Heavy Civil Mechanical
The project comprised the installation of a 168-inch butterfly valve in the Colgate Penstock. The scope of work included: modification of the existing penstock, relocation of air release valves, and installation and commissioning of a flow-meter and hydraulic system. The project involved extensive modification to the existing 14-foot diameter penstock to accept the installation of the 168-inch butterfly valve. All welding and fabrication was completed under ASME Boiler & Pressure Vessel Code VIII and Welding & Brazing Qualifications IX.
The critical deadline for the project was December 8th, by which time the penstock needed to be recommissioned to allow the power plant to be returned to normal operation. Failure to meet the deadline would have resulted in liquidated damages of $25,000 per day for the first 8 days and $3,000 per day thereafter. The two critical phases of work were the penstock modifications and installation of the 168-inch butterfly valve.
The major challenges and risks associated with the project included:
- Operating within a 9-week schedule.
- Maintaining critical alignment of the penstock during modifications.
- Fabrication of the spool sections at an offsite facility located in Bakersfield.
- Relocation of the butterfly valve from its temporary foundation to its permanent foundation in-line with the penstock.