Plumber's Licensing Exam: General Plumbing Regulations

This guide covers all those rules about how to install piping without discussing pipe sizes, capacities, or any of the hydraulics involved with designing and installing a plumbing system. We must protect the building, the plumbing system, and the people who will use it. In this guide, we will consider some of the practical rules for actually getting the piping into the ground and the building.
The plumbing system is only a portion of a complete building; so, when plumbers are working, they must look beyond “the pipes” to the other aspects of a building’s construction. The integrity of the building must be maintained and the safety and comfort of the occupants must be kept in mind.

Objectives
- Connect to municipal systems
- Identify materials not allowed in a sewer system
- Provide vermin protection
- Protect a plumbing system
- Protect a building from the plumbing system
- State underground piping practices
- Explain bathroom design regulations
- Test a new drainage system
- Test a new supply system

Key Terms:
adhesion
ambient
effluent
gray water
green
head
ID
potable
psi
psig
sanitary drainage system
WC

General Principles of Plumbing Regulations
Connections to Building Sanitary Drainage Systems and Water Supply Systems
This portion of the regulations simply states that all plumbing fixture drains must be connected to the building sanitary drainage system, and all fixtures that need a water supply must be connected to the water supply system of the building. This seems obvious, but occasionally you will find situations where this has not been done. Many older homes may have the kitchen sink and/or the gray-water fixtures connected to a separate drain from the sanitary sewer. This drain may lead to a manufactured or homemade seepage pit located on the property. It may even simply lead out to a drainage ditch. (Refer to IPC 301.3, 301.4; UPC 305.1)

Real-Life Situation: Ace Plumbing Company is bidding on the contract for the new addition to the Springfield Elementary School. There are many design features that Sophia, the Ace estimator, must consider. The existing school was built in 1952. Trenching will be necessary next to the old school’s foundation. What must be done to protect the old foundation as well as the new building drain? Is the earth in the area of the new addition stable enough for bedding a pipe in a trench? Sophia knows from the plans of the old school that lots of fill was necessary because the school was built on the old Bigler swamp. Can pipe connections be made to the old school’s building drain, or will a new connection to the sewer main be needed? Do we have the necessary equipment for testing the new system?

The motivation to make these drains separate was to reduce the quantity of water flowing into an inadequate septic system. When automatic clothes washers became popular after 1947, many homeowners thought the excess water would reduce the effectiveness of the bacteria in their septic tank.

Figure: Seepage Pit

The purpose of the requirement to connect all water-using fixtures to the water distribution system of a building is to prevent the flushing of fixtures with some outside and uncontrolled water source, like using a bucket to flush a toilet rather than connecting the building water supply to the toilet tank.
In locations where water usage must be carefully restricted due to limited supply or when a building owner chooses to build green, gray water is collected and stored, and then reused for the flushing of water closets and urinals, which do not require potable water to operate properly.

Materials Not Allowed in a Sewer System
You can probably think of a number of materials that should not be put into a sewer system. Think of what could happen if a certain material or liquid were introduced into a sewer system. That way, you don’t have to memorize a list of disallowed materials. Think of just one item; got it? Now, think of what might happen to the people working on the plumbing system (like you!) if they were unaware of or unprepared for that harmful material. Consider the ability of the sewage disposal system to handle this material; could the system render the material harmless to the environment? Think about the pipes, the building, and the main sewer system. Could they safely carry this material without a blockage occurring or the piping being aggressively corroded? What about the final destination of the material, be it a river, ocean, or leach field? Would plants, animals, and the air be able to tolerate the introduction of this material? (Refer to IPC 302; UPC 303)
A sewage disposal system is designed to receive organic waste and turn it into harmless effluent that is ready to be put back into our environment—you know, the stuff that is normally flushed down the toilet and washed down the kitchen sink. The system is also designed to handle the extra water, soap, and detergents that go down the same building drain. If the material is highly acidic, caustic, radioactive, flammable, or poisonous, it does not belong in a sanitary sewer. In the case of industrial waste, many varieties of exotic and harmful substances are routinely disposed of. Such waste must be treated in a manner that renders it harmless before it can be put into a sewer system. If it cannot be made harmless, it cannot be put down a drain; it’s as simple as that. In some cases, this can be as minor as cooling the water to 140°F (60°C), which is the highest temperature of wastewater allowed in a building drainage system.

