Measuring and testing – With fluid pressure
Reexamination Certificate
1999-10-29
2002-04-30
Larkin, Daniel S. (Department: 2856)
Measuring and testing
With fluid pressure
C073S049100, C073S049500, C073S049800
Reexamination Certificate
active
06378356
ABSTRACT:
I. BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to waste, vent, and gas pipe testing devices and more specifically to on-site waste, vent, and gas pipe testing devices used either during building construction or after building construction is completed, and prior to water and gas being supplied to a building site.
2. Description of Related Art
In the past, pipe installed in a building for the purpose of bringing gas utility to the building or to removing waste from the building was tested at the time that gas and water were supplied to the site by utility services. However, in the last 7 years there has been an increasing trend to reduce early stage real estate development costs by delaying installation of utility service until a building has a planned occupation date. In that case, the developer is faced with the problem of ensuring that the installed piping meets local plumbing codes (for example, the Uniform Plumbing Code (UPC), the Canadian Standards Association (CSA), the International Committee of Building Organization (ICB), and others) for gas and waste prior to the utility being supplied. This is accomplished by using pressurized air to test the integrity of the pipes.
The air testing procedure is described in the UPC book. Standards published in the 1994 UPC book must be met until January 1999. After January 1999, the standard published in the 1997 UPC book will be implemented. Section 712.3 sets forth the air testing procedures and standards for waste pipes. Section 1204.3.2 sets forth the air testing procedures and standards for gas pipes.
Waste pipe systems have been air tested using an air-pressure fitting constructed to fit the standard waste plumbing pipes, having, for example, 1½″, 2″, 3″, or 4″ inside diameter (i.d.), corresponding to 2½″, 2¾″, 3¾″, or 4¾″ outside diameter (o.d.), respectively. Unless otherwise noted, when a pipe is describe as having a specific diameter, such as for example, a 4″ pipe, the dimension is referring to the inside diameter (i.d.) of the pipe. The air test is made by attaching an air compressor testing apparatus to a clean-out, waste riser, or other suitable opening in the pipe system, closing all other inlets and outlets to the is system, and forcing air into the system until there is a uniform gage pressure of five pounds per square inch (5 psi or 34.5 kPa). The outside air-pressure source is then disconnected, the 5 psi pressure must be held by the pipe system without introduction of additional air for at least 15 minutes. The pressure must be an measured using a gauge having at least {fraction (1/10)} pound incrementation; the range of the gauge is not limited for waste testing.
Gas pipe systems have been tested using an air-pressure fitting constructed to fit the standard gas pipe, having for example, ½, ¾″, 1″, 1¼″ or 1½″ diameters. Until 1999, the pipe system must be tested to a uniform pressure of 15 psi and held for no less than 15 minutes. The pressure is measured using a 30 pound gauge having one pound incrementation. After 1999, the pipes will be tested to a uniform pressure of not less than 10 psi and held for no less than 15 minutes with no perceptible drop in pressure. The pressure must be measured using a gauge having {fraction (1/10)} pound incrementation and a range that does not exceed twice the test pressure applied, in this case 20 pounds.
Because waste and gas pipe systems have different pipe sizes and are tested to different gas pressures requiring different air gauges, the people who conduct the tests have been burdened with carrying around cumbersome air-pressure fittings, devoted to one or the other type of systems. To use an air test on a waste pipe, plumbers in the field have resorted to assembling heavy awkward devices in order to connect a small ⅜ inch air valve to a waste pipe having an inside diameter between about 1½″ and about 4″. Additionally, because of the awkward construction of the air-valve to waste-pipe adapters, the delicate pressure gauges are constantly breaking, as they are carried around in a bin of fittings, resulting in high replacement costs. Repairing them in the field, or making new ones is frustrating and frequently results in cut fingers from hose clamps or other parts.
A typical structure of an air-valve to waste-pipe fitting used by plumbers in the field would comprise, 1) a nipple capable of connecting on one side to an air supply and on the other side to a gas pipe; 2) a hexagonal pipe that is closed on one end, except for a hole through which the air-valve is threaded and sealed and second hole in the side through which an air gauge is fitted and sealed; 3) a round male connector pipe attached to the hexagonal pipe on one side; 4) a flange connected, on its small end to the second end of the connector, and on its wide end to a male adapter; and 5) connected to the other end of the ABS adapter a set of bushings, and gaskets, sized to adapt to the waste pipe diameter, secured in place by a corrugated hub and two hose clamps surrounding the rubber gasket. This arrangement of standard pieces found in a plumber's supply kit is about 14 inches long. Most of the length is taken up with adapters and connectors that increase the diameter of the fitting. This contraption serves the purpose of connecting an air valve to a waste pipe but is extremely awkward and cumbersome. Additionally, it is necessary to carry several of these around with each adapting the ⅜″ air valve to a different diameter waste pipe.
It would be very desirable to have a compact sturdy unit that could also be used for air-pressure testing waste piping systems. It would be even more desirable to have a single compact unit that could also be used to air-test both waste and gas piping systems. And it would be yet more desirable to have a single compact unit that could be used to test both waste and gas piping systems without changing the pressure gauge.
II. SUMMARY OF THE INVENTION
It is an object of this invention to provide a compact sturdy air-test unit having an air valve on one end that couples to an air pressure source, and having a coupling for a waste pipe on the other end. It is a further object of the invention to provide a single compact air-test unit that can be used to air-test both waste and gas piping systems. It is still another object of the invention to provide a single compact air-test fitting, that has a single air-pressure gauge that meets the standards for both gas and waste testing, the fitting being capable of coupling to both waste and gas piping systems.
The present invention comprises an apparatus for gas-pressure testing comprising, a) at least two concentric couplings, each coupling having a diameter that is different from the others, wherein each coupling has an inside and an outside and each coupling is approximately centered on a long axis of the fitting and located so that each coupling is capable of attaching to a target pipe in the presence of the other couplings; b) a test gas inlet valve located on a portion of the long axis of the fitting that is adjacent to the outside of the coupling having the largest diameter; and c) a test gas pressure gauge located on a portion of the long axis of the fitting that is adjacent to the outside of the coupling having the larger diameter.
REFERENCES:
patent: 3459229 (1969-08-01), Croft
patent: 4027525 (1977-06-01), Mull
patent: 4103537 (1978-08-01), Victor
patent: 4599890 (1986-07-01), Girone et al.
patent: 5548993 (1996-08-01), Alexander
patent: 564899 (1944-10-01), None
patent: 2088567 (1982-06-01), None
Marks Daniel L.
Ruiz James L.
Coudert Brothers LLP
Larkin Daniel S.
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