FIN SERVICES IN TALL BUILDING High rise building

Services in tall buildings

1. PIPES The pipe material is selected while keeping in view the forces to be resisted by it . The usual stresses to which pipes are subjected are as follows: (1) stress due to change of direction, (2) stress due to internal water pressure, (3) stress due to soil above the pipes, (4) stress due to water hammer, (5) stress due to yielding of soil below pipes, and (6) temperature stresses. The final selection of material for the pipe is done by considering various factors such as availability of fund, type of water to be conveyed, carrying capacity of the pipe, maintenance cost, durability, etc. Following are the various materials which are used for pipes: (1) Asbestos cement pipes (2) Cast-iron pipes (3) Cement concrete pipes (4) Copper pipes (5) Galvanised iron pipes (6) Lead pipes (7) Plastic pipes (8) Steel pipes (9) Wood pipes (10) Wrought-iron pipes.

2. (1) Asbestos cement pipes: made from a mixture of asbestos fiber and cement. used to convey water under very low pressure and their use in conveying and supplying water. Advantages : Disadvantages : ( i ) The inside surface of pipes is very smooth. ( i ) The pipes are brittle and cannot be also expected (ii) The joints are easily formed. to resist vibrations of traffic when placed under road. (iii) Pipes are anti-corrosive and cheap in cost. (ii) The pipes are not durable. (iv) pipes are light in weight, easy to handle and (iii) The pipes cannot be laid in exposed places. transport. (v) The pipes are very suitable for distribution (iv) The pipes can be used only for very low pressures. pipes of small size.

3. 2) cast iron: The cast-iron pipes are manufactured from pig-iron and the inner and outer surfaces of the pipes are given suitable treatment for granting protection against corrosion. Depending upon the ability to withstand pressure, the cast-iron pipes are sometimes classified into four categories, namely Class A cast-iron pipes can withstand a pressure of 60 m head; those of Class B, 120 m of head; those of Class C, 180 m of head; and those of Class D, 240 m of head. Advantages: ( i ) The cost is moderate. (ii) The pipes are easy to join. (iii) The pipes are not subject to corrosion. (iv) The pipes are strong and durable. (v) The service connections can be easily made. (vi) The usual life of cast-iron pipes under normal conditions is about 100 years or so. Disadvantages: ( i ) The breakages of these pipes are large. (ii) The carrying capacity of these pipes decreases with the increase in life of pipes. (iii) The pipes are not used for pressures greater than 0.7 N/mm². (iv) The pipes become heavier and uneconomical, specially when their size increases beyond 1200 mm diameter.

4. (3) Cement concrete pipes: The cement concrete pipes may be plain, reinforced or prestressed with diameters varying from 500 mm to 2500 mm or more. The plain cement concrete pipes are used for low heads upto about 15 m. The reinforced cement concrete pipes are adopted for heads upto about 75 m and for larger heads, prestressed cement concrete pipes are used. Advantages: ( i ) The inside surface of pipes can be made smooth. (ii) The maintenance cost is low. (iii) The pipes are durable with useful life of about 75 years. (iv) cast at site of work and thus there is reduction in transport charges. (v) These pipes are heavy (vi) These pipes do not require expansion joint (vii) not affected by the atmospheric actions or by ordinary soil. (viii) will not collapse or fail under normal traffic loads when placed below roads. (ix) there is no danger of rusting and incrustation. Disadvantages: ( i ) The pipes possess no tensile strength and they cannot withstand high pressures. (ii) The pipes are heavy and difficult to transport. (iii) The pipes are likely to crack during transport and handling operations. (iv) The repairs of these pipes are difficult. (v) These pipes are affected by acids, alkalies and salty waters. (vi) These pipes are likely to cause leakage due to porosity.

