General Questions about Zerust^® VCIs

1. How do Zerust VCI Products Prevent Corrosion?

Zerust VCI products prevent corrosion in several ways.

1. By acting as a protective barrier from external dirt and abrasion, and also as a barrier to help block the diffusion of corrosive acid gas pollutants from outside the Zerust packaging material (such as sulfur dioxide or hydrogen sulfide) - thereby preventing contact of these corrosive gases with enclosed metal surfaces.
2. By vapor corrosion inhibitors that passivate the electron flow between the anodic and cathodic areas on metal surfaces and interrupt the electro-chemical corrosion process.
3. By adding water repulsion properties to the metal surface, which inhibit water from permeating the metal surface and providing the electrolyte for corrosion reactions.

The vapor corrosion inhibitor portion of Zerust products is made of proprietary chemical formulations that are invisible, odorless, non-toxic, non-reactive, non-flammable and non-allergenic. These chemical formulations release a corrosion inhibiting vapor that diffuses throughout an enclosure and settles on exposed metal surfaces to form a microscopic corrosion inhibiting layer.

This protective layer will remain on the surface of the metal as long as there is no significant, continuous exchange of air within the enclosure. Ideally, there should be less than one air exchange per day (for example, when an electrical cabinet or package is opened briefly and occasionally). Once the metal part is removed from the enclosure, the corrosion inhibiting layer is no longer kept in place by equilibrium with the Zerust VCI source, and it dissipates from metal surfaces (typically within about an hour) leaving the metal part clean, dry and corrosion-free

2. How is Zerust better than conventional coatings, etc.?

The vapor diffusing properties of our corrosion inhibiting formulations offer an important advantage over conventional inhibitor coatings since the traces of these gas molecules penetrate into inaccessible crevices, gaps, and slots, reaching the surfaces of complex-shaped articles that are difficult to coat. They are adsorbed onto the surface of the metal to form a corrosion inhibiting protective layer that is just a few molecules thick. Zerust products may also include acid gas absorbing chemicals in the packaging material to act as a barrier and add another dimension to the protection of the metal content. These "scavenging" chemicals react and neutralize the polluted air that may diffuse through the Zerust material. Also used are various combinations of physical barrier properties that optimize the corrosion prevention and physical protection needs of our customers . These may range from plain low density polyethylene (LDPE) material to combinations of higher strength, higher tear resistance, higher resistance to sunlight or UV, static charge dissipation, and lower diffusion for moisture or acid gas molecules.

Zerust products offer corrosion protection without having to be in direct contact with or coated onto the parts that are being protected. Metal parts merely need to be enclosed in or with a Zerust product (where airflow is minimized) for protection to occur. With Zerust, it is no longer necessary to apply messy oils, greases and other corrosion protection compounds and incur the cost of their removal.

3. Does Zerust have any effect on electrical or electronic components?

Test data show that Zerust products do not adversely affect electrical and electronic components. In fact, the corrosion inhibiting molecules actually help improve the reliability of electrical and electronic components by preventing corrosion that is too small to be seen by the naked eye. It is absolutely safe to use Zerust packaging products to prevent corrosion of any instruments, devices and equipment which contain electric and electronic components.

4. Are there any inhalation or contact risks with Zerust products?

Test data and review of corresponding scientific literature show that there are no inhalation or contact risks with Zerust products. Zerust products have been reviewed and cleared for use by factory, government and military personnel by the appropriate occupational health departments, including those of all major automotive manufacturers worldwide.

5. What is VCI and VCI Film?

VCI stands for Volatile Corrosion Inhibitors. Zerust / Excor applies VCI technology to inhibit corrosion on metal. VCI Film is packaging that generally consists of polyethylene film that has been impregnated with chemical formulations that are unique to each manufacturer. While the underlying formulations can vary significantly, the finished products all function similarly in that they release very low concentrations (typically in parts per ten-thousandth) of invisible corrosion inhibiting vapors into the surrounding air. The vapor molecules subsequently condense onto exposed metal surfaces and form a molecular corrosion shield that can protect against rust and other forms of corrosion for up to five (5) years, and even longer in some cases. When the VCI packaging is later removed, all vapor corrosion inhibiting molecules rapidly evaporate. This leaves the metal parts clean and ready for immediate use.

