ºÃÉ«ÏÈÉúTV

Read our policy.

City office development Part L cost breakdown
Ìýelement cost (or saving)cost/m2 gfa £% of total cost
Part L (2002) compliant scheme Construction cost of base scheme17,800,0001,913.98Ìý
Shell and core 9,300 m2 @ 1,640ÌýÌýÌý
Category A fit out 6,375 m2 @ 400ÌýÌýÌý
ÌýÌýÌýÌý
Enhancements to scheme to comply with Part L 2005: Option 1 40% glazingÌýÌýÌý
External walls, windows and doors81,4008.75Ìý
Extra over double glazed curtain walling; for solar-control glass; average U-value improvement from 2.2 to 2.0 1,300 m2 @ 40ÌýÌýÌý
Extra over paint-backed glazed panels for improved insulation; average U-value improvement from 0.35 to 0.27 1,960 m2 @ 15ÌýÌýÌý
Extra; increase airtightness to achieve 7 m3/hr/m2. No cost addition as standard is already achieved with unitised curtain wall 3,260 m2 @ nilÌýÌýÌý
Heat source, space heating, air treatment and ventilation(174,500)(18.76)Ìý
Extra for; increased efficiency of condensing boilers to 89% 460kW @ 15ÌýÌýÌý
Saving for; reduced boiler capacity and pipework sizes due to improved facade performance and heat recovery; reduction of 350 kW (350)kW @ 275ÌýÌýÌý
Extra for: coefficient of performance for air cooled chillers increased to 3.1. No cost addition as chillers are typically specified to achieve this COP 806kW @ nilÌýÌýÌý
Saving for; reduced chiller capacity and pipework sizes due to improved facade performance and heat recovery; reduction of 275 kW (275) kW @ 315ÌýÌýÌý
Saving for; reduced power loads to mechanical plant, reduced sizing of sub-mains distribution Item @ (5,000)ÌýÌýÌý
Extra for; allowance for heat recovery installation to air handling plant; run-around coils Item @ 6,500ÌýÌýÌý
Builders’ work in connection2,0000.22Ìý
Extra over costs of additional builders’ work in connection with heat recovery installation Item @ 2,000 ÌýÌýÌý
Preliminaries and contingencies(18,900) (2.03)Ìý
Contractor’s overheads, site establishment and site supervision Allow 17% Item @ (13,900)ÌýÌýÌý
Contingency sum Allow 5% Item @ (5,000)ÌýÌýÌý
ÌýÌýÌýÌý
Construction cost – building only including costs of Part L compliance 17,690,0001,902.16Ìý
Extra over costs of Part L compliance(110,000)(11.82)(0.62)
ÌýÌýÌýÌý
Enhancements to scheme to comply with Part L 2005: Option 2 100% glazing, high performance glass, fixed louvresÌýÌýÌý
External walls, windows and doors522,40056.17Ìý
Extra over double glazed curtain walling; high performance glass; average U-value improvement from 2.2 to 1.8 3,260 m2 @ 40ÌýÌýÌý
Extra; increase air tightness to achieve 7m3/hr/m2. No cost addition as standard is already achieved with unitised curtain wall 3,260 m2 @ nilÌýÌýÌý
Extra; fixed external shading 2,450 m2 @ 160 ÌýÌýÌý
Heat source, space heating, air treatment and ventilation(57,800) (6.22)Ìý
Extra for; increased efficiency of condensing boilers to 94% 470 kW @ 40 ÌýÌýÌý
Saving for; reduced boiler capacity and pipework sizes due to improved facade performance and heat recovery; reduction of 340 kW (340) kW @ 275ÌýÌýÌý
Extra for: water cooled chillers in lieu of air cooled Item @ 10,000 ÌýÌýÌý
Saving for; reduced chiller capacity and pipework sizes due to improved facade performance and heat recovery; reduction of 340 kW (340) kW @ 315ÌýÌýÌý
Extra for; distribution circuit to water cooled chiller; complete Item @ 100,000 ÌýÌýÌý
Saving for; reduced power loads to mechanical plant, reduced sizing of sub-mains distribution Item @ (5,000)ÌýÌýÌý
Extra for; allowance for heat recovery installation to air handling plant; thermal wheel Item @ 19,000ÌýÌýÌý
Builders’ work in connection1,0000.11Ìý
Extra over costs of additional builders’ work in connection with heat recovery installation Item @ 1,000 ÌýÌýÌý
Preliminaries and contingencies104,40011.23Ìý
Contractor’s overheads, site establishment and site supervision Allow 17% Item @ 81,000ÌýÌýÌý
