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Most people embarking on a renovation would like to forget about plumbing. Plumbing isn't glamorous or exciting. Unlike carpentry, it's hid den within the walls of the house. No one will ever admire it. People will merely assume it's there and will be inconvenienced if it does not operate properly. Like it or not, a renovator has to come to terms with plumbing, whether to properly plan extensions to the system or to resolve existing problems. In this section we attempt to demystify plumbing by examining the various components that make up the system. The cycle of bringing water in, through, and out of a house breaks down into three basic phases. The starting point is the source of water, be it a municipal water main, a private well, or another source. Next there must be a distribution system inside the house which makes the water accessible to the various fixtures and faucets, to the hot-water heater, and to the heating system (if applicable) in the building. Finally, the used water and any waste have to be drained and disposed of by means of a sewage disposal system. Before moving ahead to explain the components of a plumbing system, a few words of ad vice are in order. Although the plumbing system in a house is relatively simple to understand, its actual design and installation are far from easy tasks. Pipes are heavy and cumbersome to handle and the connection work is sometimes tricky. Leaky connections can damage walls, floors, and fancy finishes. Because faulty plumbing installations can be a health hazard, most communities require a license to do plumbing work. We believe it's wiser to hire a plumber. Those of you who live in apartments are cautioned even more strongly. Keep in mind that you have people living all around you. Any mishap or inconvenience will affect not only you but your neighbors as well. For this reason, in addition to the requirements of the building code, the co-op board or management agent will probably not allow work by anyone other than a licensed plumber. Perhaps your talents would best be used in hooking up fixtures once the pipes are installed, if the codes permit it. Be sure to consult all codes and the appropriate building officials before going ahead with any aspect of the design or installation of the system. Even if you do hire a plumber, it's helpful to have an understanding of how the system operates and what materials can and should be used. GETTING WATER TO THE FIXTURES The primary function of the water supply system is to make water available to the various fixtures in the house. It consists of a water supply main, a water heater, hot- and cold-water pipes, valves, air chambers, and a meter (pumps and storage tanks are required for private systems). Water is pushed into the fixtures by either gravity, street pressure, or circulating pumps. Municipal mains get the necessary pressure by gravity since reservoirs are situated at high altitudes or water is stored in water towers. In private systems where cisterns are used, the water pres sure is obtained by means of a circulating pump. In well systems the joint effort of a well pump and a storage tank supplies the necessary pressure. The pump pulls the water out of the well and into the tank. Once there, the compressed air in the tank pushes the water out of the tank and into the supply main. The water supply main (the pipe bringing the water from the source to the house) is a very important component of the system since any problems in the main could potentially cut off the water supply. In cold climates, the main is always located well below the frost line to avoid any danger of the pipe freezing and bur Make sure this is the case at your house. Upon entering the building, the supply main (like a tree) branches out to reach the fixtures and supply them with hot- and cold-water service. Any special provision, such as water-softening treatment or installation of a water meter, occurs at this point, before the main has been subdivided (frequently softening equipment is installed in the hot-water supply). Afterward, the main sup ply line is divided into a hot- and a cold-water main. The hot-water main is connected to an electric, oil, gas, or solar water heater, where the water is brought up to a higher temperature. (Houses using hydronic—that is, steam or hot water—heating may utilize the boiler as the heating medium.) Once the water is heated, the pressure in the pipes directs it to each fixture branch pipe via intermediary branch lines and risers. These lines are hidden by snaking them through walls, floors, and ceilings.* The cold-water system, on the other hand, by passes the water heater. It branches out in parallel with the hot-water supply into intermediary pipes, risers, and fixture branch pipes until each fixture is reached. Integral parts of the cold- and hot-water supply systems are the valves for the regulation of the flow of water. Some valves can be gradually opened or closed to get the desired quantity of flow. Other valves are designed to completely close off the flow or open it to full capacity. Shut off valves such as these are installed throughout the system to isolate sections and facilitate re pairs. For instance, a shutoff valve is provided in the water supply main and on both sides of any meter before it branches out into hot- and cold- water mains. They are also installed at each fixture branch pipe and horizontal branches leading to the kitchen and bath. The main cold-water shutoff may be outside the house, in a pit or box, depending on utility company