Questions about Flange Savers™

1. Must the corrosion exhibited, on existing installed flanges, be removed before installation? If yes, what are the processes involved? (e.g. must the badly corroded flanges be detached and removed completely to facilitate the corrosion removal process?)

While the Flange Savers would work even if there is already corrosion, our recommendation is to do some basic cleaning (wire brush any flakes of paint/rust/etc.) before using the Flange Savers.

2. Must the flanges and their associated parts (i.e. bolts and nuts) be cleaned and treated post corrosion removal and before installation? If yes, what are the recommended products to be used and processes involved?

The Flange Savers can be applied to operating systems without the need for removing/cleaning the individual flanges/nuts & bolts, etc. The solution fits over the flanges/valves.

3. What is the average downtime per corroded flange for item (a)&(b) to be carried out? Am I right to assume that the system ops will be affected during the downtime? If yes, are there any proven methods deployed to minimise such impact on system ops to the customers?

There should not be any down time since the Flange Savers are installed over operating lines.

4. What is the replacement interval?

The typical replacement interval is 12-24 months. Zerust can deliver Flange Savers for periods of greater or lesser replacement frequencies for special orders from clients.

5. Are there any specific training and qualification processes involved before a person can perform the above tasks?

No special training or qualification process is required. There are installation videos available online and the Zerust team is available to train key client resources as appropriate.

Questions about ReCAST-R Tank Roof Protection

1. How does the solution work?

Dispensers attached to the tank roof release proprietary vapor phase inhibitor formulations into the tank that forms a vapor barrier which separates the corrosive environment from the metallic surface of the tank roof support structures.

2. What kinds of vapor spaces within tank roofs can be protected?

Any vapor space within the tank roof can be protected. This even includes sections of the side walls of the tank above the level of the stored product (parts covered by the oil/product typically do not need to be protected) and support structures. Intended service life and inspection requirements will need to be considered in determining dispenser positions.

3. Will the inhibitor leak out of the tank - especially if there are vents? Will this affect the efficiency of the system?

A small amout of inhibitor will escape if the tank is vented. However, this does not decrease the efficiency - the vapor pressure of the inhibitor generates a level of inhibitor significantly higher than that needed to protect the roof parts. Once the venting is completed the concentration will return to its normal protective level.

4. How quickly does the inhibitor get depleted?

The rate of inhibitor depletion depends on how often the tank is emptied and refilled and any venting that occurs. However, the dispensers are sized to contain extra inhibitor to compensate for additional losses between monitoring inspections. NTIC periodically inspects the tanks and dispensers and replenishes the inhibitor as required.

Will the pressure build up inside the tank and cause risk of over-pressure?

The quantity of inhibitor vapor released is very small (molecular level layer), compared with the volume of the tank vapor space, and will not cause a rise in the pressure of the tank. Therefore, "over-pressure" conditions will not exist.

6. Does the inhibitor contaminate the product stored in the ASTs?

The inhibitor does not contaminate* the stored oil product(s). NTIC will work with clients on a case-by-case basis to revalidate this issue based on the specific tank, stored product and client contamination allowances. * This has been tested for products protected to date and would need to be re-tested based on each client's tolerance limits for the specific stored product. NTIC has multiple formulations of the proprietary inhibitor to ensure any contamination is within specified tolerance limits.

7. Can the solution be applied to old tanks, or only new tanks/roofs?

The solution can be applied to both new and old tanks. On old tanks, even if corrosion has started, the solution, once deployed, would inhibit further corrosion. There is a minimum thickness of roof material required for the solution to be deployed. NTIC will work with clients on a case-by-case basis to ensure this requirement is met.

8. When can the solution be implemented and how long does it take to install it?

The Installation of the dispensers can be done during any routine tank stoppage (maintenance) and currently is estimated to take 4-5 working days for a tank that is 50m in diameter. NTIC will coordinate installation with the client. After the initial installation, routine maintenance and replenishment can be done without stopping tank operations.

