Safe products for hazardous environments

However, the market for explosion proof hoists and special cranes appears to be bucking the downward trend, and doing much better than the market for standard lifting equipment.

Wagner cites the example of several recent major contract awards for the Middle East and Asia for explosion proof equipment. The orders had been on hold but have now gone live, giving a positive indication for the future, he says.

Stahl is a leading manufacturer of wire rope and chain hoists for service in Zone 1 and 2 explosion hazard environments in the offshore exploration and production industries and the onshore refining and petrochemical sectors. Typically, Stahl hoists are used on suspension and overhead travelling cranes, blow-out preventer (BOP) and pipedeck handling cranes, well-bay, and floating production, storage and offloading (FPSO) vessel turret-house hoists and deck-mounted davits.

Explosion proof hoists and cranes are characterised by the use of spark proof materials such as bronze, and by having units sealed to protect them from the flammable gases or dusts that are likely to characterise the hazardous environment.

Jim Satchwell, managing director of UK-based crane builder J Barnsley Cranes, is also starting to see postponed projects being revived in the petrochemical industry. His company is developing proposals first negotiated more than 12 months ago and only now just being reinstated. He says there has been no slowing down of enquiries in recent weeks and in fact, if anything, enquiries are rising.

Sparrows Offshore Ltd, which claims to be the world’s leading crane management provider for the offshore industry, reports no noticeable reduction in its maintenance, inspection and refurbishment activities.

Both Sparrows Offshore and J Barnsley Cranes are long-standing partners of Stahl. Based in Aberdeen, Scotland, Sparrows has been a Stahl partner for more than 25 years. This year, having opened a new facility in Stavanger, Norway, Sparrows has been appointed as sole agents in Norway and its offshore waters for the sale, service, inspection, repair and refurbishment of Stahl’s EX explosion protected cranes and hoists. At the same time, the UK North Sea agency for Stahl was also renewed.

Refurbishment

Projects recently completed by Sparrows include complete refurbishment of well bay cranes on BP’s Clair and Bruce offshore production platforms, both Zone 1 environments. The BP Bruce project included supply of a 40t crane and a radio remote control system. The radio transmitter is able to register the loads being lifted by the crane as well as all the normal functions necessary for crane operation.

One of J Barnsley Cranes’ biggest projects of the past 12 months was a contract worth well over GBP1m (USD1.5m) to supply Zone 1 certified explosion proof cranes and monorail hoists to Kuwait National Petroleum in the Middle East. J Barnsley Cranes has also recently been awarded a £1.2m contract to supply 12 explosion proof electric overhead cranes to Algeria. In both cases, all hoists and control equipment are supplied by Stahl.

Stahl is unusual among suppliers of explosion proof hoists, it says, in that all componentry, including gearboxes, motors and controls, is manufactured in-house rather than by third parties. Wagner reports that the company has also just developed a range of new explosion proof panel boxes and end carriages, which it plans to launch soon.

Other major projects of the past year for Stahl Crane Systems include supply of equipment to the Adriatic LNG (liquefied natural gas) terminal. Adriatic LNG is an Italian company owned by affiliates of ExxonMobil (45%), Qatar Terminals Ltd (45%) and Edison SpA (10%).  The company has an offshore LNG receiving and re-gasification terminal in the northern Adriatic Sea, soon to start production. The terminal has a net capacity of 250,000 cubic metres of LNG. It consists of a concrete gravity-base structure (GBS), containing inert ballasting material, sitting in a 30m depth of seawater. The GBS was constructed in Algeciras, Spain last year, will ultimately be located 15 km off the East coast of Italy.

Numerous hoists, cranes and pieces of lifting equipment designed for Zone 1 use were supplied by Stahl’s subsidiary in Spain under a contract worth more than EUR2m. Engineers from Stahl Crane Systems Ltd of the UK completed the commissioning phase once the installation was positioned in the Adriatic Sea. “Many of the individual installations had to be specially designed because of very restricted dimensions,” says Stephen Young, managing director of Stahl’s UK operations. “Compliance with the ATEX rules and regulations demand each and every aspect of the design, manufacture, erection and commissioning to be considered.”

Sparrows Offshore from Aberdeen has a team aboard the installation for operation, maintenance and inspection of all the handling equipment.

