DCD Design Note 130.0

Feynman Computer Center Network Rewiring:

Third Floor Infrastructure

Darryl Wohlt

March 1, 1999

The data communications wiring on the third floor of the Feynman Computer Center (FCC) needs to be augmented and ultimately replaced by a new cabling system that provides high-bandwidth dedicated media and centralized management.

This Design Note incorporates air-blown fiber technology, which has been successfully used in several Fermilab locations including the second floor of FCC, to extend this centralized dedicated media system to the third floor. Each desk will have a nearby data outlet with at least one fiber receptacle, which is in turn cabled via a tube cable infrastructure to a central fiber distribution system (Fibrmax), and therein patched to a dedicated port in the central network electronics.

The initial work will be the installation of a "backbone" infrastructure consisting of multi-cell tube cables, stemming from the building concentration point on FCC2E to three tube distribution units (TDUs) strategically placed on the third floor. This work package will include the installation of new outlets in select offices, which will connect to the TDUs via single-cell tubes.

All subsequent wiring requests will be handled by the new cabling plant. An effort will be launched to replace old wiring throughout the third floor. The existing FCC 333 wiring concentration point will operate until no longer needed, then dismantled.

The total cost for labor and materials to install the basic infrastructure and 11 office drops is estimated to be $37,724.71 .

Three tube distribution units (TDUs) will be positioned in the northeast, northwest and southcentral areas of FCC3, such that each will cover roughly one third of the data outlet locations on the floor. The existing Hoffman box in the FCC3E electrical closet will become one of these TDUs, and new boxes will be installed in the other two locations.

A bundle of 19-cell tube cables will be pulled from the FCC2E Fibrmax TDU to the FCC3E TDU. There will be enough cells in this bundle to connect to every outlet box on the third floor (based on an estimated maximum).

A proportionate number of 19-cell tube cables will run from the FCC3E TDU to the other two TDUs on the third floor.

A trail of bridle loops and/or J-hooks will be installed above the suspended ceiling along the hallways, all the way around the floor. This hardware will suspend the 19-cell tube cables and all of the 1-cell tubes (at least part of the way) to be pulled from the TDUs to their respective outlet boxes.

Six (6) riser-rated 19-cell tube cables will be pulled between the FCC2E Tube Distribution Unit (TDU) (behind and below Fibrmax Rack 2) and the existing Hoffman box in the FCC3E electrical closet. At least one additional 2-1/2" hole will need to be punched in the FCC2E TDU, six holes will be required in the bottom of the FCC3E TDU, and four holes will be needed in the top of the FCC3E TDU.

The FCC2E electrical closet has a concrete floor which is approximately even with the raised floor in the computer room, hence the tube cables from the underfloor TDU must penetrate the closet wall above floortile level. These floor and wall penetrations must be sealed and covered.

The tube cables will then pass behind the FCC2E closet’s Hoffman box on their way up to the FCC3E closet, pass through the existing floor penetration, and terminate in the FCC3E TDU.

Figure 1. FCC2E: Tube cables from TDU to electrical closet

The existing Hoffman box in the FCC3E electrical closet will be used as the FCC3E TDU. 1-cell tube cables will be pulled from here to local office outlet boxes and the DCG Lab, and 19-cell tube cables will connect this TDU to the other FCC3 TDUs.

Figure 2. FCC3E TDU and tube cables to other TDUs

A 24"x20"x8" Hoffman box will be pre-punched (in a designated shop area), painted, then wall-mounted as a TDU just below the hallway ceiling, above the left entrance door to FCC 311, with three (3) 4-inch conduit stubs extending from the top of the box through the suspended ceiling. A double trail of 4" bridle loops or J-hooks will run above the suspended ceiling between this TDU and the FCC3E TDU, each pair spaced no more than 4 linear feet from the next pair. This hardware may be clamped to the beams where possible, or screwed into the corrugated steel ceiling.

