Qualification — Issue 8 | The Hysteresis

The Standards Map

Subsea and UUV Pack Qualification: Governed Rows and Named Voids

By Ronan Adike— July 31, 2026

Feature image for article: Subsea and UUV Pack Qualification: Governed Rows and Named Voids

ABS governs lithium battery installation in underwater vehicles down to the subclause: pre-installation risk analysis, an enumerated set of BMS protection functions, third-party cell certification, pressure testing to design depth, vehicle trials. It never puts a value on any of it. The most consequential clause on this card, §10/11.5.6(a), contains exactly one number, and that number is the one-atmosphere applicability trigger. What follows extracts every published requirement in the lane, sorts the missing values into the ones your program owes and the ones nobody has written, and names the largest void: propagation under external hydrostatic pressure. It also corrects Issue #6.

The Standards Map

Subsea and UUV Pack Qualification: Governed Rows and Named Voids

By Ronan Adike— July 31, 2026

ABS governs lithium battery installation in underwater vehicles down to the subclause: pre-installation risk analysis, an enumerated set of BMS protection functions, third-party cell certification, pressure testing to design depth, vehicle trials. It never puts a value on any of it. The most consequential clause on this card, §10/11.5.6(a), contains exactly one number, and that number is the one-atmosphere applicability trigger. What follows extracts every published requirement in the lane, sorts the missing values into the ones your program owes and the ones nobody has written, and names the largest void: propagation under external hydrostatic pressure. It also corrects Issue #6.

Document Landscape

Eight documents surface repeatedly when planning subsea battery pack qualification. Most governing authority concentrates in one source: the ABS Rules for Building and Classing Underwater Vehicles, Systems and Hyperbaric Facilities, January 2025 edition, confirmed unchanged through the January 2026 Rule Change Notice. IEC 62619 and UN 38.3 play supporting roles. Two ISO standards are included because they do not govern batteries, and citing them as though they do is a traceable DVP error.

The pattern across these documents is consistent: safety architecture requirements are enumerated (housing type, BMS functions, certification basis), while performance thresholds are not. Energy, C-rate, cycle life, and depth derating are delegated to the vehicle program. Most DVP rows trace back to ABS, but the numeric content of those rows is yours to define and defend.

Last verified: July 31, 2026.

Document Landscape

Eight documents surface repeatedly when planning subsea battery pack qualification. Most governing authority concentrates in one source: the ABS Rules for Building and Classing Underwater Vehicles, Systems and Hyperbaric Facilities, January 2025 edition, confirmed unchanged through the January 2026 Rule Change Notice. IEC 62619 and UN 38.3 play supporting roles. Two ISO standards are included because they do not govern batteries, and citing them as though they do is a traceable DVP error.

The pattern across these documents is consistent: safety architecture requirements are enumerated (housing type, BMS functions, certification basis), while performance thresholds are not. Energy, C-rate, cycle life, and depth derating are delegated to the vehicle program. Most DVP rows trace back to ABS, but the numeric content of those rows is yours to define and defend.

Last verified: July 31, 2026.

Battery Safety

ABS §10/11.5 Sets Subsea Pack Safety Architecture

January 2025 edition (unchanged per 2026 notice) requires third-party certification to UN 38.3, UL 1642, or IEC 62619; marine suitability evidence; housing selection (one-atmosphere or pressure-compensated); and BMS functional requirements per §10/11.5.4. No energy density, cycle life, or C-rate thresholds appear. DVP action: create rows for certification basis, housing type selection, and each BMS function enumerated in §10/11.5.4.

Pressure Testing

§10/11.5.6 Requires Pressure Test, Leaves Protocol Open

Mandates pressure testing to design depth with satisfactory operation demonstrated, plus Surveyor-witnessed BMS functional testing. Cycle count, hold duration, pressurization rate, and monitoring instrumentation are not prescribed. The program defines these in consultation with ABS at plan approval. DVP action: define and document the pressure test protocol as a program-specific line item, not a standard citation.

