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4.2.15. Installing & Testing Regulators . Installers should know the regulator installation practices that manufacturers recommend for proper regulator operation. . In this module you will learn to identify: NFPA 58 requirements for regulator installations
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4.2.15 Installing & Testing Regulators Installers should know the regulator installation practices that manufacturers recommend for proper regulator operation. • In this module you will learn to identify: • NFPA 58 requirements for regulator installations • Regulator features that require protection • Regulator system installations • The use of special application regulators • Procedures for conducting regulator performance tests
NFPA 58 NFPA 58 2001 2004 NFPA 58 Requirements for Regulator Installations 3.2.12.1 A two-stage regulator system, an integral two-stage regulator, or a two-psi regulator system shall be required on all fixed piping systems that serve ½-psig appliance systems normally operated at 11 inches water column…. Single-stage regulators shall not be installed in fixed piping systems after June 30, 1997. 3.2.12.5 The point of discharge from the required pressure relief device on regulating equipment installed outside of buildings in fixed piping systems shall be located not less than 3 feet horizontally away from any building opening below the level of such discharge… The point of discharge shall also be located not less than 5 feet in any direction away from any source of ignition, openings into direct-vent (sealed combustion system) appliances, or mechanical ventilation air intakes. 6.7.3 6.7.4.5
NFPA 58 NFPA 58 2001 2004 NFPA 58 Requirements for Regulator Installations 3.2.12.4 All regulators for outdoor installations shall be designed, installed, or protected so their operation will not be affected by the elements (freezing rain, sleet, snow, ice, mud, or debris). This protection shall be permitted to be integral with the regulator. 6.7.4.4 Regulators should be installed in new vapor distribution systems only after the successful completion of the piping pressure tests required by NFPA 58 and 54 have determined the piping system to be leak-tight. (See 3.2.22 of NFPA 58, 2001 edition.) When regulators are replaced in existing vapor distribution systems, the system must be leak checked after the regulator is installed, and before placing appliances into gas service.
Regulator Features that Require Protection Figure 1. Integral 2-Stage Regulator
Figure 2. First-Stage Regulator Under Dome, Vent Sloping Down Identifying Regulator System Installations First-Stage Regulator Installations for Aboveground ASME Tanks. Primary regulator protection of a first stage regulator consists of: • Installation under the tank dome • Positioning the regulator with the vent pointed or sloping downward • Verifying the vent screen is in place • Ensuring that the bonnet cap is sealed and properly tightened Making a loop in the pigtail connection to the tank’s service valve provides piping flexibility. The loop also serves to limit the flow of water that might be present in the propane into the regulator orifice.
Identifying Regulator System Installations Figure 3. Parallel Manifold First-Stage Regulators
Identifying Regulator System Installations First-Stage Regulator Installations for Underground ASME Tanks. Primary regulator protection of a first stage regulator consists of: • Installation under the tank dome • Positioning the regulator with the vent pointed or sloping downward with a U-shaped vent pipe away adapter installed to the highest point available at the top of the tank dome • Verifying the vent screen is in place in the pipe away adapter • Ensuring that the bonnet cap is sealed and properly tightened to prevent entry of ground water
Identifying Regulator System Installations Figure 4b. Forming U-Shape Figure 4a. Assembly of Vent Pipe Away Figure 4d. Pipe Away at Top of Dome Figure 4c. Installed First-Stage Regulator
Identifying Regulator System Installations The purpose of the U-shape at the top of the pipe away adapter is to create an air trap, and prevent the entry of ground water into the regulator’s upper spring case. Figure 5. Manufacturer-Fabricated PVC Pipe Away Vent Assembly
Identifying Regulator System Installations Second-Stage Regulator Installations.Second-Stage regulators are typically installed outside the building in the gas service entrance piping (Figure 6). The piping layout for a particular vapor distribution system may require the installation of more than one second-stage regulator to provide service to gas appliances in locations that cannot share common piping runs. Figure 6. Second-Stage Regulator Installation Figure 7. Second-Stage Regulator with Protective Cover
NFPA 54 2002 Identifying Regulator System Installations When second-stage regulators are installed inside a building, they must be vented to the outside atmosphere (Figure 8). The vent outlet must be pointed down and have a screen-protected opening. 5.5.1 stipulates that design operating pressure for piping systems located inside buildings shall not exceed 5 psi. Figure 8. Indoor (Basement) Installation
NFPA 54 2002 5.5.1 stipulates that design operating pressure for piping systems located inside buildings shall not exceed 5 psi. Identifying Regulator System Installations 2-PSI Service Regulator Installations.The installation of 2-psi service regulators is similar to the installation of second-stage regulators with two differences: • 2-psi service regulators must be installed in combination with downstream line regulators that reduce appliance input pressure to approximately 11 inches water column. • 2-psi service regulators should be installed outside the building at the service entry.
