in thickness has been found to contribute no significant
problems to already damaged books.  Studies conducted by the
Research and Testing Office of the Library of Congress have
uncovered no evidence of any damage to cellulosic and protein-
aceous materials caused solely by the action of freezing.

Freezing as a salvage method has other advantages.  It can
stabilize water-soluble materials such as inks, dyes, and water
stains etc. which would otherwise spread by wicking action if
they were dried from the wet state by conventional drying meth-
ods.  Freezing provides the means by which water-soluble com-
pounds will remain stable during a freeze-drying process which
involves the removal of water by sublimation.  This is the only
known drying method capable of drying without further spreading
of water soluble compounds, provided that the frozen state of the
material is maintained before and throughout the drying process.

COLD TEMPERATURE STORAGE CONDITIONS
The size and formation of ice crystals is governed by the rate
and temperature of freezing.  Blast freezing used for certain
types of food-stuffs is designed to quickly freeze in a few
hours, often involving temperatures in excess of -50 degrees
Celsius.  The advantage of quick freezing is that ice crystals
are kept very small, resulting in a limited amount of swelling.
Availability of blast freezing facilities may not be possible
following water damage, so in normal circumstances, freezing will
be slower and therefore the formation of ice crystals larger, but
this should not cause problems for the majority of library and
archive collections.

Once frozen, cold temperature conditions should be maintained at
about 0x Fahrenheit (-18x Celsius ).  Lower temperatures will do
no harm but higher temperatures may increase the size of ice
crystals.

PREPARATION FOR FREEZING
Before freezing, it may seem tempting to wash away accumulated
debris particularly if this is the result of a river flood, but
this is rarely advisable or safe  because of lack of time,
skilled workers and a pure water supply, and the quantity of
material to be handled.  (Aqueous washing to remove smoke damage
should never be attempted under any circumstances).

Washing should never be attempted by untrained persons as this
will cause further damage, nor should time be taken for this
purpose if so little skilled help is available that any signifi-
cant delay in freezing the bulk of the materials would result.
The washing of materials containing water-soluble components,
such as inks, watercolors, tempera or dyes should not be attempt-
ed under any circumstances.

Experience has shown that such materials, as well as those that
are fragile or delicate, can be seriously or irreparably damaged
by untrained workers attempting to clean and restore on-site.
Such materials need expert attention and hours of careful work if
damage is to be kept to a minimum.  The period of emergency
action and ~first aid~ is a dangerous and unsuitable time for the
careful work required to restore materials to near-original
state.  The general condition of the damaged material will deter-
mine how much time can be spent in preparation for freezing.  At
the very least, bound volumes should be wrapped with a single
fold of freezer paper, or silicone paper, if it is likely that
their covers will stick together during the freezing process.

All rare, intrinsically valuable and delicate material should be
prepared for freezing separately from other materials and also in
separate categories so that each can be located and identified
before they are dried.  Each category may require a different
type of drying than used for the other less sensitive materials.
For instance, early printed books and manuscripts are made up of
a variety of material including vellum, leather, paper, wood
metal, ivory, inks and water color media.  Others will be deli-
cate and or highly water sensitive.  These will need to be dried
very carefully and if freeze-drying is used it should be under-
taken with the minimum amount of internal chamber heating.  If
only a few items are involved it may be preferable to send them
directly to a certified conservator for immediate treatment.

CONTAINERS AND METHODS OF PACKING FOR FREEZING
The choice of packing containers should be carefully considered.
Although corrugated board boxes are cheaper to purchase, locate
and store on site than plastic type milk crates, they may re-
strict the rate and efficiency of drying and also be prone to
collapse when filled with wet material.  If it is possible to
decide in advance what method of drying is to be used, be guided
by the technical requirements of the vendor~s drying system.  For
instance, if freeze-drying is to be used, one cubic foot plastic
milk crates might be preferred, since these provide open spaces
within the interlocking crates to aid in the efficient out--
gassing of ice by sublimation.

With some forms of vacuum drying where sublimation does not
occur, corrugated boxes may be quite suitable, depending on the
location of the heat source in the chamber.  In either case,
containers should not be larger than approximately one cubic
foot, to avoid excessive weight, a vital consideration for
workers removing material from site and also to help reduce
damage from collapsing boxes.  Usually boxes will be prepared for
freezing on pallets and this is where the weight of heavy wet
boxes can collapse and cause additional damage to material within
the pile.  To avoid this, use plastic milk crates or very sturdy
corrugated boxes for the wettest material and re-box file records
if their original boxes are saturated with water.  Endeavor to
use one size and type of box.  If this not possible, do not mix
sizes when packing on pallets.  The number of boxes per pallet
should be no more than can be supported without collapse.

