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Properly Storing Sodium Hydroxide in Chemical Storage Tanks

Sodium Hydroxide (NaOH), also known as caustic soda or lye, is a common inorganic compound that is typically used as a strong chemical base. It has a wide variety of uses such as making paper, drinking water, medicine and is even used in food preparation. It can be found in many household items such as drain cleaner, detergents, and bath soaps. While this chemical is widely used, its properties present special storage and handling challenges. 


What is Sodium Hydroxide?

In its pure form, Sodium Hydroxide is a white solid that can be found in flakes, granules or pellets. It is generally used as a solid or a 50% solution. In liquid form, it is colorless and denser than water. It also becomes “slippery” and tends to find weak points in storage containers resulting in leaks. 

In all forms, it is highly corrosive and reactive. As a solution, it will react with many metals including aluminum, magnesium, copper, and zinc. It also reacts readily with organic tissue such as human skin or eyes. Exposure to sodium hydroxide, even if only for a few seconds, can result in permanent eye damage and severe chemical burns. For this reason, it is critical to ensure it is handled and stored properly. 

Challenges When Storing Sodium Hydroxide


Due to its corrosive and slippery nature (approximately 79 mPas at 68 degrees F), storing sodium hydroxide can be a bit tricky. When evaluating your storage options, make sure you consider these two crucial elements. 

1. Temperature: If it is not stored at appropriate temperatures (above 60° F), the chemical will crystalize and turn solid, resulting in unnecessary chemical waste and damage to the storage system itself.

2. Secondary Containment: Because of the potential hazards involved, secondary containment is an absolute environmental and safety priority.

Download the secondary containment guide

How Should Sodium Hydroxide Be Stored?

While there are many options for Sodium Hydroxide storage, a rotationally molded cross-linked polyethylene tank is ideal. This process produces a seamless tank, meaning it is nearly impossible for the chemical to find leaks. 

The fittings attached to the tank is another important part to consider. Selecting a tank with an IMFO fitting is a great choice because the flange is actually a molded part of the tank itself, rather than an insert that could leak or fail. The IMFO fitting also ensures long-term performance of the overall system because it eliminates the need to drill into the tank's sidewall to install a mechanical fitting.

Tank With Heat Trace System

You should also consider a heat trace system and polyurethane insulation to solve the issue of crystallization at lower temperatures.

If you do not already have secondary containment in place, or are looking for a better option, a SAFE-Tank is a great solution. This "tank within a tank" allows for greater safety by providing a system that has 110-percent secondary containment. In addition, the tank's high-density XLPE construction means greater strength, so strong that Poly Processing Company offers a five-year full warranty.

Looking for more information on sodium hydroxide storage? 
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Topics: Chemicals