In this latest cost model, the Cost Research and Engineering Services Departments of Davis Langdon & Everest and Mott Green & Wall examine the capital costs of structured cabling installations. A number of recent commercial projects have been examined to establish benchmark costs for IT installations.
Background to the model

Fast and reliable communications, together with the ability to present, analyse and store information are the cornerstones of all commercial enterprises.

The increasing processing power of computers and the availability of cheap telecommunications has resulted in organisations becoming reliant on the efficient and secure functioning of their IT installations. This will increase as the use of electronic commerce grows.

The role of a structured cabling system is to ensure that changes to staff turnover, voice and data systems can be accommodated at minimal cost without additional cabling or rerouting. They should also be specified with sufficient bandwidth capacity for future changes.

Costs of structured cabling have fallen significantly, and its benefits are such that it is being specified on some projects to provide distribution for climate and lighting control, bems connections and other IT connections in ceiling voids.

This model provides detailed costs for a structured cabling installation in a financial institution, and identifies the different costs associated with on-floor IT distribution for trading floors and general office space. Indicative rates for a range of key system components are also given.

IT cabling is provided by diverse routing with two or more sub-equipment rooms per floor and outlet boxes fitted to desks and wired on an alternate 'salt-and-pepper' basis.

Cost drivers

The principal drivers influencing the cost of a structured cable system are:

  • cable quantity – significant discounts on cable costs are available on larger communications fit-out projects – costs for Category 5 (enhanced) cable can range from £0.40 to £1.00, depending on the project size and the degree of price competition achieved;

  • density of grid outlet points – a high density of sub-floor outlet points allows flexibility of space planning and a high level of diversity, with adjacent desks fed from different sub-equipment rooms (sers);

  • number of sers and vertical risers – multiple sers and risers on each floor increases flexibility and resilience. An enhanced installation may require base build modifications to provide additional riser capacity. The maximum permissible run of Category 5 cable is 90 m and, on very large floor plates, three or four sers may be necessary to provide diverse feeds to all workstations;

  • containment – IT cable is typically clipped directly to the sub-floor or laid in the basket. To avoid potential cable damage or degraded performance, where tray or basket is used cable mat should be specified. Manufacturers of the proposed category six cable will not provide performance guarantees unless the installation meets quality standards;

  • cable quality – the additional cost of material associated with using Category 5 enhanced copper cable is approximately 10%.

    PROJECT DETAILS

    Cost datum 2nd quarter 1999 Gross internal floor area (GIFA) 26 000 m2 Net internal area (NIA 18 600 m2 Trading floor occupancy One person per 7·2 m2 General office space occupancy One person per 10 m2 Procurement route Construction management with competitively tendered trade contract packages Value of structured cabling trade contract £1 500 000

    INSTALLATION COSTS

    PABX room Positioning, connecting and interlinking free issue distribution frames and cabinets for pabx and primary cables, complete with terminal strips £5.00/m2 NIA - £47.80/person Main equipment room Positioning, connecting and inter-linking optical fibre frames within free issue cabinets
    £5.00/m2 NIA - £47.80/person Vertical cabling (voice) Category 3, 100 pair, multi-core copper cable from voice frames to sub-equipment rooms (sers), including links between sers (allow £350 per run)
    £1.30/m2 NIA - £12.40/person Vertical cabling (data) Category 5 (enhanced), four pair, multi-core copper cable from main equipment room to sers, including links between sers (allow £40 per run)
    £9.00/m2 NIA - £86.00/person Multi-core fibre optic cable, from main equipment room to ser, including links between sers (allow £600 per run)
    £2.10/m2 NIA - £20.00/person Sub-equipment rooms Positioning, connecting and interlinking free issue terminal frames, patch panels and cabinets for voice and data services, based on a minimum of two sers per floor
    £6.00/m2 NIA - £57.30/person Horizontal cabling Combined voice and data cabling using Category 5 (enhanced), four pair, multi-core copper cable from frames in ser to desk-mounted outlet boxes Allowance for trading floors based on a 1·8 m x 1·8 m grid @ £90/m2 of affected area (allow £300/point)
    £12.80/m2 NIA - £122.30/person Allowance for general office and support space based on a 2·4 m x 2·4 m grid @ £30/m2 of affected area (allow £180/point)
    £25.70/m2 NIA - £245.50/person Desk-mounted outlet boxes, strain relief bracket, 5 m-long Copex flexible protective conduct. Floor grommets by others Trading floor allowance based on ten-way outlet boxes with RJ45 sockets on a 1·8 m x 1·8 m grid @ £22/m2 of affected area (allow £72/point)
    £3.10/m2 NIA - £29.60/person Allowance for general office and support space based on six-way outlet boxes with RJ45 sockets, spaced on a 2·4 m x 2·4 m grid @ £8/m2 of affected area (allow £45/ point)
    £6.90/m2 NIA - £65.90/person Testing and commissioning
    £3.50/m2 NIA - £33.50/person Specialist contractor's preliminaries and site establishment at 7%
    £5.60/m2 NIA - £53.50/person Total
    £86.00/m2 NIA - £821.60/person

    INDICATIVE COMPONENT RATES

    Rates are applicable to contracts valued at over £1 500 000. On small projects, Category 5 copper cable can cost up to £1 per metre. Copper cable prices have fallen substantially over the last year due to reduced costs of raw materials, competition in the market place and improved installation practices. Frames Supply and install unloaded 8 m x 8 m cabinet; 47 u height, including cabinet supports and earthing
    £750-£900 each Supply and install unloaded patching frame, including frame supports and earthing
    £500-£600 each Supply and install full loaded 24-way patch panels
    (voice) £80-£100 each (data) £100-£120 each Cable Twelve core fibre optic cable, including connectors
    £6-£7/m Four pair Category 5 enhanced lsf cables, including tying and cable labels
    £0.40-£0.50/m 100 pair Category 3 lsf cables, including tying and cable labels
    £4/m Outlets Ten-way outlet box (desk-mounted only); fully loaded; split conduit and strain relief anchor point; including forming and termination of outlets
    £70-£75 each Six-way outlet box (desk or floor box mounted); fully loaded; split conduit and strain relief anchor point; including forming and termination of outlets
    £40-£45 each Four-way outlet plate; fully loaded; fixed to sub-floor; excluding floor grommet and flexible conduit
    £20-£25 each Allowance for patching flyleads; 5 m long; including RJ45 terminations both ends
    £5 each Cable management Fully addressable proprietary on-line database
    £85 000-£150 000 Manually updated spreadsheet database including all initial data entry
    £25 000

    EXCULSIONS

  • Free issue cabinets and frames to equipment rooms;
  • Termination of service providers' incoming cables within pabx and main equipment rooms;
  • Service providers' connection harges;
  • Telephone switch equipment and handsets;
  • IT equipment;
  • Voice/data cable containment systems, cable mat, three compartment outlet boxes to raised floors in office areas;
  • Small power installation;
  • Specialist installations to computer rooms including air conditioning, clean power, ups and fire suppression;
  • Builder's work in connection, including the lifting of floor tiles and supply of cable grommets;
  • Construction manager's fee and resource costs;
  • Professional and prescribed fees;
  • Contingencies and design reserve;
  • Inflation beyond 2nd quarter 1999;
  • Tax allowances;
  • Value Added Tax

    • Source

    Building Sustainable Design

    Topics