design &
facilities Management
As with traditional or newly
designed data centres, a key
consideration when choosing a
raised floor is: What loadings,
especially point loadings, will
the incoming equipment impose
upon the floor? Once these are
known, the choice of a raised floor
designed and manufactured to the
PSA Specification will ensure that it
carries a ‘3’ times safety factor.
For a data centre, design loadings
of not less than 4.5kN over a 25mm
square and Uniformly Distributed
Load (UDL) of not less than 12kN/
m2 form part of the PSA Heavy
Grade Specification, but in certain
circumstances the PSA Extra Heavy
Specification may be adopted – this
calls for a four point load of 11kN to
be applied equally on four points,
each of 25mm 2 , on a 200mm x
200mm square configuration at any
point on the system.
Evidence should be sought from
an independent third party to prove
that the system offered complies
with these requirements. Generally
this would be from a UKAS
accredited organisation such as
Building Testing Limited of Woking.
However, data centre floors
are having to carry ever greater
loads as more cooling equipment
is added to computer and server
cabinets to deal with the increased
heat they are generating as a
result of the massive flow of
electronic information.
As a result, there is a
requirement for loadings that
exceed even the Extra Heavy
rating, and manufacturers have
responded by producing systems
with new pedestal and stringer
designs to give more than twice the
Extra Heavy Specification loading.
Having chosen the performance
requirements of the raised floor, ie.
point load and UDL, consideration
should also be given to how the rack
and other equipment is to be moved
into place – the static load applied
to a raised floor can be increased
quite dramatically by dynamic loads
as the equipment is positioned.
Therefore it is frequently the case
that spreader plates will be used
during the fit out stage.
No containment
Physical containment
Cooling needs
On a daily basis, there is no
greater strain put on a data centre
than the need to continually cool
IT equipment. In fact, up to 50
per cent of a data centre’s total
annual energy consumption can
come from its cooling needs,
which obviously makes the
question of how to be both more
effective and more efficient a
question constantly on the minds
of facility managers.
In response, raised access floor
manufacturers can now provide
virtual containment systems that
dramatically reduce bypass airflow
and maximise the amount of
airflow which can be captured and
used to cool equipment.
Unlike traditional airflow
panels, virtual containment utilises
directional airflow panels which
angle airflow toward the face of the
rack, nearly eliminating bypass air
while increasing cooling capacity
and energy efficiency. These panels
can achieve a 93 per cent Capture
Index – the amount of air delivered
through the panel that directly
enters the face of the server rack
in front of that panel - significantly
reducing the amount of bypass air.
Additionally, advances in
directional airflow panel design
have introduced multi-directional
panels where airflow is split evenly
and angled in two directions. This
allows for directional airflow to
racks on either side of a cold aisle in
a legacy data centre that has only
Virtual containment
May 2017 | 21