ISO 15783:2026: The Sealless Pump Standard's First Revision in Twenty-Three Years

The only international standard written specifically for sealless rotodynamic pumps has been revised for the first time in twenty-three years. ISO 15783:2026, Seal-less rotodynamic pumps — Class II — Specification, was published on 7 May 2026 as a 48-page second edition, replacing the 2002 first edition and its 2008 amendment. For a machine family whose entire premise is that there is no shaft seal to leak, the specification that defines what buyers and makers must agree on had stood still since before most of today's supply base existed.

This article sets out what the standard is, what its revision record shows, how it sits beside the heavy-duty sealless specification, and where the public record stops. It is not a compliance determination.

What does ISO 15783 cover?

Sealless pumps in the Class II band of duties — chemical processes, water treatment and petrochemical service — driven either by permanent-magnet coupling or by canned motor.

The standard's own scope description defines the machine precisely: a pump whose inner rotor is completely contained within the pressure vessel holding the pumped fluid, so that the containment boundary is closed by static seals — gaskets and O-rings — rather than by a dynamic shaft seal. The two families are the magnet-drive pump, where torque crosses a containment shell through a magnetic coupling, and the canned-motor pump, where the motor rotor runs inside the pressure boundary and only the stator stays dry.

The document sets requirements for design features bearing on installation, maintenance and operational safety, and — significantly for buyers — defines which items must be agreed between purchaser and supplier. Its stated order of precedence when documents conflict is itself a specification discipline: the purchase order first, then the data sheet, then this standard, then other standards.

What does the revision record show?

A three-year revision project ending a twenty-three-year freeze.

ISO's catalogue records the project approved in October 2023, the draft ballot in April 2025, the final draft stage in November 2025 and publication on 7 May 2026. The standard replaces ISO 15783:2002 together with its Amendment 1 of 2008 — which means the operative text the industry had been citing was, in substance, written at the turn of the century.

European adoption has followed immediately: distributor records show EN ISO 15783:2026 already published as the identical European text, with national equivalents in place. For a specification used in chemical and petrochemical procurement, that simultaneity matters — the EN line is what CE-adjacent project documents in Europe will cite.

How does it sit beside API 685?

The two documents divide the sealless world by duty severity rather than by geography.

API 685 is the petroleum industry's heavy-duty sealless specification, written for the refinery and petrochemical duties where API 610 would otherwise govern; API 610's own notes point sealless enquiries to it. ISO 15783 is the Class II specification — the chemical-process and general-industrial band, aligned in its reference discipline with ISO 5199. A procurement document that says "sealless" without naming which of the two frameworks governs has not yet said much: the containment philosophy is shared, but the inspection, testing and documentation expectations differ by class.

That division is also the practical reading of the revision's timing. The heavy-duty line moved with API 685's third edition in 2022; the Class II line has now moved with ISO 15783's second edition in 2026. Both halves of the sealless specification map have been redrawn within four years of each other, after long freezes on both.

Where does the public record stop?

At three places.

The clause-level changes are not in the free record. ISO's catalogue gives the edition, the date, the page count, the scope and the lifecycle; the revised text itself is a paid document, and this article has not read it. Any list of "what changed" that is not traced to the standard's own foreword should be treated as unverified.

The standard does not certify any pump. Conformity is established per unit against the purchaser's order and data sheet — the document's own precedence rules make the contract, not the catalogue, the top authority.

Coverage is Class II. Duties that belong to the heavy-duty sealless specification are outside this document's scope by design, and nothing in the revision record suggests that boundary moved.

What does the trend add up to?

Two movements, both visible in the public record.

Sealless containment has moved from a niche specification to a maintained one. A standard that sat unrevised for twenty-three years — through the entire rise of magnet-drive and canned-motor pumps in chemical service — has been rewritten, and its European adoption landed in the same season.

And the specification map is being re-drawn in pairs: the heavy-duty sealless line (API 685, 2022) and the Class II line (ISO 15783, 2026) now both reflect current practice, which removes the excuse for procurement documents that cite either one vaguely.

What has not changed is the physics that made the standard necessary: the shaft seal remains the most common leak path on a process pump, and these two documents define the machine families built to delete it.

What this article does not cover

Note that this article does not reproduce the standard's requirements, does not compare specific pump models, does not assess any manufacturer's conformity, and gives no prices. It records the publication and the public catalogue record of a revised standard. It is not a compliance determination.

Where the next constraint sits

A sealless design answers the leak path at the shaft; a separate US rulemaking has just made the leak path a matter of annual instrument monitoring at chemical plants — that story is in US EPA's Chemical Manufacturing Area-Source Rule: Annual Method 21 Monitoring Reaches Pumps.

And the question of when a sealless machine is the wrong answer — solids, shear sensitivity, duty point — sits inside the selection order set out in Chemical Pump Selection Guide: Risk, Medium and Duty Point — in That Order.

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