By: Clyde H. Zelch as published in MRWA Water Lines
The truth is that every water storage facility should be closely inspected at intervals of not more than every five years. Most should be inspected more often. About every two or three years.
They cannot in fact really be inspected closely if they are not first washed out so the inspector can look at the quality of coating condition of the steel in the bottom of the tank as well as the sides and roof.
Qualified firms with both structural knowledge and the practical experience to assist tank owners in maintaining their tanks have developed throughout the country. Most of these independent companies who act as engineers, advisers, and inspectors avoid entering into contracts for actual repairs so they can provide professional opinions without bias:
- Pre-bid inspection to determine the present condition of the tank.
- Bid specifications for all bidders, same quality and quantity of work.
- Inspection of work in process. Specification enforcement.
To be lacking in any one of these phases can result in something less than a satisfactory job. A regular prebid (or premaintenance) program is part of good planning, helps with budgeting and lessens the chance of major surprise expenditures.
With independent unbiased inspections, the bid specifications can be written to cover all necessary maintenance and repairs. An accurate indepth inspection should cover:
- Structural integrity of foundation, tower and tank.
- Sanitation – Condition of access hatches or manways, roof vents and overflows.
- Safety factors:
- A. Ladders inside and out.
- B. Balcony floor and rails.
- C. Coatings condition, interior and exterior.
- 1. Dry film thickness.
- 2. Adhesion quality.
- 3. Ability to be repaired or recoated.
- 4. Percent of failure.
- D. Steel condition.
- 1. Rusting.
- 2. Pitting, number and depth of pits.
A complete report on condition of tank and structure with recommendations, and pictures, should be prepared for the owner.
Bid specifications can then be prepared to cover all necessary work, leaving little to surprise or chance. Sometimes, however, the exact condition of steel cannot be determined until it has been blasted.
Specifications should also cover the time of guarantee and methods of guarantee inspection and enforcement.
Inspection of work in process, critical phase or full time, is a necessary part of a long-lasting tank renovation project. Some towns or rural water districts have a person on hand to provide daily inspection, who can work closely with a professional inspector to assure that specifications and good painting practices are being followed.
When you have a new tower built to AWWA standards, that tower carries a one year guarantee on both structure and coatings. That guarantee means nothing if you do not have your tower inspected before it expires. If repairs are necessary, they have to be made then by the original contactor with no cost to the owner.
The time to start a sound, long term maintenance program is right now, whether your tower is new or old.
The consequences of not following a reasonable maintenance program will be increased cost of ownership and or shortened usable lifespan of tank.
Take your pick, truth or consequences!