• • • SAFETY IN ENGINEERING • • •


DURABILITY AND RELIABILITY IN HARSH ENVIRONMENTS: HOW ROBUST LIGHTING PREVENTS SAFETY FAILURES


In hazardous and heavy-industrial settings, lighting is doing far more than illuminating tasks By Stuart Head, Technical and Compliance Manager, Petrel Ltd


aren’t visible, labels can’t be read, and critically, in explosive atmospheres, a fault can become an ignition source unless the fitting is engineered to fail safely. That’s why we design for durability and ‘failure by design’, if something goes wrong, it stays contained.


I


Why durability is a safety issue Ingress, corrosion and mechanical shock are the big three enemies of reliability. IP66/67 is often the baseline for harsh areas, and high IK ratings prevent one-off knocks from becoming future leak paths. Selecting the right IP/IK for the cleaning regime and environment is essential.


Materials, sealing


and thermal design Corrosion resistance is a system decision: alloys, coatings, fasteners, glands, optics and gaskets must all suit the environment. Thermal management is just as critical. Ex equipment is built to IEC 60079 (e.g., flameproof ‘Ex d’, increased safety ‘’Ex e’, encapsulation ‘Ex m’, dust ‘Ex t’) to control surfaces, arcs/sparks and fault energy, so foreseeable faults don’t translate into ignition.


What’s new: lighter,


safer 3rd-gen LED platforms Our latest LED luminaires add weight-optimised housings and simplified installation hardware, practical changes that reduce risk during work at height. Variable fixing centres, quick-fit bolts, captive diffusers and integral isolators shorten time at height; higher lm/W means fewer fittings to hit a given lux target.


t’s a safety control measure. When luminaires corrode, leak or suffer impact damage, the consequences cascade: emergency routes


Failure-by-design (faults stay contained) • Ex d (flameproof): Internal ignition is contained and cooled.


• Ex e (increased safety): Prevents arcs/sparks and limits temperature in normal and certain fault conditions.


• Ex m / Ex t: Critical parts are encapsulated and surfaces controlled for dust atmospheres. These are implemented across Petrel platforms.


Why this really matters


in food & beverage Food plants mix combustible dusts (flour, sugar, starch) with aggressive washdown. Here, ‘failure by design’ is non-negotiable and material choice is part of the control strategy. We specify polycarbonate encapsulation/optics instead of glass in zones around process lines to: • eliminate glass-shard contamination risk if a lens is struck;


• achieve higher impact resilience (IK10 with polycarbonate vs lower with glass on some variants);


• resist chemicals with hard-coated, abrasion-resistant grades, while keeping IP66/67 intact through repeated washdowns.


Examples across the range include high-impact polycarbonate diffusers on linear luminaires and polycarbonate tubes on certain Ex d products used in wet environments both chosen specifically for hygiene and impact performance in F&B.’


Maintenance, inspection


and the human factor Durability makes maintenance predictable and safe. IEC 60079-14/-17 set out initial and periodic inspection requirements; designs with safe


isolation, captive hardware and clear access reduce human error and avoid compromising flamepaths or seals. Where dust layers are present, IEC 60079- 31 (Ex t) and surface temperature limits are key.


Trend: higher IP/IK, simpler


servicing, smarter monitoring Specifiers across process, pharma and food are moving to IP66/67 and IK09/IK10, with emergency luminaires using automatic test to IEC 62034 for auditable compliance without production disruption.


Failure modes & consequences


(and how to head them off) Moisture ingress and driver failure. Match IP to washdown; specify quality glands; UV-stable polycarbonate optics.


Impact damage and cracked optic / seal breach. Select polycarbonate IK10 options; add guards near mobile plant. Over-temperature and T-class breach. Verify ambient/heat sinking; pick the right Ex concept for gas/dust group.


Maintenance error and disturbed flamepaths / dropped parts. Design for maintainability; follow IEC 60079 inspections.


A practical specifier’s checklist


(food & beverage focus) • IP66/67 with documented cleaning assumptions; smooth, easy-to-clean externals. • Dust protection to IEC 60079-31 with surface temperature verification for flour/sugar environments.


• Ex concept matched to the zone and hazard (Ex d/Ex e/Ex t), fail safe by design.


• Prefer polycarbonate optics/encapsulation in hygienic and high-impact areas; use hard-coated grades where chemicals are present; note IK10 advantage. • Choose modern, lighter 3rd-gen LED platforms with variable fixing centres and captive diffusers to shorten time at height.


Reliability is safety. In flour mills, bakeries and bottling halls, robust IP/IK/Ex design plus failure-by-design engineering, and polycarbonate in place of glass where hygiene and impact risks are highest, ensures that if a luminaire does fail, it won’t become AN incident.


https://www.petrel-ex.co.uk/lighting-products 26 ELECTRICAL ENGINEERING • OCTOBER 2025 electricalengineeringmagazine.co.uk


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