Pls find below the excerpts from an article, which I feel would be useful...
Earthquake
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The raised floor greatly increases the difficulty of assuring or determining a seismic rating for a data center. Supporting equipment above the floor on a grid greatly compromises the ability to anchor equipment. Because each installation is different, it is almost impossible to test or validate the seismic rating of an installation. This is a very serious problem in cases where a seismic withstand capability is specified.
In and around Kobe Japan, during the great earthquake of 1995, data centers experienced an extraordinary range of earthquake damage. Many data centers which should have been operational within hours or days were down for more than a month when a large number of supposedly earthquake-rated raised floor systems
buckled, sending IT equipment crashing through the floor. Damaged equipment needed to be fished out and repaired or replaced in complex and time consuming operations.
During the World Trade Center collapse of 2001, nearby data centers which should have survived the tragedy were seriously damaged and experienced extended down time when impacts to the buildings caused raised floor systems to buckle and collapse.
A down time of 5 weeks as was typical near Kobe, corresponds to 50,000 minutes as compared with the 5 minutes per year of downtime required to achieve 5-nines reliability. This is 10,000 times worse than the 5-nines design value. If earthquake downtime is considered 10% of the availability budget, then the data centers near Kobe could not achieve 5-nines reliability unless an earthquake of that magnitude were to occur
only once every 100,000 years, which would not be a realistic assumption.
In areas which are subject to any earthquake activity it is unreasonable to expect 5-nines availability using a raised floor. Even an attempt to do so would be effectively unverifiable. This is one of the reasons why telephone central office facilities do not use raised floors. This is the single most compelling reason why raised floors are no longer desirable for high availability data centers.
I remember in 2001 there are fe datacener destroyed. Also friend of mine was colocated his servers close that area and all of them have been destroyed. Raised floor is not a good idea.
I think it's interesting but you have to realise the physical limitations of not having a raised floor. In our gateways we only run power cabling under the floor as this then allows good airflow from the CCU's. All other cabling runs overhead on cabletrays and fibre raceways.
If there was no raised floor I can't see how you would direct chilled air effectively. Also, if everything was run overhead it would be very difficult to work and manage.
When raised floor must be used in an area prone to earthquakes, you may want to consider the following:
Use Siesmic rated underfloor stands that bolt to the slab and then bolt the racks to the stand.
Use 4' stringers for the raise floor, installed in a herringbone pattern.
Years ago people used to specifiy telecom equipment as NEBS compliant (I believe NEBS was a Belcore Standard). When telecom and data started merging, people started requiring IT equipment to be NEBS compliant as well. My understanding at the time was that NEBS specified how long quipment was supposed to last (i.e. cards saty seated in slots, not shake apart, tip, etc..) based on some test specification of shaking, frequence, etc... I haven't heard anyone refer to this standard in a while and don't know if there is a new standard. But the idea is the same, it's not just the builing infrastructure that must be able to handle a quate but the IT and commuincations equipment as well.
My company WorkSafe Technologies is the leader if protecting mission critical vibration sensitive equipment in an earthquake. I think you might be interested I what we have done for The Boeing Company and Microsoft here in Seattle, Washington. Take a look at our web site if you'd like. www.iso-base.com.
Concern about using Raised floor - Earthquake !
