JEFFERSON PARK — Streets throughout the Far Northwest Side are alive with the sounds of construction crews digging up lawns, streets and sidewalks to replace aging cast iron pipes with plastic pipes in an effort to deliver natural gas to homes and businesses more safely and effectively.
The work, which started at the beginning of April, replaces pipes that have been in service for decades and are slowly crumbling due to rust caused by exposure and Chicago's brutal winters. While crews work, sidewalks have been blocked off and parking restricted in front of many homes.
People's Gas, which is part of Chicago-based Integrys Energy Group, will spend $2.5 billion to replace 2,000 miles of pipe and to move gas meters outside in an effort to increase safety — and eliminate the need for regular in-home inspections to check for life-threatening leaks.
Pipes made of cast iron and ductile iron are prone to corrosion, and will eventually rust after repeated hard freezes, despite the utility's best effort to repair the pipes, People's Gas spokeswoman Jennifer Block said.
"Just like the streets are full of potholes, the same thing happens underground," Block said, especially since frost during a harsh winter can reach five to six feet beneath the surface.
The cast iron pipes — some of which were buried and put in service around 1900 — will be replaced with polyethylene plastic, commonly called PE, which will be safer, easier to maintain and allow natural gas to be delivered to homes and businesses more effectively, Block said.
"These are prudent upgrades," Block said. "They are the right thing to do."
Replacing the pipes will reduce the chances of gas explosions like the one that leveled two buildings in New York City and killed eight people, Block said.
Homeowners can expect to fork over between 4 percent and 5.5 percent of their bill during the 10-year life of the project to pay for the new PE pipes and the relocated meters, Block said.
The PE pipes are superior because they are easier to repair, Block said. In addition, the new pipes allow People's Gas to send natural gas through its system at a much higher pressure, she said.
Currently, gas travels through the cast iron pipes at low pressure — no stronger than the force of a child blowing out birthday candles on a cake, Block said.
Once each chunk of the system has the new pipes, the gas will travel at medium pressure — which is similar to the force that water travels through a fire hose, experts said.
"You can hear and smell it, and you'll see it bubbling up if there is a leak," Block said. "That makes it safer from an emergency standpoint."
In addition, many newer, high-efficiency appliances need the higher pressure natural gas to operate most efficiently, Block said.
In addition, the gas traveling at a higher pressure prevents water from getting into the pipes. At low pressure, moisture in the gas can freeze and contribute to corrosion, Block said.
"The system will be easier to repair, less costly to operate, safer and more effective," Block said.
Most major cities have installed PE pipes to replace their iron pipes, which once replaced wood pipes. In some cases, the new pipes will be laid inside the existing pipe. If that is not possible, the pipes will be laid under the street, Block said.
As part of the work, most residential gas meters will be moved outside people's homes for convenience and safety, Block said.
While the pressure of the gas is reduced as it enters home through a valve, it can be a place where leaks originate, Block said.
"It is better to vent in the open air rather than inside a home," Block said.
In case of an emergency requiring the home's gas to be shut off, an outside meter will be more accessible than one inside a potentially locked home, Block said.
In addition, People's Gas will no longer have to go through the time-consuming process of inspecting the meters for leaks every three years, Block said.
Meters will continue to be read wirelessly by trucks traveling up and down city streets, Block said.
Once the work is completed, the torn-up grass and uprooted trees will be replaced, Block said.
"We know our work can be a disruption," Block said. "We try to restore what damaged as quickly as possible."