building services by moeez1

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									Architectural Technology – 6
Assignment: Building Services

                                Submitted by:

                                Abdul Moeez (020)
Building Services:
         A high-rise or we can say any building is not a functional building if it does not have the building
services. No one can inhabit in it until and unless it gets the require building services in the place. HVAC,
air conditioning ducts, Plumbing, sewerage, Trash chutes, laundry chutes, fire fighting, lifts, escalators,
electricity connection etc all these items are the building services in a high-rise.

HVAC system:
    Window and split ACs are used for single rooms or small office spaces. But the central air
conditioning systems are used when large buildings, hotels, theaters, airports, shopping malls etc
are to be air conditioned completely. It is not economically feasible to put window or split air
conditioner in each and every room. Further, these small units cannot satisfactorily cool the
large halls, auditoriums, receptions areas .
Electric cooling equipment can be classified according to the following general categories:
            o Refrigerant Type/Method:
                  DX = Direct expansion
                  Water Chiller
                  Ammonia Chiller

             o Method of Heat Rejection:
                  Air Cooled
                  Water Cooled

       Chilled water air conditioning system:

         Water cooled chillers are the most energy efficient, and in larger tonnages, allow units to be
built that would not be practical in air cooled models. Unlike the air cooled chillers, cooling towers are
an integral part of the chiller system. Their efficiency impacts the over all system efficiency. Therefore,
chiller energy management measures often focus on the cooling tower operation. Variable speed fans
and pumps, improved water treatment systems and better cleaning practices can dramatically impact
the operating costs of the cooling tower.
         In the given figure, one of the long, round tube bundles is the condenser and one is the
evaporator - which are actually shell and tube heat exchangers. The rectangle shaped box is the electric
drive motor and the rounded unit being driven is the compressor. The compressor compresses the
refrigerant into the condenser tube, where its temperature raises. Water from the cooling tower is
circulated through the 'other side' of the condenser heat exchanger, cooling the refrigerant and heating
the cooling tower water. The refrigerant then flows to the evaporator where it is allowed to rapidly
expand, dropping its temperature; cooling tower water is pumped to the tower to be cooled.
         Water from space conditioning coils is circulated on the 'other side' of the evaporator heat
exchanger, which lowers the water temperature and raises the refrigerant temperature. The water is
then pumped to water/air coils located in air handlers that serve the conditioned space; the refrigerant
returns to the compressor where the cycle is repeated.
                                 Image of a water cooled chiller

                                 Relationship diagram for water cooled chiller

         Operating costs for cooling equipment is highly variable with the size and type of equipment.
The most expensive equipment to operate is small, air-cooled unit air conditioners. The most efficient
are the large water cooled centrifugal chillers. Small equipment is rated in EER (Energy Efficiency Ratio)
and large equipment is generally rated in kW per Ton. The higher the value of EER the more efficient is
the equipment, the lower the kW per Ton the more efficient.
                               Figure showing how a water chiller functions

Spaces required for water cooled chiller are as follows:

      Central Air Conditioning Plant Room:
      Air Handling Unit Rooms
      Cooling Tower
      Horizontal ducts to air condition the space
      Operator room

Water supply:
    Gravity tank system:
        We should pay careful attention to zoning the water systems. First, high and low
pressures need to be determined. Plumbing codes usually limit the high water pressure to 80
psi. Using 70 psi will result in more manageable flow rates at the fixtures, reduced water
hammer and lower velocities. These characteristics will result in lower operating costs and a
longer life of the system.
        Figure showing the presence of horizontal distribution for both pressure difference and purging of air.

         A minimum pressure of 40 psi is recommended for the comfort of the end users. With a
pressure differential of 30 psi, a zone can be no more than 69 feet in height (30 ft x2.31 ft/psi). Using a
typical floor to floor height, for a hotel, of 11 feet, no more than six floors can be served by a single
zone. Reduction of the class of valves when a safe working pressure has been reached is a good
professional practice.
         Issue of considering both hot and cold water distribution is the ability to purge air from the
system. The best way to purge air from the system is simply to provide horizontal distribution on the
floor below the highest floor in each zone. This allows the air to collect in each riser and float to the top,
where it is purged every time that a fixture on the top floor is used. This is rarely noticed by the end user
unless the fixture is seldom used. If the water heater is on the roof, a down feed system makes good
        Spaces required for plumbing:

       Gravity tank
       Second gravity tanks
       Water heaters (geysers)

       Drainage and sewerage:

    The building drainage loads must be reasonably estimated to design an effective and healthy
drainage system. The probable loads of the drainage systems in high-rise residential buildings are
investigated and design figures are proposed for the 'fixture-unit' approach. The probable wastewater
discharge flow rate in a group of domestic appliances, for a vertical drainage stack and the
corresponding stack size for high-rise residential buildings are examined, and compared with the design
guides used for local buildings.

