How do you prepare a tank for cleaning without confined space entry?

You can prepare a tank for cleaning without confined space entry by deploying remote-controlled robotic crawlers and high-pressure water jetting systems that operate entirely from outside the vessel. These systems handle the physical cleaning work while personnel remain in safe, open areas. This approach eliminates the most dangerous phase of tank maintenance and is increasingly the preferred method across petrochemical, marine, and energy sectors. Below, we cover the key questions maintenance engineers and operators ask before setting up a remote tank cleaning operation.

What makes confined space entry during tank cleaning so dangerous?

Confined space entry during tank cleaning is dangerous because the interior of a storage tank can contain toxic or flammable vapours, oxygen-depleted atmospheres, and residual product that creates slip, engulfment, or explosion hazards. When high-pressure water jetting is added to the equation, the risk profile increases significantly due to the force of the jets, airborne mist, and unpredictable surface conditions underfoot.

Several factors compound the danger in a typical tank cleaning scenario:

• Atmospheric hazards: Tanks that have held hydrocarbons, chemicals, or biological residues can retain toxic gases such as hydrogen sulphide or hydrocarbon vapours at concentrations that are immediately dangerous to life.
• Oxygen deficiency: Inert gas blanketing used to prevent explosions during emptying can leave dangerously low oxygen levels inside the tank.
• High-pressure water jetting risks: Jetting at pressures between 500 and 3,000 bar (7,252 to 43,511 PSI) in an enclosed space amplifies the risk of ricochets, pressure injection injuries, and disorientation from noise and mist.
• Limited egress: A worker incapacitated inside a tank faces a difficult and time-consuming rescue, especially through narrow manholes.
• Visibility and communication: Mist, residue, and confined geometry make it hard to see, hear, or signal for help.

Safety organisations including SIR (Netherlands), EWJI (Europe), WJA (UK), WJTA (USA), and DIRV (Germany) all publish guidance that classifies tank interiors as confined spaces requiring strict permit-to-work procedures. Their frameworks consistently emphasise that eliminating entry is always preferable to managing the risks associated with it.

What does ‘no confined space entry’ mean in a tank cleaning context?

In tank cleaning, ‘no confined space entry’ means that all cleaning, surface preparation, and inspection tasks are performed remotely using equipment operated from outside the vessel. No personnel enter the tank at any point during the cleaning phase. The approach relies on robotic systems, remote-controlled tools, and camera-based inspection to complete work that would traditionally require workers inside.

This is more than a safety preference. In many jurisdictions and industry standards, no-entry cleaning is now the baseline expectation for routine tank maintenance where remote technology makes it feasible. The principle applies across oil storage tanks, cargo holds, process vessels, and similar enclosed steel structures.

Practically speaking, no confined space entry shifts the operator’s role from physical presence inside the tank to remote supervision at a control station outside it. The operator monitors camera feeds, controls the robotic crawler’s movement, and adjusts jetting parameters without ever crossing the threshold of the vessel. Cleaning effectiveness is assessed through visual inspection systems rather than direct observation.

How do you prepare a tank for remote cleaning operations?

Preparing a tank for remote cleaning requires isolating the vessel, removing bulk product, ventilating the atmosphere to safe levels, and ensuring access points are large enough for the cleaning equipment. Thorough preparation is what makes no-entry cleaning both safe and effective. Skipping or rushing any step can compromise the operation before the robot enters the tank.

A practical preparation sequence looks like this:

1. Isolation and de-inventorying: Close and blank all connected pipework. Drain or pump out as much residual product as possible. The less material left inside, the more effective the remote cleaning will be.
2. Atmosphere testing: Use calibrated gas detectors to measure oxygen content, flammable gas concentration, and toxic vapour levels at multiple points inside the tank. Document results and establish a baseline before any equipment is introduced.
3. Ventilation: Force-ventilate the tank using explosion-proof fans until the atmosphere meets the safe working thresholds defined by your permit-to-work system and applicable standards. Continue monitoring throughout the operation.
4. Access point assessment: Measure manhole diameters and confirm they are large enough to pass the robotic crawler through. For example, compact systems like the MagTrack Mini are designed with transport and narrow-access deployment in mind, but clearances still need to be verified before mobilisation.
5. Surface condition review: Where possible, use a camera on a pole or inspection drone to survey the internal surface condition. Knowing the level of sludge, scale, or coating degradation helps you select the right jetting pressure and tool configuration.
6. Water and vacuum infrastructure: Position the high-pressure pump unit, water supply, and vacuum recovery system outside the tank. Route hoses and cables through the access point in a way that does not restrict the crawler’s movement or create trip hazards for personnel working at the entry point.
7. Permit-to-work activation: Issue the formal confined space permit (even for no-entry operations, the tank is still classified as a confined space and requires a valid permit), assign a standby person at the entry point, and brief all personnel on emergency procedures.

