Natural Gas Regulator Sizing and Effects of Altitude
How does altitude affect gas regulator sizing? When sizing a natural gas regulator, we need to consider six factors to select the most suitable regulator for the application, including location to adjust for the effects of altitude.
Types of Regulators
Before sizing and choosing a regulator, know what purpose the regulator will serve. Gas regulators control gas pressure, and they help in four primary applications:
- Appliance regulators control the gas pressure of an appliance.
- Line gas regulators are between a service regulator and an appliance regulator on a gas line.
- Service regulators reduce service line gas pressure to delivery pressure.
- Pressure regulators reduce, control, and maintain the pressure of a specific portion of a pipe system.
Parameters Needed for Regulator Sizing
Six parameters help size and recommend the most suitable regulator for various applications. These aspects are:
- Gas type
- Available Inlet gas pressure; measured in pounds per square inch gauge (PSIG), inches of water column (in. W.C.), or ounces (oz.) (Keep in mind that 1 PSI = 16 oz. = 27.7 inches W.C.)
- The desired or regulated outlet pressure; measured as above
- The capacity, flow rate, or gas load is the end user’s requirement to be supplied, measured in SCFH, BTU, or MBH. Where SCFH=standard cubic feet per hour, BTU=British Thermal Unit, and MBH=1000 times BTU
- Desired pipe size
Universal Standards at Sea Level
- Natural gas: 1 CFH = 1000 Btu/hr
- Propane: 1 CFH = 2550 Btu/hr
- Butane: 1 CFH = 3200 Btu/hr
- SCFH – standard cubic feet per hour (at 14.4 psia — sea-level atmospheric pressure at 60F)
Altitude Effect in Gas Regulator
Atmospheric pressure reduces with altitude, so we need to ascertain the regulator location; to determine elevation.
As we increase elevation by 300 meters (approximately 1000 feet), there is an approximate 4% reduction in atmospheric pressure. Assuming that the Colorado Front Range elevation is about 1608 meters (5300 feet), it would mean that there is an approximate 21% reduction in pressure from a sea-level location.
One CFH of natural gas at sea level is approximately 1000 BTU/hour. However, along the Colorado Front Range, a cubic foot of natural gas is about 830 BTU.
Regulator Sizing Program for Itron Regulators
In “How to select the correct gas pressure regulator?” I revealed how we use our selection information and sizing charts to select the appropriate regulator for our applications. Here, I introduce the Itron Regulator Sizing Program with the caveat: this program works for sea-level applications and does not consider altitude effects.
Example of Regulator Sizing
The following is the selection information we’ve gathered for an application we desire to have sized. Go to the regulator sizing program and enter the following information:
- Internal Relief Only
- Gas Type: Natural Gas
- Available Inlet gas pressure: 2PSIG – 5PSIG min-max
- Desired outlet pressure: 8” WC
- Capacity: 750 SCFH
- Pipe Size: 1” NPT inlet and outlet
The program quickly selects two regulators for this application by answering this. If you do not receive a prompt email for your applications, check your spam mail.
If you are not at sea level, call your local gas regulators distributor, and they will assist you in sizing a regulator for your applications. Or, we are happy to help you.
Image by Simon Steinberger from Pixabay.