Two (2) 19-cell riser-rated tube cables will be pulled from the top of the FCC3E TDU to the FCC3NW TDU, and properly terminated for tube coupling. These tube cables will follow one trail of bridle loops or J-hooks, leaving the other for 1-cell tube cable distribution.

Figure 3. FCC3NW TDU and tube cables to FCC3E TDU

In the same way, another 24"x20"x8" TDU will be pre-punched and installed above the left entrance door to FCC 328, and two 19-cell tube cables will be pulled from it to the FCC3E TDU.

A third trail of ceiling-mounted loops or hooks will run between the FCC3SW and FCC3NW TDUs, following the hallway passing offices 325-306-302. This trail will carry 1-cell or multi-cell tube cables from either the FCC3NW or the FCC3S TDU to office locations in this area.

 
Figure 4. FCC3SW TDU and tube cables to FCC3E TDU

All fibers blown to FCC3 will terminate in the FCC2E Fibrmax, Rack 2, Housing 3. When this housing fills to capacity, a new housing will be mounted at the same height in Rack 3.

The TDU previously installed below Fibrmax Rack 3 was recently moved to Rack 1. Another TDU needs to be installed in its place, and pre-punched for a maximum number of 19-cell tube cables.

This project installs 114 cells to FCC3, and a Fibrmax housing holds up to 180 fiber pairs. Some of the fiber bundles blown to the office outlets may be 3-pair rather than 1-pair, and it is possible that at some point a second Third Floor Fibrmax housing will be needed. Rather than guessing how many of the six 19-cell cables we should run to the Rack 3 TDU in anticipation or pulling additional 19-cell cables to it, this design calls for connecting the FCC2E Rack 2 TDU to the Rack 3 TDU via the adjacent side panels. Fiber bundles from FCC3 can then follow the original tube cable path to the Rack 2 TDU and, if necessary, be conveniently diverted to Rack 3.

The TDU-TDU connection can be made using a pair of 4" conduits between the two TDUs, or any suitable combination of pipes that provides enough capacity for all floors. Since the Rack 3 TDU is empty and the Rack 2 TDU is still fairly open, this is a good time to get this done. The convention will be that new tube cables are to be connected to the Rack 3 TDU only when the Rack 2 TDU is filled, unless there is a substantial argument to do otherwise.

The installation of office outlets will follow the FCC2 model and the pertinent DHG Tech Notes. A 1-cell tube cable will be pulled from each outlet box to the nearest FCC3 TDU, using the bridle loop/J-Hook suspension system. Additional loops/hooks will be installed along the route where needed.

The SM6 outlet box may be installed over existing faceplate locations with an adapter, or in a new outlet location. It will be fitted with one or three dual-SC connector bulkhead(s), and a 1-pair or 3-pair fiber bundle will be blown to it from the Fibrmax. If installed over an old outlet, that wiring will be abandoned and should also be removed to whatever extent possible. If it is a new outlet location, a 4"x4" electrical box will be mounted inside the wall 36" above the floor, and a 1" flexible conduit will be extended upward from the box’s upper righthand corner to a point approximately 12" above the horizontal wall support at the ceiling. The conduit can then be bent to meet the incoming cabing from the bridal suspension system. The SM6 box will be mounted to the electrical box.

The office outlet locations selected for this part of the project are:

• FCC 344 (DCG Lab, 3 pairs)
• FCC 341 (both walls)
• FCC 342 (north wall)
• FCC 326 (NW wall)
• FCC 326a (SE wall, 3 pairs)
• FCC 328 (SE wall)
• FCC 328 (SW wall)
• FCC 328a (west wall)
• FCC 335 (west wall, 3 pairs)
• FCC 339 (east wall)
• FCC 340 (west wall, 3 pairs)

The cost for labor and materials is broken down in the following spreadsheets. Related drawings follow the spreadsheets.

Figure 5. Locations of TDUs on FCC3

Figure 6. Locations of DCG outlets

Figure 7. Locations of ESE outlets