Although faster freezing and drying will result if boxes are not
packed tightly, the contents will distort during the drying
operation.  To achieve the best drying results for books, they
should be packed closely together so that drying is done under
some restraining pressure.  A book should never be packed foredge
down as the weight of the text block will cause an inversion of
its natural round shape.  Pack books spine-down or flat and avoid
placing larger volumes on top of smaller ones to avoid sagging
which will be costly to correct during restoration.

The decisions taken at this stage will greatly affect the outcome
and costs of the processes used for cold storage, drying and
restoration.  It has, unfortunately, not been sufficiently
appreciated in the past that care in packing at this stage will
significantly reduce post-recovery costs.

High costs certainly occur if boxes are stacked on pallets in
mixed sizes which will increase the potential for collapse under
the weight of water, crushing and damaging the material in the
process.

It should be possible to move the wet materials directly from
library to freezing facility, preferably in refrigerated trucks
which can be drawn up to the loading site.  For small collections
of books and documents, dry ice may be used to freeze the materi-
al for transport in un-refrigerated trucks to long-term freezing
facilities. (Gloves should be worn at all times when handling dry
ice).

VACUUM AND FREEZE DRYING TECHNOLOGIES
It is important to understand that the processes used by vacuum
and freeze-drying companies differ considerably depending on the
specific requirements of the material to be dried.  The majority
of these companies have developed their technologies for food.
Few have had experience in drying paper and books and therefore
may not know if their normal operating system would be safe, or
cost effective for this purpose.  Freeze-drying has a number of
significant advantages over vacuum drying since water remains in
the frozen state during sublimation, a process which removes
water from the solid state to the gaseous state.  This avoids
most of the problems associated with expansion, sticking and
wicking of water sensitive and soluble media.  Vacuum drying,
generally considered to be a process that changes a liquid to a
vapor, will result in a much greater risk of expansion, distor-
tion, sticking, and staining.

Although both drying methods have been found to produce satisfac-
tory results in a number of disaster recovery events, comparison
between the two following a disaster has not been made.  Our
preference is for freeze-drying because it is the least ~aggres-
sive~ of the two methods.  However, there are situations where
for instance, archival documents have been affected and where
there is a low percentage of intrinsically valuable material,
where vacuum drying has provided satisfactory results.  The
choice between the two should be governed by the nature, value
and condition of the damaged material.  Rare collections of
significant value need to be dried with due regard to the sensi-
tivity of the substrate and media and it is for this reason why
we suggested earlier that such materials be segregated form the
less rare.

Freeze-drying which is used to dry animal specimens, does so at
very low internal chamber temperatures, lower than is used for
most food processes.  One animal specimen may take several weeks
to dry.  At this slow rate of drying the costs are high.  Most
paper and book material can withstand higher temperatures than
those used to dry delicate animal specimens and there is a need
for thermal energy to make the process efficient and cost effec-
tive.

If a vacuum or freeze-drying chamber is designed to operate with
internal chamber heat sources, these must not touch the material
to be dried, to avoid over heating and scorching.  The internal
temperature of a chamber should be no greater than 100 degrees
Fahrenheit (37.8 degrees Celsius).  For sensitive materials,
including early book material where there is a mix of paper,
vellum leather and wood etc., below ambient temperatures or those
used to dry animal specimens should be used, to dry the material
slowly and under carefully monitored conditions.  (Note: In
specifying an upper limit of 100 degrees Fahrenheit we consider
this to be a safe temperature.  There is insufficient data at
this time to evaluate the effects of higher temperatures).

It is important to realize that the success of any large drying
system depends on the ability of the system to stop the develop-
ment of mold during and after the drying process.  Be aware of
the risks in accepting material returned from commercial drying
processes unless there is a guarantee that none will be returned
damp or wet.  If mold develops after return, it may not be
possible to detect it, if the material remains boxed.  If care
was taken to segregate mold-contaminated from non-contaminated
items during recovery, boxing and freezing, this will help deter-
mine if the drying was carried out properly.  If mold develops in
the non-contaminated material, the chances are that either the
drying was not done correctly or that drying was not complete.