Vermin Protection
The most notable vermin we as plumbers must deal with is the rat. Rats can carry a wide array of diseases and they effectively transmit them to other animal populations, including humans, through their own body fluids, dead carcasses, and the fleas they carry. The most famous disease to which they have subjected the world is bubonic plague, or the Black Death. We have all learned about the plague’s devastation of Europe during the Middle Ages. (Refer to IPC 304; UPC 313.12)
There have been other plague epidemics throughout history. Plague still roams the earth in the fleas on the backs of the rats we hate to see, but cannot eliminate.
That is why we must do our part to control rats. The IPC and the UPC are almost identical on the steps required for making a plumbing system rodent-proof. The smaller dimension of any opening of drain grates can be no larger than 1/2 inch. For example, a floor drain can have openings that extend 4 inches or more in one direction, but the opposite dimension, which creates a rectangle, can be no larger than 1/2 inch. All pipes that go through floors, ceilings, or walls must have the space around them covered with a metal plate or collar. These prevent rats from getting out of the sewer system if they are already in it, and prevent them from getting into the sewer system if they are inside a building.

Fact: The first documented plague epidemic was long before the Middle Ages. From about 500 a.d. to 700 a.d., an epidemic killed about a quarter of the world’s population from Ethiopia, up through the Middle East, and into Europe.

Protecting the Plumbing System
We want to protect our good work from manmade and natural forces. Wherever metallic pipes pass through concrete, or through a soil that is corrosive, the pipes must have a protective sheath, or covering, that is at least 0.025-inch thick.

That’s about as thick as this line: _______________
The covering also has to be flexible enough to allow for expansion and contraction to prevent scraping of the pipe. (Refer to IPC 305, 306; UPC 313.0–313.11, 314.0–315.4)
When a pipe passes under or through a wall, it must be protected from damage that could occur if the wall shifts and the weight of the building bears down on the pipe, or creates some other force to be transferred to the pipe due to movement of the building. This is accomplished by running the pipe through a supporting sleeve or by building an arch over the pipe.
Piping must be protected against damage from expansion and contraction due to temperature changes. This can occur with changes in the ambient temperature, or when the temperature of the liquid flowing through the pipe changes. If a straight section of pipe is rigidly supported on both ends, great stress and probable damage would occur when its temperature changed, generating expansion or contraction. Either the design of the piping or the piping supports must accommodate this natural movement. Expansion joints or loops in the piping are used to allow such movement. Imagine a worm trying to sink back into its hole (like a pipe that suddenly has chilled liquid flowing through it) but a robin is firmly holding on to it. The worm has to let go of the earth or rip apart; either way the worm dies. The point is, something’s got to give.
Freezing is a common nemesis of water-conducting pipes. Those who live in Miami and San Diego may not have to be too concerned about this, but most of the rest of us do. If you live in a colder climate, you have seen the results of the irresistible force of ice expanding inside a pipe. Broken pipes and building damage can be quite expensive. Any pipe intended to conduct a liquid that will freeze under a normal weather condition must be protected. This can be done with freeze-proof hydrants, pipe burial at least 6 inches below the local frost line in the case of supply piping, and insulation with a heat source. Sewer pipes do not have to meet the “frost line” rule because they are not normally filled with water and they only flow when water runs down a drain. Generally, the minimum depth required is 6 inches, but this can vary by region and by a specific situation. You must check the local code.
During new construction or remodeling, pipes are installed that must pass through the framing members of the building in order to conceal them. Unless those pipes are made of cast iron or galvanized steel, they must be protected from the possibility of damage when finish nails or screws are used to fasten the wall and ceiling panels to the framing members. This is done with what are commonly called nail plates. They are fastened to the frame at any point where the surface of a pipe passing through a framing member is closer than 11/2 inches to the face of the frame. A little-known and less followed rule concerning nail plates is that they must extend 2 inches beyond the edge of the framing member in the direction where panels are to be applied to protect against the likelihood of a fastener missing the stud.

Tips:
Have you ever heard the old myth that hot water freezes faster than cold water? Obviously, hot water will not freeze faster than cold water if they are both subjected to freezing temperatures at the same time. Say you put a coffee can full of hot water and one full of cold water in your freezer. The hot water must lose all that extra heat and cool down before it will begin to freeze. The can of cold water will have a head start on freezing. However, water that has been heated and cooled to the same temperature as cold water will freeze faster than the cold water. The reason for this is that microscopic air bubbles are driven out of water when it is heated. The little bubbles act like insulation (minimal as it may be) for the cold water. This often occurs in plumbing systems when piping that has had no water drawn from it for a long period of time, such as overnight, is subjected to frigid temperatures and freezes.


