Explosion Proof Lighting Blog | Guides & Technical Articles

October 2026 · 8 min read

When a hazardous area lighting project goes wrong, the fitting is almost never the part that failed — the specification is. A Zone 2 light ordered for a Zone 1 area. An IP65 fitting washed down with a hose. A certificate that exists but doesn't match the model. All of these are decided before the purchase order is signed, which is why this checklist exists: six steps to run in order, each with the question to answer and the evidence to collect. Print it, run it, and the order takes care of itself.

Step 1: Confirm the Area Classification

Everything downstream depends on one document: the area classification drawing (or hazardous area dossier). It tells you the zone (0, 1, 2 for gas; 20, 21, 22 for dust), the gas group (IIA, IIB, IIC) and the temperature class required (T1–T6) for each area.

The zone decides the equipment category you may install; the gas group and temperature class decide which specific fitting is allowed. Our Zone 1 vs Zone 2 guide covers the boundary in detail, including the real cost difference between the two.

Step 2: Match the Protection Concept to the Zone

Once the zone is confirmed, the Ex marking on the fixture is not a matter of preference — the protection level (Gb for Zone 1, Gc for Zone 2) must cover it:

Two notes that prevent the classic mistakes. A Zone 1 (Gb) fitting may always be used in Zone 2 — over-specifying is legal, just usually more expensive. And the gas group travels independently: our Zone 2 flood light is IIC while our Zone 1 flood light is IIB, so "the higher zone must be the better gas rating" is not a rule.

Step 3: Define the Environment, Not Just the Zone

The zone classification says nothing about water, dust density without explosion risk, salt, impact or cold. Those are separate lines on the datasheet, and this is where the fitting either survives fifteen years or becomes a maintenance item:

Step 4: Run the Lighting Calculation

"Same wattage as before" is not a lighting calculation — especially when converting from HID to LED, where the same watts can mean very different delivered light. The calculation needs: the task area, the mounting height, the target maintained lux, and the photometric file (IES/LDT) of the proposed fitting.

Typical design practice for the areas where our fittings go — treat these as orientation, your project specification governs:

Two things worth requiring from the supplier at this step: the delivered luminaire lumens (not the LED chip rating), and the willingness to run the layout for you. A manufacturer with photometric files for every model can return a spacing layout within a day; a reseller cannot.

Step 5: Verify the Paperwork

Before the purchase order, collect and check four documents — not screenshots, the actual items:

1. Certificate for the exact model. Number in the issuing body's public register; holder is the manufacturer; marking matches the quotation. Our certification verification guide shows the format.
2. Production quality assurance (QAN). Confirms series production is audited — the type certificate alone does not.
3. Declaration of Conformity. Links the shipped units to the certified type.
4. Installation, operation and maintenance manual. Legal requirement, and the source for gland torques, spare parts and inspection intervals.

Step 6: Plan the Installation and the Maintenance

The last step is the one that happens on site, and it has its own short list:

• Glands and entries. Every unused entry closed with the certified plug; every gland matched to the actual cable diameter. An open or oversized entry defeats the certification.
• Mounting and access. Can the fitting be reached for lens cleaning? At 12 m, the cleaning interval you can actually perform is the one that determines maintained lux.
• Junction boxes counted? Every circuit split inside the classified area needs a certified box — the most commonly forgotten line item.
• Emergency fittings included? Escape routes in classified areas need certified emergency or exit luminaires; order them with the main batch.
• Spares. Glands, gaskets and — where applicable — LED modules, held for the service life you are promising your plant.

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