requirements. Valves are also instrumental in the drainage of the water supply system. Houses situated in cold climates need to have their water supply system totally emptied if they are to remain unheated for a period of time during the winter. Otherwise, freezing water inside the pipes can cause severe damage to the system. To facilitate drainage, all the horizontal branch pipes are pitched toward one or more drain valves. (Pipe hangers are used to adjust pipes to the correct pitch.) Water pipes can be noisy. You may have heard a loud bang (water hammer) while quickly closing a faucet. This is caused by water pressure and can be corrected by installing an air chamber in both the hot- and cold-water supply at each fixture. In spite of the fancy name, an air chamber is simply an extra run of pipe located at each fixture. The extra length of pipe is filled with air. Water can get into it only by compressing the air. The compression in turn provides a cushion to prevent the bang. A device called a petcock may be in stalled in the air chamber to recharge it with air. In addition to air chambers, there are mechanical shock absorbers; these provide a more sophisticated and efficient solution to the problem of water hammer. Another approach to the standard hot-water system is to provide a continuous hot-water circulation by cycling water back to the heater. The purpose of recirculating the unused water is to prevent it from cooling off while standing in the pipes near the faucet. Instead, it flows back into the heater, allowing the fixture branch pipe to receive new hot water. This system is more expensive but in a large house it provides hot water on demand. Supply Pipe Materials There are numerous materials available for sup ply piping. If you are lucky, your house will have copper supply piping (more correctly called tubing) from top to bottom. Other materials that you may find are lead, galvanized steel, brass, and , in new homes, even plastic (Inset II). Should your house have lead piping, there is only one solution: it needs to be replaced. Lead pipes may leach poisonous substances into the water. Each of the other materials poses different problems in terms of durability and joinery. Piping materials can be rated in terms of corrosion resistance, method of connection, cost, and acceptability by the various codes. Materials range from plain or galvanized steel to cast iron, brass, copper, and plastic. To further complicate matters, the selection of one material alone does not solve all your problems. Codes sometimes specify one material for the water supply system, another one for the drainage system or for a particular section of each system. Occasionally they stipulate that certain materials may not be used at all. What might prove to be a very good choice for water supply pipes might not be so efficient for drainage, or vice versa. In essence, the problem isn't simple. We have tried to narrow down the choices by rating the materials in terms of performance, corrosion, and ease of installation. (Needless to say, if the code says otherwise, it wins.) In addition, consideration must be given to the problem of joining different supply pipe materials within one installation. [ WATER HEATERS: A water heater is a heat transfer mechanism by which cold water is brought up to a higher temperature. The heat can be generated electrically or by means of oil or gas firing. Houses with hydronic heating systems may use their boilers as the heat source.* Solar collectors offer another method for heating water. There are many systems commercially available which will supply between 40 and 100 % of a house’s requirements. The extra components of a solar system involve south-facing collectors of between 30 and 100 square feet in area, circulating lines, a storage tank, a pump, and connections to tap into the conventionally powered hot-water heater. The angle of the collector is calculated by adding 5 degrees to the latitude (number of degrees above the equator) of your house. Besides the difference in the method of heat generation, water heaters can be of the tank or tankless type. Tankless heaters are utilized on small compact houses. Tank-type heaters, on the other hand, are employed to have a large amount of water quickly available and assure a better sup- ply of hot water at all times. Another advantage of tank-type heaters is that the size of the heater itself may be reduced because there is always a supply of water in the tank. SIZING A TANK-TYPE HEATER The size of the water heater needed varies according to the hot water used per person per day. Water consumption per person may range from 20 to 100 gallons per day (gpd). These variations take into account the use of water-consuming appliances such as dishwashers and washing machines. For our calculations, we’ll use a comfortable 100 gpd, projecting the use of a dish washer and washing machine. You should keep in mind, however, a few tips which will reduce your hot-water requirements. Use spray-type faucets and short or insulated runs of pipe. In addition, washing machines, dishwashers, and other water-consuming appliances should be run at peak capacity. By following these suggestions, you can reduce the 100 gpd per person figure by two- thirds. To calculate the size of the heater, a few points must be kept in mind. First, it has been estimated that the peak hot-water demand in residences occurs within a four-hour period. This maximum hourly demand, however, represents only about one-seventh of the total daily demand. Second, a tank large enough to hold one-fifth of the daily hot-water requirements is recommended. Keep in mind that the figure representing the total tank capacity is deceiving, since when more than 70 % of the tank’s volume is drawn, the water starts to cool. For this reason, the tank’s total capacity is multiplied by a factor of .70 in order to arrive at a net capacity (in other words, to find out how much hot water it will realistically supply). The calculations follow; Let’s assume a family of five. 1. Determine the total daily hot-water requirement: 5 people x 100 gpd per person = 500 gpd total demand. 