When you purchase an Explosion Proof (EX) lift truck, you are trusting that the vehicle is built with quality, compliant components that are then tested as a full system. These components are crucial to the integrity of a piece of equipment that is certified to operate in a hazardous environment.
You may have asked yourself, “What are these components that keep my coworkers safe?” Our experts are here to break down the elements that make up an explosion proof forklift.
EX Enclosures An EX Enclosure is a case or housing that has been tested and approved to contain electrical components. Although the joints of EX enclosures will permit the entry of explosive vapors, the strength of the enclosures must contain any internal explosion.
Mineral Insulated (MI) Cable
MI cables were developed to meet the needs of a noncombustible, high heat- resistant, and water-resistant cable. MI cable has from one to seven electrical conductors. These conductors are insulated in a highly compressed mineral, normally magnesium oxide, and sealed in a liquid tight, gastight metallic tube, normally made of seamless copper. RICO uses MI cables where space is constricted, and flexibility is key.
Intrinsically Safe (IS) Wiring
By definition, intrinsic safety is an explosion protection technique applied to electrical equipment and wiring intended for installation in hazardous locations. The technique is based upon limiting both electrical and thermal energy to levels which are incapable of igniting a hazardous mixture which is present in its most easily ignitable concentration.
Static Conductive Tires
All wheels and tires shall be made of non-sparking material. At least two tires and wheels shall be made of electrically conductive material, or some other equivalent static discharge device shall be provided. Electrically conductive straps or chains may not be used to meet this requirement.
Mechanical Spark Protections
The perimeter of the truck, including the forks and other exposed portions, must be covered in a non-sparking metal like brass, bronze, copper, or aluminum material. This requirement is intended to reduce the potential for ‘friction’ type sparks that may be generated if/when the truck meets other objects.
Complying with UL 583 standards, an EX rated battery, or an EX-rated battery box eliminating the need for an EX battery, will be used will all models. An EX battery cannot be charged in the hazardous area, it must be removed and charged in a safe area.
If drive belts are used as part of the vehicle build, they must be constructed from electrically conductive material. There shall be no slippage of the belt that may cause temperature rises that could ignite the explosive atmosphere.
Flame paths provide a way for the burning gasses to escape from the device as they expand during an internal explosion; but only after they have been cooled off and their flames quenched.
- Some examples include the lid of an enclosure (Ground Surface Flame Path) and the entry of the conduit into an enclosure (Threaded Flame Path).
Seals prevent passage of gasses, vapors, and flames from one portion of the electrical installation to another through the conduit.
Threaded Rigid Metal Conduit
An acceptable wiring method. Conduit is made up of EX rated piping, elbows, couplers, etc. The conduit assembly must contain a seal and all connections must be wrench-tight with at least five full threads of engagement.
Explosion proof lift trucks are required in locations that have been classified as hazardous. Questions about hazardous classifications or who classifies an area as hazardous? For more information regarding hazardous classes, divisions and groups, read our blog on hazard classifications.
An EX forklift is a piece of industrial equipment that provides protections is constructed with components that eliminate sparks and are specifically tested and classified for use in explosive hazardous locations. Only EX trained technicians should perform maintenance and repairs to maintain proper compliance for this equipment.
For additional training or information on these ratings or to request a quote, be sure to contact us to speak with one of our experts!