The Cause of 40% of Chemical Tank Failures

Statistics indicate that approximately 40% of chemical tank failures are due to a fundamental problem. Incompatibility of the materials used in the tank’s construction with the stored chemicals. This improper chemical reaction leads to corrosion or decomposition of the tank material, causing leakage or even explosions, exposing facilities and personnel to serious risks.

Common Causes of Incompatibility:

Chemical Corrosion:

When chemicals are stored inside an improperly designed tank, they can react with the material from which the tank itself is made. Such as plastic or metal. This reaction isn’t necessarily immediate; it occurs gradually over time. As the tank walls begin to lose their solid structure due to constant exposure to the chemicals. The severity of corrosion varies depending on the nature of the chemical, its concentration, and its temperature. The type of material the tank is made of also plays a pivotal role in its resistance to corrosion. As damage accumulates without apparent notice. It may lead to complete corrosion of parts of the tank’s inner wall. Leading to leakage of stored materials, or in the worst case, a hole or explosion in the tank, posing a significant risk to public safety and surrounding property.

Physical Degradation:

In some cases, not only does corrosion occur, but the molecular structure of the material from which the tank is made actually degrades. Certain chemical compounds, particularly those with a highly acidic or alkaline nature. It can cause the bonds in the plastic material to break or weaken at the molecular level, altering its physical and mechanical properties. This degradation is not easily visible, but over time, the material begins to lose its flexibility and rigidity, becoming more susceptible to tearing or collapsing under pressure. This may appear as microscopic cracks or brittle areas within the tank walls. That may go unnoticed if regular inspections are not performed. This degradation is one of the most dangerous forms of reaction, as it renders the tank unsafe even without a visible leak.

Internal Reactions:

When more than one chemical is stored in a single tank, or when mixed without careful consideration of their potential interactions, dangerous and unexpected internal reactions may occur. Some of these reactions produce toxic or explosive gases or new compounds with chemically unstable properties, which can lead to a sudden increase in pressure within the tank. If the tank is not equipped with safety valves or materials resistant to these conditions, the results could be disastrous. Some chemicals can also react with residual materials from previous shipments, even in small quantities. This is known as a residual reaction and can cause damage to the tank without the user even realizing the exact cause. Therefore, it is essential to understand the nature of each substance before storing it and ensure that the tank is thoroughly cleaned between uses to prevent any unwanted reactions.

Read also: What are the benefits of using chemical tanks suitable for chemical storage?

Top solutions to avoid this problem:

Choosing the appropriate materials for manufacturing:

Choosing the raw material from which the tank is made is one of the most important decisions that directly affects the efficiency and safety of the storage process. Not every type of plastic or metal can withstand interaction with various chemicals. Some materials are quickly affected or damaged upon contact with certain compounds. Therefore, it is essential to carefully study the properties of the chemical to be stored, such as pH, chemical composition, expected temperature, and density, and then match these properties with materials that offer appropriate resistance. For example, tanks made of regular polyethylene cannot be used to store strong acids or solvent-based organic compounds. Fiberglass-reinforced or polyvinyl chloride-constructed materials may be more suitable. Environmental conditions, such as external temperature and humidity, must also be considered, as these can also reduce the tank’s lifespan or affect storage reactions.

Conducting Preliminary Compatibility Tests:

Even if a material has been chosen that appears suitable in theory, it is essential to conduct practical tests to verify the actual compatibility of the tank with the chemical to be stored. Some materials may exhibit different behavior upon prolonged exposure, temperature changes, or interaction with impurities or moisture. Therefore, compatibility testing is an essential step to detect any unexpected potential for harmful reactions or changes in the physical or chemical properties of the stored material or the tank structure. These tests typically involve examining samples under conditions resembling actual operating conditions and monitoring any changes that may appear over time. This helps in making informed decisions that ensure safety and prolong the tank’s operational life.

Using protective linings or coatings:

In some cases, the base material of the tank may not be sufficient to withstand chemical influences for extended periods. Therefore, an additional solution is to apply protective layers or internal linings. These linings, whether made of resistant polymeric materials or special coatings such as epoxy. Form an additional barrier that prevents direct interaction between the tank’s inner walls and the chemical. These coatings not only provide protection but also help reduce corrosion, prevent odor absorption, and facilitate cleaning and maintenance. However, these coatings must be fully compatible with the type of material being stored and applied according to precise standards to ensure adhesion and prevent corrosion or cracking over time.

Regular Maintenance:

Even with the best materials and highest manufacturing standards, chemical tanks cannot be relied upon without a regular maintenance plan. Regular maintenance detects any early signs of corrosion, deterioration, or weakness in the walls. Allowing them to be addressed before they develop into a serious problem that affects the facility’s safety. Maintenance typically includes inspecting the internal walls, ensuring the integrity of the connections, and reviewing pressure and temperature data if the tanks are equipped with monitoring systems. Maintenance also provides an opportunity to reassess chemical compatibility, especially if the type of stored materials or storage conditions change. Failure to do so can lead to undesirable surprises, such as sudden leaks or tank collapse, which can lead to significant material and environmental losses.

