New world order

5 October 2001

Bill McRobbie considers the global influence of the European Machinery Directive and the central role of the humble load pin in the new world order

Gradual consolidation of the world? economic markets has had a huge impact on a number of industries; none more so than manufacturing and construction. Here, rules governing safety standards and operating procedures have left an indelible mark on the way we produce our goods and how we build our buildings.

Since its introduction in the mid 1990s (1995 in the UK) the Machinery Directive has caused European manufacturers and builders to reassess how they go about their business. Intended to create a single European market, the effect of the directive has been to introduce identical requirements for machinery safety in every country within the European Economic Area.

However, as the world? economic regions melt into one, its influence will extend far beyond the designated economic boundaries of Europe.

Since the directive has encouraged the development of new health and safety standards, crane manufacturers have shouldered the burden of the far-reaching changes which will supersede the existing A and M crane classification standards. Instead, the revised crane safety standards require crane manufacturers to build cranes that meet the expected life cycle demands of each application.

Safety initiative

The scope of CEN/TC 147, the program for developing safety standards to support the Machinery Directive, is such that cranes, equipment for lifting persons on or with certain cranes, and power-driven winches and hoists all fall under its remit. Hand powered lifting machines, non-fixed load-lifting attachments and manually controlled load manipulating devices will also be affected by its comprehensive set of stipulations.

According to the European Committee for Standardisation (CEN), the size of the market covered by CEN/TC 147 represents up to 25% of the material handling equipment market; a sector which only five years ago was worth E23bn. This enormous market is, however, not entirely monopolised by European Union manufacturers. Cranes from Eastern Europe, China, Taiwan, Japan, Argentina, South Korea and the USA regularly make their way into the bountiful European market, and therefore must attain the same levels of safety as their European equivalents.

Written by a number of technical experts displaying pertinent and up-to-date industry knowledge, the CEN/TC 147 work programme (created in 1998) is intended to be relevant, practicable, verifiable and applicable to existing market conditions. The resulting harmonised standards will, according to the CEN, ?educe the cost of the technical file requested by the Machinery Directive and provide solutions for manufacturers/ suppliers to claim compliance with the Machinery Directive?

The new standards also represent a huge departure from the existing regulations that demand all lifting equipment be manufactured to specified quality standards. Rather, CEN/TC 147 considers the projected performance levels of the crane and the extent of its future use. A recent CEN publication outlined the objectives of the new standards: ?hey address intended use and foreseeable misuse, they specify requirements for the anticipated life of the machine, and they specify requirements that are tangible enough to be verified without hindering future innovation.? These elements are encapsulated in specific work programmes of CEN/TC 147 ?prEN13001-1 and prEN13001-2 ?relating to design and load effects.

Condition monitoring

A UK journal, The Engineer, last July considered the new safety regulations and the impact they may have on crane manufacturers. ?n theory, there will be no reference to ratings at all in the Provisional European Norm standard for cranes, prEN 13001,?the magazine reported. ?t will be a particular problem with cranes designed for general workshop use where the customer is less likely to be able to predict what the precise pattern of loads and usage will be.?This reflects the shift in emphasis from the existing classification system towards more predictive machine monitoring and appreciation of life cycle demands. Under the new system, end users will supply manufacturers with a prognostic duty cycle to ensure that the crane specified meets the expected demands of the application. The manufacturers will be required to complete a full technical and safety analysis of each design to make sure it complies with the Machinery Directive.

Pin position

The key element in the development of the new standards has been the emphasis placed on machine monitoring and the ability to predict the extent of usage throughout a crane? life cycle. This has implications for both the customer and the manufacturer.

For instance, the new legislation has inevitably stimulated demand for life cycle monitoring systems, which are being used not only to extrapolate subsequent duty cycles, but also to predict when equipment will require maintenance or ascertain whether a machine is operating outside its specified performance characteristics. The recent focus on machine monitoring thereby has the potential to reduce downtime and minimise the risk of overloads and catastrophic failures. In essence, the new regulatory demands are enhancing the end users?appreciation of the stresses and strains their equipment is put under and should encourage a safer working environment.

To achieve this enhanced level of vigilance, crane manufacturers are increasingly incorporating load pins into their latest designs. These force sensors allow end users to monitor cranes to ensure that they are operated within their predicted performance parameters, set out in the anticipated duty cycle.

Feel the force

Force measurement is one of the most versatile methods of monitoring the performance and operation of industrial equipment, and transducer-based strain gauges are the most reliable and effective force-measuring technology. In the industrial lifting sector these transducers are known as load pins and are typically manufactured from high strength alloy steel or aerospace quality stainless steel.

Load pins measure load against time and can therefore identify and register peak loads during a working cycle. Used with other monitors, load pins can provide a regular flow of data relating to the operation of, and load on, a crane.

Although the transducer forms a small part of an overall monitoring system, its significance within that system is unquestionable. Without reliable and accurate load measurement, end users would find successful life cycle predictions impossible and safety initiatives flawed. For that reason, most leading load pin manufacturers design their products around the principle that transducer performance is directly related to the quality of components used during the manufacturing process. Consequently, most manufacturers continue to employ foil strain gauges because they provide the most reliable transduction solution for modern force sensors.

However, the quality of the output signal can be the differentiating factor between productivity gains and catastrophic failure. For instance, standard low-level analogue outputs are often unsuitable for crane applications and, if used, are highly dependent on the quality of the end user? processing equipment. Load pin manufacturers that design transducers around the specific demands of the application, rather than simply modifying standard components, can therefore guarantee optimum performance and reliability.

Outside influence

The Machinery Directive, and the programmes developed to encourage the safety standards to support it, has impacted on many different areas of manufacturing, processing and logistics. Its influence has been such that although many of its standards are yet to be approved, manufacturers are already changing the way they manage their business in hurried preparedness.

However, while the CEN/TC 147 programme is ongoing and the prEN13001 projects are still under approval, the Machinery Directive itself is undergoing an extensive overhaul. The results of this process are expected to be implemented in 2006 and will undoubtedly encourage further standardisation across Europe.

The influence of the directive will undoubtedly extend outside the realms of the EU because of the ever-widening industrial circles in which modern day businesses operate. Most obviously, manufacturers outside the EU will be forced to meet the regulations if they intend to sell their products in Europe.

More importantly, as crane operators in Europe begin to enjoy the competitive advantages of less unexpected downtime and increased safety afforded by enhanced conditioning monitoring, the rest of the world will understandably demand similar levels of added value. The reverberations caused by the Machinery Directive, and the heightened awareness of condition monitoring, will consequently echo throughout the modern world and at the centre of it will be the transducer-based load pin.