Chilled ceilings and beams | Archive Titles

Table 1: system selection criteria
Element	Chilled ceiling/ perimeter beam	Passive chilled beam	Active chilled beam
Cooling capacity (W/m² floor area)	80 (with perimeter beam), 40-50 (without perimeter beam)	80-120	80-150. Potential problem with draughts if exceeded.
Ease of maintenance	Minimal – no moving parts	Minimal – limited for cleaning the coil of dust.	Minimal – limited for cleaning the coil of dust.
Layout flexibility	Good – large cooled surface area. Chilled elements are designed to fit into conventional ceiling tiles.	Limited – beams must be positioned at particular spacings. Needs careful planning around grid lines.	Limited – beams must be positioned at particular spacings. Needs careful planning around grid lines.
Acoustics	Good – no moving parts. Possible noise from water flow in pipework attached to ceiling panels.	Good – although may need to generate white noise to compensate for quiet operation.	Good – although may need to generate white noise to compensate for quiet operation.
Aesthetics	Good – ceiling tiles with chilled elements are indistinguishable from normal tiles.	Featured, exposed beams are more aesthetically pleasing. If beam is in ceiling, grille may be different to ceiling tile.	Featured, exposed beams are more aesthetically pleasing. If beam is in ceiling, grille may be different to ceiling tile.
Comfort	Good – uniform coverage due to large numbers of active tiles.	Air discharged downward, so less predictable air movement. May reduce output if above heat source.	Good – predictable air movement patterns due to forced convection.

Table 2: Chilled ceilings and Beams – Cost Comparison
	Fan coil unit £/m2 (gifa)	Chilled ceiling with perimeter chilled beam £/m2 (gifa)	Passive chilled beam £/m2 (gifa)	Active chilled beam £/m2 (gifa)
Shell and core: all figures in terms of gross internal floor area (gifa)
Disposal installation – condensate drainage	1.20
Heat source – gas-fired boilers, gas supply, twin walled stainless steel flues	6.50	6.50	6.50	6.50
LTHW installation
Pipework distribution in plantrooms and risers, pumps, pressurisation unit, water treatment, insulation	7.00	7.00	7.00	7.00
CHW Installation
Roof mounted, air-cooled packaged chiller plant, pipework distribution in plantrooms and risers, pumps, pressurisation unit, water treatment, insulation	25.00	23.00	23.00	23.00
Air handling plant
Supply/extract air handling plant, ductwork to plantrooms/risers, insulation	19.00	23.10	23.10	23.10
Electrical installation – allowance for electrical supplies to mechanical plant	3.90	3.90	3.90	3.90
Controls installation
Head end supervisor, motor control centres, outstations, sensors, controls and all power and controls wiring	13.70	13.90	13.90	13.90
Total shell and core cost	76.30	77.40	77.40	77.40
Category A fit out all figures expressed in terms of net internal area (nia), based on a net:gross efficiency of 75%	£/m2 (nia)	£/m2 (nia)	£/m2 (nia)	£/m2 (nia)
Floor finishes – extra over for:
350mm raised floor void, including cavity barriers, for displacement ventilation		4.00	4.00
Seals to form airtight plenum		5.00	5.00
Forming holes in raised floor tiles and fixing free issue supply air diffusers		0.60	0.60
Dust sealing to underfloor plenum		1.00	1.00
Ceiling finishes – extra over for:
Cost of perforated metal mega panel suspended ceiling suitable for chilled ceiling installation		22.00
Disposal installation – condensate drainage	5.60
1) LTHW Installation
LTHW Distribution, pipework, insulation, connections to fan coil units	17.50
Perimeter heating, pipework, insulation, trench heating installation		26.60	26.60	26.60
2) CHW installation
Chilled water distribution to office areas at high level, pipework, insulation, connections to chilled elements		32.00	29.00	29.00
Chilled water distribution pipework, insulation, connections to fan coil units	26.50
Chilled ceiling elements, 70% active tiles, copper elements, flexible connections, shut off couplings.		69.00
Passive chilled beams, flexible connections, shut off couplings			45.00
Active chilled beams, flexible connections, shut off couplings				50.00
Ceiling mounted four pipe fan coil units	32.10
3 ) Air handling
Supply and extract ductwork, insulation grilles and diffusers	47.20
Supply and extract ductwork, insulation, extract grilles				35.00
Extract only ductwork and grilles		27.20	27.20
Supply only floor grilles		12.50	12.50
4) BEMS installation
Sensors, control valves, power, control and network wiring	12.00	15.00	15.00	15.00
Total Category A fit out cost	140.90	214.90	165.90	155.60
The following exclusions apply to the costs shown in the table: inflation beyond second quarter 2001; general builder's work; main Contractor's preliminaries, attendances, overheads and profit; professional fees and prescribed fees; contingency and design reserves; tax allowances, vat.