servicing large buildings

Services for large buildings

Increase in size requires new solutions

Big buildings need big ideas

• Holes in the wall can ventilate small buildings

• Holes in the walls can’t ventilate deep buildings

• Ducted mechanical ventilation needed

Ventilating deep buildings

• Mechanical air handling needed to reach the interior

• Large ducting needed to move air around in large volumes at low speed

• Increased building volume needed to accommodate the large ducting

• Servicing costs both directly (air handling systems) and indirectly (increased building size to house mechanical plant) raise the basic costs of large buildings.

Water supply in tall buildings

pump

Pressure release valves now needed

Water to short buildings delivered by gravity, no problems

Water to tall buildings

• Just scaling up a small system doesn’t work

• Pumping needed• Only stored water can be used, so

health problems• Pressure in pipe work can be immense

at lowest levels• Then you need hot water too…

Heating tall buildings

Boiler plant

Pressure enormous at base, water too hot

Pressure low at top, water too cold

High temperature fluids transport heat more efficiently.

Circulating, very high temp steam

Boiler plant- generating high temp, high pressure steam

Heat exchangers on each floor (calorifiers) Use steam to heat low pressure water locally

Protecting enclosure needed, steam is dangerous

Heating tall buildings

• Again, scaling up small plant doesn’t work

• High temperature steam needed• Local calorifiers and heating controls

needed, probably on each floor• Safety is endangered, so protected

enclosures and warning systems needed

• Heating tall buildings is expensive.

Air-conditioning tall buildings

Individual, local a/c units can be used. This is madness, messy, environmentally disastrous, noisy and uses up all the available wall space.

Centralised a/c

Cooling plant, usually on top floor, vents heat, creates and circulates very cold water

Local air intake, air cooled by cold water

OR

Ducted conditioned air from air conditioning plants every 10 floors or so

And there’s more

• What about electricity?– 240V AC will not provide enough power for

a large building, it’s only enough for a single house.

– 3 phase power supply is needed, which is far more dangerous

– Protective enclosures needed for the high tension supplies, which are tapped for a 240 V supply at each floor

Electricity supply for tall buildings

High tension bare copper conductors, “Bus bars” run up a protected service shaft. Provide “3 phase” supply

Each floor taps off a single phase, 240V supply from one live bus bar and the neutral bar

Where’s the floor space gone?

• Services for multi-storied buildings devour floor space.

• We haven’t even put the lifts and stairs in yet

Hang the services on the outside?

• Pompidou Centre, Paris• HSBC HQ, Hong Kong

Stick them on top?

• “Chippendale Building” New York

• Seagram building, New York

Plan view

Service tower

Office floor

What about lifts?

• Multi-storey buildings have lots and lots of people in them

• One lift for 1,000 people on 100 floors is not going to work very well…

Double Decker lifts

• Simple solution which halves the problem

• Each floor of the lift serves alternate floors in the building

• Escalator needed to the second lowest level

• Problems arise with disabled access.

• Building must have an even number of floors and all floor heights identical…

Multiple lifts

• Several lift shafts will help, but they take up an enormous amount of floor space

• The ground floor of a modern skyscrapers may have 25-33% of its ground floor area devoted to lifts and lobbies.

Multi-level lift grouping

Sky lobby

Sky lobby

Ground lobby

High speed lifts just between lobbies

Zoned lifts served by lobbies

In some large buildings there may be several lifts in a lift shaft, one above the other.

Sky lobby, Central Plaza building Hong Kong

• Sky lobbies often used for café’s gardens, a/c equipment, anything to make people forget that they are having to change lifts, whether they want to or not

Burj Dubai: tallest building in the world

Summary

• Servicing tall and large buildings is highly complex, inevitably expensive and in some cases dangerous.

• Qualified services/mechanical engineer needs to be part of the design team

• Do not scale up small service installations to meet the needs of large buildings, it doesn’t work

• Article about use of a sky lobby in Austriahttp://www.architectureweek.com/2002/0130/environment_1-1.html