9. What is the service life of the solution?

The dispensers, once installed, can be expected to last 30-40 years. The inhibitors need to be replenished periodically. The frequency of replenishment will depend on client requirements (3-months, 6-months, even 24-months) and will be done by NTIC throughout the life of the solution contract. The dispensers can be removed and may be re-installed on other tanks.

10. Are there any environmental, health and safety issues to consider?

The inhibitor formulations comply with relevant EPA and OSHA guidelines in the US. NTIC operates the overall system, but also provides clients with safe handling guidelines and training. The dispenser meets UN Group II (oil & gas) criteria for equipment with no electrical or moving parts. The dispensers also have been designed to withstand winds over 130mph (Category III hurricane) and to minimize any risk of lightning strikes. There are no moving or electrical parts involved in the device.

11. What kind of ongoing maintenance is required?

The system is hermetically sealed and requires little/no maintenance. The system only requires that NTIC replenishes the inhibitor in the dispenser to ensure continuous corrosion mitigation. This system can be serviced during normal operations of the tank (i.e. without tank stoppage).

12. What is the cost to deploy this solution?

The system pricing depends on multiple factors. The inhibitor formulation needs to be selected based on the corrosive environment generated by the product and other factors generated by the application conditions and the operating environment. The age of the tank, the service life required by the client, the size of the tank, etc. are all considerations that affect the price. Clients can expect significant savings on their lifetime cost to maintain/replace tank roofs.

Questions about ReCAST-SSB Tank Bottom Protection

1. On what types of ASTs can this solution be implemented?

Any AST where the bottom rests on a sand/soil bed can be protected with this solution. The solution can also be used to to inhibit corrosion on tanks with concrete foundations and/or bituminous layers under the tank bottom. Furthermore, traditional cathodic protection systems can be augmented/retrofitted with the NTI system for more effective tank protection.

2. How quickly do the inhibitors get depleted?

The rate of depletion of the inhibitors depends on the relative humidity, presence of a lining material, average temperatures, nature of the sand/soil, and the rate at which moisture saturates the sand/soil bed. NTI periodically inspects the tanks and replenishes the inhibitors as required.

3. Can the solution be applied to old tanks, or only new tanks/bottoms?

The solution can be applied to both new and old tanks - however it can only be implemented when a new tank bottom is either being constructed or when a tank bottom is being fully replaced.

4. What is the service life of the solution?

The service life depends on client requirements - but the system can be sized to last 30-40 years. The inhibitors need to be replenished periodically. The frequency of replenishment will depend on client requirements (6-months, 12-months, etc.) and will be done by NTIC throughout the life of the solution contract.

5. How does the inhibitor spread evenly throughout the sand bed?

The initial load of inhibitors are mixed with the sand of the bed during construction of the tank, or replacement of the tank bottom. Additional loads are delivered through a dispensing pipe system installed in the space below the tank bottom. In addition, the proprietary inhibitor mix is ionic in nature and migrates to any area where electrochemical corrosion cells are formed.

6. Are there any environmental, health and safety issues to consider?

The inhibitor formulation complies with relevant EPA and OSHA guidelines in the US. NTI operates the overall system, but also provides clients with safe handling guidelines and training.

7. What kind of ongoing maintenance is required?

The system only requires that NTI replenishes the inhibitor below the tank bottom periodically to ensure continuous corrosion mitigation. This system can be serviced during normal tank operations (i.e. without tank stoppage).

8. What is the cost to deploy this solution?

8. The system pricing depends on multiple factors. The inhibitor formulation and the CP design need to be selected based on the corrosive nature of the soil and other factors generated by the application conditions and the operating environment. The service life required by the client, the size of the tank, the material of the tank bottom, etc. are all considerations that affect the price. Clients can expect significant savings in their lifetime cost to maintain/replace tank bottoms.

Contact us to learn how Zerust can help you manage your corrosion problems.