User Manual

Siemens Switzerland Ltd 34
Building Technologies Division
Room preparation
When a room is being prepared to host an extinguishing system, some key
integrity aspects have to be taken into account:
• All windows have to be fixed closed or automated to be operated by the
extinguishing control system, before the extinguishing agent is
released.
• Doors have to be automated (magnet device or similar) to automatically
closed by the extinguishing control system, before the extinguishing
agent is released.
These aspects are mandatory according to VdS in Germany, and strongly
recommended for all systems in other countries.
Door fan test
The data center is an environment where many different technologies are
installed and constantly maintained. Therefore, several different suppliers enter
the premises to update, service or replace infrastructure. This also means the
room is often physically changed, because of new cabling being installed,
modifications in ducts and trays and unavoidable new openings being drilled.
The tightness of the room is the key factor to assure the extinguishing agent
concentration build-up, Siemens strongly recommends that door fan tests are
performed before installing the extinguishing system and then regularly once or
twice a year.
The door fan test offers a simple, cost-effective and environmentally friendly
method for measuring room tightness. To test a room, a fan is placed in the
entrance door. It blows air into the extinguishing area to create a positive
pressure or removes air from the room to create a negative pressure, creating an
overpressure or partial vacuum of approx. 50 Pa, and allowing any leaks to easily
be located.
The door fan tests yield two important results:
• Predicted hold time: An indication of how long the protected area will
retain the extinguishant for
• Equivalent Leakage Area (ELA): The total area of leakage
Room cleanness after
installation of an
extinguishing system
Since the beginning of the extinguishing practice in data centers, high
importance has been given to the fact of using “clean” agents. That is the reason
why inert gas and chemical agent systems have such a great acceptance for this
application: no residue and no need for cleaning up after a discharge. This topic
is of key relevance when infrastructure highly sensible to dirt and dust particles is
present, like servers and disk-drives in data centers. After discharge of an
extinguishing system, and during the entire flooding process, there will be air
flows and turbulences within the protected room. This is normal in every
extinguishing process, and in all type of technologies. Therefore, special
attention should be paid to the cleanness of the room, when extinguishing
systems are installed. The risk of blowing years of cumulated dust and dirt on
cabinets and other objects, into the sensitive equipments, is unacceptable. The
sensitivity of IT infrastructure to dust and dirt is so high, that in many cases the
data center rooms work with a positive room pressure, means they have
constantly a higher pressure than the rest of the building, so no particles can get
into the data center when doors open (due to the overpressure).