Figure (a) showing the detail of sewerage pipe and (b) showing the sewerage pipe functioning on different floors by single pipe.

         Water sanitation is one of the major aspects which cause big problems if not dealt properly. A
maximum pressure of 45 psi is recommended for the drainage of flush and a maximum pressure of 60
psi is recommended for grey water.

                  Core development:
        The size and location of the service core in a high-rise is mostly governed by considerations that
include the basic requirements of meeting fire-egress policy, achieving basic efficiency in human society.
The layout in turn, should serve to maximize returns and to satisfy the requirements of vertical transport
and the numerous vertical service shafts.
        The service core can provide the principal structural element for both the gravity load-resisting
system and lateral load-resisting system, with the latter becoming increasingly important as the height
of the building increases. The core provides the stiffness to restrict deflections and accelerations to
acceptable levels at the top of the building.
        All penetrations for services through the walls of the service core need to be designed to
maintain fire integrity for the prescribed period of time. The core configuration is normally finalized at
an early stage of design development because of its implications for the functional layout of the

Elevator Shaft Configuration:
          One of the first elements to identify the internal configuration is the extent to which vertical
transport will be provided within the building. The architect looks at the elevator grouping and
arrangement that meet design criteria such as average waiting times, handling capacities, and so on.
          A large bank of elevators is the main element in a service core design and all other elements are
designed around it. The vertical transportation of people within a high-rise building will also depend on
local fire regulations. The fire department may require a fire section between the elevator lobby and
elevator shafts.

Elevator Shafts within the Service Core
        Once the location of the service core on the floor plate has been determined, the exact size of
the core needs to be established to calculate the area efficiencies. It is next necessary to define design
criteria for the services shaft and the elevator system. Elevator shaft dimensions can easily be obtained
for all the components of the elevator system.
          In organizing the configuration of elevator banks in the service core, it is necessary to ensure
that a bank of two, three, or four elevators in line shares a common fire-protected shaft without a
dividing structure, so avoiding a single enclosed elevator shaft. If single enclosed elevator wells are
necessary for structural reasons, the designer must ensure air relief slots to allow adequate air relief.

Elevator Lobby Configurations
         "Outward facing" elevators are the most efficient, this is because the lobby is accountable as
part of the net usable area on most typical floors. The lobby of "inward facing" elevators (or two banks
of elevators facing each other) can be included as part of the core but the arrangement is less efficient in
terms of net usable area versus gross floor area. For inward facing elevators, the designer must ensure
that both ends of the lobby are kept open.
As a general guide, for a single line of elevators, a minimum lobby width of 8.2 feet (2.5 meters) is
generally recommended.

Garbage chute:
        Garbage chutes are common in high-rise apartment buildings and are used to collect all
the building's garbage in the one place. Often the bottom end of the chute is placed directly
above a large waste receptacle. This makes garbage collection more efficient and hygienic.
Garbage chutes are mostly made of HDPE (High Density Polyethylene) pipes. The joints are
homogeneous and do not break easily. The whole system is washable and maintenance free. HDPE is
highly durable and has high impact strength for handling all types of garbage. A trolley with wheels is
provided at base for collection of garbage which is then picked by a dump truck.
        To meet the high standards expected at most hotels and buildings, chute doors can be
manufactured from high grade stainless steel.

                        Figure showing the process of garbage chute system
Fire hazard control & exits:
        A fire can rapidly spread and endanger many lives; however, with modern firefighting
techniques, catastrophe is usually, but not always, avoided. To prevent fires from starting, a
firefighter's duties include public education and conducting fire inspections.
          The primary risk to people in a fire is smoke inhalation (breathing in smoke; most of those killed
in fires die from this, not from burns). The risks of smoke include:
      Suffocation due to the fire consuming or displacing all the oxygen from the air;
      Poisonous gases produced by the fire;
      Aspirating heated smoke that can burn the inside of the lungs.

