New antistatic rules for lift trucks handling flammable waste

Forklift trucks used in solvent recovery and waste treatment plants will be required to have even greater safety measures from November 2017.

The new EN1755:2015* standard is expected to affect the management of ATEX compliant lift trucks when static becomes considered a "normal" occurrence in Zone 2 hazardous areas.

"The challenge for waste management sites is that they are handling high volumes of flammable materials with different flashpoints, temperature classes and characteristics, so the risk of fire and explosion is always present," says Rob Vesty from safety company Pyroban that converts equipment so it cannot be the source of an ignition.

"Waste is a highly-regulated industry and the rules are set to change for lift trucks at the end of 2017," he says. "Most waste sites operate 2.5-3 tonne capacity diesel forklifts in their Zone 2 drum or IBC storage areas, which is where the biggest changes apply."
EN1755:2015 supersedes EN1755:2000 which is the EU standard that explosion protected materials handling equipment is designed or converted to, to achieve ATEX 2014/34/EU** compliance.

"One of the key changes is that static is now considered a "normal" occurrence in Zone 2 hazardous areas, affecting the technical design of the truck," says Rob. "Static build up and friction can create enough energy to cause ignition."

As well as affecting the requirements for tyres, this will also impact other elements of a forklift truck, such as seats, arm rests, cabin sides and hydraulic systems in Zone 2. Although Pyroban's ATEX conversion will address these issues, but EN1755 changes will impact how treatment plants manage their fleet day-to-day. Under the revised standard, tyres must now be antistatic in Zone 2 hazardous areas, assuming they are travelling at more than 6km per hour.

"Specifying non-standard tyres increases lead times, sometimes up to 10 weeks," says Rob. "Treatment plants may face downtime if explosion protected parts supply is not considered early enough by their procurement teams or the lift truck dealer. Many of these businesses have large fleets over numerous sites, so it could make a big difference."

In addition to static, there are many other ways a standard forklift can be the source of ignition in a waste management application, such as a spark from unprotected electrical equipment or heat from motors, brakes and other components.

One of Pyroban's conversion for trucks operating in Zone 2 is known as system6000. It includes the use of gas detection, restricted breathing enclosures, stainless steel cladding for forks and surface temperature cooling to ensure the motors, brakes, electrics and other components remain below the auto-ignition temperature of the flammable materials.

For waste management sites, the safety system has to allow for a variety of flammable material which arrives from chemical, pharmaceutical and other manufacturing industries to be destroyed or recycled into new raw materials or energy. Chemical liquids, contaminated water, sludge, aerosols, glue, ink, paint and more may be processed.

To detect the wide range of potential hazards, the gas detection system uses either pellistor or Infra-red based gas detection technology. Operators are assured the gas detection system is working correctly each day because system6000 auto-calibrates and self-tests at start up.
"EN1755:2015 has also led to changes to any device or controller carrying out a safety function, which includes the gas detection system. The systems now need to fulfil the requirements of PLr=C*** in accordance with EN ISO 13849-1**** or SIL 1 in accordance with EN61508-1*****," advises Rob.

To ensure ongoing compliance the dealer needs to make sure that engineers are fully trained and aware of the updates to EN1755. Approved parts should be used, which may also be affected by the EN1755 update, and approved service schedules should be followed. Pyroban also recommends that an Ex-ASA (annual safety audit) is carried out yearly. This ensures equipment is fully protected and working correctly in line with EN 60079-17.2007******, particularly in the tough environment of a waste management site where there are many corrosive substances being handled.

EN1755:2015 changes affect all lift trucks operating in Zone 1, 2, 21 and 22.

*EN1755:2015 - Industrial Trucks. Safety requirements and verification. Supplementary requirements for operation in potentially explosive atmospheres
**Directive 2014/34/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to equipment and protective systems intended for use in potentially explosive atmospheres
***PLr - Determination of Required Performance Level
****EN13849 – Safety of machinery – Safety-related parts of control systems
***** EN61508-1 - Functional safety of electrical/electronic/ programmable electronic safety-related systems. General requirements
******EN60079-17:2007 - Explosive atmospheres. Electrical installations inspection and maintenance

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