2. Determine the maximum hourly demand: 500 gpd (total demand) X 1/7 (maximum hourly demand factor) 71 .4. 3. Find out the amount of water needed to satisfy the four-hour peak load: 71 .4 (maximum hourly demand) x 4 = 285.6 gallons. 4. The tank’s capacity should be one-fifth the total daily requirement: 500 gpd (total daily requirement) x 1/ = 100 gallons. 5. Determine the tank’s net volume: 100 gallons (total volume) x .70 = 70 gallons. 6. Since the water needed to satisfy the four hour peak load is 285.6 gallons and the net capacity of the tank is 70 gallons, there are still 215.6 gallons of water (285.6 — 70) that the water heater must heat. 7. To find out the heater’s hourly output, divide 4 (peak hours) into 215.6 gallons of water which remain to be heated: 215.6 gallons/4 peak hours = 53.9 gallons per hour (gph). In order to satisfy the house’s hot-water requirements, the water heater in the example must be able to produce 54 gallons of hot water per hour. This particular type of water heater can be of the internal or the external type: internal is where the heating mechanism is literally immersed in the boiler; external is where it sits outside the boiler but receives hot water from the boiler as the heating medium. ] There are many ways of joining pipes: threading, soldering, brazing, caulking, gluing (or cementing), and mechanical connections. The most commonly used methods are threading, soldering, and gluing. Threading is a tedious and difficult job, involving cutting a length of pipe, fitting a threader into the pipe, turning it until enough thread has been cut, screwing the pipe into the fitting, and applying a compound or joint tape. A solder joint, on the other hand, involves only cut ting, slipping on the fitting, and soldering the connection. An entire assembly of pipes can be set without turning any of the parts. Although neither one of these two can be considered elementary procedures, soldering is easier than threading. This is very important when you consider how many connections you have to make. Steel and brass pipe require threaded connections. Plastic pipe is the easiest to assemble, merely requiring cutting and applying a cement. The biggest drawback, however, is that once the pipes are glued together they can't be taken apart. In terms of corrosion resistance, copper and plastic rate better than plain or galvanized steel, iron, or brass.* Plastic piping is presently widely available. Its great ease of installation, low cost, light weight, and self-insulating qualities make it a very attractive choice. Its use is still sometimes restricted by code because of its possible health hazards. (Controversy still exists as to its potential toxicity.) Many codes don't allow its use, particularly for the water supply system.) Red brass is an exception, offering excellent corrosion resistance. It is alloyed with copper, and although it's almost pure copper, it's correctly called brass. Copper is a very popular choice and the one we recommend in particular for the water supply system. It isn't subject to attack by acids or corrosion and is therefore more durable. In addition, it comes in both rigid and flexible form. Because it requires solder joints rather than threading, it's relatively simple to assemble. It is more expensive than either ferrous or plastic piping, but it's cheaper than brass. In addition, it's widely accepted by building codes. Connecting New Pipe to Old Connecting to the existing piping is a tricky maneuver. If your existing pipes are galvanized steel, you may find that when you try to cut into them to make a connection they appear to disintegrate, particularly at the threads. We have often found in renovation work that whole sections of galvanized steel piping, although seemingly in reason ably good condition, fall apart when new plumbing pipes are being attached to them. The best solution is to replace them all. If you live in an apartment, this may not be an option. You would be best advised, however, to have all the pipes replaced within your apartment and all the way to the building riser which supplies your apartment. Discuss this in advance with the building manager or superintendent. The use of PVC and other plastic piping materials has long been a source of controversy. Potential health hazards were originally raised in terms of the inhalation of PVC fumes by workers in the plastics industry. In addition, it has been suspected that minute amounts of PVC may “leak” from PVC bottles into the contained liquid. (This suspicion was responsible for the FDA ban on the use of PVC in liquor bottles and food containers.) In the event of a fire, plastic piping and tubing can become a source of hazardous fumes. A wide range of plastics is currently being used for piping, including PVC. This plastic piping comes with ratings for various uses, including heat resistance, pressure, and even potable water use. We don't recommend the use of plastic for the water supply system. Should you decide (and are allowed by code) to do so, make sure to research the