Puntledge River Penstock Repairs
The scope of work consisted of abrasive blasting, relining and coating the penstock interior and exteriors. 12,000 feet of 12 foot diameter nearly flat interior linings and exterior coatings. In order to complete the project on schedule shifts were utilized. New manways were installed at strategic locations for facilitate access over the long runs. Logistics are key. Total manpower loading was approximately 15 men per outage.
Scope Of Work
The scope of work consisted of abrasive blasting, relining and coating the penstock interior and exteriors. 12,000 feet of 12 foot diameter nearly flat interior linings and exterior coatings. In order to complete the project on schedule shifts were utilized. New manways were installed at strategic locations for facilitate access over the long runs. Logistics are key. Total manpower loading was approximately 15 men per outage.
Duration
3 month outages
Puntledge unit 1 interior Fall 2021 3000LF
Puntledge unit 1 exterior Spring 2019- Fall 2021
12000LF
Surface Preparation
UHP removal of existing Coal Tar Enamels and lead based paints. SSPC-SP1O near white metal blasting.
Coating System
100% solids plural component epoxy lining installed at 40-60 mils DFT robotically; Duromar 2510HB utilized. Exteriors MCU coating systems
Special Environmental Requirements
Zero VOC coatings were used. Very little blast emissions were required. Testing was completed to verify discharge to ground of washing water.
Work Description
This work is the critical path for all outages. Specialized rigging and complete using robotics for abrasive blasting and coating operations.
Safety
Confined space of this type was extremely sensitive. Specialized engineered rigging was used to complete the inclined sections safely and efficiently. Most areas of work were confined space, therefore continuous monitoring and hole watch was necessary. Rescue drills were completed with in house trained teams. Containments had to be virtually emission free because very sensitive wilderness areas.
Challenges
Extremely Tight Critical Path Schedule (7-10’s 2 shifts utilized), Coordination of a 15 man crew. Difficult access due to long lengths of piping (1000 LF between manholes). Specialized equipment and winches designed to complete long pipe runs with limited access.
