Plumbing Design PDF

5 ENGINEERING UTILITIES 2 PLUMBING DESIGN THE WASTE PIPE It is important to know the different parts of the The Drainage Pipe refers to an installation that receives piping installations and their functions. The and conveys discharges from water closet with or effectiveness...

5 ENGINEERING UTILITIES 2 PLUMBING DESIGN THE WASTE PIPE It is important to know the different parts of the The Drainage Pipe refers to an installation that receives piping installations and their functions. The and conveys discharges from water closet with or effectiveness of plumbing installation depends upon without waste coming from other fixtures. the strict observance of the natural laws of nature such as : gravity and the atmospheric pressure that affect The Waste Pipe is any pipe in a drainage installation that the whole system. Most of the failures encountered in receives the discharges of any fixture except water closet plumbing installation , were due to the non - and conveys the same to the soil branch , soil pipe or observance of these natural laws , and the grave abuse house drain. Fixture refers to slop sink , lavatory , urinals of its function. , bathtub and the like except water closet. Generally , Waste Pipe is smaller in size than the soil The Vent Pipe in a plumbing system functions as air pipe. Smaller because of the kind of waste it receives passage or conduit to ventilate the drainage and waste from the various plumbing fixtures. pipe installation. The Drainage installation of a plumbing system As already discussed , solid human waste is discharged comprises three major component parts : by water closet only to either the soil branch , soil pipe , soil stack or house drain. Categorically , any pipe that Drainage , The Waste and The Vent or simply called receives and conveys human waste is affixed by the DWV System. word "Soil " such as ; soil branch , soil stack etc. THE WASTE PIPE Soil Branch refers to a horizontal pipe affixed by the GENERAL CONDITIONS FOR A GOOD WASTE word soil. The word soil connotes a pipe receiving PIPE INSTALLATION: discharges from water closet. On the other hand , if this soil branch does not receive discharges from 1. By making the right choice of materials. water closet but from other fixtures only , it will be classified as Waste Pipe. 2. By conservative use of fittings. Soil Stack is a vertical pipe installation where the soil 3. Right location of the cleanouts. branches terminate. The pipe is called stack being in stalled vertically , and the word soil is affixed because 4. Right slope or grade of the pipelines. it receives human waste from soil branch. Otherwise , it will again be classified as Waste Stack. 5. Using the right size of pipe. When a waste pipe is not directly connected to a soil 6. Correct manner of joining the pipes and stack or house drain , it is called Special Waste. 7. Providing stable and rigid support. THE WASTE PIPE 1.) THE RIGHT CHOICE OF MATERIALS Injudicious use of fittings should not be allowed in plumbing installations. Short cuts that will not The materials intended for waste pipe installation , allow smooth passage of waste should be avoided. could be well selected from those that were enumerated in Lecture 2. The character of the waste to Pipe joints and fittings were specially designed to be drained , and the service to which it is intended for make smooth changes of directions , turns or , dictates the kind of materials to be used. offsets. But sometimes , their application may not be in accordance with the purpose for which they were made. 2.) CONSERVATIVE USE OF FITTINGS Pipe installations that fails or break too soon , may The smooth flow of waste inside the pipe is a primary have been due to any of the following causes : consideration in all types of plumbing installations. Most of the waste pipe line failures were attributed to 1. THE USE OF TOO MANY FITTINGS. the unwarranted use of accessories and too many fittings , or be cause of using the wrong type of 2. THE USE OF WRONG TYPE OF FITTINGS. fittings in a given location. Conservative use of fittings refers to the right choice of the right kind of fittings for a particular change of directions , turns or offsets. THE WASTE PIPE RECOMMENDATIONS: 1. Do not use short radius fittings on a vertical to horizontal directions or horizontal to horizontal changes. THE WASTE PIPE RECOMMENDATIONS: 1. Do not use short radius fittings on a vertical to horizontal directions or horizontal to horizontal changes. 