Power Adequacy

§19/33.3 States the Objective, Not the Number

The 2024 rule requires the on-board power source to have adequate capacity for mission duration. Full stop. No Wh floor, no Wh/kg target, no C-rate limit, no DOD ceiling, no derating factor. Energy budget, margin policy, and worst-case assumptions are entirely program-defined. DVP action: build energy adequacy analysis as a program-owned deliverable traceable to this clause.

Vehicle Trials

§19/37 Acceptance Tests Include Battery Functional Demonstration

Five Surveyor-witnessed tests are mandated: piping hydrostatic, insulation resistance, functional testing of all systems, test dive, and sea trials. Battery pressure and BMS functional tests per §10/11.5.6 map to the functional testing and test dive events. Trial procedures remain program-defined. DVP action: link battery test rows to the §19/37 acceptance test sequence and confirm Surveyor witness points.

Industrial Safety

IEC 62619 Scopes Industrial Batteries, Including Marine

Edition 2.0 (2022-05-24, stability date 2026) covers secondary lithium batteries for industrial applications, marine vehicles included. Contains a battery-system propagation test (Clause 7.3.3) and abuse tests. Clause-level acceptance criteria require the licensed standard text. Does not address subsea pressure envelopes or mission-specific profiles. DVP action: cite for safety and abuse test rows; do not cite for pressure or performance.

Transport Qualification

UN 38.3 Governs Transport, Not Operational Suitability

Rev 8 Amendment 1 (2025) establishes transport eligibility through type-level abuse tests. ABS §10/11.5.1(c) also accepts it as battery-safety certification evidence. The 20 Wh/cell and 100 Wh/battery values are transport-classification thresholds, not performance specifications. DVP action: maintain separate rows for transport eligibility and ABS certification basis. Do not conflate the two claims.

Gap Marker

ISO 20682 Explicitly Excludes Batteries From AUV Scope

Published February 2026, this first-edition AUV risk standard covers sensors, communication, and digital-mission components. Its abstract explicitly excludes batteries and electrical motors. No ISO standard currently governs AUV battery qualification. DVP action: do not cite for any battery row. Included here to prevent misassignment.

Pressure Structures

ISO 21173 Governs Pressure Hulls, Not Battery Housings

Edition 1 (2019, confirmed 2025) specifies hydrostatic pressure testing for pressure hulls, viewports, hatches, connectors, and buoyancy materials. Battery packs and housings fall outside its scope. Battery housing pressure testing is governed by ABS §10/11.5.6(a). DVP action: do not cite for battery housing rows. Included to prevent a common misassignment.

Pressure Architecture Study

A Novel Pressure Compensated Structure of Lithium-Ion Battery Pack for Deep-Sea Autonomous Underwater Vehicle

Compares structural weight fractions of rigid-hull and piston-based oil-immersed battery housings across 300–6,000 m (3–60 MPa). Reports ~18.3% system-level mass reduction at 6,000 m for the compensated design. Provides architecture-selection evidence only. No acceptance criteria, no cycling under pressure, no thermal runaway characterization. Tier 3 source.

What's missing for DVP use?

No qualification thresholds, no cycle-life data under pressure, no safety outcomes. Acceptance criteria must still originate from ABS §10/11.5.6 or program specification.

Where does it help?

Architecture trade-off data spanning the full 300–6,000 m envelope, useful for housing concept selection before a program freezes design depth.

Review of Energy Technologies for Unmanned Underwater Vehicles

Open-access 2026 review independently corroborates Li et al.'s mass-reduction figures and adds a technology comparison: 140–180 Wh/kg system-level (gravimetric) for oil-filled architectures versus 100–130 Wh/kg for rigid hulls. Identifies 2,000 m as the depth where rigid-hull structural mass begins dominating system weight. Tier 3 peer-reviewed analysis, not standard-set values.

What sourcing tier applies?

Tier 3 analysis-derived figures from a peer-reviewed review. Engineers should pull the Li et al. primary text before committing any DVP row.

What threshold matters?

2,000 m is identified as the critical depth where rigid-hull structural mass sharply erodes payload capacity and system-level specific energy.

