ARCHITECTURAL TECHNOLOGIES

ASSIGNMENT:

“SERVICES IN HIGH RISE BUILDINGS”

SUBMITTED BY:

AMMAD HAIDER

CIIT/FA06_BAR_006/ISB

12TH MAY, 2010.

HVAC SYSTEM:

The HVAC system brings outdoor air into a building, humidifies or dehumidifies it, and heats or cools it to meet the ventilation and thermal comfort needs of the occupants and to dilute the contaminants inside the building.

A typical HVAC system consists of a supply air system, a return air system, and an exhaust air system. It generally also contains heating and cooling units, a humidifier, air filters, and fans, which treat and move the air. Controls are used to ensure that the system functions as desired.

Supply air is a mixture of outdoor air and return air (recirculated air) that is treated, conditioned, and supplied to the room by the HVAC system.

Return air is air from the room that is recirculated into the mixing chamber by the HVAC system.

Exhaust air is the air from the room that is exhausted from the building by the HVAC system.

Mixing Chamber: The mixing chamber is the location in which the outdoor air and the return air are mixed so that the supply air is relatively uniform in temperature. Mixing is especially important in the winter when the outdoor air can be significantly colder than the return air.

Air filters: All supply air is passed through filters to remove dust, smoke, and other particulate air pollutants. Some filters include absorbent media, which

remove some gaseous pollutants. Filters must be changed according to the manufacturers recommendations.

A typical HVAC system has three basic components. These components are: (a) outdoor air intake and air exhaust ducts and controls; (b) airhandling units (a system of fans, heating and cooling coils, air filters, controls, etc.); and (c) an air distribution system (air ducts, diffusers, and controls; return and exhaust air collectors; grilles and registers; return and exhaust air ducts and plenums).

THE RETURN AIR SYSTEM : The return air system removes a portion of the supply air from the

occupied zones and returns this air to the airhandling units for exhaust or recirculation. One of two methods is used to return air to the HVAC system: the ducted return or the plenum return (the plenum is the space between the finished ceiling and the floor slab above). Ducted returns collect air from each room or zone using return air devices in the ceiling or walls of the occupied spaces that are directly connected by ductwork to the air-handling unit. The plenum return collects air from several rooms or zones through return air devices that empty into the negatively pressurized plenum.

The effectiveness of the return air system plays a key role in indoor air

quality since the HVAC system can only exhaust, filter, or condition indoor air that is returned to the handling unit.

Regardless of whether the HVAC system has a ducted return or a plenum return, increasing the seal integrity of the return air system and air-handling units will help to ensure that more air is returned to and reconditioned by the air-handling unit. This can be accomplished by improving the seam seals, recoiling and replacing failed gaskets, and sealing unlined structural conduits.

AIR MOVEMENT:

Most problems in high-rise residential buildings result from the interplay between movement of air, moisture and heat. Winds can exert significant pressures, forcing air into a building and drawing it out through leaks and cracks in the building envelope.

The effect of air leakage on building performance is significant. It can cause considerable occupant discomfort and contribute to deterioration of buildings through moisture damage.

In winter, the vertical air movement of stack effect results in cooler air entering the lower levels of a building and rising as it warms.

The taller the building and the greater the temperature difference between the inside and outside, the greater the stack pressure. Lower levels tend to be under heated, while upper levels are overheated. This effect can also cause back drafting and uncontrolled smoke movement during fires.

Tightening the building envelope helps counter the movement of air caused by the stack effect. It prevents moisture migration into and out of the building envelope, improves occupant comfort and reduces energy costs. It allows for the integration of smaller, more appropriately sized mechanical systems, which also reduces operating costs.

Moisture can result in the deterioration of building cladding systems over time and cause other structural damage. Cracks and penetrations in the building envelope provide opportunities for moisture or water penetration, which can lead to mold and rot within the walls, as well as more visible damage.

Key means for protecting against moisture and water damage

in high-rise buildings include improved detailing and construction procedures, shedding water away from the building envelope, pressure-equalized rain screen wall systems and improved air leakage control.

WATER SUPPLY IN HIGH RISE BUILDINGS:

In the overhead system, the main flow pipe runs as directly as possible to the top floor, and then is run horizontally, drop risers being taken out wherever required, these pipes entering a main return in the basement, which carries the return water back to the boiler, the drop risers thus doing the work of flow and return. This system probably provides more evenly heated water than most other systems of supply

Water supply from single boiler Water supply from double boiler

FIRE HAZARDS AND CONTROLS WATER SPRINKLER SYSTEM:

The water supply fire pump and standpipe are ready to have fire sprinkler cross mains and branch lines with sprinklers added to complete a fire sprinkler system.

FIRE RATED WALLS:

The wall assembly is used to protect the emergency staircases from fire to enter into the area for at least one hour.

EMERGENCY EXITS AND STAIRWAYS:

The most important function that we ask of a building in case of fire is that it let people reach safety quickly. An alarm system must alert them immediately to the presence of fire. Manually operated alarm boxes must be provided and identified by signs at frequent intervals in a building. Automatic alarm systems, which sense smoke, heat, flame, or the ionization products of combustion, are becoming increasingly common. 

CORE DEVELOPMENT-VERTICAL CIRCULATION, CHUTES AND RISERS:

GARBAGE CHUTES: This system provides an effective infrastructure to enhance recycling in high rise building.

Centralized recyclables chute is conveniently accessible to all residents.

Flexible storage capacity customized to suitbuilding conditions.

Minimum storage space required at chutechamber compared to conventional system.

Can be integrated with different collectionsystems such as pneumatic conveyance system, direct discharge to rear-end loader truck, wheel bins etc...

Can be retrofitted to existing buildings.

FREIGHT ELEVATORS AND DUMB WAITERS:

Dumb waiters that are used in situations when light lifting solutions are required.

Freight elevator is used in high rise factories and other buildings serving the needs of vertical movement of goods. These lifts are corrosion resistant and resistant to fire hazards that can protect goods and people from accidental losses.