Explosion-Proof Guindaste Guia do Comprador: Zones, Gas Groups, and Normas
If you are sourcing a crane for a petrochemical plant, LPG terminal, paint line, or solvent recovery building, the lifting equipment is only half the purchase. The other half is the hazardous-area classification that dictates how the crane is built, protected, and certified. Getting this wrong means a crane that cannot be commissioned — or worse, an ignition source hanging over a process unidade. This guide covers the practical decisions: zone, gas group, temperature class, and the documentation an exporter must provide.
Step 1: Confirm the Zone Before You Confirm the Guindaste
Explosion protection starts with the area classification drawing issued by the plant's process or safety engineer. The crane supplier cannot and should not assign the zone. What the supplier needs from you is:
- Zone 1 or Zone 2 (gas/vapour) or Zone 21/22 (combustible dust) at the crane's travel path and hoist position.
- Gas group: IIA (propane, methane), IIB (ethylene, refinery hydrogen streams), or IIC (hydrogen, acetylene).
- Temperature class: T1–T6, driven by the auto-ignition temperature of the worst-case substance. T4 (135°C max surface) is the common petrochemical default; T6 (85°C) is required for some solvents and carbon disulphide.
A frequent mistake is specifying the whole crane to the worst case in the plant. If only the hoist trolley enters Zone 1 while the bridge and runway sit in Zone 2, the bridge motors and panels can be built to a lower (cheaper) protection level. This split-specification approach is standard practice and can reduce cost significantly on a 20-ton double-girder unidade.
Step 2: Understand Ex d IIB T4 vs Ex d IIC T6
The marking Ex d IIB T4 means flameproof enclosure (d), gas group IIB, temperature class T4. Ex d IIC T6 is the most demanding common combination: it covers hydrogen and acetylene atmospheres and limits any surface to 85°C.
Practical implications for crane design:
- Flameproof motor and brake enclosures with certified flame paths — this affects motor frame size, so an Ex d hoist is physically larger and heavier than an equivalent standard hoist. On an LH hoist double-girder crane (5–50T), plan for increased wheel loads and a taller approach dimension.
- IIC construction requires tighter flame-path gaps and more robust enclosures than IIB. For hydrogen service, expect longer lead times and fewer qualified motor suppliers.
- T6 constrains brake and motor surface temperature, which usually means derating or forced ventilation. A 10-ton Ex d IIC T6 hoist may need a larger frame than the same capacity at T4.
- Anti-static and spark-resistant measures: brass or stainless wheel treads, non-sparking buffer materials, and conductive (anti-static) control cable sheathing.
- Earthing: continuous bonding across bridge, trolley, hoist, and load hook, with a dedicated earth conductor in the festoon or cable chain.
For heavy petrochemical duty — catalyst handling, coker service, or reactor bay work — the QD universal double-girder crane (5–150T) or YZ metallurgical crane (5–125T) platform is tipicamente the base machine, re-engineered with Ex d components and a hazardous-area control panel. Where the plant also wants remote or automated operation, a QDS smart unmanned configuration can be supplied with explosion-proof drives and intrinsically safe (Ex i) sensors and limit switches.
Step 3: Certificação — ATEX, IECEx, and What Else
For European petrochemical projects, the crane must carry ATEX marking under Directive 2014/34/EU (Equipment Category 2G for Zone 1, 3G for Zone 2), and the notified body certificate must cover the complete assembly — not just individual motors. IECEx is the parallel international scheme and is widely accepted in the Oriente Médio, Southeast Asia, and Austrália.
Ask the supplier for:
- EC-Type Examination Certificate listing the crane assembly and all Ex components.
- Component certificates for motors, brakes, panels, limit switches, and festoon systems.
- Nameplate and marking drawing showing Ex d IIB T4 Gb or Ex d IIC T6 Gb, plus the IECEx/ATEX certificate number.
- Declaration of Conformity and the technical file reference.
Regional schemes matter too. For Rússia and CIS: EAC (TR CU 010/020). For the Gulf: GCC/SASO. For Nigéria: SONCAP. For Quênia: KEBS. A supplier serving 60+ countries should be able to align the Ex certification package with the destination market's customs and inspection regime — this is where inexperienced exporters lose weeks at port.
Step 4: Specification Checklist for the RFQ
- Zone and gas group at bridge, trolley, and hoist positions (state separately if different).
- Temperature class and the substance driving it.
- Capacidade and span — e.g. 16T LH double-girder, 22.5 m span, Zone 2 IIB T4.
- Protection level required: Ex d, Ex e, Ex i, or a combination.
- Control method: pendant, radio remote (Ex-rated), or cabin; specify if the cabin must be pressurized.
- Destination country and required certification scheme.
- Ambient conditions: outdoor, corrosive, high humidity, or dusty.
Steel grade for the structure is normally Q345B for main girders and Q235B for secondary members; design is calculated to GB/T 3811, with FEM 1.001, DIN 15018, or CMAA #70 available on request if your project specification calls for it. Elétrica components from Schneider, Siemens, ABB, or SEW are specified where the client's approved vendor list requires them.
Prazo de entrega and Commercial Reality
Explosion-proof cranes are not stock items. Expect 30–45 days production for most configurations, longer for IIC T6 or large-span QD units, because flameproof motors and certified panels are procured to order. There is no MOQ — a single 5-ton Ex d IIB T4 hoist is a normal order — and a 4-hour quotation turnaround applies if you supply the zone, gas group, temperature class, capacity, span, and destination country in the first message. Every unidade ships with a 12-month warranty.
To move forward, send your area classification and duty requirements to WhatsApp +86 193 9277 7259 or yuhua0095@gmail.com. Hefei Chunhua Hoisting Machinery Co., Ltd (founded 2003), in the Anhui industrial crane manufacturing belt, builds across five categories and 81 standard models — overhead, gantry, parking, light lifting, and manipuladores — and will confirm the correct Ex marking for your zone before quoting.