- - AGRICULTURAL CORE CURRICULUM - - (CLF2000) Advanced Core Cluster: AGRICULTURAL MECHANICS (CLF2550) Unit Title: Plumbing ____________________________________________________________________________ (CLF2551) Topic: PLUMBING Time Year(s) MATERIALS 2 Hours 3 / 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson the student will be able to: Learning Outcome #: (L-1) - Properly identify plumbing materials. (L-3) - Understand the purposes for the various plumbing materials. Special Materials and Equipment: Examples of different pipe materials, slides demonstrating installation of each type of material, examples of materials used to make joint connections. References: Burke, Stanley R., & Wakeman, T. J. (1990). MODERN AGRICULTURAL MECHANICS (2nd ed.). Danville, IL: Interstate Publishers. Cooper, Elmer L. (1987). AGRICULTURAL MECHANICS: FUNDAMENTALS AND APPLICATIONS Albany, NY: Delmar Publishers. Editors of Reader's Digest. (1973). COMPLETE DO-IT- YOURSELF MANUAL (7th ed.). Pleasantville, NY: Reader's Digest Association. Ripka, L. V. (1978). PLUMBING INSTALLATION AND DESIGN. Alsip, IL: American Technical Publishers. RESOURCES: Black and Decker Home Improvement Library. (1990). HOME PLUMBING PROJECTS & REPAIRS. Available from: Cy DeCosse Inc., 5900 Green Oak Drive, Minnetonka, Minnesota 55343 1-800-328-3895 Evaluation: Unit Exam TOPIC PRESENTATION: PLUMBING MATERIALS A. Plumbing systems supply water and take away wastes by routing pipes to and from fixtures or appliances. Plumbing is a two-part system: 1. The water supply system carries fresh (potable) water from a source such as a well or street main to a fixture. 2. The Drain-Waste-Vent (DWV) system carries excess water and waste away to a septic system or municipal waste treatment center. 3. Plumbers and pipefitters are people who install and repair plumbing systems. 4. The Uniform Plumbing Code (as well as local plumbing codes) should be followed when installing pipes, fittings, and fixtures in order to provide a safe operating system. 5. In agriculture, many liquids in addition to water (e.g., milk, soybean oil) are carried through specially designed pipes to points of storage and processing. B. Plumbing the Home and Farmstead 1. Designing a plumbing system for the home and/or farmstead requires a knowledge of and familiarity with plumbing materials. a. A pipe is any rigid tubelike material. b. Tubing is any pipe that is flexible enough to bend. c. A nipple is a short pipe under 12 inches in length. d. A fitting is a connecting device used to join pieces of pipe or to connect pipe to other objects such as fixtures, appliances, or pumps. e. The size of pipe is generally based on the inside diameter (ID) which is a nominal size, not the actual size. However, the outside diameter (OD) may occasionally be used to measure the size of the pipe. 2. In agricultural mechanics, most work completed with pipe and pipe fittings may be considered to be a part of plumbing. C. Material Identification in Plumbing Construction Pipes 1. Steel pipe is available in three grades: standard (sch 40), extra strong (sch 80), and double extra strong (sch 120). a. Extra strong (sch 80) and double extra strong (sch 120) are used primarily in commercial and industrial settings. b. All grades of steel pipe have the same outside diameter for a given size which permits pipe threading with the same die; it also allows the use of the same sized pipe fittings for all three pipe grades. The additional wall thickness results in reduced inside diameters. 2. Two types of steel pipe are primarily used in plumbing: black iron and galvanized steel. a. Black iron pipe is used for gas, steam, and emergency fire systems. b. Black iron pipe has no coating; therefore it provides little resistance to rust. When used for underground gas lines, black iron pipe comes with a Poly-Vinyl-Chloride (PVC) coating to protect it from corrosion. c. Before 1970, galvanized pipe was used mainly for water supply and cold water systems. It is still used in combination with other materials because of its strength and ability to support cantilevered weight. d. Galvanized pipe will meet the minimum pressure requirement of 125 psi when standard (sch 40) is used. e. Galvanized pipe not only creates greater friction losses than copper and plastic pipes do, but it also has a greater tendency to scale and thus it reduces flow capacity. f. Galvanized pipe lasts at least 30 years in most soils. 3. Connecting steel pipe in plumbing construction requires two types of fittings: threaded and dielectric fittings. a. Threaded fittings are tapered threads which create an interference fit that should not be used in combination with other threads such as machine or hose threads. 1) Threaded fittings are extremely time consuming to make. 2) Threaded fittings require some type of pipe thread compound such as pipe joint compound or Teflon tape to create a water tight seal. b. Dielectric (nonconducting) fittings (couplings or bushings) are necessary when dissimilar pipes are used in combination with copper pipe or tubing in order to minimize electrolysis which causes corrosion. 4. Additional Standard Information Regarding Steel Pipe a. The standard length of steel pipe is 21 feet. b. Steel pipe is sized according to the nominal ID. c. Steel pipe is the best material for resisting mechanical or fire damage. d. Water quality should be considered before selecting pipe materials. Investigate the local plumbing code. e. Galvanized pipe nipples can be purchased in half-inch increments up to 6 inches and 1-inch increments from 7 to 12 inches. 5. Copper pipe is available in two types: rigid pipe and flexible tubing. It is used in water supply and Drainage-Waste-Vent (DWV) systems. a. Rigid copper pipe is available in four wall thicknesses and is color coded. 1) Thin-walled (type M-red) is usually adequate for home plumbing. 2) Medium-walled (type L-blue) is generally used for commercial plumbing. 3) Thick-walled (type K-green) is used on outside work that may be subject to mechanical damage or for underground burial. 