Pushing boundaries in tank inspection: A safe and certified robotic platform for hazardous environments

In the global energy sector, the urgency to balance safety, operational uptime, and environmental stewardship has never been greater. Nowhere is this more evident than in the inspection of aboveground storage tanks (ASTs) — critical infrastructure assets in midstream and downstream operations that often contain highly volatile products. The tension between inspection rigor and asset availability has long been a bottleneck — until now.

Traditionally, comprehensive inspections require draining, cleaning, and manual entry — processes that pose significant risks, interrupt operations, and introduce safety, environmental, and financial liabilities. Recognizing these persistent limitations, Valkim Technologies, in close partnership with HMT, Chevron Terminals, and a cadre of veteran API 653 professionals, has developed and field- deployed a fully pneumatic, IECEx/ATEX Zone 0-certified robotic platform capable of delivering in- service inspection data — without personnel ever breaching manways or shutting down operations.

This paper outlines the evolution, technical approach, and real-world application of this platform, representing a tangible step toward safer, smarter, and more sustainable inspection practices in flammable vapor space environments across the energy value chain.

Designing for the extreme: A true zone 0 solution

While many robotic systems claim “confined space” capabilities, few are certified for continuous- use in explosive atmospheres (Zone 0) — and fewer still are designed from the ground up for mechanical, non-electric operation. Our response to this challenge is the PneuBot: a compact, non-electric crawler engineered specifically for in-tank deployment during live service.

PneuBot is powered entirely by compressed air, eliminating ignition risk. All motors, valves, and actuators are pneumatically actuated. It carries a tethered sensor suite with its own certifications; therefore, a variety of mission objectives can be addressed.

Critically, the system allows precise UT readings to be taken directly from structural components without needing tank shutdowns or confined space entry. The absence of onboard electronics enables IECEx Zone 0 certification, a necessary requirement for flammable atmospheres found in the vapor space of many tanks with internal floating roofs.

Real-world validation: External and internal floating roof tanks

This system has already been successfully deployed on two external floating roof tanks and one internal floating roof (IFR) tank in live service. During these inspections, we collected API 653- compliant UT readings from several critical locations:

• Horizontal UT on the deck, sketch plates, and pontoons
• Vertical UT at manways, rim plates, gauge poles, and floating roof leg sleeves
• Visual assessment of internal IFR components via highresolution ATEX-rated camera, including the topside of the floating roof and support structures

These inspections were performed while tanks remained online and operational, delivering regulatory-grade data to the asset owner without requiring degassing, cleaning, or shutdown.

Unlike drones, which provide valuable remote visual data but are not IECEx Zone 0 compliant, our system is capable of contact-based wall thickness measurements inside flammable vapor atmospheres — addressing a critical gap in robotic inspection. In essence, we bridged the space where aerial visual meets certified contact NDT, creating a hybrid model grounded in safety and precision.

Collaborative engineering: Partners driving progress

This platform was not developed in isolation. Our work with HMT, one of the world’s most experienced tank manufacturers and inspection solution providers, helped guide practical engineering decisions from the earliest design reviews to field deployment strategies. Their understanding of floating roof dynamics, material interfaces, and client operational constraints directly influenced the platform’s durability and mobility features.

Likewise, Chevron Terminals provided operational access, performance feedback, and internal alignment across health, safety, and engineering disciplines. Field leads such as Eric Hardien, and technical reviewers including Daniel Ramirez, Mauricio Calva, and Derek Hibler, ensured the robotic system aligned with real-world inspection needs — not just regulatory minimums, but actual performance under field pressures.

Their shared mindset — “If we’re not evolving together, it won’t happen.” — became a mantra that helped us push through legacy constraints and legacy thinking.

Embedded expertise: Learning from the API 653 field

A critical component of this journey has been the oversight and guidance of Curtis Stewart, a 30- year API 653 expert who has lived every step of tank inspection — from internal visual assessments to code interpretation and reporting standards. His mentorship was essential in ensuring that our inspection workflow delivered data that was not only innovative but also defensible, auditable, and ready for engineer-of-record review.

By validating our UT data collection and positional documentation against API 653 and SNT-TC-1A standards, Curtis helped solidify the platform’s role as a true in-service substitute for manual inspection — not just a novel robot.

From proof to practice: Repeatability and results

With field deployments now underway, the PneuBot platform is demonstrating strong outcomes:

• Operational Continuity – Eliminates tank shutdowns, reduces inspection impact to operations
• Worker Safety – No confined space entry or exposure to flammable atmospheres
• Inspection Accuracy – Captures location-tagged UT and RVI data that enables digital twin integration
• Turnaround Efficiency – Reduces typical inspection cycles from weeks to less than 24 hours in many cases

All inspections to date have been performed in accordance with ASTM E2853/ E2853M-22, which governs remote visual examination systems. This standard provides the assurance needed by inspection engineers and regulators that robotic data is equivalent in quality and process control to human-in-the-tank work.

Next steps: Creating a robotic inspection standard

We recognize that technology alone does not move the industry forward — standards do. Valkim is currently authoring a Recommended Practice (RP) for robotic in-service tank inspection, integrating SNT-TC-1A-compliant personnel procedures, API 653 equivalency, and ASTM inspection protocols.

Our goal is not just to make robots usable — but to make robotic inspection certifiable.

Collaboration over invention

This platform represents more than engineering success. It represents a cultural shift in how asset owners, service providers, and innovators work together. By combining industry-tested knowledge with cutting-edge mechanical design and validating each decision in the field with partners like HMT, Chevron, and Curtis Stewart, we’ve created a new class of inspection tool: one that is fit for purpose, certified for risk, and ready for repeatable deployment.

We are proud to share this milestone with the global community, not as a finished product, but as the beginning of a movement — toward smarter, safer, and more collaborative inspection solutions that leave no one behind.

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This article was developed by specialist Kimberley Hayes and published as part of the fifth edition of Inspenet Brief magazine August 2025, dedicated to technical content in the energy and industrial sector.