Stahl’s Middle East operation remains busy. Stahl CraneSystems FZE, based in Dubai and headed by Frank Hildebrandt, has been involved in the development of special explosion proof monorail hoists working above LNG gas tanks. Tank hoists are fitted and run on monorails or jib cranes that service the tanks for withdrawal of the gas pumps out of the tank. These pumps, usually positioned at the bottom of the tank, are fitted with their own stainless steel wire rope. When the pump is being withdrawn, these ropes are attached to the hoist barrel with special fixings. Usually the required lifting height for pump withdrawal is approximately 50m.

Specialist

While Stahl is perhaps the name most readily associated with electric-powered explosion proof hoists, since it has chosen to focus on this specialist field, other manufacturers have stepped up their product offering to conform with the European ATEX regulations (For complete information on the European Union ATEX regulations, see www.hoistmagazine.com/atex), which are now six years old.

SWF Krantechnik of Germany has redesigned its explosion proof electric chain hoists and now offers the SKCex (for loads up to 2,000kg) and SKFex (for loads from 2,000kg up to 5,000kg). They are suitable for zones designated as:

- Zone 1+2 II2G c Ex de IIB T4 (gas);

- Zone 1+2 II2G c Ex de IIC T4 (gas);

- Zone 21 II2D c Ex tD A21 IP66 T120 (dust).

New features include choices of different types of suspension, curved trolley rails or trolleys with low headroom. Other features include an enclosed chain guide in solid cast metal that integrates the load-bearing components into a single sub-assembly. This means that the load is supported where it is applied: the suspension is direct and the power flux is not transmitted through the housing.

At last year’s NA materials handling trade show in Cleveland, USA, Spanco Inc. launched its first ever wire rope hoist, called the Lift Boss wire rope hoist, and the Beam Boss beam tractor drive, which have the option of explosion-proof controls and spark resistant wheels.

New from French hoist manufacturer Verlinde Technologies is an ATEX-certified version of its VHR manual chain hoist, for loads up to 10t. They are available in either push pulley or chain-operated trolley versions, with ATEX directional trolleys.

The mechanics have been redesigned with stainless steel and bronze to eliminate the risk of sparks during use. Gear pinions have been machined rather than cast by foundry. The hoods are chrome-plated and the hooks clad in bronze, and the hand chain is stainless steel. Technical performance specifications are the same as on the standard version of the VHR.?Verlinde’s ATEX-certified explosion proof product line extends to full range of crane and hoisting equipment.

Verlinde’s recent contracts include the supply of 18 overhead cranes to the National Iranian Oil company, eight electric-powered belt type hoists for Coca Cola’s plant in Manaus, Brazil, and several overhead travelling cranes with electric chain hoists to car manufacturer PSA Peugeot Citroen, for a facility where batteries are charged.

In Singapore, crane builder Jenmon last year supplied and installed a pair of Verlinde’s explosion-proof Eurobloc EX VT hoists onboard an FPSO vessel for Exxon Mobile. A rack and pinion drive system keeps the cranes on track and in position when the ships bank, and storm locks keep the cranes in position during harsh weather.

Other manufacturers of explosion proof electric powered hoists and cranes include Van Leusden Special Cranes of the Netherlands, Vector Lifting of Australia and Smaco Engineering of India.

Where the circumstances are appropriate, air power may often be preferred to electric power for hoisting equipment in hazardous areas, with suppliers such as JD Neuhaus (JDN), Ingersoll Rand and Red Rooster meeting market needs. Air hoists are inherently well suited to explosive atmospheres because they are naturally less likely to spark than electric ones. However, there may be insurmountable logistical issues with installing a suitable compressed air line.

JDN, for example, offers air hoists and cranes in standard versions for Zones Ex II 2 GD IIA T4 and EX II 3 GD IIB T4. By adding a galvanised copper plated hook and block and a brass safety catch, the added spark protection meets the requirements of Ex II 2 GD IIB T4. To meet the requirements of IIC the running wheels of the trolleys and travelling gears are made of bronze.

Similarly, the ATEX version of Ingersoll Rand’s Palair Premium air hoist has all the moving mechanical parts made of bronze or stainless steel and the motor and the mechanical systems are inside a sealed casing.