The Fiber Optic Association - Tech Topics
Architects
and building engineers
take note: your rules and mind set for the design of future office
buildings will change. Specifically, the size of and need for
wiring closets will be reduced. Eventually, wiring closets can
disappear! This reduction in size and importance is due to two
trends, which have been and, currently, are gaining importance
and strength. These two trends are: the increasingly frequent
justification for fiber to the desk [FTTD]; and voice over IP
[VoIP].
Fiber to the desk is finding increased acceptance because of several
factors, the most important of which is reduced initial installed
cost. This reduced initial installed cost results from reduction
or elimination of three sets of costs.
The first of these sets is the cost for construction. With commercial
costs in the range of $100-$200 per square foot, elimination of
ten foot by fifteen foot wiring closets in a ten story building
saves $150,000 to $300,000.
The second of these sets is the cost of network equipment in the
closets. Such equipment includes hubs, switches, enclosures and
patch panels. This equipment is replaced with ports in a centrally
located distribution facility. This relocation results in at least
two cost reductions: reduced cost/port through increased port
utilization and reduced network maintenance costs, Since this
equipment is not completely eliminated, but relocated, it is difficult
to quantify the size of this cost reduction.
The third of these sets is the support costs, which is the cost
of equipment required to support the network equipment in the
closets. These support costs include the costs for racks, cable
trays, surge suppression, dry fire suppression and dedicated
environmental
control. The largest of these costs tends to be the cost for dedicated
environmental control.
When containing substantial electronics, closets must have dedicated
temperature control. This control compensates for two common
conditions.
The first condition is the need for reverse control during the
cool season. In cool seasons, electronics in wiring closets need
cooling while the rest of the building needs heating. The second
condition results from energy conservation: many commercial office
buildings have no, or minimal, the environmental control during
weekends. The cost of dedicated control can be $5000-$20,000 per
closet, or $50,000 to $200,000 for a ten story building with one
closet per floor. When these three sets of costs are reduced or
eliminated, it is possible to achieve total saving of $500,000
for a ten-story building with one closet per floor. Recently,
a BICSI RCDD justified use of fiber to the desk even though the
fiber switch blades were nearly three times the cost of UTP switch
blades.??call mike to check out this reference
??find quote for Getty museum @$50,000/closet
The old argument against fiber to the desk has been increased
cost of the fiber electronics. [Note that the cable and connectors
have been at cost parity with UTP costs for several years.] While
this argument has some validity, it ignores the most important
cost, which is total installed cost. When the support costs of
wiring closets are eliminated, the fiber electronics can be more
expensive than UTP electronics and still allow for a total initial
installed cost which is less than that of the horizontal UTP/vertical
fiber design. Believe it or not, fiber becomes cheaper than UTP!
Recent work by Pearson Technologies Incorporated and the Fiber
Optic LAN subcommittee of the EIA demonstrates this new reality.
This work has resulted in a cost model and spreadsheets that
demonstrate
reduced initial installed cost in certain scenarios for both new
builds and retrofits.
When the fiber to the desk design is used, there is no need for
wiring closet space for electronics and supporting hardware. In
the model, the connections between horizontal and vertical riser
fibers are by mechanical splices, which can easily be housed in
a wall-mounted enclosure. Such an enclosure is smaller and less
expensive than rack mounted enclosures, which include integral
patch panels and volume for fiber service loops. Because of this
reduced size, such wall mounted enclosures can be mounted anywhere
in office space and do not need a closet for their use!
Fiber to the desk network designs result in a reduction in the
space required in closets. Closet size and cost can shrink. In
fact, the cost model assumes only a 50 % reduction in the size
and cost of the wiring closets. With this reduction, a number
of the fiber to the desk scenarios offer initial installed costs
which are lower than those for the horizontal UTP, vertical fiber
network design.
The wiring
closets are still required
for telephone connections. However, when VoIP is integrated into
the network, such connections are already provided by the fiber
to the desk design. Then, wiring closets become unnecessary. With
this elimination of wiring closets, the cost model supports fiber
to the desk more strongly than at the present.
In addition to changes in wiring closets, architects and building
designers will respond to changing requirements elsewhere in the
building. With increased fiber counts in the vertical riser, architects
will need to increase conduit sizes. With increased number of
connections and electronic ports in the central distribution facility
[CDF] for network services, architects will need to increase the
CDF size. This facility, in the basement or at another central
location, will require increasing space to accommodate the ports
which were in the separate wiring closets. The use of the small
form factor connectors and their electronics will reduce this
increase in space to less than one for one.
These changes in rules and mind set will have consequences for
those other than architects and building designers. The manufacturers
of mechanical splices, wall mounted enclosures, small form factor
fiber connectors, and 100BaseSX electronics will see increased
opportunities. Switch manufacturers will find demand for increased
fiber port count switches. Cable manufacturers will find demand
new designs with higher fiber counts in smaller cables for riser
applications. The 600 µm buffer tube may become the king
of the indoor network. The MT type connectors may find increased
use in the CDF.
Small form factor connector manufacturers will find increased
demand for their products, since their size enables reductions
in enclosure volume, cost and room size in the CDF.
In conclusion, fiber to the desk is not a technology justifiable
in the future. It is a technology justifiable now. Architects,
building engineers and network planners need to reexamine their
network design decisions to ensure that initial installed cost
and life cycle cost analyses support their decisions to implement
anything other than FTTD!
Eric R.
Pearson, CPC, CFOS
President
© 2002 Pearson
Technologies
Incorporated