Forklifts and Material Handling

Where a truck works on a rig

A rig forklift moves pallets, drums, sack goods and small containers between the laydown area, the stores and the pipe deck. Decks are steel, often wet and sometimes sloped, and much of the open deck is a classified hazardous area. A standard warehouse truck has hot surfaces and sparking parts that can ignite gas, so it can only work in a safe area.

Hazardous-area conversion

A conversion makes the truck safe for a given zone.

• Zone 2 needs ATEX Category 3G equipment, or IECEx equipment protection level Gc.
• Zone 1 needs Category 2G, or level Gb, which is a heavier and costlier conversion.

On a diesel truck, a typical conversion cools the exhaust and engine surfaces, adds a flame arrester and an air inlet shutoff valve to stop overspeed, and encloses or replaces sparking electrics. Many conversions clad the forks to cut spark risk. Active systems add gas detection that shuts the engine down when gas reaches a set level. The certificate states the gas group, such as IIA or IIB, and the temperature class, such as T3 or T4.

Key specifications

Standards and certification

ISO 3691-1 covers safety of powered industrial trucks. EN 1755 adds requirements for trucks working in potentially explosive atmospheres, and the conversion is certified under ATEX or IECEx. A forklift is lifting equipment, so UK LOLER requires a thorough examination at least every 12 months, or every 6 months if it lifts people. The lifting points used for crane transfer need their own certificate.

Failure modes and inspection

• Mast and chains. Check channels and rollers for wear, and measure chain elongation against the maker's limit. Inspect chain anchors and pins.
• Forks. ISO 5057 sets in-service fork checks for surface cracks, difference in tip height, positioning locks, legible marking and wear. Measure heel thickness against the original and the maker's discard limit.
• Hydraulics. Look for cylinder drift, leaking seals and hose condition.
• Steering, brakes and tyres.
• Frame and battery tray. Check for corrosion, which salt air speeds up.
• Conversion. Test the gas detection shutdown, surface temperature sensors and air inlet shutoff, and check that every flameproof enclosure and seal is intact.

Documentation

• Conversion certificate whose serial number matches the truck
• Service history since conversion, from the converter or an approved agent
• Last thorough examination report
• Lifting point certificate
• Running hours and gas detector calibration records

Integration and compatibility

Check the truck's laden wheel loads against your deck plate and hatch cover ratings. Confirm where it will refuel or charge, since battery charging belongs in a safe area. The truck's mass, with any attachments, must sit inside your crane's offboard rating for the transfer.

Refurbishment and recertification

Any non-certified part fitted since conversion can void the certificate. A truck with a lapsed or missing conversion file usually needs a new conversion assessment, which removes most of the saving on a used unit. Unused surplus trucks from cancelled projects are good value if the conversion paperwork stayed with them. Pyroban is a well-known converter. For the slings that lift the truck aboard, see crane attachments and rigging.