Different types of pipes are used for underground drains construction. The properties of these pipes and type of drainage required decides the selection of pipes. Underground drain pipes are subjected to various types of chemical and physical attacks, so these must be kept in mind during their selection.
Concrete drainage pipes are available as precast pipes in various sizes and shapes such as round and elliptical. Precast concrete pipes provide easy fittings and easy to install. These have following advantages:
Adaptability - The precast concrete pipes can be designed, built and installed as per specifications and requirements at construction site.
Strength - The underground concrete drainage pipes can be designed to withstand any combination of loads.
Hydraulic Efficiency - It provides required Manning's "n" value of 0.012 for better hydraulic efficiency.
Availability - Precast concrete pipes are produced locally to meet local needs, so it is readily available for construction without much transportation.
Economy – It offers long service life, thus it is cost-effective for use in underground drains.
Concrete pipes can be coated both internally and externally using proprietary coatings to improve its resistance against various chemical attacks underground.
2. Asbestos Cement Drainage Pipes
Asbestos cement pipes are used for wastewater and storm water drainage. The use of the asbestos fibers in place of reinforcing steel makes the AC pipes lighter in weight and provides adequate strength.
AC pipes have good resistance to hydrogen sulfide corrosion and aggressive soils as it does not have reinforcement steel. This pipe provides low operating costs because the smooth walls of the pipe provides low friction factors.
There are four types of AC drainage pipes such as Non-pressure pipes for sanitary sewers, pressure pipes for local water mains, storm drain pipes for carrying storm drains and transmission pipes for use as water mains.
3. Iron Drainage Pipes
Iron pipes are used for drainage works where the strength of pipe is most important and not for general purpose such as gravity flow. The uses of iron pipes in locations such as under shallow depth, under road surface, in water logged ground where large soil movement is expected.
4. Clay Drainage Pipes
Clay pipes are used for drainage works at it resists various substances such as acid and alkaline attacks. But, organic solvents could affect the plastic materials and rubber rings used for flexible joints of clay pipes.