1990 AIC Objects Specialty Group Paper Presentation
THE CONSERVATION ENVIRONMENT AT THE WH MATHERS MUSEUM:
A Long-Term Path to Success
29 May 1990
The basic design concept expressed in the WH Mathers Museum at Indiana
University, is among the best conservation environments found today in museums
of any size. Unfortunately, most new museums don't work right the first day.
In the case of the Mathers, improving the conservation environment to finally
achieve the original design goals has been an on-going process over the past
eight years since construction, and is still not complete.
Several problems have limited the success of the environment, most due to
design changes made before construction, without review or advice from the
conservation environment consultant. Several important problems have been
addressed, including installation of reheat controls for dehumidification, low
ambient controls for the package chiller to allow all-season cooling, trouble-
shooting of the particulate filter failure, and retrofits to the cold box. The
museum still has problems with summer humidity control, evidently due to
inherent system deficiencies due to cost cuts and improper design. With one or
two final modifications, to bring the system consistent with the original
design concept, the Museum should have a conservation environment second to
Most of the improvements are due to the continued efforts of the museum staff,
the Indiana University Engineering Services, and a local engineer who has taken
particular interest in the Mathers Museum environmental performance. After the
consultant leaves, after the architect leaves, after the contractor leaves,
constant diligence with the right resources has proven to yield steady progress
toward a first-class conservation environment. The ultimate responsibility and
ability for achieving a good conservation environment lies with the institution
and the user.
William P. Lull, Principal, Garrison/Lull, PO Box 337, Princeton Junction,
NJ 08550, (609) 259-8050; and,
Ms. Judith Sylvester, Conservator, WH Mathers Museum.
Mr. Thomas C. Dorste, Plus Four Architects, 101 West Ohio Street - Suite
1540, Indianapolis, IN 46204, (317) 684-3100 (design architect).
The William H. Mathers Museum was designed in 1979-1980 as a storage, exhibit
and study facility to support the museum's historic and ethnographic collection
and mission. It was one of the first museums designed with primary priority
given to the conservation aspects of the facility design, anticipating the
current attention to conservation environments. This attention was evidenced
by the participation of a consulting conservator as part of the design team,
and extensive conceptual design development to achieve the conservation
The primary merits of the museum environment, as originally designed and as
- a transition from little natural light in the entry display areas to no
natural light in the main display area, allowing conservation light levels;
- the storage area is one of the first lit with high-pressure sodium lights,
selected for their low ultraviolet light output and high quality lighting;
- a skylight in the conservation lab for natural-light inpainting;
- space for a future fumigation chamber;
- constant volume/minimum outside air HVAC systems, gaseous pollution control
on the outside air, and humidification/dehumidification for humidity
The museum has experienced some difficulty with some aspects of the environment
afforded the collection, many due to lack of follow-through on the original
design concepts, substitutions, and deletions for cost control.
QUALITY OF THE CONSERVATION ENVIRONMENT
Several aspects of the museum environment are consistent with ideal
conservation environment goals.
DAYLIGHT AND LAYOUT. Except for the areas adjacent to the entries, the display
and storage areas have no daylight. Both storage and display have large, open
layouts, providing considerable flexibility. Many small museums are hampered
by the architectural expression in the layout, some with highly modulated wall,
roof and window areas, forcing the exhibit design to make major considerations
of the building design; in contrast, the Mathers layout is an open, clean and
unobstructed "L." Many museums also face a considerable challenge in
maintaining the proper and safe conservation environment due to daylight and
windows in display areas; the Mathers does not have these problems. Adequate
storage is a common problem in small museums, since the design attention is
usually focused on the more glamorous display areas. Most architects assign
storage to the various parts of the design that do not fit other functions,
yielding inadequate and fractionalized areas for storage; in contrast, the
Mathers provides a major storage area and support facilities which show as much
thought and design attention as the display areas.
[Slides available of entry, gallery and storage areas.]
24-HOUR OPERATION. Unfortunately, most museums have either seasonal shutdown
of heating or cooling, or both, and many must fight for continuous fan
operation. The HVAC systems at the Mathers operate continuously, providing
all-season on-demand heating by the museum's hot water boiler/hot water system,
steam humidification boiler, and all-season cooling by the package chiller
(after post-construction "low ambient controls" modification). Constant fan
operation provides constant tempering and filtration.
[Slides available of air-handling units, boiler and chiller.]