Pressure Architecture Study

A Novel Pressure Compensated Structure of Lithium-Ion Battery Pack for Deep-Sea Autonomous Underwater Vehicle

Compares structural weight fractions of rigid-hull and piston-based oil-immersed battery housings across 300–6,000 m (3–60 MPa). Reports ~18.3% system-level mass reduction at 6,000 m for the compensated design. Provides architecture-selection evidence only. No acceptance criteria, no cycling under pressure, no thermal runaway characterization. Tier 3 source.

What's missing for DVP use?

No qualification thresholds, no cycle-life data under pressure, no safety outcomes. Acceptance criteria must still originate from ABS §10/11.5.6 or program specification.

Where does it help?

Architecture trade-off data spanning the full 300–6,000 m envelope, useful for housing concept selection before a program freezes design depth.

Pressure Architecture Study

Review of Energy Technologies for Unmanned Underwater Vehicles

Open-access 2026 review independently corroborates Li et al.'s mass-reduction figures and adds a technology comparison: 140–180 Wh/kg system-level (gravimetric) for oil-filled architectures versus 100–130 Wh/kg for rigid hulls. Identifies 2,000 m as the depth where rigid-hull structural mass begins dominating system weight. Tier 3 peer-reviewed analysis, not standard-set values.

What sourcing tier applies?

Tier 3 analysis-derived figures from a peer-reviewed review. Engineers should pull the Li et al. primary text before committing any DVP row.

What threshold matters?

2,000 m is identified as the critical depth where rigid-hull structural mass sharply erodes payload capacity and system-level specific energy.

Authority Structure

The Subsea Authority Chain Runs Through Class, Not ISO

If you are populating a UUV pack DVP and looking for the ISO number that anchors it, there isn't one. The exclusion is written into the documents themselves.

ISO 20682:2026, AUV risk and reliability, published February 2026, states in its public scope that batteries and electrical motors for AUV use are excluded. ISO 21173:2019 (confirmed 2025) governs hydrostatic pressure testing of pressure hulls and buoyancy materials, not battery packs.

Class fills the space. Marine classification societies write the technical rules and survey against them, one body holding a function that aviation splits between the regulator and the standards body. ABS §10/11.5 (January 2025) addresses lithium installation, BMS functions, and pressure exposure directly.

For your DVP, that means class rules define which demonstrations are required without setting the thresholds those demonstrations run against. Design depth and mission duration remain program inputs.

Last verified: 31 July 2026.

Authority Structure

The Subsea Authority Chain Runs Through Class, Not ISO

If you are populating a UUV pack DVP and looking for the ISO number that anchors it, there isn't one. The exclusion is written into the documents themselves.

ISO 20682:2026, AUV risk and reliability, published February 2026, states in its public scope that batteries and electrical motors for AUV use are excluded. ISO 21173:2019 (confirmed 2025) governs hydrostatic pressure testing of pressure hulls and buoyancy materials, not battery packs.

Class fills the space. Marine classification societies write the technical rules and survey against them, one body holding a function that aviation splits between the regulator and the standards body. ABS §10/11.5 (January 2025) addresses lithium installation, BMS functions, and pressure exposure directly.

For your DVP, that means class rules define which demonstrations are required without setting the thresholds those demonstrations run against. Design depth and mission duration remain program inputs.

Last verified: 31 July 2026.

TAKE NOTE

Three authority chains, compared

eVTOL: FAA AC 20-184 / EASA SC-VTOL MOC → DO-311A, ASTM F3830-26 as accepted means of compliance. Regulator on top, standard underneath.

Drone/UAV: Regulator points directly at IEC 62619:2022 and ASTM F3005-22. Standards body is primary.

Subsea/AUV: ABS or DNV class rules are top and substance. IEC 62619 and UN 38.3 appear inside them as referenced baselines, not as coordinate authorities.

Not ABS-specific. DNV publishes parallel AUV rules (Underwater Technology, Pt.5 Ch.8, 2021 edition). IACS has 12 member societies operating equivalent structures.

Why class got there first. DNV GL's 2016 maritime battery handbook stated plainly that no international standards existed for large maritime batteries. Class rules filled that gap and still hold it.

Still program-defined under class: design depth value, mission duration, thermal rejection path, acoustic constraints, post-abuse containment, connector leakage acceptance.

Source Trail