Pipes

Pipes

Pipes are of very important field in almost in industry. Pipes are used mainly to transfer fluids from placer to another. Its shape is a hollow cylinder. There are many codes and standards used for piping engineering design such as:The most important and common code for pressure piping is ASME B31 B31.1 for power piping B31.2 for fuel gas piping B31.3 for process piping B31.4 for pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids B31.5 for Refrigeration Piping and Heat Transfer Components B31.8 for Gas Transmission and Distribution Piping Systems B31.8S for Managing System Integrity of Gas Pipelines B31.9 for Building Services Piping B31.11 for Slurry Transportation Piping Systems B31G Manual for Determining Remaining Strength of Corroded Pipelines

I think the most important codes for water desalination industry are ASME B31.3 and ASME B31.4

Pipes materials:-

1- Plastic pipes: Plastic pipe comes as either ABS (acrylonitrile-butadiene-styrene) or PVC (polyvinyl-chloride). Most homes since mid-1970 have plastic pipes and fittings because its inexpensive and easy to use. Simply glue the joints using a primer and liquid cement.

ABS: This black pipe was the first plastic pipe to be used in residential plumbing. Today, many areas dont allow ABS in new construction because joints can come loose.

PVC: This white or cream-colored pipe is the most commonly used pipe for drain lines. Its corrosion resistant and chemical resistant.

2- Metallic pipes:-These pipes are mainly used for pressure piping and can withstand high temperatures unlike the plastic pipes. Examples are at the below table

Pipe thickness selection:

Design criteria for thickness selection are Temperature, Pressure, and the material of the pipe.

According to ASME B31.3, Section 304

After calculating the minimum thickness for design pressure and adding the corrosion allowance, we choose the pipes according to ASME B36.10M standard

we take the nearest largest thickness and get the schedule and the STD for every nominal (inner) diameter

Pipe connection:

1- Welding: welding of pipes is very common to connect pipes. Its permanent connection and should be inspected carefully using non-destructive tests NDT tests (such as radiographic test).

2- Using flanges:

Flange is shown in the blow figure

Flanges are selected based on the temperature and pressure, for every group of flanges there are ratings that specify the flange. According to ASME B16.5 standardExample,

Pipe fittings:-A fitting is used in pipe plumbing systems to connect straight pipe or tubing sections, to adapt to different sizes or shapes, and for other purposes, such as regulating or measuring fluid flow.

1- Elbow

2- Coupling

3- Reducer

4- Tee

5- Cross

6- Cap

7- Valves