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Saluki Sleuths

Saluki Sleuths | Diving down into the mysterious steam tunnels at SIU

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SIU Steam Tunnels
Anna Twomey and Jeff Gleim with the SIU Alumni Association learn about the steam pipes from SIU Director of Facilities and Energy Management Mark Owens during an authorized tour of the steam tunnels underneath the Carbondale campus.

The steam tunnels which crisscross underneath the Southern Illinois University campus on Carbondale have long held fascination for SIU students, alumni, staff and area residents. The latest episode of “Saluki Sleuths” aims to unearth some of the secrets from below the surface.

The tunnels are not secret passageways or shelters, explained Mark Owens, the Director of Facilities and Energy Management at SIU. Instead, they are part of an elaborate system designed to keep campus buildings warm in the winter and cool in the summer.

“They’ve heated and cooled classrooms, offices and dorm rooms since the 1950s,” he explained.

With some of them being first built in the 1940s and others as recently as the late 1970s, the roughly four miles of tunnels are made out of reinforced concrete, he said. Some are circular in nature, but others are square or rectangular in shape. Most of them are big enough for a person to walk through. In many places, there is enough natural light from vents and openings to navigate without a flashlight.

The tunnels are home to a multitude of pipes that are used for the distribution of steam into buildings throughout the campus. The pipes also bring condensate – steam cooled to the point that its turned back into water – back to the university’s power plant. The tunnels also house telephone and power lines for the campus. In all, about 70 SIU buildings are networked together through the system of tunnels.

“The power plant is the heart of the steam system,” Owens explained. “The power plant produces steam through our boiler system and pumps it across campus. The tunnels provide the veins to the different buildings to provide the heating and cooling.”

Even in the summer, the tunnels (which can reach an ambient temperature of over 100 degrees in some months) and the pipes within them are vital.

“We’re always producing steam even in the summer when you think, ‘Why would we need steam?’ Roughly 40% of the campus is actually cooled by steam. We have chiller systems that have turbines. Steam pushes the turbines and provides condensation. And then chilled water is pumped to buildings,” he explained.

Owens said the system is extremely efficient, continuously using 85% of the water that is put in to heat and cool the campus.

“It’s a looped system,” he explained. “Condensate returns and goes back into the power plant to be heated again.”

The tunnels are necessary in a steam system, he added.

“The reason that you have a tunnel instead of direct buried cable is because there’s expansion with steam in the pipes and obviously as the pipes age you need to maintain them. You need to visually inspect them and so you need a tunnel so someone can walk through and visually inspect how your pipes are doing and maintain them,” he said.

Very few people are authorized to enter the tunnels as they can be a dangerous place. Most of the entrances are deep within locked areas of campus buildings or otherwise discreet. SIU maintenance personnel make regular visits through the tunnels, checking on the condition of both the pipes and the tunnels themselves.

He said repairs to the tunnels happen regularly and several larger repair projects are scheduled for the coming years, all in an effort to keep the campus comfortable.

More information on the tunnels and a look inside will be featured in the November edition of the SIU Alumni Association’s “Saluki Sleuth” video released on the association’s Facebook page, Thursday evening.

SIU Chancellor Austin A. Lane talks about efforts to recruit new students from Southern Illinois.


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