Mechanical and Electrical Systems Essay
PowerPoint® Presentation
Chapter 7-*
PowerPoint® Presentation
Chapter 7
Testing and Inspecting Plumbing Systems
Plumbing System Tests • Sanitary Drainage and Vent Piping Tests • Stormwater Drainage Piping Tests • Potable Water Supply and Distribution Piping Air Tests • Final Air Tests • Smoke Leak Detection • Plumbing Test Procedures
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Portable air compressors are used to supply air for the test.
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A hand pump or portable air compressor is used to force air into the plumbing system, and is typically used when testing smaller installations, such as a one-family dwelling. See Figure 7-1. For larger installations, such as commercial or public buildings, an engine-driven air compressor is used as the compressed air source. An adequate supply of air hose is required to convey air from the air compressor to the test opening connection.
Inflatable test plugs must be properly positioned before conducting an air or water test.
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Several types of devices are used to seal or plug openings in plumbing systems when performing an air test, including test plugs and caps and pipe plugs and caps. An inflatable test plug is an inflatable rubber device inserted into the plumbing system to seal openings during an air or water test. Deflated test plugs are properly positioned within the pipe and inflated with a hand pump or air compressor to seal an opening. See Figure 7-2. Inflatable test plugs are available in 3/4″ to 18″ pipe sizes. A mechanical test plug is a test device inserted into the end of a pipe or other opening and secured in position by tightening a hex or wing nut. The O-ring of a mechanical test plug is inserted into the pipe or opening and the hex or wing nut is tightened, resulting in the O-ring expanding and sealing the opening or pipe. Mechanical test plugs are available in 3/8″ to 12″ pipe sizes.
Mechanical test plugs and caps are installed on fixture drains.
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A test cap is a reinforced rubber cap installed on the outside of an opening and secured in position with a stainless steel hose clamp. See Figure 7-3. Since a test cap is visible when properly installed, there is less possibility of the test cap being left in place after testing and inspection. Test caps are available in 1 1/2″ to 8″ pipe sizes.
A test gauge assembly for an air test can be job-built.
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A test gauge assembly is a test device used to measure pressure within waste and vent, water, gas, air, or other piping systems to ensure that the system is maintaining the proper pressure. In addition to measuring air pressure within a plumbing system, the test gauge assembly also permits air to be admitted to the system. Job-built test gauge assemblies are constructed of a ball valve, reducing tee, two nipples, and a test gauge. See Figure 7-4.
A manometer is used to verify a 1″ water column for a final air test.
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A final air test (also called a manometer test) is a test of the plumbing fixtures and their connections to the drainage system. The traps are filled, the vent stacks and building drain are plugged, and a manometer tube is inserted into a plumbing fixture (usually a water closet). Air is introduced to the system until a pressure of 1″ of water column is reached. This pressure must be main-tained for the period of the test. See Figure 7-5.
A test plug is placed at the wye beneath a front main cleanout when performing an air or water test of the building sewer.
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The following steps are required to air test sanitary drainage and vent piping:
1. Plug the piping at the front main cleanout with an inflatable rubber test plug. See Figure 7-6.
…Complete procedural list on page 162.
Vent terminals and fixture drains must be plugged before performing air or water tests.
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2. Plug the vent openings in the roof and the fixture drains with the appropriate mechanical test plug, test cap, or inflatable test plug. See Figure 7-7.
…Complete procedural list on page 162.
Inflatable test plugs are inserted into test tees to isolate sections of piping.
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3. If the building piping is being tested in sections, isolate the section being tested with short test plugs inserted in the appropriate test tees. See Figure 7-8.
…Complete procedural list on page 162.
When performing an air test, the 5 psi reading on a test gauge assembly must be maintained for 15 min.
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4. Attach the test gauge assembly to the system; this is usually done at a lavatory or sink drain opening. See Figure 7-9.
…Complete procedural list on page 162.
An inflatable sealing test plug is used to isolate piping for a water test.
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The following steps are required to water test sanitary drainage and vent piping:
1. Plug the piping at the front main clean-out with an inflatable rubber test plug.
2. Plug all the vent openings in the roof except one, and plug the fixture drains with the appropriate mechanical test plug, test cap, or inflatable test plug.