2. Use long sweep fittings on horizontal changes. 3. For vertical to horizontal direction of changes , the Y and 45 ° fittings are most appropriate. THE WASTE PIPE RECOMMENDATIONS: 1. Do not use short radius fittings on a vertical to horizontal directions or horizontal to horizontal changes. 2. Use long sweep fittings on horizontal changes. 3. For vertical to horizontal direction of changes , the Y and 45 ° fittings are most appropriate. 4. The T fitting was designed for vertical run with lateral branches only. Its use on horizontal installation will create a tilted or crooked joint connection called " Premature Waste Line Defects " THE WASTE PIPE 3.) LOCATION OF CLEANOUT The waste pipe installation must be provided with an ample number of cleanouts , strategically located , to be opened in case of pipeline trouble. Cleanout is a receptacle of the plumbing system accessible on floor , walls or ceiling. It is equipped with a plug or flush plate so designed as not to impair the aesthetical view of the room. The location of cleanout must be indicated in the plan. It should be sized equal to the diameter of the waste pipe , where it is to be connected. This is to avoid interference in the rodding or cleaning process. Cleanout must be readily accessible to the plumber in case of waste line stoppage. THE WASTE PIPE 3.) LOCATION OF CLEANOUT 4.) RIGHT SLOPE OR GRADE OF WASTE PIPE The waste pipe installation must be provided with an The ideal position of horizontal waste pipe , were ample number of cleanouts , strategically located , to those installed at 2 % slope. Meaning , the pipe be opened in case of pipeline trouble. was installed with an inclined ratio of 2 centimeters per meter length. Cleanout is a receptacle of the plumbing system accessible on floor , walls or ceiling. It is equipped Waste pipe must be of sufficient diameter to afford with a plug or flush plate so designed as not to impair adequate velocity of flow in order to make them as the aesthetical view of the room. nearly self - scouring as is practical. The latest scientific tests and experiments conducted by the The location of cleanout must be indicated in the plan. National Bureau of Standards sponsored by the It should be sized equal to the diameter of the waste Housing and Home Finance Agency , showed that , pipe , where it is to be connected. This is to avoid wet venting and stack venting are safe in certain interference in the rodding or cleaning process. type of installations. The experiments revealed that the Trap Seal Loss occurs when the grade or slope Cleanout must be readily accessible to the plumber in of the pipe is increased from 2 % to 4 %. case of waste line stoppage. THE WASTE PIPE 5.) DETERMINING THE SIZE OF WASTE PIPE There are those who believed that by making the drainage pipe larger than what is necessary , will The National Plumbing Code on the size of waste pipe increase its service efficiency. This belief without provides that: scientific basis , has triggered disagreement among people in the plumbing industry. Disagreement on "The waste pipe diameter shall be adequate enough to this matter however , was resolved when the serve the installation of fixtures in a general way , but Uniform Plumbing Code Committee formulated the best way is to fit the diameters of commercial pipe data as guide and references in determining the into the fixture pattern in the most efficient manner“ size of the waste and other drain pipes. The size of waste pipe intended to receive waste from The data formulated by the Committee for the fixture must be of sufficient diameter. This is to incorporation in the Plumbing Code were product accommodate the velocity of flow , making them as of countless tests and experiments conducted for nearly scouring as necessary to prevent the silting of years. In addition , installation experiences that the pipe. were proven satisfactory in service compiled over a long