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 suit
building conditions.
• Minimum storage space required at chute
chamber compared to conventional system.
• Can be integrated with different collection
systems 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.
