There are a host of variables to consider before a tank lining is successfully installed, beginning with a comprehensive review of specification and application procedure’s
Typically, the first considerations are: What will the tank lining be subjected to? How long does it need to last? Is the expectation realistic? A coatings supplier must have access to details of the tank and its contents - past, present and future.
Specification
This information will provide the basis for a specification, but other critical factors must be considered including surface preparation and health and safety issues, for example:
-Is the tank structurally sound and do any mechanical repairs have to be carried out?
-Is a freshwater wash needed to remove salts?
-Is the tank free of previous cargo contamination?
-Are there any site-specific regulations or conditions that may prevent the job being carried out, such as nearby welding operations?
-Can the necessary machinery, such as generators, dehumidifiers, heaters and extraction equipment be accessed?
-The time schedule – is it achievable?
-Is the specification practically achievable?
-Does the budget match the specification?
Health and Safety
It is, of course, imperative that any proposed specification can be carried out safely, without damage or injury to the plant and its environment or to the people working in the vicinity. Procedures must include essential precautions such as gas testing and ventilation to prevent the danger of explosion and ensure a safe atmosphere for anyone asked to go into the tank. Issues such as work permits, entry permits, personal protection and ensuring the equipment is fit for service must all be considered.
It’s not uncommon for plant managers to believe, for example, that ventilation is unnecessary when someone goes into a small tank for a short period. Nothing could be further from the truth. Adequate safety lighting is another area often neglected, yet it’s basic common sense that if a job is to be done properly and safely, people need to see what they’re doing.
Surface Preparation and Coatings Application
An uncompromising approach to surface preparation is critical to coatings longevity of service. It doesn't matter how much coating is applied, if surface preparation is compromised the coating will not adhere, leading to premature coating failure.
Successful application depends on a range of factors:
-Experienced and trained operators are vital.
-All those involved must be fully conversant with the relevant technical datasheets, working procedures and health & safety information relating to the products.
-In surface preparation, consideration of the abrasive and blasting method are essential, as well as the sequence (such as the underside
-Of the roof before the floor) so that a minimum blast standard of Sa21/2 is achieved.
-The correct choice and use of ventilation, dehumidification/heating.
-Good vacuum cleaning equipment.
-Suitable spray equipment, which may require a heating block and/or plural component equipment, depending upon ambient conditions and coating characteristics.
-The effect of ambient conditions on overcoating times (length of time between coats) must also be considered.
-The applicator must have suitable wet film measurement equipment and know how to use it.
-They must also have a dry film thickness gauge for checking the finished job – or between coats - and be capable of carrying out a spark test on completion.
-Appropriate personal protection must be provided, as circumstances dictate.
-The contractor must keep adequate quality assurance records.
-The client must be kept informed throughout the contract.
-Finally, adequate lighting must be provided.
Selection of the correct lining, properly applied, will provide long life protection with minimum downtime.
