Chemicals, corrosives, crude oil, diesel, and other potentially dangerous materials are common materials stored and transported via storage tanks. And, like any sort of tank that's designed to store and transport materials or waste, it needs to be routinely cleaned out to ensure the health of the tank itself as well as the surrounding environment.

The nature of storage tank cleaning involves working in confined spaces combined with the contaminants that remain inside the tank that can increase the risk of fire, explosion, chemical exposure, and more.

In this post, we'll dig into why it's important to clean your tanks and how workers can stay safe while doing so. Here's a closer look at what you need to know about tank cleaning safety procedures. But first, an overview of tanks and what they're used for:

What are Tanks Used for?

Simply put, storage tanks are used to store and haul hazardous waste . With capacity ranging from 2,000 gallons to 30,000 gallons, it's not uncommon to see these tanks being pulled by trucks on highways throughout America as they travel to their destination.

When storage tanks are used routinely to store and transport waste, they must be cleaned regularly to ensure they remain in good enough condition to continue safely carrying hazardous materials and chemicals.

Why do Tanks Need to be Cleaned?

Industrial tank cleaning should be routinely performed to avoid wear and tear on the tank itself. Like within any enclosed space, debris and tank sludge have the potential to build up on tank bottoms over time. This causes corrosion and the potential for leakage. It can also cause oxidation, which can limit the overall storage capacity of the tank itself. The bottom line is that an unkempt tank can lead to safety risks for not just the environment, but for your workers too.

When do Tanks Need to be Cleaned?

This is a difficult question to answer based on the various situations that may require tank cleaning. For instance, tanks should always be cleaned before any material changeovers take place to ensure that any previous materials don't contaminate any new materials being stored. Another point to consider is if a tank was previously carrying a highly reactive or corrosive material; it should be cleaned before new materials are added to avoid a possible reaction between the different substances (explosion, toxic gas release, fire, etc.).

To maintain productivity and efficiency, plant managers often carry out tank cleanings during planned shutdowns or schedule routine maintenance repair periods. The size of the tank and what material the tank was holding dictate how long it takes to thoroughly and safely clean.

How Storage Tanks are Typically Cleaned

Tanks are typically cleaned using pressure washers. The pressurized water helps remove any contaminant buildup from the tank walls to make the tank as clean as possible, however, this can also release contaminants into the air.

Safety Hazards and Tank Cleaning

Why are storage tanks so dangerous to clean? Aside from their role in holding hazardous waste and materials, there are a few other reasons that make these cleaning projects dangerous.

For starters, there's usually only one point of entry to storage tanks - and workers need to enter the tank itself to properly clean it. This also leads to poor ventilation or oxygen deficiency—without proper ventilation or an oxygen supply, gases in confined spaces are not “diluted” by oxygen or released from the tank, meaning there are higher concentrations of these noxious gases within the tank.

With a low oxygen level and minimal airflow, it's critical workers have the proper PPE. Limited openings combined with the fact that storage tanks are not designed for human occupancy are why tanks are considered a "confined space."

Then, there's the hazardous waste and other materials that these tanks are designed to store and transport, which can produce toxic vapors and release gases that have the potential to cause explosions, lead to radiation exposure, and more.

The bottom line is that only trained professionals should attempt confined space tank cleaning operations. Professionals need to be properly certified, have a permit required for confined space work, and follow OSHA tank cleaning procedures for locking out and tagging out the tanks each day.

Additionally, workers need to be aware of how to properly dispose of any waste following tank cleaning to not harm the environment and stay in line with any regulations regarding hazardous waste disposal .

Minimize Tank Cleaning Hazards with the Right PPE

Ensuring workers are properly trained and certified to perform tank cleaning is one thing. Keeping them protected with the right PPE is just as important. Here's a look at the recommended Occupational Safety and Health Administration (OSHA) tank cleaning PPE:

  • Hardhat: This keeps workers safe from any overhead hazards.
  • Eye protection: OSHA suggests that workers wear both eye protection and side shields to properly protect their eyes from any potential hazards.
  • Gloves: Heavy-duty leather gloves are recommended, as workers may encounter objects or debris featuring sharp edges. Workers may also come into contact with chemicals.
  • Boots: Any footwear should be ANSI-approved to ensure proper protection.
  • Respiratory protection: A few factors that make tanks so hazardous to clean are their confined space nature and the risk of contaminants in higher concentrations. These contaminants should not be inhaled, and respiratory protection is critical.
  • Depending on the contaminants inside, N, R, or P95 filters should be inserted into respirators. It's also important that workers undergo respirator fit testing to ensure its proper functionality.

  • Harness and retrieval lines: When cleaning certain tanks, workers must be harnessed with retrieval lines attached to them to ensure that they're properly accounted for and can make a swift exit if something goes wrong.
  • Full body suits: If there's a risk of contaminant exposure to the skin, full-body suits should be considered. These disposable coveralls cover the skin and the entire worker's body, preventing skin contact with any potential contaminants such as chemicals  or biohazards .

It's important to note that the PPE mentioned above includes the basic safety equipment before entering a fuel tank or any storage tank. Depending on the material that the storage tank was holding, additional PPE or procedures may be required for cleaning and desludging crude oil tanks, petroleum tanks, diesel tanks, and so on. For example, tanks don't have overhead lighting inside to make it easy to see and carry out a thorough cleaning. Temporary lighting or headlights may also be needed.

Movement may also be restricted, and it may even be difficult to communicate within the tank if everyone is wearing a respirator. For these reasons, additional PPE and safety measures, like checking hazardous gas concentration levels before entering the tank, may be required.

Safety Tips for Industrial Tank Cleaning

PPE is important for keeping workers safe while tank cleaning, but there are various other best practices to follow as well:

  • Safety first: Before any tank cleaning takes place, a plan should be created and reviewed by all participating personnel. This plan should include more than just tank cleaning procedures, but it should also assess any potential risks.
  • For instance, it should account for any valves that need to be turned off. This plan should also include all and any necessary permits required to carry out tank cleaning.

  • Prepare for the worst: It's better to prepare for the worst-case scenario than to be caught off-guard and unprepared. A confined space rescue team should be on standby, and workers should know where to go to retrieve emergency medical kits.
  • Ensure only trained professionals are performing tank cleaning: Only trained professionals should perform tank cleaning services. These professionals need to be properly certified and know how to work in confined spaces, how to use the cleaning tools/machinery, how to properly don PPE and/or other safety equipment, as well as how to properly dispose of the waste after cleaning.

As you can see, there's considerable risk involved in tank cleaning - even for a trained professional. That's why it's crucial to eliminate as much risk as possible. Outfitting your professionals with the right PPE can help prevent both short- and long-term illnesses, or worse.

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