Contingency sum Allow 5% Item @ 23,400ÌýÌýÌý
ÌýÌýÌýÌý
Construction cost – building only including costs of Part L compliance18,370,0001,975.27Ìý
Extra over costs of Part L compliance570,00061.293.20
ÌýÌýÌýÌý
Enhancements to scheme to comply with Part L 2005: Option 3 100% glazingÌýÌýÌý
External walls, windows and doors735,00079.03Ìý
Extra over double glazed curtain walling; for low-e coating; average U-value improvement from 2.2 to 2.0; no additional cost as standard already achieved with curtain wall 3,260 m2 @ nilÌýÌýÌý
Extra; increase air tightness to achieve 7m3/hr/m2. No cost addition as standard is already achieved with unitised curtain wall 3,260 m2 @ nilÌýÌýÌý
Extra; motorised external shading 2,450 m2 @ 300ÌýÌýÌý
Heat source, space heating, air treatment and ventilation(57,800)(6.22)Ìý
Scope of works and costs as breakdown for Option 2ÌýÌýÌý
Electrical installations10,0001.08Ìý
Extra for; power supplies to motorised louvres 200 @ 50ÌýÌýÌý
Special installations50,0005.38Ìý
Extra for; control wiring to motorised louvres 100 @ 500ÌýÌýÌý
Builder’s work in connection4,0000.43Ìý
Extra over costs of additional builders’ work in connection with heat recovery installation and motorised louvres Item @ 4,000ÌýÌýÌý
Preliminaries and contingencies158,80017.08Ìý
Contractor’s overheads, site establishment and site supervision Allow 17% Item @ 121,800ÌýÌýÌý
Contingency sum Allow 5% Item @ 37,000ÌýÌýÌý
ÌýÌýÌýÌý
Construction cost – building only including costs of Part L compliance 18,700,0002,010.76Ìý
Extra over costs of Part L Compliance900,00096.785.06
ÌýÌýÌýÌý
External walls, windows and doors 551,30059.28Ìý
Extra; increase airtightness to achieve 7m3/hr/m2. No cost addition as standard is already achieved with unitised curtain wall 3,260 m2 @ nilÌýÌýÌý
Extra over costs of; externally ventilated double wall facade with motorised blinds in lieu of standard unitised curtain wall; average U-value 1.60 2,450 m2 @ 225ÌýÌýÌý
Heat source, space heating, air treatment and ventilation (57,800) (6.22)Ìý
Scope of works and costs as breakdown for Option 2ÌýÌýÌý
Electrical installations10,0001.08Ìý
Extra for; power supplies to motorised louvres 200 @ 50ÌýÌýÌý
Special installations50,0005.38Ìý
Extra for; control wiring to motorised louvres 100 @ 500ÌýÌýÌý
Builders’ work in connection4,0000.43Ìý
Extra over costs of additional builders’ work in connection with heat recovery installation Item @ 4,000 ÌýÌýÌý
Preliminaries and contingencies122,50013.17Ìý
Contractor’s overheads, site establishment and site supervision Allow 17% Item @ 94,500ÌýÌýÌý
Contingency sum Allow 5% Item @ 28,000ÌýÌýÌý
ÌýÌýÌýÌý
Construction cost – building only including costs of Part L compliance18,480,0001,987.10Ìý
Extra over costs of Part L compliance680,00073.123.82
Key performance criteria to meet Part L standards
General design criteria
Occupancy8 m2/person
Outside air rate10 l/s/person
Small power load15 W/m2
Ìý
Option design criteriaBase Option 1Option 2 Option 3Option 4
Ìýscheme40% 100% 100 %100%
ÌýPart L glazingglazing, highglazing, glazing,
Ìý(2002) solar performancemotoriseddouble wall
Ìýcompliantcontrol glass, fixed louvresfacade with
ÌýÌýglasslouvresÌýmotorised
ÌýÌýÌýÌýÌýlouvres
Ìý
Glass U-value (W/m2K)2.202.001.802.001.60
Cladding U-value (W/m2K)0.350.27ÌýÌýÌý
Heating load (kW)810460470470470
Cooling load (kW)1,080806740740740
Power (kW)770550470470470
Solar heat gain52%42%18%18%18%
Lighting load (w/m2)1312121212
Heat recovery; ÌýÌýÌýÌýÌý
run-around coilsÌý50%ÌýÌýÌý
Heat recovery; thermal wheelÌýÌý70%70%70%
Airtightness @ 50 Pa, ÌýÌýÌýÌýÌý
m3/hr/m2107777
Boiler efficiency80.8%89%94%94%94%
Air cooled chiller ÌýÌýÌýÌýÌý
coefficient of performance2.253.1ÌýÌýÌý
Water cooled chiller ÌýÌýÌýÌýÌý
coefficient of performanceÌýÌý4.04.04.0