NU BU1 W2 Hot and Cold Water Supply PDF

Building Utilities 1 Hot and Cold-Water Supply  Building Utilities 1 Household Water Supply Public water distribution Household water supply Direct pressure...

Building Utilities 1 Hot and Cold-Water Supply  Building Utilities 1 Household Water Supply Public water distribution Household water supply Direct pressure distribution House service/ main Indirect pressure distribution Riser Branches  Building Utilities 1 Provisions of Water Distribution System adequate supply with adequate pressure sufficient valves and blow offs for repair without interruption and to allow flushing closed and protected reservoir and avoid cross connections with inferior water system tight connections to avoid leakage, avoid submerged mains and branches effective circulation of water with minimum dead ends Guarded against contamination from repair works, replacement or extension of mains Lay the mains above and away from sewers  Building Utilities 1 Cold Water Supply System Building Classification and Its Basic Requirements Small Dwellings Large Buildings a. All water except a. Directly from the drinking water mains via supply pipe supplied indirectly from cistern/s b. Preferable for b. Indirectly from a drinking water be cold-water storage directly supplied from cistern the water main c. Combination  Building Utilities 1 Direct vs Indirect Water Supply System  Building Utilities 1 Direct vs Indirect Water Supply System Direct water supply Indirect water supply  Building Utilities 1 Combination Direct and Indirect Water Supply System  Building Utilities 1 Cold Water Supply 1. Normal water pressure from the public main 4. Direct 2. up-feed Overhead pumping feed system system 3. Air pressure distribution system  Building Utilities 1 Normal water pressure from the public main  Building Utilities 1 Overhead Feed System Advantages Disadvantages 1. Water supply distribution 1. The water inside the tank is not affected by the peak is exposed to the natural load hour even if the elements thus it may be pressure at the water contaminated. main becomes low. 2. Power interruptions will not 2. The system has many parts affect the water supply inside thus requires high maintenance the building cost. 3. In case the pumping unit 3. The pumping unit and the breaks down, the time required entire installation occupies to replace parts will not affect valuable space. the regular supply of water. 4. Requires stronger foundation to sustain heavy load  Building Utilities 1 Air Pressure Distribution System Advantages Disadvantages 1. Compact pumping unit 1. In case of power failure requires limited space. therefore loss of air pressure and loss of supply, add stand-by generator. 2. The air-tight water chamber makes it more sanitary. 3. The oxygen in the compressed air serves as purifying agent, making it more palatable. 4. Offers economy by installing smaller pipe diameter. 5. Few parts therefore less initial construction and maintenance cost. 6. For small, medium and large buildings. 7. It serves zones of 10 storeys or floor interval in buildings of extreme height.  Building Utilities 1 Direct Up-feed Pumping System Advantages Disadvantages 1. Used on tall buildings that could 1. Depends on electricity, stand-by not be served adequately by generator is necessary. main. 2. Delivers at optimum rates up to full demand. 3. Various pumps equipped with sensors and with different capacities work depending on the volume of water demand. 4. The programmed sensor allows minimum and maximum operating pressure, therefore the pressure is constant, less maintenance cost. 5. Eliminates construction of large house water tank. 6. Avoids cost of heavy structures/foundation to carry the house tank.  Building Utilities 1 Hot Water Supply System Hot Water Supply System Types Storage Type Instantaneous Type Boiler System Electric Gas fired Multi-point Single-point  Building Utilities 1 Direct vs Indirect Hot Water Supply System Directly supplied heater Indirectly supplied heater 1. Constant flow rate needed to maintain 55° C temperature difference between 1. High installation cost feed water and heated water 2. Pressure and flow variations will affect temperatures at outlets 2. Constant pressure from storage for shower and other fittings give more stable temp. control 3. Showers are not recommended due to loss of constant temp. control & pressure 4. Use only thermostatically controlled shower mixer