material thoroughly. [ HOW TO IDENTIFY PIPE MATERIALS: A tried-and-true method for identifying pipe materials is the knife-and-magnet test. If the magnet sticks, the pipe is of a ferrous material such as galvanized steel or cast iron. Galvanized steel is gray; cast iron is black. The magnet will not stick to copper, brass, or lead. Scratch the pipe with the knife. Copper pipe will be an orange-gold color. Brass, on the other hand, will be a yellowish gold color. Lead is silvery gray and feels soft when scratched with the knife. ] A further consideration in renovation is joining dissimilar materials. Joining ferrous to nonferrous pipes results in galvanic action. For this reason, whereas connecting copper to red brass isn't a problem, connecting galvanized steel to copper or brass will leave you with a problem-ridden installation. There are instances, such as in the case of an apartment building, where even if you replace all the piping within your apartment with copper, you still may need to hook up to a main supply riser made of steel. Special fittings or adapters designed for this purpose are available. Pipe Sizing The sizes of pipes vary according to their function within the system and the amount of water they must carry. The principle is well illustrated in the structure of a tree: the farther away from the trunk, the smaller the branch. A branch pipe bringing water to a sink carries less water than the main that supplies the entire bathroom and is, therefore, smaller in diameter. The sizes of pipes necessary for one- or two- family houses are rarely calculated. The required sizes are often outlined by codes or by tried-and- true rules of thumb. If you live in an apartment building, you have to use the building’s guide lines (which would have been dictated by the building code). For preliminary design purposes, we have compiled a list of the most common sizes used for supply copper tubing in residential work. (Keep in mind that pipe sizes vary according to the material used.) Consult your local building code before finalizing the sizes. Do not make these sizes any smaller unless you want to hear humming in the pipes or have low water pressure. Making the pipes larger than required does not hurt. WATER SUPPLY PIPE SIZES Supply main: 1” Hot- and cold-water mains: 1” Intermediary branches: 3/4” Branches to each fixture: 1/2” Pipe Fittings In their run through the house, pipes have to change direction, branch into other pipes, reduce large pipes into smaller ones, and so on, while at the same time permitting the uninterrupted flow of water. Pipe fittings are provided for this purpose. They can be soldered, threaded, or specially designed, as in the case of plastic or cast-iron piping. It all depends on the material you are using. Copper piping is connected by means of soldered fittings. How to Modify and Map out the Water Supply System 1. Start by determining the material of the existing piping. If you have galvanized steel or lead, plan to replace all the piping. Those with cop per or brass piping need be concerned only with extending or modifying the existing system to accommodate the renovation plans. Should the sup ply pipe be plastic, you must investigate issues of code compliance and potential health hazards. 2. Check the water pressure. There are various problems that can result in low water pressure. The town may have a recurrent problem with the water pressure. Talk to the local authorities. There may be other culprits. The main supply pipe into the house may be too small. It should be at least 1” in diameter. If the supply pipe is large enough, then the problem may lie with the pipes within the building. They could be too small, might be kinked, or have deposit buildup. Lack of water pressure in houses connected to a well may be the result of a worn-out pump or lack or water in the well. A well pump running excessively is often a sign of trouble. 3. Is your existing hot water heater large enough to handle your present load? Does it have enough capacity to meet the additional demands you are planning for your plumbing system? Investigate the advantages of going to a larger size. 4. Check to see if the existing water drainage system is vented. (It isn't uncommon for older buildings to have unvented piping.) If it's not vented, you must include the venting of these pipes in your renovation plans. 5. Make sure that the existing pipe sizes meet code 153 requirements. You may have to increase the size of some pipes. 6. Take a look at your preliminary plans and examine the locations of the proposed bathrooms, kitchen, laundry room, and any other area requiring plumbing. Are they efficiently arranged? Can they be moved closer? Can they share a “wet” wall by being back to back or by being stacked? It should be evident at this point why grouping fixtures together facilitates the design and installation of a plumbing system. The closer the fixtures, the shorter the pipe runs and therefore the less work and expense. In addition, when the distances between baths or other plumbing fixtures are excessively long, the code may require that you install a circulating hot-water line. 7. Keep in mind that, with the exception of basements (where pipes may be left exposed), pipes are usually concealed inside walls, floors, and ceilings. Wherever you require a new pipe or are replacing an old one, all these finishes need to be ripped apart and later patched and repaired. However, nothing prevents running exposed piping if the aesthetics aren't displeasing to you. 8. Show all the fixtures on the plan and provide each one of them with a hot- and a cold-water supply pipe (as required). You can indicate the pipes as circles in the wall next to the fixture. 