Alliant facility nearing completion

Cleaning, testing process to begin later this month


A low rumbling may be heard in Marshalltown beginning in late November and into December at Alliant Energy’s Marshalltown Generating Station as a cleaning process takes place.

“You’re pushing steam through the piping,” said Scott Reigstad of Alliant of the upcoming “steam blow” cleaning and testing process. “It’s to clean and… test the integrity of the piping.”

The steam blow will be a one-time process and should begin Nov. 28 and run continuously through Dec. 20, he said, adding the timetable is a rough estimate and may be subject to change.

“It’s going to be 85 decibels about 15 feet from the facility,” Reigstad said, adding that noise level close to the building will be about the same as a blow dryer or a kitchen blender. The noise “is going to dissipate pretty quickly as it gets further from the facility.”

He said he did research on the noise level through the American Speech-Language-Hearing Association.

While it shouldn’t interfere with residents’ day-to-day lives, Reigstad said those in the immediate vicinity of the facility may hear a periodic low rumbling sound. This is perfectly normal for the process, he said, adding onlookers may also see large amounts of steam billowing from station.

“(Residents) could see excess steam and hear a low rumbling sound,” he said.

The purpose of the steam blow is, in part, to prepare the station for the installment of a new heat recovery steam generator, Reigstad said. The steam blows are critical to ensuring a safe and stable heat recovery steam generator system.

Cleaning the piping and testing the integrity of the system will help ensure the steam system works when the facility opens.

“(The station) is about 95 percent complete,” Reigstad said, adding some final performance testing will be done over the next few months. He said the facility should be ready for full operation by April 2017.

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Contact Adam Sodders at (641) 753-6611 or