User Manual

Basics in archives and libraries
16
Building Technologies 049_Archives_and_Libraries_A6
V10271399_a_en.doc
Fire Safety & Security Products 03.2009
– Objects rarely consist of a single material. They are often made up of different
materials with sometimes very different requirements (e.g. a book made of paper
with leather binding furnished with metal closing). In this case, the range of cli-
mate aimed for can only be a compromise.
– The chemical decay process is, amongst others, dependent on temperature and
humidity, whereas high temperatures and high humidity speed up decay. Fur-
thermore, relatively low humidity can lead to brittleness and damage in organic
materials.
– Unfavorable climatic conditions can lead to pest infestation (e.g. mould).
– The users would like a comfortable climate while they are working, where they
neither have to sweat nor be too cold. On the other hand objects would prefer it
in general cooler at modest relative humidity.
– Not every effort is justifiable. How much effort can be made with high or low out-
side temperatures in order to stay within the climatic target area?
Climate fluctuations
Together with the absolute climate values, climate fluctuations must also be borne
in mind. A slow, seasonal shift of the climate values within certain limits is seen as
unproblematic and it makes sense in an ecological and economical way. Excessive
temporary fluctuations on the other hand should be avoided if possible which can
be achieved by e.g. solid construction of the building. Buildings above ground are
usually subject to higher temperature fluctuations than those under ground,
whereas those under ground more often struggle with humidity of the earth sur-
rounding them or even ground water.
If certain object groups have to be stored cool such as chemically unstable film and
photo material for example, it must be ensured that an acclimatization zone (sluice)
lies between the storage zone and the processing zone, so that the objects can
adapt to the appropriate climate. If this is not allowed for, it can result in damaging
condensation on the objects.
Climatisation
Active climatisation (as opposed to passive climatisation) is always connected with
a relatively large technical effort and therefore investment costs and overheads.
Practically speaking, construction and building materials are chosen in such a way
that as little as possible active climatisation is needed and that the building’s cli-
mate is stable in itself.
Depending on the usage frequency of the rooms, the rate of the air exchange can
be kept relatively low (comparatively high “air age”). This way, the purified and
converted air volume as well as the flow speed of the air can also be kept low.
Early specification of achievable, moderate climate requirements which mainly
considers the requirements of the items to be stored creates the basis for finding
an appropriate climate solution which is sustainable long-term.
Tuning of ventilation and air conditioning systems always takes place over a longer
time period (very often up to one year!). This phase should be completed fully
and
successfully before
the users move into the rooms. Parallel measuring of the cli-
mate values by the user in this phase has proven very useful to realize system
malfunctioning.