4.2.19

1. 4.2.19 Performing Pressure Tests on Gas Distribution Lines Gas personnel must understand how to perform pressure tests on gas distribution lines to ensure the system is gas tight. • In this module you will learn to identify: • NFPA 54 regulations that apply to pressure testing of a propane distribution system • Basic elements of pressure testing • Procedures commonly used to pressure test propane piping

2. NFPA 54 2002 NFPA 54 Regulations that Apply to Pressure Testing 7.1.4.1 Test pressure shall be measured with a manometer or with a pressure measuring device designed and calibrated to read, record, or indicate a pressure loss due to leakage during the pressure test period. The source of pressure shall be isolated before the pressure tests are made. Mechanical gauges used to measure test pressures shall have a range such that the highest end of the scale is not greater than 5 times the test pressure. 7.1.4.2 The test pressure to be used shall be no less than 1-½ times the proposed maximum working pressure, but not less than 3 psi, irrespective of design pressure. 7.1.4.3 Test duration shall be not less than ½ hour for each 500 cubic feet of pipe volume or fraction thereof. When testing a system having a volume less than 10 cubic feet or a system in a single-family dwelling, the test duration shall be a minimum of 10 minutes. The duration of the test shall not be required to exceed 24 hours.

3. NFPA 54 2002 NFPA 54 Regulations that Apply to Pressure Testing 7.1.1.3 Where repairs or additions are made following the pressure test, the affected piping shall be tested. Minor repairs and additions are not required to be pressure tested provided that the work is inspected and connections are tested with a non-corrosive leak-detecting fluid or other leak-detecting methods approved by the authority having jurisdiction. 7.1.1.4 Where new branches are installed from the point of delivery to new appliance(s), only the newly installed branch(es) shall be required to be pressure tested. Connections between the new piping and the existing piping shall be tested with a non-corrosive leak-detecting fluid or approved leak-detecting methods. 7.1.1.5 A piping system shall be tested as a complete unit or in sections. Under no circumstances shall a valve in a line be used as a bulkhead between gas in one section of the piping system and test medium in an adjacent section, unless two valves are installed in series with a valved “tell tale” located between these valves. A valve shall not be subjected to the test pressure unless it can be determined that the valve, including the valve closing mechanism, is designed to safely withstand the pressure.

4. Identifying Basic Elements of Pressure Testing Test Medium.According to NFPA 54, 7.1.2, the test medium shall be air, nitrogen, or carbon dioxide, or an inert gas. Do not use oxygen or fuel gas. Test Pressure.NFPA 54 requires a test pressure that is 1 ½ times the maximum working pressure for the piping section, but not less than 3 psig. For example, pipe supplying propane vapor to a second-stage or 2-PSI service regulator may have a working pressure of 10 psig. In this situation, the test pressure is at least 15 psig (1 ½ x 10).However, the second stage pipe supplying propane to the appliances has an operating pressure of 11 inches water column. In this situation, the test pressure is at least 3 psig, and appliances and their controls are not connected to the piping system during the test. Test Duration NFPA 54 and most state and local codes require a 10 minute test duration for single-family dwellings and small capacity distribution systems with less than 10 cubic feet (1,840 lineal feet of 1” steel pipe). However, if the distribution piping is more than 10 cubic feet, NFPA 54, requires a test duration of 30 minutes for each 500 cubic feet of piping. Regardless of size, NFPA 54 states that the duration of the test need not exceed 24 hours.

5. Figure 1. Test Gauges Installed At Piping Connections at Two 2-PSI Piping Service Entrances NFPA 54 Regulations that Apply to Pressure Testing Pressure Measuring Devices.NFPA 54, 7.1.4.1 requires: Test pressure shall be measured with a pressure measuring device designed and calibrated to read, record, or indicate a pressure loss due to leakage during the pressure test period. The source of pressure shall be isolated before the pressure tests are made. Mechanical gauges used to measure test pressures shall have a range such that the highest end of the scale is not greater than 5 times the test pressure. For example, a 0-15 psi gauge should be used for a 3 psig pressure test, while a 0-75 psi gauge is required for a 15 psig test.