What equipment is used for tank cleaning without entry?

Tank cleaning without confined space entry relies on remote-controlled magnetic crawler robots fitted with high-pressure water jetting or abrasive blasting tools, combined with vacuum recovery systems that collect water and debris without spillage. The combination of a robotic carrier and interchangeable modular tools allows a single platform to handle surface preparation, residue removal, and cleaning across a wide range of tank geometries.

The core equipment categories used in no-entry tank cleaning include:

• Magnetic crawler robots: Electrically driven crawlers that attach to the steel interior walls and floor using powerful magnets. They carry the cleaning tools and are operated via remote control from outside the tank. Systems like the DERC MagTrack are built around a universal modular carrier that accepts a full range of interchangeable tools, with jetting capability up to 3,000 bar (43,511 PSI).
• Blast Can (vacuum dome): A closed waterblasting attachment installed on the front of the crawler. It is connected to a vacuum unit so that both water and debris are collected without leakage, leaving a clean and dry surface. This is particularly useful for oil storage tank cleaning where surface cleanliness is a prerequisite for inspection or recoating.
• Curved Blast Can: A variant engineered for surfaces with significant curvature, handling radii up to 3 metres (approximately 10 feet). This makes it well suited for smaller storage tanks up to 6 metres (approximately 20 feet) in diameter and for the curved sections of ship hulls.
• Swing Arm tools: Open waterblasting or sandblasting attachments used for structures like wind girders and other internal framework where vacuum containment is not required. Height and angle are adjustable while the crawler is in motion.
• ReCycleBlaster: A closed-circuit vacuum blasting tool for surface preparation that recycles abrasive, reduces airborne particles, and establishes the required surface roughness profile without releasing harmful dust into the environment.
• High-pressure pump units: Positioned outside the tank, these supply water at pressures typically ranging from 500 to 3,000 bar (7,252 to 43,511 PSI) depending on the cleaning task and surface condition.
• Vacuum recovery units: Connected to the blast can, these create the suction needed to collect spent water and debris and transfer it to a waste collection system outside the tank.
• Camera and inspection systems: Onboard cameras on the crawler and supplementary inspection tools allow operators to monitor cleaning progress and surface quality in real time without entering the vessel.

What are the key safety checks before starting remote tank cleaning?

Before starting remote tank cleaning, you must confirm that the atmosphere is safe, all equipment is pressure-tested and leak-free, the crawler’s magnetic adhesion is verified for the surface condition inside the tank, and a standby person is stationed at the entry point with emergency equipment ready. These checks are not optional formalities. They are the foundation of a safe no-entry operation.

Work through the following checks systematically before activating the system:

• Atmosphere re-test: Even after ventilation, re-test the tank atmosphere immediately before deploying the crawler. Residual pockets of gas can persist in low points or behind internal structures.
• Equipment pressure test: Pressure-test all hose connections, fittings, and jetting tools at operating pressure before the crawler enters the tank. A hose failure at 1,000 bar (14,504 PSI) or above inside a confined space is a serious incident even without personnel present, because it can damage the robot and contaminate the tank interior.
• Magnetic adhesion check: Verify that the crawler’s magnets hold correctly on the specific steel surface. Factors such as surface coating thickness, scale build-up, or surface curvature can affect holding force. The MagTrack Mini, for instance, includes height-adjustable magnets and omni-wheel rear support to maintain grip across varied surface conditions.
• Vacuum system performance: Confirm the vacuum unit is drawing correctly and the blast can seal is intact before jetting begins. A poor seal means water and debris will not be fully contained.
• Remote control function test: Run the crawler through all movement and tool functions at low speed outside the tank before entry to confirm all controls respond correctly.
• Emergency stop verification: Test the emergency stop function on both the crawler and the pump unit. Confirm that activating the stop immediately halts jetting and crawler movement.
• Standby personnel briefing: The standby person at the entry point must know how to stop the operation, how to retrieve the crawler if it becomes stuck, and how to initiate an emergency response. This role is required under guidance from SIR, EWJI, WJA, WJTA, and DIRV even when no personnel are inside the tank.
• Permit-to-work confirmation: Confirm the permit is active, signed, and that all personnel on site understand the scope of work and the exclusion zone around the entry point during high-pressure jetting.

When should confined space entry still be considered despite remote cleaning options?

Confined space entry should still be considered when the tank geometry prevents adequate robotic coverage, when internal structures such as heating coils, baffles, or complex pipework cannot be reached by a crawler, or when post-cleaning inspection requires physical verification that remote cameras cannot provide. Remote cleaning eliminates the need for entry during the cleaning phase, but it does not always eliminate every reason to enter a tank entirely.

Situations where entry may remain necessary include:

• Complex internal geometry: Tanks with dense internal pipework, heating elements, or structural supports may have areas a crawler cannot access. In these cases, remote cleaning handles the majority of the surface area, and a targeted, short-duration entry is used only for the inaccessible sections.
• Final inspection requirements: Some inspection standards and client specifications require a physical inspector to enter and verify surface cleanliness, coating condition, or structural integrity before the tank is returned to service. Remote cameras can support this process but may not fully replace it in all regulatory contexts.
• Equipment retrieval: If a crawler becomes stuck or malfunctions inside the tank and cannot be remotely recovered, a short-duration entry may be necessary to retrieve the equipment. This is planned for in the risk assessment before the operation begins.
• Sludge depth exceeding crawler capability: If residual sludge or sediment is deep enough to prevent the crawler from moving or making magnetic contact with the steel floor, manual removal of the bulk material may be required first before remote cleaning can proceed.

In all cases where entry is deemed necessary, the full confined space entry protocol applies. The atmosphere must be retested, a rescue team must be on standby, and the entry must be covered by a valid permit. The goal is always to minimise the duration and frequency of entry, using remote technology to handle as much of the work as possible first.

How MagTrack Supports No-Entry Tank Cleaning

We developed the MagTrack system specifically to address the challenges that maintenance engineers, operators, and field technicians face when cleaning storage tanks safely and efficiently. Rather than a one-size-fits-all approach, MagTrack is a modular platform that adapts to the specific demands of each tank cleaning operation.

Here is what MagTrack brings to a no-entry tank cleaning setup:

• Modular tool system: The universal carrier accepts interchangeable tools including the Blast Can, Curved Blast Can, Swing Arm, and ReCycleBlaster, so one platform covers multiple cleaning and surface preparation tasks.
• High-pressure capability: All water jetting tools operate at pressures up to 3,000 bar (43,511 PSI), covering the full range of tank cleaning requirements from light washing to heavy-duty coating removal.
• Closed waterblasting with vacuum recovery: The Blast Can attachment collects water and debris without leakage, leaving a clean, dry surface ready for inspection or recoating without any personnel inside the tank.
• Compact deployment option: The MagTrack Mini is a lightweight, 2-wheel-drive crawler with a fixed blast can, designed for easy transport and access through narrow manholes, including on offshore oil rigs. The 2025 model features an improved drivetrain and redesigned blast can with a better vacuum seal for a drier result and smoother driving experience.
• ATEX Zone 2 certification available: For operations in potentially explosive atmospheres, the MagTrack Mini is available as a certified ATEX Zone 2 unit, meeting the safety requirements of hazardous area work.
• Remote operation: All crawlers are remotely controlled, keeping operators safely outside the tank throughout the cleaning process.

If you are planning a tank cleaning project and want to discuss which MagTrack configuration suits your vessel geometry and cleaning requirements, get in touch with our team and we will help you find the right solution.