ABSTRACT
Most fluids are transported along pipelines that provide effective containment. Fabricated from a range of materials, the pipes themselves are designed to withstand the abrasive or corrosive properties, the pressure and flow. Ducts and other conduits including open channels are also used to transport fluids and, again depending on the properties, are constructed of appropriate materials. The ability to cause a fluid to flow through the pipe or duct is dependent on the applied force. This may be in the form of gravity or the force supplied by a mechanical device such as a pump or compressor. The rate of flow caused is governed by the pressure requirements that are required to be overcome and include elevation, pressure of the fluid, and frictional effects. In determining an appropriate pipe to be installed for a particular fluid system, a detailed analysis of these requirements must be undertaken. While narrow-bore pipes or tubes may be inexpensive compared to large-bore pipes mostly due to the amount of extra materials, a complete analysis should consider operating and capital expenditures. It should be noted that the frictional effects that must be overcome are proportional to the reciprocal of the fifth power of the diameter. In effect, this means that by reducing the diameter by half, the pressure increases by a factor of 32. The economic pipe diameter therefore corresponds to the minimum cost of purchase and operation.
