Water Storage Tank Maintenance

CEU TYPE: Technical
TRAINING CLASSIFICATION:
IEPA#: 8012

TOPIC: Over the past few years, underwater tank inspection methods have been increasingly utilized by water utilities. Underwater methods can be more convenient than traditional drained inspections, but also have their own drawbacks. Water system operators often focus primarily on selecting the method of inspection, while the actual goal of the inspection becomes obscured. The large majority of the surface area of storage tanks (and associated painting costs) consists of the exterior, dry interior and wet interior roof. The inspection method selected does not matter for these areas as they are not immersed. Therefore obtaining a thorough and accurate inspection report is generally more important than the inspection method employed.

The essential elements for all tank inspections regardless of the inspection method are reviewed. These elements include:

1) Structural Condition
2) Coating Conditions
3) Cathodic Protection System Applicability
4) Public Health Considerations
5) OSHA and Safety Considerations
6) Operation and Maintenance Considerations
7) Cleaning Considerations
8) State Regulatory Concerns

Also discussed are AWWA recommended qualifications for inspection firms and the required contents of the inspection report including:

1) Photos or Video of All Areas of Interest
2) Cost Estimates for All Recommended Repairs
3) Engineering Analysis of Relevant Alternatives
4) 5-10 Year Budgeting Estimates

The remainder of the talk discusses the relative advantages of each inspection method for accomplishing these objectives, and whether a float inspection should also be included. System specifics that determine the preferred method such as the size, style, and number of tanks are also discussed. Color slides accompany the talk and include photos of drained and underwater inspections.

Joseph Hoban, Dixon Engineering, Inc.

Brad Schotanus, Dixon Engineering