An industry organization estimated that the global cost of corrosion is approximately $2.5 trillion annually. Implementing corrosion prevention best practices could result in savings of between 15 to 35 percent of the global cost of corrosion. A coating management plan provides cost effective protection of substrates subject to corrosion significantly mitigating your corrosion costs.
S&ME provides coating services for everything from flagpoles to aircraft carriers. We can provide coating application observations, coating forensic studies, or holistic coating management. Our primary markets are water, wastewater, heavy industry, and transportation. Our coating personnel have NACE International (NACE) certifications and our specifications reference International Concrete Repair Institute (ICRI) and Society for Protective Coating (SSPC) standards.
The steps in a coating management plan are similar regardless of the market. The following identifies the steps for inspecting a water tank.
An annual inspection is performed on the tank to identify operational issues. The tank is climbed and the exterior, interior dry and interior wet visible from accessible manway(s) are observed for coating, sanitation, security, and safety issues. Items specifically observed include safety climb device functionality, lighting, antenna attachment, vent screen integrity, locks, over flow pipe, etc. The tank does not have to be drained for this inspection.
Tank Washout & Inspection
Water tanks accumulate sediment and deposits which can decrease the effectiveness of the disinfectant and could result in taste and odor problems. The American Water Works Association (AWWA) recommends that water tanks be washed out and inspected at least once every three years and, where water supplies have sedimentation problems, once a year.
With the tank drained, all tasks associated with the annual tank inspection are performed on the tank interior dry, interior wet, and exterior. The tank interior is cleaned with a high pressure sprayer. All sediments are removed from the tank. Photographic documentation of the tank condition before and after the washout is prepared. If the coating protection is suspect, the existing coating thickness and adhesion are measured using standard coating methodology to determine suitability for over coating. If not previously tested, the tank coatings are tested to determine lead content. At the completion of the washout, the tank is disinfected in accordance with industry practice.
A report is prepared documenting the tank condition and any repairs required. The time when recoating will be necessary is projected for planning purposes subject to subsequent Tank Washout & Inspections.
Coating Specification Development and Bidding
If it is determined during the tank washout and inspection that re-coating is required, technical specifications are prepared for bidding and performance of the work. The technical specifications are prepared in Construction Specification Institute (CSI) format and reference various ICRI, SSPC, and NACE standards. The specifications provide contractor minimum experience requirements, the location coatings are to be applied, coating to be used, surface preparation required, ambient weather conditions under which coating may be applied, owner specified constraints on work hours, scheduled repairs, and unscheduled repairs(unit rate basis) that may be required. The specifications include the application of “stripe coats” (application of a thinned coating to penetrate difficult to coat surfaces such as bolt threads and weld seams), caulking of seams prone to corrosion, and coating system void detection (holiday detection).
Most elevated water tanks are owned by municipalities and require competitive bidding. We assist our clients in soliciting and evaluating bids, and perform inspection during coating application.
Coating Application Inspections
Surface preparation and coating application must comply with the coating manufacturer’s recommendations to achieve the expected coating service life. We provide NACE certified personnel to observe surface preparation and coating application in accordance with the specifications on a full time basis. A Daily Coating Report is prepared to document our observations and tests. Unit rate pay quantities are documented in the Daily Coating Report. Depending upon the stage of construction and materials used, our coating application inspections typically address:
- Monitoring relative humidity, dew point, and temperature relative to coating application requirements
- Cleanliness testing of air and abrasives used for surface preparation
- Inspecting blasted steel for standard compliance
- Measuring substrate anchor surface profile (surface roughness)
- Documenting coating material used and batch date
- Monitoring paint mixing procedures
- Documenting the coating/re-coating schedule
- Measure coating dry film thickness (DFT)
- Testing for voids in the coating system (Holiday Detection)
- Monitoring of particle containment devices
- Photo documentation
- Soil sampling before and after if lead abatement is needed
- Daily documentation of on-site activities