4) Drainage-Waste-Vent (DWV-yellow) may be used in any DWV system. This is the thinnest-walled form of copper pipe. b. Additional Information Regarding Rigid Copper Pipe 1) Rigid copper pipe diameter is measured by the nominal ID. 2) The OD is a given nominal size which remains the same for all four weights of pipe. 3) Rigid copper pipe is sold in standard 10 and 20 foot lengths. 4) Rigid copper pipe can be soldered only; it cannot be flared. 5) Rigid copper pipe, although comparatively expensive, is easy to work with in both new installations and modified systems. The savings in labor will generally offset the high cost of materials. c. Flexible copper tubing, unlike rigid copper pipe as described above, is not color coded. However, it is graded according to two types of wall thicknesses and is marked every eighteen inches with its type and manufacturing information. 1) Medium-walled (type L) is used in most homes, principally for gas service lines. 2) Thick-walled (type K) is used in most homes for underground water service lines. 3) There is no thin-walled or DWV type of flexible copper tubing. 4) The chief advantage of flexible copper tubing is its flexibility; it can easily be bent across the knee. However, care must be taken to avoid kinking. 5) Flexible copper tubing is resistant to most corrosion. 6. Plastic pipe, similar to copper pipe, is available in two types: rigid pipe and flexible tubing. a. Rigid pipe is manufactured out of three different synthetic products: PVC, ABS, and CPVC. 1) PVC (polyvinyl chloride) is used primarily for cold water supply, DWV, and irrigation lines. 2) ABS (acrylonitrile butadrene stryene) is used exclusively for DWV systems. 3) CPVC (chlorinated polyvinyl chloride) is used in hot and cold water supply. Although it costs three to four times more than pvc it normally is used because it withstands heat and maintains its strength. The local plumbing code should be checked prior to CPVC installation. b. Plastic rigid pipe is available in three weights: schedule 40, 60, and 80; all weights meet the minimum pressure rating of a closed water system. (Other lighter weight [ie. class 125] pipe is also available, but it should be used only for landscape irrigation purposes.) c. Additional Information Regarding Rigid Plastic Pipe 1) Rigid plastic pipe is sized according to its nominal ID. 2) Rigid plastic pipe is available in standard 20 feet lengths. 3) The OD remains constant while the ID varies according to weight; this allows the use of the same fittings. 4) All types of rigid plastic pipe can be joined to their respective fittings by using an appropriate solvent cement (solvent-welded) for the job. Time and temperature play an important role in getting a good seal. 5) Local codes generally forbid the use of rigid plastic pipe behind or within walls. Sch 80 is recommended for out-of- ground exposed work. d. Flexible plastic tubing is available in only two types of synthetic material: PE (polyethylene), commonly used in landscape drip irrigation, and PB (poly-butylene), a relatively new material used indoors for hot and cold water supply systems. e. Additional Important Information Regarding Flexible Plastic Tubing 1) The inside diameter of flexible plastic tubing remains constant while the outside diameter varies according to the quality. 2) Flexible PE tubing can be used only for outside cold water systems such as wells or sprinklers. 3) Flexible plastic tubing is connected to itself or steel pipe by using polystyrene fittings and couplings. Stainless steel base clamps are used to secure the slip joints. Solvent is not used. 4) There are several advantages to working with flexible plastic tubing: low material cost, ease and speed to work with, and flexibility. 5) Flexible plastic tubing does not normally corrode; however, it will deteriorate with extended exposure to direct sunlight. If it is not exposed to direct sunlight, flexible plastic tubing has a long life expectancy. 6) Flexible plastic tubing creates less friction loss than metal pipes do. D. Identification of Miscellaneous Material Used in Plumbing Construction: 1. Steel pipe requires the application of a sealant to ensure a leakproof fit. a. Pipe thread compound, which commonly contains Teflon, is used on the threads of pipes to prevent leaks. b. Teflon tape can be used as an alternative to pipe thread compound. 2. Solder is the medium used to join copper pipe and fittings. a. Solder comes in a variety of types. 50-50 solder is a combination of 50% tin and 50% lead and is suitable for moderate temperature and pressure. If a stronger joint is required, 95-5 solder (which is 95% tin and 5% antimony,) may be used. b. 50-50 solder is no longer allowed for use in water supply systems because of its lead content. Therefore, check the local plumbing code, and use a lead-free solder such as 95-5 where appropriate. c. Flux is necessary to remove oxides, promote wetting, and protect surfaces during heating. It should not be relied upon to clean the surfaces of copper pipe and fittings. Manual cleaning is required. 3. Plastic pipes and fittings are joined by a solvent weld joint. a. Primer is essential for a solvent weld joint in plastic pipe. Priming cleans the surface, removes glaze, and starts the softening process to make a proper joint. Use the appropriate primer for the type of plastic pipe being used. b. Solvent glues or cements are available for ABS, PVC, CPVC plastic pipe. Use the appropriate type for the pipe being used. All purpose or universal solvent glues are convenient to use when using more than one type of plastic pipe. __________________________________________________________ ACTIVITY: 1. Take a short tour of the school grounds and identify the types of plumbing materials found. 2. Visit an agricultural enterprise and observe the types of plumbing materials used for supplying water and carrying away various wastes. __________________________________________________________ 7/10/91 JD/JD/tf #%&C