OUTSIDE AIR/GASEOUS FILTRATION. The Mathers systems are designed for minimum
outside air. Although the recirculated air is only filtered for particulates,
the outside air is filtered with 1" carbon panel filters in a "V"
configuration. Since the system is not designed for air-side economizer
operation, there is not the threat of high volumes of outside air being
introduced, which recent studies at Battelle Laboratories have shown to lead to
gaseous pollution contamination, as well as excursions in humidity. Although
1" of carbon might not be ideal in an urban environment, it may be appropriate
for rural southern Indiana. The fact that the air has even this modest gaseous
filtration places it in the top 5% of museums for gaseous pollution control.
[Slides available of filter housing and replacement filter panels.]
ADEQUATE WINTER HUMIDITY. Winter humidity generally holds above 40% RH,
protecting the organic collection from the critically damaging effects of low
winter humidity. This is very important for the textiles and ethnographic
materials found in the collection. While the winter humidity is not ideal, it
is superior to the majority of museums found in northern climates, and means
that the annual low-humidity damage that most collections face will not be
visited on the Mathers collection.
[Hygrothermograph of winter humidity.]
LOW TEMPERATURE STORAGE. Although not part of the original design, the cold
storage box provides the character of low temperature storage many new museums
are adding, and many existing museums wish they had. The Cold Box now provides
and average 50% RH, with only the rapid humidity cycling typical of DX cooling,
and with proper collection containerization, this final environmental problem
should be satisfied.
[Slide available of exterior of Cold Box.]
PAST ENVIRONMENTAL PROBLEMS - WHAT IT TOOK TO GET THERE
ENVIRONMENTAL PERFORMANCE PROGRESS. Ms. Sylvester has kept excellent records
of the museum's environment and the efforts over the past several years to
improve the conservation environment.
[Slide of early hygrothermograph performance.]
ORIGINAL HVAC CONCEPT. The original HVAC design concept identified by the
conservation environment consultant, in work with the consulting conservator
and architect, was the use of package "computer room" air conditioning units to
provide reliable heating, cooling, humidification and dehumidification. These
were chosen because they are inherently designed to provide close tolerance
humidity control and 24-hour/all-season full environmental control.
[Slide of typical package systems available.]
ACTUAL HVAC DESIGN. Without review by the conservation environment consultant,
the design engineer changed the design from package computer room units to
chilled-water air-handling units and a package chiller. Although such a scheme
can work and work well, chilled water systems have many more degrees of
freedom, and there are many more chances for such a system to have design
inadequacies to hold proper humidity, as opposed to the package computer room
units (which is why they were recommended). This change and associated system
inadequacies may have been made as part of a cost-reduction program.
Unfortunately, since the changes where not properly reviewed for their impact
on the conservation environment, the cost reductions lead to an inadequate
system, and resulted in an overall greater cost. As feared, the design
engineer did not understand the implications of full humidity control with a
chilled-water system at part-load conditions, and an inadequate system was
[Slide available of air-handling unit.]
REHEAT. The original construction did not provide reheat control operation for
dehumidification, although this is almost always required for dehumidification.
This was immediately evident to Mr. Thomas T. Wells, PE, an interested local
consulting engineer, versed in specialized environmental systems. Upon the
local engineer's recommendation, the University undertook installation of
controls to bring on the heating coils (in the reheat position) to provide
reheat. It is expected that the design engineer had anticipated the need for
reheat, hence the location of the heating coils, but the reheat control was not
made part of the contract documents and was not provided in the temperature
control contractor's design.
WINTER CHILLER OPERATION. There was evidence of problems in the ability to
provide cooling and dehumidification in winter. Since the Mathers had its own
chiller, it should not be subject to any campus-wide reset or shutdown of
central chilled water. Unfortunately, the package chiller at the Museum was
not "winterized," it could not operate at outside temperatures much below 50
degF. Although the chiller was inherently capable of such operation, it needed
an accessory (which could have been installed relatively inexpensively at the
factory) to allow it to operate in cold weather. Again, this problem was
identified by the local engineer, Mr. Wells, and the University undertook
installation of "low ambient" controls to allow the chiller to operate in
winter down to near 0 degF outside.
[Slide available of chiller.]
IMPROVED PERFORMANCE. With these two improvements, reheat and low-ambient
controls, the humidity performance has improved.
[Slide of later hygrothermograph performance.]
