Forklifts for Chemical Plants and Paint Shops: Matching the Explosion Proof Forklift Application to Each Zone
A tank farm, a filling line and a finished goods warehouse in the same plant rarely need the same truck. This article explains how to read a zone drawing, pick the right explosion proof forklift application, and confirm the six details that decide whether a unit can legally work in your building.
1. One plant, four different risk areas
Walk through a coatings factory and you pass through areas that look similar but are classified differently. The tank farm and reactor area usually holds the highest concentration of solvent vapour, but that vapour is released in bursts, and the area is often open or well ventilated. The filling line runs continuously, with open containers, small spills and operators standing next to the nozzle all shift. The finished goods warehouse is mostly sealed drums and pails, but it is often the largest enclosed space on site, with the highest racking density and the longest travel distances. Raw material stores in between can be dust-classified rather than gas-classified if powders are decanted there.
Each of these areas drives a different equipment answer. A stand-on pallet truck is the natural machine on a filling line where loads move 20 to 60 metres at a time and the operator steps off constantly. A reach truck suits high racking in a finished goods warehouse where aisle width matters more than travel speed. A counterbalance truck is what you need if the load has to be lifted over the side of a tank bund or a mixing vessel, because reach legs cannot straddle a raised lip.
The mistake that costs money is buying one Ex-rated truck for the whole site and assuming it covers everything. The second mistake is buying a truck rated for zone 1 when the area is zone 2, and paying for protection the process does not require.
2. Reading the classification before you read the brochure
Four pieces of information determine whether a truck is acceptable. First, is the hazard gas or dust? Second, which subdivision of the gas group or dust group applies? Third, what is the temperature class, meaning the highest surface temperature the equipment may reach? Fourth, which zone applies — 0, 1 or 2 for gas, and 20, 21 or 22 for dust?
Zone 0 and zone 20 mean the atmosphere is present continuously. Zone 1 and zone 21 mean it is likely during normal operation. Zone 2 and zone 22 mean it is unlikely and, if it occurs, only briefly. In practice, almost no material handling equipment is built for zone 0 or 20, because those zones are normally inside tanks, pipes and closed vessels where no truck can go. Reach trucks and counterbalance trucks are typically specified for zone 1 or zone 2 gas, and for zone 21 or zone 22 dust. Forklifts working in zone 2 are the most common configuration in coatings and ink plants, because open containers are handled by operators at fixed stations and the truck stays on marked travel routes.
Temperature class is where buyers get caught. T4 means the surface temperature stays at or below 135 °C. T3 allows up to 200 °C, T2 up to 300 °C. If your solvent has an ignition temperature of 210 °C, a T3 machine is not acceptable and you need T4 or better. Ask your process engineer for the auto-ignition temperature of every solvent in the area, take the lowest one, and pick the class below it. A truck rated for a higher temperature class than you need is not a safety margin — it is a machine you cannot use in that zone.
| Situation | Atmosphere | Typical zone | Gas/dust group | Min. temperature class |
|---|---|---|---|---|
| Paint and solvent mixing shop | Solvent vapour | 1 or 2 | IIA / IIB | T3 or T4 |
| Solvent filling and drumming line | Solvent vapour, open containers | 1 | IIA / IIB | T4 |
| Ink production with pigment powder | Solvent vapour plus dust | 2 / 22 | IIB / IIIB | T4 |
| Pharmaceutical dust handling | Combustible dust | 21 or 22 | IIIA / IIIB | T135 °C |
| Oil and gas storage, tank bund area | Hydrocarbon vapour | 1 or 2 | IIA | T3 |
| Finished goods warehouse, sealed containers | Low risk, unclassified | None | — | Standard truck |
The combination seen most often on our order book is IIB T4 Gb for the gas side and IIIB T135 °C Db for the dust side. IIB covers ethylene and most common solvents, and stops short of IIC, which is hydrogen and acetylene territory. If your area is IIC, that is a different conversation and a different machine.
3. How to choose
- Confirm your zone number from the area classification drawing, not from a colleague's memory. Say "zone 1, IIB, T4" out loud before you request a quote — the numbers drive the price more than the capacity does.
- Match capacity to the heaviest load, then add margin. The WR Ex range covers 1000 to 3500 kg on counterbalance models, and 2000 kg on both the CBD20Ex stand-on pallet truck and the CQD20EX stand-on reach stacker.
- Measure the narrowest aisle and the racking height before choosing a truck type. Reach trucks with Ex protection are the right answer when aisle width falls below roughly 2.8 m at 6 m lift height; a counterbalance truck needs noticeably more turning room.
- Check whether the truck has to leave the classified area. Mixed-duty sites often run a standard truck outside the zone and a dedicated Ex unit inside, rather than paying Ex cost on every machine on site.
- Ask about corrosion before paint. Chemical plants with acid vapours or regular washdown need sealed connectors, coated chassis and IP-rated motors, and that requirement sits on top of the Ex rating, not inside it.
- Budget the certification paperwork. Ex equipment arrives with a nameplate, a certificate and a document set; make sure your own inspection team can file it, because a truck in the yard without matched paperwork fails its next inspection.
4. FAQ
What is the difference between IIBT4Gb and IIIBT135 °C Db?
IIB T4 Gb is the gas rating: gas group IIB, surface temperature limited to 135 °C, equipment protection level Gb, suitable for zone 1 and zone 2. IIIB T135 °C Db is the dust rating: dust group IIIB (non-conductive dust), surface temperature limited to 135 °C, protection level Db, suitable for zone 21 and zone 22. A truck carrying both markings can work in areas where solvent vapour and combustible dust occur in the same room, which is common in pigment and ink production.
Can I use a standard electric forklift in my solvent store if I keep the doors open?
No. Ventilation reduces the likelihood of an explosive atmosphere but does not change the zone on the classification drawing, and an inspector works from the drawing. An open door also does not remove the ignition risk from a standard truck's motor, contactors, plugs and static build-up. If the drawing says zone 1 or zone 2, the truck has to carry the matching Ex marking.
Which truck suits a paint filling line best?
A stand-on pallet truck is usually the right machine. The CBD20Ex handles 2000 kg with the operator riding on the platform between stops and stepping off at the nozzle, which keeps travel time down on short 20 to 60 metre runs. For a filling line that also feeds high racking, the CQD20EX stand-on reach stacker gives 2000 kg with a tighter turning radius than a counterbalance truck.
Does the Ex rating cover corrosion from acid or solvent spills?
No. Explosion protection and corrosion resistance are separate requirements. If your area sees regular spills, washdown or acidic vapour, specify a corrosion package on top of the Ex rating: coated chassis, sealed electrical connectors, stainless fasteners and IP-rated drive components. Confirm this at the quote stage, because retrofitting seals and coatings later is more expensive than ordering them with the truck.
How do I handle static on an Ex forklift?
Static control comes from the whole system, not the truck alone. Conductive or antistatic tyres, a bonding strap or earthing chain, and antistatic footwear for the operator all matter. Grounding points in the filling area should be bonded, and drum handling should include a verified earth connection before any transfer starts. Ask for the truck's static dissipation path to be documented so your own safety officer can sign it off.
What are the six things I must confirm before ordering an Ex truck?
Confirm the zone number (0/1/2 or 20/21/22), the gas or dust group (IIA, IIB, IIC or IIIA, IIIB, IIIC), the temperature class (T1–T6 or T135 °C for dust), the required capacity in kilograms, the aisle width and lift height at the point of use, and any corrosion or washdown requirement. Get all six in writing from your process engineer before the truck is specified, because each one changes the configuration.