Read more about: The inspection and maintenance procedures for chemical tanks.

The Difference Between Chemical Tanks and Plastic Water Tanks

Although plastic water tanks and chemical tanks are superficially similar. Both in terms of shape and general manufacturing method. The profound differences between them become apparent when considering their intended use and the surrounding conditions. Water tanks are designed to store a light, non-corrosive liquid, such as water. Chemical tanks must withstand harsher environments, including chemical reactions, varying temperatures, and potentially highly toxic or corrosive compounds. These differences require precise technical and engineering specifications for chemical tanks. Making them more complex in terms of design, materials, and manufacturing specifications.

Read also: What are the types of chemical tanks?

Design and Reinforcement:

External design and internal reinforcement are among the primary points of distinction between the two types. Water tanks are often constructed in a relatively simple manner. Due to the low liquid pressure and the absence of dangerous chemical effects. Concave reinforcement shapes are used in the tank walls to provide the necessary strength to support the weight of water alone. Chemical tanks, however, require a stronger and more resistant structure to withstand the pressure generated by the weight of high-density chemicals. As well as to resist potential chemical effects. Therefore, convex reinforcements are used to better distribute pressure. And special metal frames or supports are often added to provide greater stability and resistance to deformation or collapse under severe operating conditions.

• Plastic water tanks: These are manufactured in a relatively simple manner, using concave reinforcement for durability.
• Chemical tanks: These require complex designs with convex reinforcements and sometimes metal supports (rings) to withstand the high pressure and weight of the chemicals.

Wall Thickness:

Wall thickness is a critical factor in determining a tank’s ability to resist pressure and corrosion. Because water is a light and non-reactive substance, water tanks are typically manufactured with thin walls, ranging from just 5 to 10 mm thick. This thickness is sufficient to store water without the need for additional layers or extensive structural support. By contrast, chemical tanks are manufactured with thick walls, up to 18 mm or more. This is to withstand the high specific gravity of the stored materials. As well as the chemical reactions and heat that may occur during storage. This thickness is also necessary to maintain the tank’s long-term stability and prevent damage or corrosion of the walls by the stored contents.

• Water Tank: Designed to store non-corrosive liquids such as water. Its wall thickness is typically thinner (typically 5 to 10 mm).
• Chemical Tank: Must be thicker (at least 18 mm) to withstand corrosion, high specific gravity, and high temperatures.

Joints and Leakage:

Regarding tank connections, water tanks are typically installed with simple joints. Either heat welding or bonding wires is sufficient for tanks not exposed to high pressure or hazardous materials. However, these types of connections are prone to leakage, especially after a period of use or during temperature changes. Chemical tanks, on the other hand, are designed with flange-tight connections. These highly efficient industrial connections ensure a secure seal and prevent leakage even under the harshest conditions. Furthermore, essential tank openings, such as the fill port, drain port, and liquid level. They are often integrated within the tank body without welding, reducing any potential vulnerabilities for future leakage.

• Water Tanks: These tanks are often welded or wired, increasing the likelihood of leakage.
• Chemical Tanks: Flange connections are used, with an integrated design for the openings (feed, discharge, and liquid level) without welding, reducing the risk of leakage.

Lifespan:

The expected operational life of a tank depends largely on the materials used in its construction and the nature of its use. Due to their ease of use and the absence of factors that cause rapid deterioration. Water tanks are designed to last an average of three to five years. This period may be extended with light use and proper maintenance. Chemical tanks are built to withstand harsh conditions and the continuous storage of active substances. That may be harmful to the structure itself. Therefore, they are designed to have a much longer lifespan, up to ten years or more, provided operating instructions and regular maintenance are followed. This long lifespan is a basic requirement in industrial facilities that rely on long-term, non-stop operation.

• Water Tanks: Their average lifespan is three to five years.
• Chemical Tanks: They are designed to last ten years or more, provided they are used and maintained properly.

Manufacturing Requirements:

The regulatory and legislative aspects are one of the most significant differences between the two types. The production of water tanks typically does not require complex licensing or oversight from specific regulatory bodies, given the limited risk they pose. Chemical tanks, on the other hand, are classified as containers for hazardous materials. Therefore, their manufacture requires special licenses from relevant authorities. Such as standards and quality bodies, and regulatory bodies for chemical safety. Compliance with strict international specifications is often required. The manufacturing process itself is more precise and undergoes rigorous quality and durability tests. To ensure that no defects could lead to an environmental or industrial disaster.

• The production of chemical tanks requires a special license from the relevant authorities. As they fall under the classification of hazardous material containers, water tanks do not require this level of qualification.