Timmie McElwain Gas/Propane Basics... President, Gas Appliance Service Riverside, RI gastc@cox.net Propane System Tests Part 1 This test must be performed on all newly installed piping. This obviously must be done before refilling the trench. The test must be done at not less than normal operating pressure. This is the method that is recommended in the CETP (Certified Employee Training Program). It is performed many times before any equipment has been installed and only the exterior piping is connected. In section 6.14 of NFPA 58 (Liquefied Petroleum Gas Code), 2014 edition, the previous test is required and specifically called Pressure Test per NFPA 58. In the 2014 edition, separate code requirements were added to distinguish between a one-time pressure test and the leak check that is required following any interruption in service. The pressure test, as defined in 3.3.59 (Definitions) is a test of the gas-tight integrity of the piping system, conducted only after initial installation or modification. This is very similar to the pressure test required by NFPA 54, National Fuel Gas Code. However, note that NFPA 58 specifically allows liquid petroleum gas ( LP-gas) to be used as the test medium, while NFPA 54 requires air or inert gas to be used. In addition, piping under the scope of NFPA 54 must be tested to at least 1.5 times the normal operating pressure, whereas the piping in NFPA 58 is only required to be tested at normal operating pressure. Where an installer chooses to meet the test conditions of NFPA 54, one test could be conducted on the entire piping system. Otherwise, separate pressure tests must be conducted on the piping upstream of the final stage regulator covered by NFPA 58, and the downstream piping covered by NFPA 54. Annex L of NFPA 58 section L.1.2 describes several widely used methods, but they are not the only methods that can be used to conduct a leak check. The method discussed in the beginning of these procedures is the preferred method. 1 The first method is performed by inserting a pressure gauge between the container gas shut-off valve and the first regulator in the system, admitting full container pressure to the system, and then closing the container shut-off valve. Enough gas should then be released from the system to lower the pressure by 10psig (69 kPag). The system should then be allowed to stand for three minutes without showing an increase or a decrease in the pressure gauge reading. This is the test being recommended in this article. 2 The second method is for systems serving appliances that receive gas at pressures of 1/2psig (3.5 kPag) or less, and is performed by inserting a water manometer or manometer pressure gauge into the system downstream of the final system regulator, pressurizing the system with either fuel gas, inert gas or air to a test pressure of 9 in. w.c. ± 1.2 As a Propane professional, one of the most important things you do is ensure customer safety. One of the ways this can be done is to make sure the customer’s vapor distribution system is leak-free and operating effectively. In order to accomplish this, there is a series of tests that have to be performed. The testing of the system is accomplished by carrying out five tests: • Pressure Test • Leak Check • Leak Test • Flow Test • Lock-up test You may have heard of these tests or at least a couple of them. The terms are often misused. There are many reasons for this, from code changes that altered the meaning to terms used in different parts of the country. We want to align with federal codes and regulations in this discussion. Be aware that codes in your area may require different test pressures and different times for tests. Check with your local authority having jurisdiction. The first test we want to cover is the Pressure Test per NFPA 58. This is a test to determine if there are leaks in the exterior portion of the piping. It is conducted only on piping from the outlet of the tank vapor service valve to the outlet of the second stage regulator. The test is performed by installing a T-block and a 300 pound pressure gauge (See Figure 1, pg.6) between the container service valve and the first stage regulator. Once the exterior piping is connected to the first stage regulator, and the regulator or meter (if one is in use) is capped or plugged, then slowly open the service valve allowing vapor pressure to fill the line. Then close the service valve and reduce the pressure reading on the block gauge by 10 lbs per square inch gauge (psig) lower than the container pressure, using the connector installed between the service valve and the first stage regulator. Keep in mind this is a release of some gas, so make sure it is safe to do so (no sources of ignition). What you are watching for is either an increase in pressure (a leaking service valve) or a drop in pressure 300 pound Block Pressure Gauge indicating a leak. If there is a leak indicated it must be repaired. On short runs of piping, leak detection solution may be used to find the leak. 4 ICM/March/April 2016
ICM March-April 2016
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