5. (4) Copper pipes: The copper pipes do not sag or bend due to hot water. Hence, their use is restricted for conveyance of hot water in buildings and steam boilers. They are not liable to corrosion and can be bent easily. But as they are costly, they are not used for distribution of water. Disadvantages: ( i ) These pipes are liable to incrustation and can be easily affected by acidic or alkaline waters. (ii) The useful life of pipes is short about 7 to 10 years or so. Advantages: ( i ) The pipes are cheap, light in weight and easy to handle and transport. (ii) The pipes are easy to join. (5) Galvanised iron pipes: These pipes are widely used for service connections and their diameters vary from 6 mm to 75 mm.

6. (6) Lead pipes: These pipes are usually not adopted for the conveyance of water. If proper care is not taken, the lead pipes may cause lead poisoning. They can be easily bent and hence, when these pipes are used, less number of specials will be required. Wrought-iron pipes: These pipes are light in weight and they can be easily cut, threaded and worked. But they are found to be costly and less durable as compared to the cast-iron pipes and hence, they are not generally used in the conveyance of water.

7. Advantages: ( i ) There is no from damage due to thawing and freezing of water in closed pipes. (ii) The pipes are cheap. (iii) durable and they possess enough strength to resist impact, sunlight and atmospheric actions. (iv) The pipes are flexible and possess low hydraulic resistance. (v) The pipes are free from corrosion. (vi) The pipes are good electric insulators. (vii) light in weight and it is easy to bend, join and install them. (viii) The pipes upto certain sizes are available in coils and therefore it becomes easy to transport them. Disadvantages: ( i ) The coefficient of expansion for plastic is high. (ii) It is difficult to obtain the plastic pipes of uniform composition. (iii) less resistant to heat. (iv) plastics may impart taste to the water. (7) Plastic pipes: The plastic is a new material of the modern age. Its various uses in many fields have made it very popular. The use of plastic in the conveyance yance of water has increased due to various types of plastic pipes available in the market. The low density polythylene pipes (LDPE) are flexible and can be used for point to point conveyance of water in long runs. The high density polythylene (HDPE) pipes are tough and can be used for conveyance of water in long runs from point to point with large diameter.

8. Disadvantages: ( i ) The maintenance cost is high. (ii) rusted by slightly acidic or alkaline water. (iii) require more time for repairs during breakdown and hence, they are not suitable for distribution pipes. (iv) deform in shape under the combined actions of external and internal loads. Advantages: ( i ) available in long lengths and hence, the number of joints becomes less. (ii) cheap in first cost. (iii) durable and strong enough to resist high internal water pressure. (iv) flexible to some extent and they can therefore be laid easily on curves. (v) light in weight (8) Steel pipes: The mild steel is used for the manufacture of steel pipes. The joints of steel pipes are either riveted or welded and hence, they vary both in length and diameter. The steel pipes are generally used for pipes having diameter greater than 1200 mm. The inside and outside surfaces of steel pipes are generally galvanised .

9. PIPE CORROSION: The term pipe corrosion is used to indicate the loss of pipe material due to the action of water. The metallic structure of pipe is attacked and dissolved by water. The pipe corrosion may be internal or external and it leads to the disintegration of metal. The former is due to the action of water flowing in the pipe. The latter is due to the action of waterlogged soil above the pipe surface. The various factors contributing to the pipe corrosion are as follows: (1) Acidity (2) Alkalinity (3) Biological action (4) Chlorination (5) Electrical currents (6) Mineral and organic constituents (7) Oxygen EFFECTS OF PIPE CORROSION: Following are the effects of pipe corrosion: (1) The pipe corrosion may lead to the tuberculation which is the phenomena of the formation of small projections on the inside surface of pipes. The small projections or turbercules are cone-shaped and they decrease the cross sectional area of pipe. The carrying capacity of pipe is thus affected. (2) The pipe corrosion leads to the disintegration of pipe line and it demands heavy repairs. (3) The pipe corrosion imparts colour , taste and odour to the flowing water. (4) The pipe connections are also seriously affected by the action of pipe corrosion. (5) The pipe corrosion may make the water dangerous for drinking and other purposes.