Figure: Protective Shield Plate or Nail Plate

Protecting the Building from the Plumbing System
Probably the most common crime plumbers commit is overzealous drilling, cutting, and notching of the support members of a building. If you adhere to the regulations of the plumbing code, this will not happen. To begin with, the code says in a general way that you must leave all parts of a building in a safe structural state when your work is done. Some general rules include not notching a bearing stud any more than 25% and a nonbearing stud any more than 40%. You should avoid notching joists whenever possible. No notching is allowed in the middle third of a joist and very limited notching should occur in other areas. You must refer to your local building code for specifics. The size and location of drilled holes are also limited by the building code. Never cut any part of a truss. A truss is designed to bear specific loads as a complete, intact structure. A truss cannot bear its designed load if any part of it is cut or drilled. (Refer to IPC 307; UPC 313.7, 313.10.3, 313.11)

Caution: Cutting and notching of the structural members of a building beyond acceptable limits not only renders the structure unsafe, but also becomes a very expensive repair for your company. Notching and drilling regulations must be strictly adhered to.

Underground Piping Practices
The UPC makes an important reference to trenching near buildings at or below the grade of the footing. If a trench is parallel to the footing, any settling of the building could damage the pipe, but more importantly the integrity of the structure could be seriously compromised. (Refer to IPC 306; UPC 315)

Installing underground pipe by jacking or tunneling methods is allowed. Generally, this is done by contractors who specialize in this unique piping practice. These methods are efficient when piping must be installed under a paved area, roadway, or another improved surface that would be expensive to repair or inconvenient for interruption of service. If true tunneling is the method used, the tunnel must be reinforced to prevent future cave-in of the tunnel on the pipe. Jacking and tunneling pipe-laying methods should be limited to areas where it is clearly the best route to go. Trenching and backfilling is the most controllable method of burying pipe and it is arguably the most reliable.

Figure: Large-Scale Trenching Project

Pipe in a trench must be continuously supported on unexcavated earth whenever possible. If you are installing a type of pipe with hub and spigot joints, holes must be dug where each hub sits to allow the body of the pipe to rest continuously on the bottom of the trench, rather than the pipe being suspended by the hubs. Now, we know that it is a rare backhoe or excavator operator who can dig a trench at the exact depth and exact pitch needed to meet the “unexcavated earth” requirement. So, what to do? Wherever the earth is dug deeper than necessary, sand or fine gravel must be placed in the trench and compacted at every 6 inches of depth. The UPC states that any material that can pass through a 3/16 -inch screen is appropriate for back fill. All rocks, frozen soil, concrete, and other large, heavy fill items must be kept away from the pipe. The single point pressure that those kinds of items can place on a pipe may push the pipe out of alignment or break the pipe. After 12 inches of fine fill has been backfilled and compacted every 6 inches, large items may be placed in the trench. It’s better if they can be kept out of the trench altogether, but that isn’t always possible.

Tips:
When laying a pipe in a trench, the top half of the pipe must be left visible for the inspector to examine before completing the backfilling operation. If it is covered, the inspector may compel you to uncover it for inspection.
Occasionally, and in some regions more than others, an excavated trench will have a bottom that is soft and cannot dependably support the pipe. This must be remedied by overexcavating the trench to two times the inside diameter, or ID, of the pipe and placing appropriate fill, such as gravel, crushed stone, or, in extreme cases, concrete, to provide a solid base to support the pipe.
After a pipe has been laid and backfilled around the bottom and sides, the top half must be left exposed until after the appropriate authority has inspected and approved the installation.
Keep in mind that you must protect this pipe that you are installing underground, anticipating that it could stay in service for fifty years, eighty years, or perhaps even longer.

Figure: Centuries-Old Water Main

Bathroom Design Regulations
The IPC has regulations governing the design of bathrooms. The UPC leaves these design considerations to the local building code. (Refer to IPC 310.1–311.1)
Interference with the normal operation of any doors or windows by any piping or fixtures is prohibited. So, if your cellar door opens halfway and then runs into an overhead soil pipe, the pipe must be rerouted. If the bathroom door swings open and then clunks into the toilet bowl, the water closet must be moved or the door must be moved.
In public restrooms, every toilet must have its own compartment with a door for privacy. All urinals must have partitions that extend a minimum of 18 inches from the wall or 6 inches from the front rim of the urinal, whichever is furthest out from the wall. The walls around a urinal must be easily washable. The partition must start no more than 12 inches above the floor and must go no higher than 60 inches. The exception to these privacy provisions is in childcare facilities where children are likely to need assistance. There are size provisions for these compartments.