Mold-infected material, if dried completely under freeze-drying
conditions, can be safely controlled for a short period of time,
so that the spores remain quite dormant if stored after drying in
an air conditioned environment maintained at 50 to 55 degrees
Fahrenheit and a relative humidity of 35 percent or lower.
However they must not be returned to the library or archive
shelves until the mold contamination has been treated.  For this
reason we recommend that at the end of the drying cycle and while
still in the drying chamber all mold-contaminated material be
sterilized.  If extreme care was not taken to separate contami-
nated from non-contaminated materials before the drying opera-
tion, we recommend that each drying load be sterilized.

REHABILITATION AFTER DRYING
If maximum benefits are to be gained from stabilization by
freezing, every effort should be made, first, to identify and
assess the value, condition, and total numbers and types of
materials damaged, and second, to draw up comprehensive lists of
those materials which can be replaced and those which should be
reclaimed and restored.  Replacement is nearly always cheaper
than restoration.  Volumes to be reclaimed will need to be
evaluated in terms of the amount of restoration needed and proba-
ble costs.  The best time to make such judgments, if a disaster
preparedness plan does not exist, is after the volumes have been
dried and before they are returned to the library or archive
shelves

The following represent basic steps that need to be taken after
drying in order to begin returning the material to normal housing
environments.

Unless a drying company can guarantee in writing that no material
will be returned boxed if it has a water content exceeding 7% by
weight, there is a high possibility that some boxes will contain
damp material that will add to the risks of post drying mold
development, and which, if allowed to develop, will quickly
spread to other uncontaminated material, if left unchecked and
therefore undetected.

It is important when preparing specification for a drying con-
tract that acceptable water content is not specified as an
average of a books total water content.  For instance the text
block of a book may be measured at far less than 7% but the water
content of the book cover boards may contain higher 7% of water.
Therefore it is necessary to specify that the waters content of
all the books composite materials be less than 7%.

Do not store the material in un-opened boxes immediately upon
return from the drying facilities, even if this seems to be the
most convenient action to take.

All books and paper file records should be unboxed and placed on
open shelving in a well ventilated, air-conditioned ~rehabilita-
tion~ area, well separated from the main collections.  The
rehabilitation area makes it easier to assess the condition of
the dried materials, as well as to identify those that can be
replaced and those that must be cleaned and restored.

A carefully organized, random inspection of mold- infected
materials should be conducted daily by personnel trained to carry
out this important task.

Whether materials have or have not been sterilized during the
drying process, it is necessary to monitor their behavior as a
check against the effectiveness of drying and sterilization and
to identify any potential for mold growth and to take the appro-
priate action, before the return of these materials to the main
collections.

We are concerned here with monitoring the ~dried~ volumes while
they are in the rehabilitation area, and after their return to
the main stacks.  This monitoring should be continued at regular
intervals for at least a year after they are returned to the main
library shelving.

In preparing the rehabilitation area, provide about twice the
number of shelves as would be needed for normal book require-
ments.  This will compensate for the effects of distorted and
expanded books and provide sufficient air space to allow the
material to regain their moisture equilibrium content which,
depending upon circumstances, may take a week or two.

Theoretically, equilibrium moisture regain can be accomplished at
the end of a drying run while the material is contained in the
drying chamber.  The chamber can be back filled with moisture to
achieve the desired result.  However this is only possible and
safe if the drying method has been guaranteed to dry the material
completely.  If there remains some partially damp material at the
end of a drying run, back filling the chamber with moisture would
make such material more vulnerable to mold growth.

The rehabilitation area should be maintained at a relative
humidity of 30 to 40 percent and a temperature of less than 65x
Fahrenheit.  Both humidity and temperature controls must be
adjustable.

It is desirable to maintain the collection in the rehabilitation
area for a period of at least six months.  At this time, tempera-
ture and humidity in the rehabilitation area can be gradually
changed to duplicate conditions in the stack areas to which they
will be returned.  At the end of this time, if no mold growth has
occurred, the volumes can be returned to the main stacks and
monitored as indicated above.  It is highly desirable but usually
not practical to leave volumes in the rehabilitation area for an
added six months in an environment that duplicates normal stack
conditions, as a check against post drying mold growth.

No materials should be returned to the main library shelves
without very careful inspection, and preferably not before all
necessary cleaning and restoration has been completed.