9. Make provision for valves throughout the system. Keep in mind that check valves are required in both the cold- and the hot-water lines to dishwashers and washing machines. 10. Establish the shortest route that the hot- and cold- water pipes must travel in order to reach the supply main and the water heater or boiler. In order to do this, examine the available walls, floors, and ceilings through which the pipes can run. Consider the structural elements within the walls and floors (studs, joists, etc.). Make sure that the pipes work with them rather than disrupt them. DRAINAGE The used water together with any waste it has collected has to be led out of the house and into a disposal system (be it a municipal sewer main or a private sewage system). This is the function of a drainage system. In addition to getting rid of the waste, the drainage system has to provide an exhaust for harmful and smelly gases generated by the waste. Two interlocking networks are pro vided for this purpose. The first is a network of pipes that carries all waste from each fixture to the sewage disposal system. The second is a venting system in parallel with the drain piping that allows gas to be exhausted to the outside while letting air in. The drainage system operates very much like the water supply. Waste from the fixtures drains to the waste pipe and is discharged into an intermediary branch line, which picks up waste from fixtures located on the same floor or in the same area. In order to reach the basement, the waste is channeled to a vertical pipe (soil stack) that runs the full height of the building (from the basement to the roof). The purpose of a soil stack is to receive the waste from all intermediary lines and transfer it to the house drain, which is the link between the drainage and the disposal system. The soil stack carries both solid and liquid waste. In large installations or where the distance between some fixtures and the soil stack is too great, a secondary stack called a waste stack is provided. In apartment houses there are sometimes two stacks, a 4” soil stack for toilets, and a 3” waste stack for service sinks. Houses may need two stacks where kitchens and bath rooms are remote from each other. Unlike the water supply system, which functions by means of pressure, the drainage system relies completely on gravity. For this reason, all waste pipes are either vertical or have a down ward pitch (1/8” per 1’ to 1/4” per 1’). In addition, drainage pipes have a large cross-sectional area to help prevent solid matter from accumulating and clogging the pipes. The venting system is an integral part of the drainage system. The soil stack, which is the main artery for drainage, becomes the “lungs” for the vents. It serves this purpose by being open at the roof. This opening allows air into the soil stack (referred to as the stack vent once it extends over the highest fixture) at the same time that gases are exhausted, preventing suction and gas accumulation in the pipes. In addition to the soil stack, a fresh-air inlet is sometimes provided at or near the house trap. Although the soil stack is the main source of air, it's difficult for air to find its way to all the fixtures unless each is provided with a branch vent. Branch vents are pipes carrying nothing but air that lead from each fixture to a vent collector. In compact installations, the collector hooks up to a vent riser. The connection between the vent riser and the soil stack occurs above the level of the highest fixtures, where the soil stack becomes the stack vent. In large installations or where distances between the vent riser and the soil stack are too great, the riser is led directly to the roof, becoming a direct ventilation source—it is common in houses for a bathroom and the kitchen sink to have a separate vent. To further prevent gases from entering the house, traps are provided at each fixture. A trap is the U-shaped pipe you always see under sinks. Every fixture has a trap but most of them are hidden within walls, floors, or the fixtures them selves. The trap literally traps water in the U. The water acts as a seal against sewer gas and drainage pipe odor penetration. Venting is essential to the proper functioning of the traps. When there is no air in the drainage system, suction (siphonage) can take place. Siphon action can draw the water out of the trap, breaking the seal and leaving an open path for gases to enter the building or room. Cleanouts are also important to the drainage system. They are openings in the pipes that give access to the interior of the system and are valuable in the event of clogging or other problems. The number of cleanouts varies according to the complexity of the piping network or as required by code. A cleanout plug, however, is always required at the bottom of the soil stack—before it turns into the house drain. A rule of thumb is to provide cleanouts at every change in direction and in sufficient number to make the entire drainage system accessible for cleaning. Other components such as a house trap and a separate fresh-air intake are sometimes included. The house trap (a trap in the house drain) has been a source of controversy. There are those who feel that although it provides further insurance against gas penetration from the disposal system, it may interfere with the efficient outflow of waste. Check your code to see whether it's required in your locality or not. A fresh-air inlet is usually included