Section 311 requires that toilet facilities are available to construction workers who are in an area where plumbing is not yet finished or will not be included in the project. Refer to your copy of the plumbing code to find the number of toilets required based on the number of workers at a site. Portable toilets are allowed, and are far more prevalent on jobsites than permanent facilities. This rule gives workers the dignity of using a proper toilet rather than having to leave the site to find a bathroom or search for a bush to hide behind.

Fact: Wooden water mains buried in Philadelphia before the Industrial Revolution were replaced in the 1970s, and that was only because they were too small to handle the amount of water needed. Those original pipes had been carefully supported, bedded, and backfilled!

Testing New Plumbing Systems
Gauges used for testing must be in a range that is reasonable for the pressure being measured. This is an important point. Specifically, you should never use a gauge that has a range of more than twice the test pressure. For pressure tests up to 10 psi, the gauge increments should be of a pound. For measurements between 10 and 100 psi, the increments should be 1/10 psi. Pressure tests at higher ranges should have increments that are 2% of the test pressure, and no gauge used should have an upper limit that is greater than twice the test pressure. (Refer to IPC 312, 107.1–107.5; UPC 319, 103.5.3–103.5.3.3)

Drainage System Testing
An important aspect of the IPC 107 section and the UPC 103.5 section is that the obligation to test plumbing systems falls entirely on the permit owner. This includes having all the equipment and labor necessary on site to perform the tests. The inspector simply observes and comments. The inspector’s job is to inspect only; he or she plays no role in performing the tests. The plumbing codes put the responsibility on the permit holder because that is where the legal recourse lies should there be any problems arising on the job. The permit holder, if it is not the plumber, will undoubtedly transfer the responsibility of testing to the plumber through the owner’s contract with the plumber. On very small jobs, such as a water heater replacement, the plumber may very well be the permit holder. On larger jobs where construction is involved, the building owner will probably be the permit holder. (Refer to IPC 312.1–312.9.2; UPC 319.1 and 319.4)
If you are testing a drainage system, the whole system must be filled with water so that it runs out of the roof vent. This puts the entire system under a pressure of at least 10 feet of head, except for the top 10 feet, which is the code requirement. In the case of a multistory building where filling the system would create unusual and excessive pressure in the lower parts of the system, testing is permitted to be done in sections. The tests must be maintained for a minimum of 15 minutes to satisfy the requirements of inspection.

The pressure created by 10 feet of head is 4.33 psig. An alternative to testing the drainage system with water is an air pressure test. Air is pumped into the system, after all the openings are plugged, up to 5 psig. Again, this pressure must be maintained for 15 minutes. It is far more difficult to find leaks in a system tested with air pressure, but the risks of freezing and water damage from leaks are eliminated.

If there is any doubt that a system is watertight, the inspector may require a smoke test. A smoke test is done by filling a drainage system with smoke and air, then capping all openings and creating a pressure of only 1-inch WC. Keeping the pressure this low is critical because too much pressure will cause the smoke to blow through the trap seals and fill the rooms with smoke, making the test useless for finding leaks. The procedure would have to be repeated after the smoke is totally cleared, resulting in a great waste of time and money.

Supply System Testing
Once again, the complete responsibility of testing lies with the permit holder. When testing a water supply system with water, potable water must be used. It may be convenient to pump water from a bucket, ditch, or pond for testing before a water main is connected, but this would contaminate the new piping system you just installed, which would then require sanitizing and testing for bacteria. Only use water from a potable supply. (Refer to IPC 312.1, 312.1.1, and 312.5; UPC 319.2–319.4)

The minimum pressure for testing water supply systems is 50 psi. If the operating pressure of the system will be greater than 50 psi, the test must be at least at the working pressure of the system.

Figure: Smoke Testing a Sewer System

Air pressure tests of 50 psi are permitted on nonplastic supply systems. Plastic piping could be subject to catastrophic failure in an air test and individuals could be injured. Instead of simply rupturing in the way that metal pipes do, plastic materials can splinter and produce a kind of plastic shrapnel. As we all know, liquids are not compressible. When a water-filled pipe breaks, the pressure is instantly relieved. The property of adhesion will tend to keep the broken pieces of pipe connected to the water. If a plastic pipe filled with pressurized air breaks, the energy of the expanding air may carry broken pieces a great distance with considerable force.