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where is the density of the fluid, is the average velocity in the pipe, is the friction factor from the Moody chart, is the length of the pipe and is the pipe diameter. The chart plots Darcy–Weisbach friction factor against Reynolds number Re for a variety of relative roughnesses, the ratio of the mean height of roughness of the pipe to the ...
From the chart, it is evident that the friction factor is never zero, even for smooth pipes because of some roughness at the microscopic level. The friction factor for laminar flow of Newtonian fluids in round tubes is often taken to be: [4] = [5] [2] where Re is the Reynolds number of the flow.
Cement-mortar lined ductile iron pipe is a ductile iron pipe with cement lining on the inside surface, and is commonly used for water distribution. Cement-mortar lined ductile iron pipe is governed by standards set forth by DIPRA ( Ductile Iron Pipe Research Association ), and was first used in 1922 in Charleston, South Carolina .
The energy consumed in manufacturing ductile iron pipe was 19.55 MJ per kg and volume of emissions released during manufacture was 1.430 kg CO 2 per kg, compared to 68.30 MJ per kg of energy and 4.860 kg CO 2 per kg emissions for PVC pipes, and 1.24 MJ per kg and 0.148 kg CO 2 per kg for concrete pipes of the same diameter. [32]
It is extremely important that the fabricated item arrive on the jobsite ready to be installed without field modification. Special care must be taken by the contractor to measure and verify dimensions. In new construction, plan dimensions usually are sufficient for ordering many fabricated items such as structural steel or precast concrete. [2]
A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving ( see below ).
Slabs are one of the greatest consumers of concrete in many buildings, [14] so reducing the slab mass can make a relatively large difference to the environmental impact of a building's construction. Biaxial slabs may be marginally cheaper than solid slabs, partly due to the lower mass.
Lift slab construction (also called the Youtz-Slick Method) is a method of constructing concrete buildings by casting the floor or roof slab on top of the previous slab and then raising (jacking) the slab up with hydraulic jacks. This method of construction allows for a large portion of the work to be completed at ground level, negating the ...