PARTICULATE CONTAMINATION. A particulate contamination problem was noted after
moving into the new facility. This initial problem may have been due to
typical particulate generation from the move, and from dust from the shop
located adjacent to storage. An increasing problem was noted however, and upon
inspection, the particulate bag filters were noted to have failed. The failure
was due to a rip in the bag, evidently inherent in the poor design of the
filter frame, which places a pointed metal edge against the bag. The failure
was not detected, because differential pressure gauges were not installed. The
filter was replaced, and current particulate filter operations appear to be
[Slide available of bag filter in frame.]
COLD BOX HUMIDITY. A cold box was added to allow low-temperature storage of
furs and other sensitive organics. Most of these storage systems have
problems, and the initial operation of the Mathers cold storage box was no
exception. The original operation of the cold box had no reheat capability,
causing the box to regularly reach saturation (high) humidity. This high
humidity lead to disuse of the cold box and an expensive insect infestation,
causing considerable damage to the collection.
[Slide of early hygrothermograph performance for Cold Box.]
DESICCANT OPTION. Several people had recommended the installation of a
desiccant dryer. Such systems are required in most cases to hold low humidity,
say 30% RH, at low temperatures; however, they are not very reliable since
their normal maintenance and service are not common knowledge to most HVAC
technicians. In some unfortunate instances institutions have had problems with
desiccant systems. In once case the desiccant compound, silica gel, was blown
into the collection space, resulting in damage to the film collection. The
other popular desiccant, lithium chloride, may cause other problems. This is
why the conservator wanted to avoid such a system.
REHEAT. The local engineer, Mr. Wells, correctly identified that the problem
of high humidity was due to a lack of reheat, since reheat could achieve the
50% RH goal for the storage. The addition of reheat was made by the
PERFORMANCE. The cold room now holds 44% RH +/- 2% RH, at 45 degF +/- 1 degF.
The only remaining instability is the few minutes in each 24-hour period when
the defrost mode brings the humidity to just over 50% RH. Over the next hour
the humidity gradually drops back to 44%. This very short-period humidity
cycling which may not in fact damage the collection, but can be addressed
through the use of storage boxes to buffer the objects in storage.
[Slide of later hygrothermograph performance for Cold Box.]
PROBLEMS STILL FACED
HIGH AND UNSTABLE HUMIDITY
In spite of the improvements provided by the reheat and low ambient controls
for the chiller, the museum environment still exceeds humidity criteria on a
regular basis, primarily in spring, summer and fall, at times actually reaching
highs over 70% RH.
CHILLED WATER TEMPERATURE CONTROL. The chiller currently has return-water
temperature control to allow efficient chiller operation and unloading. The
problem with this is that under part-load conditions, which is virtually all
the time, the chilled water tends to be close to 55 degF, rather than the 42
degF temperature needed for dehumidification. This leads to the inadequate
control of high-humidity seen in the museum.
As identified by the local engineer, Mr. Wells, the chiller should have supply-
water temperature control and hot-gas bypass - options specified in the design,
which the chiller could have had installed at the factory, but which were
deleted by the manufacturer to reduce costs. As field retrofits, these are
more expensive than if the options had been installed at the factory. They are
being considered by the University, and should reduce the upper levels of the
CHILLED WATER COILS. Only 4-row chilled water coils are used. For effective
dehumidification one would expect much deeper coils; the local engineer's
calculations suggest much deeper coils, possibly 10- or 12-row, may be
required. If the improvements from the identified chilled water temperature
control and hot-gas bypass modifications to the chiller do not provide adequate
dehumidification performance, the cooling coils will need to be replaced.
Since deeper coils will require more fan pressure, a new fan/motor may be
WEAK LINKS PERSIST. While reheat and low-ambient controls for the chiller are
part of the solution to the high-humidity problem, as a chain is limited by its
weakest link, so the high humidity problem may persist until the chilled water
control and deeper coils are installed.
STORAGE CONTAMINATION FROM THE SHOP AREA
The Museum workshop is adjacent to the storage area, and is suspected of
exposing the collection to saw dust and other contaminants. Not anticipated in
the early design, fire egress requires a seldom-used door that opens directly
between the spaces. This problem may be addressed by better gasketing of the
door, and better exhaust use and particulate control in the workshop.
THE COST OF NOT HAVING THE PROPER ENVIRONMENT
The criteria set for museum environments to meet preservation and conservation
goals are not purely theoretical or arbitrary; they are intended to create
conditions that extend the life of the collection and protect it from damaging
events. The compromises in the Mathers environment have led to additional
costs to the museum, the University and the collection.
