This month the Cost Research and Engineering Services Departments of Davis Langdon & Everest examine the capital cost of mechanical and electrical installations for out-of-town office developments. The cost model covers design criteria and costs of a wide range of recent speculative and purpose-built projects to establish cost and specification benchmarks. It is based on the m&e services for a high-quality office building containing a displacement ventilation system, static heating and cooling provided by trench heaters, and a chilled ceiling installation. The costs set out in this cost model are applicable to office developments completed to a Category A fit-out standard.
BACKGROUND TO THE MODEL

Capital costs for services installations in budget rural office developments were examined in the Building Services Journal, November 1995. Since that model was compiled, many recent developments in out-of-town locations have featured building services installations designed to higher specification standards.

Purpose-built schemes featuring mixed-mode ventilation systems, displacement ventilation and static heating and cooling have become increasingly common, although for many speculative developments, fan-coils are the preferred option where air conditioning is required.

In common with urban offices, BCO specification standards have not been widely adopted for out-of-town developments. Table 1, summarises key design criteria extracted from the latest edition of the BCO guidance. The highest and lowest values identified from the study of the design criteria of a range of recent projects are also given.

PROJECT DETAILS

Cost datum 1 quarter 1999

Location Outer London

Gross internal floor area (GIFA) 12 000 m²

Nett lettable area (NLA) 9500 m²

Procurement route Construction management, with competitively tendered lump sum Trade Contract packages

Project contract period 18 months

MAIN DESIGN PARAMETERS

External design temperatures
Winter -48C (saturated)
Summer 298C db/208C wb

Internal design temperature Offices 22°C ± 2°C

Occupant density Climate control 1:10 m² - Toilet provision 60/60@1:10 m²

Fresh air ventilation 23 litres/s/person

Cooling loads Small power 20 W/m² - Lighting 15 W/m²

Primary power Equipment 20 W/m² - Lighting 15 W/m²

Lighting Office areas 500 lux

Public health installation Sanitary fittings WC suites, wash basins, cleaner's sinks, disabled toilet facilities, showers
£4.30/m² GIFA
£5.45/m² NLA

Domestic hot water Local electric heaters, pipework distribution, insulation and trace heating
£2.00/m² GIFA
£2.55/m² NLA

Disposal – soil, waste and ventilation Above ground internal pipework – cast-iron and uPVC
£4.55/m² GIFA
£5.75/m² NLA

Disposal – rainwater Above ground cast-iron and aluminuim gutters and drainpipes, connections to below ground drainage
£4.00/m² GIFA
£5.05/m² NLA

Cold water services Mains incoming water service, storage tank, booster pumps, pipework distribution, water treatment and insulation
£4.80/m² GIFA
£6.05/m² NLA

Public health total
£19.65/m² GIFA
£24.85/m² NLA

MECHANICAL SHEEL & CORE SERVIES

Heat source Gas-fired boilers approximately 1400 kW. Duty, twin-walled stainless steel flues, gas supply
£4.50/m² GIFA
£5.70/m² NLA

LTHW installation

Pipework distribution in plantrooms, cores and risers, pump, pressurisation unit, water treatment, insulation, radiators/convectors to circulation areas, over door heaters to entrance
£13.70/m² GIFA
£17.30/m² NLA

Chilled water installation Roof-mounted, air-cooled packaged chiller plant approximately 1500 kW. Duty, pipework distribution in plantrooms, cores and risers, pumps, pressurisation unit, water treatment, insulation
£30.40/m² GIFA
£38.40/m² NLA

Toilet ventilation Extract plant, ductwork, grilles, insulation and attenuation
£3.00/m² GIFA
£3.80/m² NLA

Air conditioning Supply and extract air handling plant, ductwork, insulation in plantrooms, cores and risers (excluding humidification)
£16.40/m² GIFA
£20.70/m² NLA

Testing and commissioning Testing and commissioning of mechanical and public health installation services including operating and maintenance manuals and record drawings
£0.90/m² GIFA
£1.15/m² NLA

Dry riser Riser including landing valve and inlet box (sprinkler installation not required)
£0.50/m² GIFA
£0.65/m² NLA

