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Author: Veress Árpád · Explosion-protection expertDAILY Ex | Ex MACHINERY 6 October 2026 | Head of Operations Edition
Today’s machinery: centrifugal process pumps - where availability and Ex integrity meet
DAILY Ex | Ex MACHINERY 6 October 2026 | Head of Operations Edition
Today’s machinery: centrifugal process pumps - where availability and Ex integrity meet
- All items below are part of random selection •
A process pump normally attracts Operations attention when flow drops, vibration rises, a seal starts leaking or the standby machine refuses to start. In a hazardous area, however, those reliability indicators can also be warnings that an ignition-control assumption is disappearing.
Today’s documentation case is the KSB Etanorm, specifically using the ETN 080-065-160 family configuration as the worked machinery example.
KSB describes Etanorm as a single-stage, back-pull-out centrifugal pump to EN 733. The current product family offers replaceable casing wear rings, mechanical-seal options and a design allowing coupling, bearing bracket and impeller removal without disconnecting the casing from the pipework. That is directly relevant to maintainability and downtime: maintenance access is designed into the machine rather than requiring removal of the entire process connection.
DOCUMENT CHECK - WHAT THE MANUAL ACTUALLY SAYS
I reviewed Etanorm - Installation/Operating Manual, document 1311.8/08-EN, 88 pages. The accessible copy identifies itself as the original operating manual; I could not establish a reliable publication date from the document metadata, so I will not invent one.
The general assembly documentation in Section 9 specifically includes size 080-065-160 among the machines using the clamped casing-cover arrangement with standardized mechanical seal. The drawing identifies, among other items, mechanical seal 433, casing wear rings and connections for priming/venting, draining and leakage drainage.
The important Ex detail appears much earlier.
Section 2.9 states that a pump/pump set may only be used in a potentially explosive atmosphere when it is marked accordingly. Crucially, the manual says that the Ex marking on the pump refers to the pump part only, giving the example:
II 2G Ex h IIC T5–T1 Gb
I did not locate a public ATEX certificate number tied specifically to an ETN 080-065-160 serialized pump set. Nor did I find an authoritative public certificate-register entry that would allow me to verify one. Verification is therefore limited. The manual’s generic Declaration of Conformity also makes clear that the signed, legally binding declaration is supplied with the actual product/order; the generic document is not a substitute for that unit-specific record.
Operational use case - illustrative
Imagine ETN 080-065-160 transferring a flammable solvent from a process vessel.
Production wants to drain the vessel lower to recover another batch quantity.
The manual provides the decision point: when draining tanks, suitable measures such as level monitoring must prevent dry running. It also requires the pump internals, seal chamber and relevant auxiliary systems to remain filled and calls for sufficient inlet pressure and appropriate monitoring.
This is simultaneously an availability, lifetime-cost and Ex decision.
Running the vessel lower may recover product today. Losing liquid coverage can damage the seal and pump, create heat, force an unplanned outage and invalidate the operating assumptions behind the Ex assessment.
The cheaper operating point can become the expensive one.
For water-like fluids between −30 and +80 °C, the manual gives an approximate minimum flow of 15% of QBEP; importantly, it warns that fluids with different physical properties may require a higher minimum because additional heat can develop. Do not transfer the 15% number blindly to a solvent.
Temperature class is equally configuration-dependent. The manual lists theoretical fluid limits including T3 185 °C, T4 120 °C and T5 85 °C, while explicitly requiring the actual pump data sheet and seal arrangement to determine the permissible operating temperature.
REQUIREMENTS WATCH - EU
A genuine ATEX harmonisation change occurred last month. Commission Implementing Decision (EU) 2026/1967, adopted 3 September and published 4 September 2026, adds EN IEC 60079-28:2026, covering protection of equipment and transmission systems using optical radiation, to the harmonised-standard framework supporting Directive 2014/34/EU.
This is not a new pump operating requirement and does not suddenly make existing Etanorm pumps non-compliant. It matters to machinery projects containing optical equipment or transmission systems and, particularly, to new procurement/design conformity assessments.
MISCONCEPTION CHECK
“ATEX motor + ATEX pump = ATEX machine.”
Not necessarily.
You still need the conformity and suitability evidence for the assembled machine, its coupling/guard, instrumentation, auxiliaries, installation conditions and intended hazardous-area duty. A component marking cannot simply be promoted to whole-machine suitability (there are many possible ways forward: E.g see -46).
CSI - CRIME SCENE INVESTIGATION | HISTORICAL CASE
Giant Industries Ciniza Refinery, New Mexico - 8 April 2004.
The U.S. Chemical Safety and Hazard Investigation Board found that a malfunctioning alkylate recirculation pump had repeated mechanical-seal problems. The documented maintenance history recorded 23 seal-related repair events between April 2003 and 7 April 2004 across the two recycle pumps.
During removal of the malfunctioning pump, personnel believed an isolation valve was closed. It was actually open. A plugged vent contributed to the mistaken conclusion that the equipment had been depressurized. Hot alkylate escaped; approximately 30-45 seconds later, explosions occurred.
Confirmed CSB findings included inadequate mechanical integrity, ineffective verification of isolation/depressurization and a previous valve-handle modification that had not received adequate Management of Change analysis.
The machinery lesson is bigger than the ignition source:
Repeated seal failure is operational data.
Twenty-three repairs are not twenty-three independent maintenance jobs. At some point the organisation must stop replacing the seal and ask why the machine keeps consuming seals.
https://www.csb.gov/giant-industries-refinery-explosions-and-fire/
TODAY’S MANAGEMENT ACTION
Owner: Operations Manager + Maintenance/Reliability Engineer.
Take your five most critical pumps operating in hazardous areas and verify one chain for each:
nameplate → actual duty → pump data sheet → Ex marking → motor/drive → seal arrangement → minimum-flow/dry-run protection → monitoring/interlocks → latest inspection → maintenance history.
Measure: 5 pumps reviewed; 0 unresolved mismatches between actual operation and documented operating limits.
Because in Ex machinery, reliability history is not separate from explosion protection.
It is often where the warning appears first.