Pullman Power Products Corporation designed, supplied and constructed a 1,000 foot, multiple-flue chimney for Allegheny Power. The chimney serves Units 1, 2 and 3 at the Harrison Power Station, which has a generating capacity of 1,920 megawatts.

The new chimney is part of the plant's environmental improvement project, which also included three new scrubbers to control sulfur dioxide emissions. Due to site space limitations, only one chimney was constructed to serve all three units. To meet the plant's requirements, Pullman designed a reinforced concrete chimney with three independent steel liners and housed the Unit 2 scrubber inside the lower portion of the reinforced concrete shell.

This unique arrangement presented a few challenges in the design and construction of the chimney. First, the diameter of the base had to be increased well beyond usual structural requirements. This called for a radical change in shell diameter immediately above the scrubber outlet inside the chimney base. Second, the scrubber area in the base of the chimney had to be isolated with a roof and floor system that had an unsupported span of 110 feet. Third, the lower 80 feet of the shell had over 80 large openings and embedments cast into the wall. Finally, the scrubber system produces a low temperature wet flue gas, so the chimney's liner system had to be corrosion resistant. Allegheny Power wanted the most reliable liner material available. A high-nickel alloy (Alloy C-276), roll-bonded clad plate was selected, which required a specially-designed arrangement of supports and expansion joints.

Over 900 tons of reinforced steel, 13,000 cubic yards of concrete, were used to construct the chimney, and more than 220,000 square feet of nickel alloy, C-276 roll-bonded clad plate and 400 tons of structural steel were used for the liner system.