CONSERVATOR'S TIME. Beyond the on-going monitoring of the environment, the
conservator has devoted significant time to following up on the problems with
the environment. This has involved data reduction and analysis of the
hygrothermograph data to characterize the environmental problems, preparation
of memoranda, meetings with museum and University staff, and solicitation of
help from outside the University.
This has required a time commitment from the museum conservator, over and above
normal monitoring tasks, resulting in a cost of to the institution in lost
services. This cost is from time when the conservator could have been working
on more productive tasks more directly related to work with the collection.
"COLD BOX" INSECT INFESTATION. The initial years of improper operation of the
cold box prevented its use to store several specific objects in the collection.
These objects were intended to be in the colder cold box environment to
suppress insect growth. Since the cold box was too moist, they had to be kept
in the general collection area, and a collection-wide infestation of clothes
The infestation caused the need for further attention and time commitment from
the conservator (above the chronic problem attention commitment), insect
extermination costs, labor to handle the collection, and conservation treatment
costs, resulting in a significant cost to the institution.
DEGRADATION OF THE COLLECTION. Separate from the damage to the collection due
to the insect infestation, damage is done to the value and validity of the
collection as it becomes subject to more and more conservation treatments,
making the collection less and less in its natural or original condition.
Every time an object is treated to correct a problem or stabilize a degrading
condition, although the object may have gotten worse if treatment had not been
made, the object is removed from its original condition. It is far better to
have the proper environment and not to have the degrading condition that
damaged the object.
An incalculable expense to the museum and the University comes from this
incremental "loss" of the collection - not only from the pieces that required
conservation due to environmental damage, no mater how non-intrusive the
treatment, but from the many objects that were not damaged sufficiently to
warrant treatment, or the objects that the museum could not afford to treat.
TOTAL COST. These costs, not reflected in the "cost to build the museum," are
nonetheless a direct result of the new museum project. Particularly on small
projects, the conservation environment systems are cost issues since, by
definition, they have been "added" over a conventional design, and are the most
attractive to the uninformed to remove. The TOTAL costs ultimately must be
weighed against the temptations to cut corners on the conservation environment.
The lessons to be learned for the Mathers experience are four:
1. Design changes without reconsideration of the original rationale and goals
can cause considerable compromise to the resulting conservation
environment, although a strong initial design concept may, on the whole,
survive. Be sure the original design concept is executed, and that there
is continued and on-going review and involvement of a conservator and a
conservation environment consultant to catch divergence from the original
2. Design changes to "save money" can be very expensive. Ad-hoc field labor
to augment systems and modify factory-built equipment can cost more than
doing it the "expensive" right way the first time. If the cost of the
damage to the collection is considered, the total cost of "saving money" at
the expense of not achieving critical aspects of the conservation
environment can be considerably more expensive than providing the proper
3. Find an interested local engineer who can provide ongoing council and
advice to identify problems and solutions. There is no substitute for a
good motivated local engineer who can make day-to-day observations, to spot
subtleties, and who can follow up on modifications to be sure they are
4. With a good basic design, a first-class conservation environment can be
achieved for a very modest cost. For substitutions and ill-advised
changes, diligent effort and the right local resources can often still
fulfill the original environmental goals envisioned in the original design.
However, if the original design places unreasonable constraints on the
environment or does not provide the basic systems to achieve the
conservation goals, then very few may be achieved.
Location: Indiana University Campus, Bloomington, Indiana
Programmed area: 14,780 assignable square feet.
Gross area: 26,716 total square feet, over two levels.
Construction Cost:$1,410,926 (1979$) with fixtures and finishes ($1,081,843
(1979$) for shell only);
or a programmed square foot cost of $95 (1979),
or a gross square foot cost of $53 (1979),
Main Gallery - 7,200 square feet (single space)
Main Storage - 6,350 square feet (single space)
Catalog Area - 575 square feet
Lab Support - 745 square feet
Cold Storage Room - 64 square feet, 560 cubic feet, located in Main Storage
Gallery Air System: 11,000 cfm (cubic feet/minute)
Storage Air System: 3,500 cfm
Lab/Support Air System: 1,500 cfm
Filtration: 80-85% ASHRAE Dust Spot
Chiller: 120 Ton (two-stage 60/60 Ton)
348 gpm (gallons/minute) chilled water
Steam Boiler: 520,000 BTU/Hr (for humidification)
Hot Water Boiler: 1,750,000 BTU/Hr (for space heating)
Cold Storage Room: 6,000 BTU/Hr Cooling, 1,650 BTU/Hr Reheat, 0.5 KW.