Out-of-town Commercial offices | Archive Titles

TABLE 1: Key design criteria for out-of-town offices
Design criteria	Specification standard
	BCO Best practice in the specification for offices	Cost model	DLE survey (lowest value)	DLE survey (highest value)
Occupational density indoor climate control (person/m²)	1:14	1:10	1:14	1:10
WC provision (gender split/person/m²)	60/60@1:14	60/60@1:10	50/50@1:12	50/50@1:12
Fresh air ventilation (litres/s/person)	8-12	23	10	23
Cooling loads
Small power (W/m²)	15	20	15	25
Lighting (W/m²)	12	15	15	16
Primary power
Equipment (W/m²)	15-25	20	15	25
Lighting (W/m²)	12	15	15	18
Lighting
Office areas (lux)	350-400	500	400	500
An analysis of the capital costs of recent projects is summarised in Table 2, Out-of-town offices cost summary, which compares schemes developed using a variety of mechanical systems. The wide range of costs is a reflection of the range of standards to which systems have been designed and the variation in quality that can be expected from scheme to scheme. It is also due to variation in the extent of fit-out that is provided as part of the Category A fit-out. Other variables, including location, programme, procurement route and contract, and market conditions also need to be factored into the capital cost equation.

TABLE 2: COST SUMMARY (£/m² GIFA)
System	Cost model	(displacement with static cooling)	Air conditioned	(fan coil units)	Mixed mode	(displacement ventilation)	Mixed mode	(cross ventilation )
Range within analysis	Low	High	Low	High	Low	High	Low	High
Element
Public health (£/m² GIFA)	15	25	15	25	15	25	15	25
Mechanical (£/m² GIFA)	200	260	160	225	160	200	125	200
Electrical (£/m² GIFA)	85	110	90	120	85	140	75	140
The costs are at 1st quarter 1999 price levels, based on an outer London location. They include allowances for a main contractor’s discount where appropriate. The costs of the main contractor/CM’s fees, overheads and profit, management, site establishment and attendances are excluded. Costs also exclude external works and contingencies.