period of time were also incorporated. Scouring means to flush or wash out , to remove dirt or grease by flowing through. THE WASTE PIPE The Uniform Plumbing Code Committee's Findings are 4. For instance , if the pipe is 100 mm diameter , Enumerated Briefly as Follows : the water flow inside the pipe must have a depth of about 50 mm to attain the scouring 1. By increasing the size of the drainage pipe , does action. This is where the 2 % slope becomes not guarantee effective scouring action , or self effective. cleaning ability of the pipe. Self - cleaning ability is present , when the liquid and waste inside the pipe 5. On the other hand , too small pipeline is subject flow smoothly and simultaneously together. to overloading of flow. The tendency is to create back - pressure , siphonage , and floor 2. Water flow inside a larger pipe is relatively shallow. flooding. The solid waste does not flow on shallow water but tend to remain at the bottom of the pipe. This is practically the most common cause of the many clogging problems of drainage installation. 3. Drainage pipe must be of the right size to have a liquid flow of about 50 % of the pipe diameter. Meaning , that the flowing water inside the pipe must have a depth equal to the pipe radius. THE WASTE PIPE 6.) MANNER OF JOINING PIPES 7.) RIGID SUPPORTS Injudicious connection of fittings should not be Pipes are typically supported by a rigid hanger or permitted in any plumbing installation. Each kind of pipe holder. Plastic pipes installed vertically are pipe has its own manner of joining recommended and supported every 1m. specified by the manufacturers. For instance , cast iron pipes are joined by the use of oakum and lead at the hub and spigot connections. Likewise , plastic pipes clearly specify the use of solvent plastic cement , or by special fitting connector. Remember that any alteration or deviation from the manufacturer's specifications will only endanger the effective ness of the pipe joints. THE WASTE PIPE THE FIXTURE UNIT The National Plumbing Code strongly endorsed the COMMON for RESIDENTIAL use of Fixture Unit Value as waste load in determining the size of the waste pipe. ITEM DRAINAGE FIXTURE FIXTURES The Uniform Plumbing Code Committee , conducted NO. UNITS (DFU) numerous tests on various plumbing fixtures in order 1 Bathtubs 2 to determine the amount of water each fixture discharges in one - minute interval through their 2 Shower 2 outlet orifices. 3 Bidets 2 4 Floor Drains 2 The tests result showed that a lavatory being the smallest fixtures , discharge waste at approximately 5 Laundry Tubs 2 one of cubic foot of water per minute interval. Based 6 Kitchen Sink 2 on their findings , the Committee finally decided to 7 Urinal 3 establish the " Unit Fixture " and called the water discharge as One Fixture Unit representing one cubic 8 Lavatory 1 foot or 30 liters of waste discharged by the fixture in 9 Water Closet 4 one minute interval. THE WASTE PIPE THE WASTE PIPE Example 1: Determine the size of a horizontal waste pipe to serve 5 Urinals, 3 Lavatories, 8 Showers, 3 Floor drains and 2 Kitchen Sinks. THE WASTE PIPE Example 2: Determine the size of a waste stack with two horizontal branch. It is to serve 10 Urinals, 3 Wash basin, 3 Bathtubs, 6 Floor drains and 2 Kitchen Sinks. THE WASTE PIPE WASTE PIPE AND OTHER FIXTURES Waste pipe is classified into two types depending upon the kind of fixtures it will serve. 1. DIRECT WASTE 2. INDIRECT WASTE DIRECT WASTE is one with terminal directly connected to the plumbing system. THE WASTE PIPE INDIRECT WASTE refers to a connection with terminal not directly connected to the plumbing system. Fixtures served by Indirect Waste are : 1. Soda fountain 2. Bar waste 3. Refrigeration 4. Drinking fountain 5. Air conditioning units THE WASTE PIPE RECOMMENDED SIZE OF WASTE PIPE (SOME) 1.) SINK WASTE The minimum is 38 mm or 1 ½ “, but the practice is to use 50 mm or 2” Pipe. 2.) SLOP SINK Is tapped either on the floor or walls. Traps on the floor shall be 75 mm or 100 mm, and 50 mm for traps on walls. 3.) BATHTUB - 38 mm to 50 mm 4.) LAUNDRY TUB - 38 mm to 50 mm 5.) SHOWER BATH - 50 mm 6.) URINAL - 50 mm 7.) LAVATORIES - 50 mm DON’T WASTE …YOUR PIPE! 5