         Often, the main way to extinguish a fire is to spray with water. The water has two roles:
In contact with the fire, it vaporizes, and this vapor displaces the oxygen leaving the fire with not enough
combustive agents to continue, and it dies out. The vaporization of water absorbs the heat; it cools the
smoke, air, walls, objects in the room, etc., that could act as further fuel, and thus prevents one of the
means that fires grow, which is by "jumping" to nearby heat/fuel sources to start new fires, which then
combine. Water may be accessed by pressurized fire hydrant, pumped from water sources such as lakes
or rivers, delivered by tanker truck, or dropped from aircraft tankers in fighting forest fires.
         In high rise construction, the key strategic objectives for fire safety are to allow safe escape for
the occupants without panic, combined with allowing safe unhindered access for the firefighters and
rescue workers to do their job.

Fire-rated glass:
        Fire-rated glass provides protected separation from the flames, heat, smoke and other products
of combustion, which is critical for safe egress. Secondly, the fire must be contained to its place of origin
and prevented from spreading, so that the structure is protected from local or general collapse. This is
due to the advantages of transparency and openness provided by glass, especially promoting easier
vision and therefore less panic and more streamlined crowd movement.
        Fire-rated glass has many applications beneficial for high rise buildings. The stairwells in the
parking garages can now be visually opened for greater security while offering protection from a burning
vehicle or other fires. Adding fire-rated glass also allows natural daylight or passive light to penetrate
dark areas that might otherwise need to use artificial lighting, thus decreasing energy usage and bills.

Open air fire
          For fires in the open, the seat of the fire is sprayed with a straight spray reducing the amount of
water required. A straight spray is used so the water arrives massively to the seat without being
vaporized before. The fire is always fed with air, but the risk to people is limited as they can move away.
It might be necessary to protect specific items (house, gas tank) against infrared radiation, and thus to
use a diffused spray between the fire and the object. Breathing apparatus is often required as there is
still the risk of breathing in smoke or poisonous gases.

Asphyxiating a fire:
       In some cases, the use of water is undesirable:
    Some chemical products react with water and produce poisonous gases, or even burn in contact
       with water (e.g., sodium);
    Some products float on water, e.g., hydrocarbon (gasoline, oil, alcohol, etc.); a burning layer can
       then spread and extend;
       In case of a pressurized gas tank, it is necessary to avoid heat shocks that may damage the tank:
        the resulting decompression may produce a BLEVE.
       Electrical fires where water would act as a conductor.
       It is then necessary to asphyxiate the fire. This can be done in different ways:
       Some chemical products react with the fuel and stop the combustion;
       A layer of water-based fire retardant foam is projected on the product by the fire hose, to keep
        the oxygen in air separated from the fuel.
       CO2, carbon dioxide.

Stand pipe:
        A standpipe or a fire hydrant is a type of rigid water piping which is built into multi-story
buildings in a vertical position, to which fire hoses can be connected, allowing manual
application of water to the fire. Within buildings standpipes thus serve the same purpose as fire
            o Dry stand pipe (dry riser)
            o Wet standpipe (wet riser)

        A "wet" standpipe, unlike the dry standpipe, is filled with water and is pressurized at all
times. In contrast to dry standpipes, which can be used only by firefighters, wet standpipes can
be used by building occupants. Wet standpipes generally already come with hoses so that
building occupants may fight fires quickly.

         Standpipes resolve a number of difficulties in getting water to the upper levels of a structure,
even when it is theoretically possible to use hose line to accomplish this. Standpipes are by definition
anchored to the building and are not prone to shifting. The use of standpipes keeps stairwells clear and
safe for fleeing occupants.
         Standpipes go in a direct up and down direction rather than looping around the stairwell, greatly
reducing the length and thus the loss of water pressure due to friction loss.

Fire sprinkle system:
        A fire sprinkler system is an active fire protection measure, consisting of a water supply
mostly linked with a stand pipe. It is highly recommended for huge commercial buildings. Each
closed-head sprinkler is held closed by either a heat-sensitive glass bulb or a two-part metal link
held together with fusible alloy. In a standard wet-pipe sprinkler system, each sprinkler
activates independently when the predetermined heat level is reached. Because of this, the
number of sprinklers that operate is limited to only those near the fire, thereby maximizing the
available water pressure over the point of fire origin.

Date of access: 10th may
Madison gas & electric
Bright hub
Energy tech pro

11th may
Plumbing engineer
Science links Japan
Arabian business
Architecture week

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