Pipes/piping plastic systems, design

The physical and mechanical properties of the principal thermoplastics of interest for process plant applications are listed in Table 3.42. Table 3.43 gives typical hydrostatic design stresses for different types of thermoplastic pipe. Plastics widely employed in piping systems are described briefly below. 

Sixsmith, T. and R. Hanselka. 1997. Handbook of Thermoplastic Piping System Design. New York Marcel Dekker. This work covers in detail the advances in plastic pipe and piping systems and applications where modern plastics can be used in place of more traditional metal pipe. Includes over 70 pages of basic reference data and nearly 200 pages of chemical resistance data. 

Avoiding bending and stress in a pipe system is a factor in the installation of plastic pipe. Unlike steel pipe, plastic pipe is not intended to support heavier weights, such as valves, anchors, and so forth. Plastic pipe is designed to support soil loads and internal pressnres up to a specified hydrostatic pressure rating. When accessories are placed in the pipeline, such as valve boxes, the accessories must be supported to prevent additional bending and stress on the plastic pipe. 

One design that is used for installation convenience, but can also allow higher efficiency, is an induced draft fan that pulls in extra air to cool the flue products to temperatures that can be safely vented through plastic pipe. Because of the fan, long horizontal venting runs arc possible with this system. 

Now our experiment has been designed We will use plastic pipe with an inside diameter of 1.6 in. and length of 50 ft and pump water through it at a rate of 27.5 gpm. Then we measure the pressure drop through this pipe and use our final equation to scaleup this value to find the field pressure drop. If the measured pressure drop with this system in the lab is, say, 1.2 psi, then the pressure drop in the field pipeline, from Eq. (2-13), would be... 

ISO 1872-1 1993 Plastics - Polyethylene (PE) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 1872-2 1997 Plastics - Polyethylene (PE) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 1969 2004 Fibre ropes - Polyethylene - 3- and 4-strand ropes ISO 3458 1976 Assembled joints between fittings and polyethylene (PE) pressure pipes -Test of leakproofness under internal pressure ISO 3459 1976 Polyethylene (PE) pressure pipes - Joints assembled with mechanical fittings - Internal under-pressure test method and requirement ISO 3501 1976 Assembled joints between fittings and polyethylene (PE) pressure pipes -Test of resistance to pull out... 

For calculation of flow in fire main systems, the design engineer should use the Hazen-Williams friction coefficient of C = 100 in the design of bare steel and concrete steel lined pipingforfire water systemsto allow for future deterioration as the system ages. A friction coefficient of C = 140 may be used for plastic pipe, such as fiber reinforced plastic (FRP) or polyvinyl chloride (PVC). 

Procedure Setup the chlorine generating apparatus as illustrated below. Note your chlorine generator does not have to be as fancy as the apparatus illustrated below, but your system should be similar in design. You can use latex tubing, PVC pipes and other plastic devices as well, steel pipes can be used, but other metals should be avoided due to corrosion. Also, observe the chlorine generator utilizing an electrochemical method. The electrochemical method is sufficient to produce laboratory quantities of gas (see the following illustration). 

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