whenever a house trap is pro vided, and omitted otherwise. Its purpose is to allow fresh air into the system. Drainage Pipe Materials The criteria for the selection of drainage pipes are slightly different from those for supply pipes. Like supply pipes, drainage piping has to handle problems of corrosion and facilitate installation. It does not, however, have to sustain the pressure that supply pipes do and toxicity considerations aren't relevant. Instead, it must allow for the easy flow of sometimes bulky waste. Due to the lack of pressure, its walls can be thinner. Because of the waste, its diameter should be larger. When you are buying drainage pipe, specify it as such. The thinner-walled piping will be a bit cheaper and lighter than that used for supply lines. Copper, plastic, and cast iron are the three most widely used materials for drainage piping. (Many codes specify cast iron as the only acceptable material, especially where drainage piping is buried.) Although cast iron costs less than copper, it's much heavier to support. In the past the technique for connecting cast-iron piping was rather complicated. Fortunately, a new joining system for cast-iron piping is now available. These no- hub couplings consist of a neoprene section protected by a thin metal ring. They are much easier to install than the traditional connections. Their use may be restricted in some locations. Copper tubing has been widely used for drainage systems. Its essential characteristics have already been described. Plastic piping is an economical and work-saving option. Although many codes don't accept plastic in the water supply system, they allow its use for drainage lines. Plastic resists corrosion, is lightweight, and is simple to install. Unless the code requires otherwise, we recommend plastic tubing for the drainage lines. On the debit side, plastic pipes are noisy. Pipe Sizing Because they carry waste in addition to water, drainage pipes are larger in diameter than water supply pipes. In addition, the system operates completely on gravity. The area of the pipes has to be large enough to prevent any waste from getting stuck and clogging the system. Conversely, too large a pipe (or too steep a horizontal pitch) isn't desirable since the liquid will run off, leaving solid matter behind. As in the case of the supply lines, the size of drainage pipes is relative to their function within the network. Obviously, a pipe draining a sink will be smaller than one carrying waste out of a toilet. Following is a list of widely used dimensions for copper and plastic tubing in residential work. (Those of you in apartment buildings need to check the building standards.) These dimensions are merely indicators; always check your code first. DRAINAGE PIPES House drain 4” Soil stack 4” Drains in kitchen 2” Drains in toilet 4” Sink and bathtubs 1 1/2” VENTING PIPES All vents 2” Pipe Fittings The type of fitting in the drainage system varies from that of the supply system because it serves a different function. Fittings are needed not only to connect the different branches within the net work but, more important, to permit maximum ease of flow of the sewage out of the building. To prevent any waste from being trapped at turnings, connections between branches and the main stack are gentle curves rather than sharp angles. (Angles are generally greater than 45 degrees with the horizontal; 90-degree angles aren't permitted.) In addition, the fittings are designed with no protrusions on their inside diameter. How to Modify and Map out the Drainage System 1. Take a look at the existing drainage piping. If the pipes are galvanized and show signs of rusted joints, they will require significant replacement. Those who have old cast-iron piping should give it a gentle tap (not too hard or it may break). If the walls sound thick and solid, they should be fine. Keep in mind that when connecting different materials (for example, cast iron to plastic) you need special no-hub fittings designed for this purpose. 2. Check to make sure that the drainage system is vented. If unvented, a venting system must be planned for. 3. Determine whether the existing drainage pipes are of adequate size (they should, at the very least, meet code requirements). If they are undersized, include their replacement in your renovation plans. 4. Check to see if there is a house trap, and whether or not it's required by code. 5. With your preliminary plans at hand showing the location of all the bathroom, kitchen, and laundry fixtures, proceed to draw a riser diagram. (This plan should also include the hot- and cold-water supply requirements.) A riser diagram is a section/elevation view of all the plumbing fixtures. This diagram allows you to visualize all the components necessary in the drainage system (drains, vents, stacks, etc.). It also serves as a checking device at the end of the planning stage. 6. Provide each fixture with a drainage pipe. Remember that horizontal drainage pipes generally run in the floors. 7. Provide each fixture with a vent. Vents are usually within the wall. 8. Establish the best route to bring the branch vents into the existing soil stack. In renovations where S the runs are too long, providing a secondary “waste stack” to handle the new fixtures may be the best solution. Keep in mind that waste stacks, like soil stacks, must run vertically through the entire house. Check for available walls where it can run. 9. Draw branch lines indicating the best and shortest run for each branch drain to the soil or waste stack. Try to keep bends to a minimum. Next: Heating Design |
