DAILY Ex | Ex MACHINERY
9 October 2026 | Head of Operations Edition

DAILY Ex | Ex MACHINERY
9 October 2026 | Head of Operations Edition

TODAY: THE DIAPHRAGM PUMP - WHEN THE PUMP WORKS, BUT THE TRANSFER SYSTEM IS UNSAFE

Air-operated diaphragm pumps are attractive to Operations. They are compact, relatively easy to maintain and can handle intermittent transfer duties without an electric motor at the pump.

But their reliability depends on more than the air valve and diaphragms. Suction conditions, material compatibility, grounding and exhaust arrangements determine whether the installation remains suitable for its intended duty.

!!!All items below are part of random selection!!!

1. REAL MACHINERY | DOCUMENTATION CASE

Manufacturer: Graco, USA.

Machine: Husky 1050A, part number 647121 - aluminium, 1-inch BSPT air-operated double-diaphragm pump, with aluminium centre section and Geolast-type wetted components.

The manufacturer specifies a maximum flow of 189 L/min, maximum air and fluid pressures of 8.6 bar, and maximum operating temperature of 66°C. These are published limits, not a guaranteed simultaneous operating point. Actual capacity depends on the duty and performance curve.

https://www.graco.com/gb/en/in-plant-manufacturing/product/647121-husky-1050.html

Documents reviewed:

Operation - Husky 1050 Air-Operated Diaphragm Pump, 312877ZAG, March 2022, pages 4–5, 9–18 and 26–27.

Repair/Parts - Husky 1050, 313435ZAS, December 2022, pages 15–18 and 21–30.

EU Declaration of Conformity, 199254U, dated 18 May 2021.

https://www.graco.com/content/dam/graco/tech_documents/manuals/312/312877/312877EN-ZAG.pdf
https://www.graco.com/content/dam/graco/tech_documents/manuals/313/313435/313435EN-ZAS.pdf
https://www.graco.com/content/dam/graco/tech_documents/declarations/199/199254/199254ENEU-U.pdf

The declaration covers specified Husky 1050A configuration patterns, consistent with this product family. It identifies:

II 2 GD - Ex h IIC 66°C…135°C Gb / Ex h IIIC T135°C Db.

The declared technical file is TF0646, lodged with Notified Body 2575. This is a technical-file reference, not an ATEX type-examination certificate number.

No independent, serial-number-specific conformity verification was available. The manufacturer's product page and declaration establish family-level evidence, not the condition of an installed machine.

The declaration also identifies a more restrictive X-marked configuration when DataTrak or pulse-count monitoring is fitted. The manual identifies ITS13ATEX27862X for DataTrak itself. That component certificate must not be mistaken for certification of the complete transfer installation.

2. WHAT THE MANUAL TELLS OPERATIONS

Page 9 explains that excessive cavitation damages fluid chambers, balls and seats, reduces efficiency and increases operating costs.

The recommended response includes reducing suction losses, improving inlet conditions or slowing the pump cycle rate.

Page 13 warns that excessive inlet pressure can shorten diaphragm life.

Page 12 contains another critical finding: if a diaphragm ruptures, pumped liquid can escape through the air exhaust.

The manufacturer therefore provides a remote-exhaust arrangement using a grounded hose and collection container. Exhaust restriction must also be avoided because it can cause erratic operation.

The maintenance instructions specify that the pump is factory-lubricated and normally needs no additional inline lubricator. Preventive maintenance should instead reflect actual service history, particularly diaphragm failures.

3. OPERATIONAL USE CASE - ILLUSTRATIVE

A chemical plant transfers a flammable solvent between containers.

Production increases the transfer rate by raising compressed-air pressure.

The pump initially delivers more liquid, but suction conditions deteriorate. Cavitation accelerates wear, and maintenance begins replacing check balls and diaphragms more frequently.

The operational decision is not simply to purchase more spare parts.

Verify suction conditions, cycle rate, fluid compatibility and the complete transfer-system grounding before approving the higher duty.

The manufacturer lists 66°C as the maximum operating temperature for part 647121. Chemical compatibility may impose a lower limit.

The published product description also uses both Geolast and G.E.T. terminology. The actual fitted materials must therefore be confirmed against the pump configuration and replacement-part records.

An unsuitable replacement can create a reliability problem and undermine the original ignition-source assessment.

4. REQUIREMENTS WATCH | EUROPE

No new machinery-specific ATEX legal obligation was verified for today.

The existing distinction remains important.

Directive 2014/34/EU, applicable since 20 April 2016, governs equipment conformity when products are placed on the EU market.

Directive 1999/92/EC, published 28 January 2000, establishes workplace explosion-protection duties, implemented through national legislation.

For new purchases, verify the manufacturer's declared configuration and intended use. For existing installations, the employer must maintain the explosion-risk assessment, operating controls and equipment suitability.

EN ISO 80079-36/-37 are technical standards supporting non-electrical ignition-risk assessment, not substitutes for either legal duty.

https://single-market-economy.ec.europa.eu/single-market/goods/european-standards/harmonised-standards/equipment-explosive-atmospheres-atex_en?prefLang=lv
https://osha.europa.eu/en/legislation/directives/21

5. MISCONCEPTION CHECK

“An air-operated pump has no electric motor, so it cannot become an ignition source.”

Incorrect.

Static electricity, mechanical friction, impact, hot surfaces and inappropriate materials remain relevant.

The Graco manual specifically requires grounding and periodic continuity checks. It also prohibits using non-conductive polypropylene or PVDF pumps with non-conductive flammable fluids.

6. CSI | CRIME SCENE INVESTIGATION

Barton Solvents, Des Moines, USA - 29 October 2007. Historical case.

During ethyl acetate transfer into a portable steel tank, a fire developed and was followed by explosions.

The U.S. Chemical Safety and Hazard Investigation Board found that conductive parts of the filling nozzle and hose assembly were not adequately bonded and grounded.

The CSB concluded that a static discharge likely ignited flammable vapour near the tank opening.

The investigation also documented inadequate fire separation and suppression. The main warehouse was destroyed, seriously interrupting operations.

Incident: 29 October 2007.
Investigation report: 18 September 2008.

https://www.csb.gov/file.aspx?DocumentId=5614

The lesson is not that a particular pump failed.

It is that a suitable pump cannot compensate for an unsuitable transfer arrangement.

7. TODAY'S MANAGEMENT ACTION

Owner: Operations Manager + Maintenance/Reliability Engineer.

Review one critical hazardous-area liquid-transfer installation, from pump inlet to receiving vessel.

Verify the actual pump configuration, process fluid, suction conditions, grounding continuity, hose and nozzle suitability, exhaust routing, diaphragm maintenance history and last modification.

Check whether installation drawings, material-compatibility evidence and the serial-number-specific equipment records are available. Without them, complete system suitability cannot be concluded.

Measure: One documented transfer-system review, with every unresolved safety-critical deviation assigned a disposition before continued operation.

TODAY'S Ex QUESTION

Are we maintaining a reliable pump — or a reliable and demonstrably safe transfer system?

Operational Ex is not about the certificate alone. It is about keeping the entire operating arrangement within its demonstrated safe condition.