Building energy management system Centralised energy management system comprising motor control centres, isolators, starters and all controls, outstations, riser network and monitoring, including head-end equipment
£18.80/m² GIFA
£23.75/m² NLA

Mechanical services total
£88.20/m² GIFA
£111.45/m² NLA

ELECTRICAL SHELL & CORE SERVICES

Mains/sub-mains distribution LV switchgear, hv cabling, distribution boards, lv sub-mains cable distribution, sub-mains distribution to mechanical plant, rising busbar and cable containment system
£19.70/m[sq} GIFA
£24.90/m² NLA

Small power Power outlets to landlord's areas
£0.70/m² GIFA
£0.90/m² NLA

Lighting Luminaires and wiring to landlord's areas
£9.20/m² GIFA
£11.60/m² NLA

Atrium lighting Luminaires and wiring
£2.80/m² GIFA
£3.55/m² NLA

External and feature lighting Luminaires and wiring
£3.70/m² GIFA
£4.70/m² NLA

Voice/data wireways Cable tray in risers
0.20/m² GIFA
£0.25/m{sq] NLA

Fire alarm Fully addressable fire alarm and smoke detection installation to L2 BS 5839, including spare capacity for future tenant extension
£2.50/m² GIFA
£3.20/m² NLA

Security CCTV, intruder detection, wireways for access control
£3.60/m² GIFA
£4.55/m² NLA

Earthing and bonding
£1.30/m² GIFA
£1.65/m² NLA

Lightning protection
£1.75/m² GIFA
£2.20/m² NLA

Electrical services total
£45.45/m² GIFA
£57.50/m² NLA

CATEGORY A FIT OUT

Electrical services Underfloor busbar power distribution system excluding floor outlet boxes
£7.90/m² GIFA
£10.00/m² NLA

Modular fluorescent luminaire to LG3 category 2, high frequency, including emergency packs, trunking, conduit, wiring, accessories and integral controls
£26.90/m² GIFA

£34.00/m² NLA

Fire alarm and smoke detection installation, fully addressable to L1
£3.90/m² GIFA
£4.95/m² NLA

Earthing and bonding
£1.20/m² GIFA
£1.50/m² NLA

Total Category A electrical services
£39.90/m² GIFA
£50.45/m² NLA

Mechanical services and public health services installation Displacement ventilation system with static heating and cooling, comprising chilled beams and ceiling panels together with perimeter heating.

Chilled water pipework distribution and insulation
£35.00/m² GIFA
£44.20/m² NLA

Static cooling elements; chilled beams to 3 m perimeter zone; chilled ceiling elements to 80% of ceiling tiles (cost of ceiling tiles excluded)
£60.00/m² GIFA
£75.80/m² NLA

LTHW pipework distribution and insulation
£10.60/m² GIFA
£13.40/m² NLA

Ductwork for displacement ventilation; supply only floor diffusers
£7.35/m² GIFA
£9.30/m² NLA

BEMS/controls installation including individual intelligent water side control to chilled beams and ceilings and perimeter heating
£17.40/m² GIFA
£22.00/m² NLA

Perimeter heating; trench heating elements
£13.70/m² GIFA
£17.30/m² NLA

Testing and commissioning
£0.90/m² GIFA
£1.15/m² NLA

Total Category A mechanical services and public health services installation
£144.95/m² GIFA
£183.15/m² NLA

Total Category A fit-out cost
£184.85/m² GIFA
£233.60/m² NLA

EXCLUSIONS

  • Inflation beyond first quarter 1999;
  • External works including statutory authority connection charges;
  • HV substation;
  • Construction managers' fees, site establishment and attendances;
  • Professional and prescribed fees;
  • Contingencies and design reserve;
  • Below slab drainage;
  • Specialist air treatment, power and fire suppression installations to computer rooms, etc;
  • Services to teapoints/kitchens;
  • Wiring and equipment for voice, data, pa, tv and satellite installations;
  • Hand dryers, drinking fountains, macerators;
  • Handheld fire-fighting equipment;
  • Tax allowances;
  • Value Added Tax.

    • Source

    Building Sustainable Design

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