CHAPTER 8MECHANICAL SYSTEMSTo be able to prepare workable construction.drawings, EAs should have the ability to recognizeand describe the materials used in mechanicalsystems, to understand their uses and functions,and to discuss the purpose and the developmentof a mechanical plan in the context of plumbingfor water distribution and drainage systems.This chapter will discuss only the plumbingand drainage portions of the mechanical systemsand the various materials used. You will not beexpected to design the system; however, as an EA,you may be called upon to prepare constructiondrawings from sketches and specifications.MECHANICAL SYSTEMS(PLUMBING)In general, plumbing refers to the system ofpipes, fixtures, and other appurtenances usedinside a building for supplying water andremoving liquid and waterborne wastes. Inpractice, the term also includes storm water orroof drainage and exterior system componentsconnecting to a source, such as a water main, anda point of disposal, such as a domestic septic tankor cesspool.The purpose of plumbing systems is, basically,to bring a supply of safe water into a building fordrinking, washing, and cooking, distribute thewater within the building, and carry off thedischarge of waste material from variousreceptacles on the premises to sewers, leech basins,and so forth, without causing a hazard to thehealth of the occupants. Codes, regulations, andtrade practices define the plumbing specifications,which vary from one location or place ofapplication to another. Although the NationalPlumbing Code is widely accepted as a guidelinefor the minimum requirements for plumbingdesigns, you must also be familiar with applicablelocal codes, especially when working withmechanical drawings and plans.AND PLANWATER DISTRIBUTION SYSTEMThe purpose of a water distribution system isto carry potable COLD and HOT WATERthroughout a building for domestic or industrialuse. A typical water supply system (fig. 8-1)consists of service pipe, distribution pipe,connecting pipe, fittings, and control valves. Thewater service pipe begins at the WATER MAIN.The water distribution pipe starts at the end ofthe service pipe and supplies the water throughoutthe building.Piping MaterialsSeveral types of pipe are used in waterdistribution systems, but only the most commontypes used by the SEABEEs will be discussed.These piping materials include copper, plastic,galvanized steel, and cast iron. Some of the maincharacteristics of pipes made from these materialsare presented below.COPPER PIPE AND TUBING.— Copper isone of the most widely used materials for tubing.This is because it does not rust and is highlyresistant to any accumulation of scale particles inthe pipe. This tubing is available in three differentFigure 8-1.-Cross-sectional diagram of a water supply anddistribution system.8-1
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