Identifying Regulator System Installations DOT Cylinder Regulator Installations—Knowing the operating characteristics of manual, automatic and check Tee connection fittings is important when you demonstrate the operation of the system to the customer. Figure 9. Exchange Cylinder Regulator Installation
Identifying Regulator System Installations Recreational Vehicle (RV) Regulators—Many campers use changeover regulators equipped with a protective cover and two portable DOT cylinders.The protective cover is used to prevent mud, water and road spray from entering regulator vents as the camper is moved around. Figure 10. Two-Stage Automatic Regulator Systems (Protective Cover Removed)
Identifying Regulator System Installations Recreational Vehicle (RV) Regulators—Vents of two-stage regulators installed on the ASME tank of an RV must be protected in one of two ways: • The regulator must be installed in a ventilated compartment that provides road spray and weather protection for the regulator. • A protective cover must be installed on the regulator to provide this protection.
Identifying Regulator System Installations Vapor Meters—Vapor metersrequire installation of a second-stage or 2-psi service regulator immediately before (upstream) the vapor meter. Figure 11. Inspecting a Vapor Meter
Conducting Regulator Performance Tests After first and second-stage regulators are installed, a system leak check should be completed as prescribed by NFPA 54, National Fuel Gas Code. When the system has been proved to be gas tight, gas distribution lines should be purged following company procedures and the requirements of NFPA 54. Next, appliances are placed into service according to manufacturers’ instructions to facilitate regulator performance tests. Regulator flow pressure and lock-up tests are typically performed on • First stage regulators (especially lock-up) • Integral two-stage regulators • Second-stage regulators • Line pressure regulators
Figure 13. Test Tap on Integral Two-Stage Regulator Figure 12. U-Tube Water Column Manometer Conducting Regulator Performance Tests To assure that the lock-up test is valid, the regulator flow pressure test is done first, making output pressure adjustments if needed; then the lock-up test is performed with the regulator set for proper flow pressure requirements. A water column manometer, calibrated gauge or other low pressure gauging device is used to measure gas flow pressure of low-pressure regulators with output pressures of 11 to 14 inches water column.
Conducting Regulator Performance Tests Because most line regulators used in dual-pressure (2-psi) vapor distribution systems may not have outlet test taps, the manometer must be located in a piping test tap downstream of the line regulator. Figure 14. Possible Manometer Test Points for Line Regulator Testing
Figure 15. Adjusting 2nd-Stage Regulator Delivery Pressure Performing Flow Pressure Tests
Performing Flow Pressure Tests Delivery pressure must not fall to less than the appliances’ required input pressures as given on the manufacturers’ appliance rating plates. If adequate flow pressure is not maintained with all connected gas appliances operating, check for the following problems: • The regulator output capacity may not be adequate to supply connected appliances • The service regulator(s) upstream of the regulator being flow pressure tested may not be properly sized or providing sufficient output pressure for gas appliance demand. • Piping may be too small and friction losses may be limiting the gas volume and pressure available to the appliances and/or regulator being flow tested.
Performing Flow Pressure Tests Note: If any of the problems listed above are present, adjusting the output pressure of the regulator being flow pressure tested will not resolve the problem, nor provide adequate gas volume and pressure to the connected appliances. Correct the problem(s) responsible for improper gas supply. Don’t attempt to re-adjust the regulator that cannot provide required flow pressure under full demand conditions.
Figure 16b. Pressure “Creeping” Up After Initial Reading to 14.8 Inches Figure 16a. Initial Observed Lock-Up Pressure 12.5 Inches Performing Lock-Up Pressure Tests If pressure fails to lock-up, if manometer readings “creep” upwards over time (Figure 16), or the lock-up pressure increases beyond 30% of the flow pressure, the regulator is malfunctioning. This problem indicates the regulator must be replaced.
Conducting Regulator Performance Tests During the course of testing regulators, be sure to visually inspect the overall regulator installation, making sure that the regulators are properly protected as required by NFPA codes and your company’s standard operating procedures. Regulator conditions, test pressures observed, the time (duration) of lock-up pressure tests, and regulator replacements should be documented on designated company service or inspection reports.
Time to See If You Got the Key Points of This Module… • Complete the Review on pages 16 - 18. • See if you are ready for the Certification Exam by checking off the performance criteria on pages 19 - 21.