Natural gas meter installation tips for diaphragm meters
A common gas meter used in residential and light commercial applications is the diaphragm meter. Here I share natural gas meter installation tips for Itron diaphragm gas meters.
Natural Gas Meter Installation
The meter installation must comply with local building and safety codes, state and federal regulations, including Title 49 of the Code of Federal Regulations, which suggests that each meter be accessible so that it can easily be read, inspected, maintained or replaced. The meter should be protected from corrosion through electrical isolation, and other damage, whether installed inside or outside. Additionally, the meter must be in a well-ventilated area and more than three feet away from any ignition or heat source.
- Diaphragm meters are not recommended to be used below -30°F or above 120°F.
- Meters read flow positively in one direction, and that direction is marked on the meter casting “inlet.”
- Before installation, assure that the meter will satisfy the application’s requirement. The maximum allowable operating pressure (MAOP) and flow rate capacity are marked on the meter badge.
- Verify that the swivel flanges are in the same plane and will not strain on the meter when the nuts are tightened.
- Blow out the service lines to clean them and assure that no debris will flow into the meter when the gas is flowing.
- The meters should be shipped, stored and installed upright and the manufacturer’s dust caps should remain attached to the inlet and outlet connections until the meter is installed.
- Install a filter or strainer on the inlet side of the meter if it is suspected that the gas supply will be dirty.
- The gas meter should be installed as close to level as possible and never be installed at the low point because liquids may become trapped at the meter.
- Place the connection washer on each swivel pilot. Support the meter so both hubs are against the connection washers and hand tighten the connection nuts. Then alternate tightening the nuts to an appropriate torque for the connection size. Do not overtighten, as it can damage the connection washer/gasket.
- Avoid excessive stress on the meter and connecting pipe.
- Under no circumstance bury a meter and avoid having the meter come in contact with soil, mulch or concrete walls. The corrosive elements of the soil and mulch and alkali content in the concrete can stimulate premature corrosion and cause a gas leak.
Meter start-up tips
- In any new installation, before turning the gas on check the pipe to verify the connections are leak-free. If a downstream valve is present, close the valve.
- To avoid high differential pressure across the meter, as it can damage the internal components, crack open the upstream and downstream valves very slowly for a few seconds. Slowly turn each valve to ¼ turn, and then slowly turn to full open.
- In a high-pressure line, if there is locked off gas downstream of the meter and the outlet valve is opened first, the meter could be damaged in a “reverse stop.” For this reason, it is recommended that installers pressurize the meter with the inlet valve so the meter runs forward.
- After the meter is pressurized, check for leaks by applying leak detection soap, or use other gas leak detectors.
- Natural gas meter types: Inferential and Positive Displacement Meters
- Gas metering instrumental in early gas distribution success