3. If the building piping is being tested in sections, isolate the section being tested with inflatable sealing plugs inserted in the appropriate test tees. See Figure 7-10.
…Complete procedural list on pages 163 – 164.
Test plugs must be carefully removed upon completion of a water test.
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8. Upon completion of a water test, the water must be removed from the system. In homes and small buildings, the air is simply released from the inflatable rubber test plug placed in the front main cleanout, allowing the water to drain into the building sewer. See Figure 7-11. In tall buildings where the pipe is tested in sections, the inflatable sealing plug is deflated and the water drains away.
…Complete procedural list on pages 163 – 164.
An ultrasonic leak detector is a sensitive microphone probe and amplifier that is used to locate leaks in water supply and distribution piping.
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Since leaks in potable water supply and distribution piping are usually small, they are difficult to locate with a soapy water solution. An ultrasonic leak detector is commonly used to locate small leaks in the system. An ultrasonic leak detector is a sensitive microphone probe and amplifier that is used to locate leaks in water supply and distribution piping. See Figure 7-12. An ultrasonic leak detector operates in the ultrasonic range of 35,000 hertz (Hz) or cycles per second to 45,000 Hz, which is the sound frequency generated by pressurized air as it escapes from pipes. The sound frequency is picked up by the microphone probe and converted into sound that can be heard by the person operating the leak detector.
For a final air test, a pressure difference of 1″ water column must be maintained.
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A manometer is used to verify the 1″ water column for a final air test. A manometer is a clear U-shaped tube partially filled with water; it is used to measure pressure within a closed system. See Figure 7-13. The procedure for performing a final air test is as follows:
1. Fill all fixture and floor drain traps with water.
2. Plug all roof stack openings.
3. Plug the building drain at the front main cleanout using a test plug.
4. Insert the manometer hose through a water closet trap seal and remove any water from the hose by blowing into one end.
5. Fill the manometer with water to the zero inch mark on the manometer ruler and place the manometer on a stable surface.
6. Attach the hose extending from the water closet to the manometer.
7. Insert another hose through the water closet trap seal and blow air into the system until a 1″ pressure difference is shown and maintained on the manometer. Only a small amount of air is required to be introduced into the system to produce the required pressure difference.
The DWV system, including all fixture traps, must be tested with a pressure equal to a 1″ water column.
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During a final air test, the piping is pressurized to 1″ water column. See Figure 7-14. Since some plumbing fixture traps contain only a 2″ water seal, excessive pressure may blow out the traps and void the final air test. During the duration of a final air test, large volumes of water cannot be added to the system quickly without blowing out fixture traps. For example, water closets or urinals cannot be flushed since large volumes of water are added to the system during the flushing process. Final air tests should be performed when other tradesworkers are not working in the building. If it is not possible to work alone in the building, turn off all flushometer valves and empty all water closet flush tanks during a final air test to prevent flushing of the fixtures. If an air test is performed over the course of more than one day, the test plug in the front main cleanout opening must be removed. Before removing the plug from the front main cleanout, remove plugs from roof vent openings to prevent siphonage of fixture trap seals.
A smoke chamber is constructed of a short section of large-diameter pipe and two reducer fittings. A smoke cart-ridge is placed inside the device to produce thick, odorous smoke.
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A smoke chamber is used to introduce smoke into the piping system. A smoke chamber is a device constructed of a short section of large-diameter pipe and two reducer fittings in which a smoke cartridge is placed. See Figure 7-15. The smoke cartridge is ignited and inserted into the pipe chamber, and the chamber is closed. Compressed air is applied to one end of the smoke chamber to distribute smoke throughout the piping system. Leaks are identified by locating smoke escaping from the piping.
An odorant is used to locate leaks during a final air test.
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Leaks in the sanitary drainage and vent piping system can also be located using an odorant test. To perform an odorant test, fixture traps are filled with water and the building drain is plugged at the front main cleanout. Two ounces of oil of peppermint or oil of wintergreen are poured into each stack and the building drain. See Figure 7-16. The stack and drain openings are closed and a pressure of 1″ water column is applied to the piping. If leaks are present, a sweet smell will be detected in the area of a leak.