6. Procedures Used to Pressure Test Propane Piping Before testing, check the installation carefully to be sure it is properly installed and meets applicable state and local codes and regulations. • All pipe, tubing, and fittings used in the installation must meet the requirements in all applicable state and local codes and standards, particularly the National Fuel Gas Code, NFPA 54. • For new installations, the underground lines and the lines inside buildings must be left uncovered for the duration of the pressure testing. • All aboveground lines must be properly supported as necessary, and protected from physical damage. • Before beginning a test, be sure the gauge(s) and test fittings are in good condition. Test fittings equipped with Schrader valves should be fitted with appropriate sealing caps and cap gaskets.

7. Procedures Used to Pressure Test Propane Piping Pressure Testing Integral Two-Stage Distribution Systems: 11 Inches Water Column Operating Pressure— Integral 2-Stage Regulator Figure 2. Pressure Testing Integral Two-Stage Distribution Lines Operating Pressure: 11 Inches Water Column This method is intended for testing the main and branch linesbefore they are connected to the appliance shutoff valves and the integral two-stage regulator. The piping system must withstand a test pressure of at least 3 psig for a minimum of 10 minutes without showing any drop in pressure.

8. Procedures Used to Pressure Test Propane Piping Figure 3. Example of Integral Two-Stage Piping Diagram

9. Procedures Used to Pressure Test Propane Piping

10. Procedures Used to Pressure Test Propane Piping

11. Procedures Used to Pressure Test Propane Piping Pressure Testing Two-Stage Distribution Systems: 11 Inches Water Column Final Delivery Pressure— 1st & 2nd Stage Regulators Figure 5. Pressure Testing Two Stage Distribution Lines Appliance Operating Pressure: 11" w.c.

12. Procedures Used to Pressure Test Propane Piping Figure 6. Pressure Testing First-Stage Line

13. Procedures Used to Pressure Test Propane Piping Figure 7. Installing Test Gauge and Fittings

14. Procedures Used to Pressure Test Propane Piping

15. Procedures Used to Pressure Test Propane Piping Figure 8. Recording the Pressure Test

16. Procedures Used to Pressure Test Propane Piping Test the second-stage line(s) by using the same basic method used for integral two-stage systems (a minimum 3-psig test for 10 minutes). Figure 9. Pressure Testing Distribution Lines Downstream of 2nd-Stage Regulator

17. Procedures Used to Pressure Test Propane Piping Pressure Testing 2-Pound Distribution Systems: 10 psig buried distribution line pressure and 2-psi delivery pressure to one or more line regulators controlling 11 inches water column final delivery pressure. If the system uses a first-stage and 2-PSI service regulators connected by a buried distribution line, the system is tested as a two-stage piping system (Figure 10). Figure 10.

18. Procedures Used to Pressure Test Propane Piping

19. Procedures Used to Pressure Test Propane Piping Figure 12. Pressure Testing First-Stage Line

20. Procedures Used to Pressure Test Propane Piping

21. Procedures Used to Pressure Test Propane Piping

22. Figure 13a. Line Regulator and Manifold Figure 13b. Line Regulator Replaced with Pipe Nipple for Pressure Test Procedures Used to Pressure Test Propane Piping To test lines in a 2-psi system that uses a single line regulator and distribution manifold:

23. Procedures Used to Pressure Test Propane Piping

24. Procedures Used to Pressure Test Propane Piping

25. Procedures Used to Pressure Test Propane Piping Figure 14. 2-PSI System with 2 Line Regulators

26. Procedures Used to Pressure Test Propane Piping Figure 15. CSST Multiple Manifold System

27. Procedures Used to Pressure Test Propane Piping Be sure to comply with your company’s pressure testing procedures, along with code requirements of jurisdictional authorities in your area. Also read and follow manufacturer recommendations for pressure testing corrugated stainless steel tubing as appropriate.

28. Time to See If You Got the Key Points of This Module… • Complete the Review on page 14. • See if you are ready for the Certification Exam by checking off the performance criteria on page 15.