By Cassie McClure
Published in Published in the Las Cruces Bulletin 09/18/20.
Every pipe put in the ground can face damage, like rainwater shifting dirt and a line being punctured by rocks. However, steel gas lines face other challenges; they can corrode with rust over time. There are specific sacrifices involved in maintaining the lines - in this case, it’s another chunk of metal, called a sacrificial anode, that takes the heat for corrosion instead of the gas line.
Similar to what might be found in a home’s water heater, these sacrificial anodes are designed and placed to protect gas lines, along with specific coating on the pipes themselves that protects the steel from the corrosive effect of the soil.
“One way to think about corrosion is that steel wants to go back to its natural state and the steel uses the weaker metal, the magnesium anode, to absorb the electrons that would cause the corrosion in the steel pipe,” said Pete Duran, Las Cruces Utilities (LCU) interim gas system operations supervisor.
Throughout the city, LCU installs magnesium anodes near a gas line, usually based on need and on schedule. The anodes can last up to 10 years and are regularly inspected. If the potential – essentially an electrical reading – in a gas pipe changes, that can be an indication that an anode might be needed.
Near the I-10 entrance on Avenida de Mesilla, a new anode was being installed by Carlos Lopez, LCU senior gas cathodic protection technician.
“This 17-pound magnesium anode can protect up to 500 feet of a gas line,” Lopez said. The metal is surround by a bag of powdered gypsum and bentonite clay. Once Lopez attaches the wires from the gas pipe to the anode about four feet away, he dumps water to activate the metal and help it settle it into the ground.
Duran said, “With the anode coming in at under a hundred dollars, it’s a much cheaper solution than to dig up an entire line when it corrodes.”
LCU can be reached at 575-528-3500 from 8 a.m. - 5 p.m. Monday through Friday. LCU provides services to approximately 100,000 Las Cruces residents and businesses.
PHOTO 1: LCU Gas Cathodic Protection Technician Carlos Lopez places a new magnesium sacrificial anode to help protect nearby gas pipes from corrosion.