EVALUATION OF LOSS
When a flood or fire-damaged collection is covered by insurance,
full settlement of a claim cannot be realized until the lost and
damaged materials have been listed and their values established.
The extent and success of possible restoration must also be
determined.  In the event that a claim is anticipated as a result
of such damage, every item should be salvaged, frozen, and dried.
After drying, the affected materials should be shelved in a
specially equipped environmental storage area, isolated from the
main stacks, and there inspected and monitored over a period of
time.  Such a policy is the best guarantee of sound judgments by
custodians, consultants, and adjusters when they must calculate
the degree of loss as a basis for compensation.

SUMMARY OF EMERGENCY PROCEDURES
Seek the advice and help of book and paper conservators with
experience in salvaging water-damaged materials as soon as
possible.

Turn off heat and create free circulation of air.

Keep fans and air-conditioning on day and night and use dehumid-
ifiers and insure a constant flow of air is necessary to reduce
the threat of mold.

Brief each worker carefully before salvage operations begin,
giving full information on the dangers of proceeding except as
directed.  Emphasize the seriousness of timing and the priorities
and aims of the whole operation. Instruct workers on means of
recognizing manuscripts, materials with water-soluble components,
leather and vellum bindings, materials printed on coated paper
stock, and photographic materials.

Do not allow workers to attempt restoration of any items on site.
This was a common error in the first 10 days after the Florence
flood, when rare and valuable leather and vellum-bound volumes
were subjected to scrubbing and processing to remove mud.  This
resulted in driving mud into the interstices of leather, vellum,
cloth, and paper, caused extensive damage to the volumes, and
made the later work of restoration more difficult, time consum-
ing, and extremely costly.)

Carry out all cleaning operations, whether outside the building
or in controlled environment rooms, by washing gently with fresh,
cold running water and soft cellulose sponges to aid in the
release of mud and filth.  Use sponges in a dabbing motion; do
not rub.  These instructions do not apply to materials with
water-soluble components.  Such materials should be frozen as
quickly as possible.

Do not attempt to open a wet book.  (Wet paper is very weak and
will tear at a touch.  One tear costs at least one dollar to
mend!)  Hold a book firmly closed when cleaned, especially when
washing or sponging.  A closed book is highly resistant to
impregnation and damage.

Do not attempt to remove mud by sponging.  Mud is best removed
from clothes when dry; this is also true of library materials.

Do not remove covers from books, as they will help to support the
books during drying.  When partially dry, books may be hung over
nylon lines to finish drying.  Do not hang books from lines while
they are very wet because the weight will cause damage to the
inside folds of the sections.

Do not press books and documents when they are water soaked.
This can force mud into the paper and subject the materials to
stresses which will damage their structures.

Use soft pencils for making notes on slips of paper but do not
attempt to write on wet paper or other artifacts.

Clean, white blotter paper, white paper towels, strong toilet
paper, and unprinted newsprint may be used for interleaving in
the drying process.  When nothing better is available, all but
the color sections of printed newspapers may be used.  Care must
be taken to avoid rubbing the inked surface of the newspaper over
the material being dried; otherwise some offsetting of the ink
may occur.

Under no circumstances should newly dried materials be packed in
boxes and left without attention for more than a few days.

Do not use bleaches, detergents, water-soluble fungicides, wire
staples, paper or bulldog clips, adhesive tape, or adhesives of
any kind.  Never use felt-tipped fiber or ballpoint pens or any
marking device on wet paper.

Never use colored blotting paper or colored paper of any kind to
dry books and other documents.

Used and damp interleaving sheets should not be reused.

Frequent changing of interleaving material is much more effective
than allowing large numbers of sheets to remain in place for
extended periods.

Newsprint should not be left in books after drying is complete.

A good grade of paper toweling is more effective than newsprint,
but the cost is much greater.




This publication was produced as a public service.  It may be
reproduced and distributed freely in part or in its entirety.
When duplicating individual articles please copy them exactly as
they appear so that proper credit will be given to the originat-
ing institution.

The editors of this publication will be collaborating on addi-
tional projects.  If there are issues which you would like to see
addressed in the future please send your ideas to:

      Preservation Policy and Services Division
      National Archives & Records Administration
      8th & Pennsylvania Avenue, NW
      Washington, DC 20408

      Fax         (202) 219-9324
      E-mail      X6A@CU.NIH.GOV
