Positive Pressurization And Ventilation; Cleaning Procedures And Equipment - Oracle StorageTek T9840 User Manual

Positive Pressurization and Ventilation

Low efficiency filters are almost totally ineffective at removing sub-micron
particulates from the air. It is also important that the filters used are properly sized
for the air handlers. Gaps around the filter panels can allow air to bypass the filter as
it passes through the air conditioner. Any gaps or openings should be filled using
appropriate materials, such as stainless steel panels or custom filter assemblies.
Positive Pressurization and Ventilation
A designed introduction of air from outside the computer room system will be
necessary to accommodate positive pressurization and ventilation requirements. The
data center should be designed to achieve positive pressurization in relation to more
loosely controlled surrounding areas. Positive pressurization of the more sensitive
areas is an effective means of controlling contaminant infiltration through any minor
breaches in the room perimeter. Positive pressure systems are designed to apply
outward air forces to doorways and other access points within the data processing
center to minimize contaminant infiltration of the computer room. Only a minimal
amount of air should be introduced into the controlled environment. In data centers
with multiple rooms, the most sensitive areas should be the most highly pressurized.
It is, however, extremely important that the air being used to positively pressurize
the room does not adversely affect the environmental conditions in the room. It is
essential that any air introduction from outside the computer room is adequately
filtered and conditioned to ensure that it is within acceptable parameters. These
parameters can be looser than the goal conditions for the room since the air
introduction should be minimal. A precise determination of acceptable limits should
be based on the amount of air being introduced and the potential impact on the
environment of the data center.
Because a closed-loop, re-circulating air conditioning system is used in most data
centers, it will be necessary to introduce a minimal amount of air to meet the
ventilation requirements of the room occupants. Data center areas normally have a
very low human population density; thus the air required for ventilation will be
minimal. In most cases, the air needed to achieve positive pressurization will likely
exceed that needed to accommodate the room occupants. Normally, outside air
quantities of less than 5% make-up air should be sufficient (ASHRAE Handbook:
Applications, Chapter 17). A volume of 15 CFM outside air per occupant or
workstation should sufficiently accommodate the ventilation needs of the room.

Cleaning Procedures and Equipment

Even a perfectly designed data center requires continued maintenance. Data centers
containing design flaws or compromises may require extensive efforts to maintain
conditions within desired limits. Hardware performance is an important factor
contributing to the need for a high level of cleanliness in the data center.
Operator awareness is another consideration. Maintaining a fairly high level of
cleanliness will raise the level of occupant awareness with respect to special
requirements and restrictions while in the data center. Occupants or visitors to the
data center will hold the controlled environment in high regard and are more likely
to act appropriately. Any environment that is maintained to a fairly high level of
cleanliness and is kept in a neat and well organized fashion will also command
respect from the room's inhabitants and visitors. When potential clients visit the
room they will interpret the overall appearance of the room as a reflection of an
96 T9840 URM
December 2012