Reaping the benefits pf predictive maintenance

Managing processes and equipment through predictive maintenance presents significant benefits. With the rapid evolution of technology, companies can obtain a higher level of intelligence while simultaneously monitoring plants, reducing downtime and ultimately cutting costs. Jez Palmer, business development manager for Schneider Electric, takes a look at how businesses can implement predictive maintenance and the subsequent benefits. 

It is not uncommon to find owners and operators looking for ways to extend the life of existing equipment as getting more out of an asset can help a business to reduce costs, improve production efficiency, performance and profitability. In addition, there is little doubt that the majority of production facilities still have enormous potential for improvement when it comes to plant performance.

Managing processes and equipment through predictive maintenance presents significant benefits.

In an industrial facility, maintenance can account for a significant proportion of operating costs. Lack of knowledge about when and what kind of maintenance is needed to maintain, repair or replace critical machinery, equipment and systems within a plant or facility, can result in ineffective use of maintenance expenditure and perhaps more significantly, loss of production. 

Monitoring the operating condition of critical plant equipment, machinery and systems provides businesses with the knowledge to effectively manage the maintenance operation. As a minimum, it provides the means to reduce or eliminate unnecessary repairs, prevent catastrophic machine failures and reduce the negative impact of ineffective maintenance operation on the profitability of manufacturing and production plants. However, the information can also optimize total plant performance, equipment life, and life cycle costs of the facility and its assets by utilising it for a predictive maintenance programme.

Predictive maintenance is a condition-based programme. Instead of relying on the average life statistics of machinery or a process, ie mean-time-to-failure, to determine when to schedule maintenance activities, predictive maintenance monitors operating conditions, efficiencies, heat distribution and other indicators to determine the actual mean-time-to-failure. This data provides the factual information needed for effective planning and scheduling maintenance activities.

Overall Equipment Effectiveness (OEE) is now widely recognised by industries as a way of measuring plant performance and can provide meaningful information that can determine a business' predictive maintenance programme. The success of OEE relies on having access to data in real-time or as close to real-time as possible, from production equipment, and then presenting the information in a way that can be understood. This requires the use of a Manufacturing Execution System (MES), which interfaces with existing SCADA, HMIs, other process control and automation systems (such as variable speed drives) as well as business systems.

For predictive or condition-based maintenance work to be effective, it's less about new technology and more about ways of bringing data to the user to give more visibility, which is possible through MES. By collating relevant information, it is possible for intelligence-based business decisions to be made using real-time information. 

The level of information provided by a MES can begin with standards reports covering areas such as alarms states and statistics, run hours, tag calculations and values for aspects including KwH and processes marked as shift parameters. In addition, users can access alarms management reports focusing on correlation, frequency, major events and longest standing, which will help identify common problem areas that may require more regular maintenance or highlight areas that could potentially fail. This ensures preventative maintenance work can be carried out before the problem results in costly and unexpected downtime.

Taking the information a step further, businesses can look at the state of a plant or specific process and analyse its behaviour. Production specific modules can provide real-time data on yield, energy consumption per output unit, output per shift, as well as actual versus targets on materials, energy, waste, emissions and product output.

Access to this level of detail can offer economic benefits in a number of ways. Information on aspects of the plant such as identifying 'lost production' - the hidden potential in a machine to deliver additional output; or quickly identifying causes that can be detrimental to production, such as operator issues and machine or material issues; or raising production consistency and reducing waste, are all factors that can have an impact on the company's predictive maintenance schedule.

As well as real-time information, historical data can be used in predictive maintenance. It can assist in planning a maintenance programme, as the records can be used to predict when issues will happen in the future, based on trends and patterns. This can help with budgeting, again controlling costs as the amount of unplanned, ad hoc work should be reduced. 

The saying 'prevention is better than cure' is never more relevant than when it comes to predictive maintenance. Embracing this philosophy holds massive potential to save money and reduce man-hours, which can have a positive impact on the bottom line. As the recession forced many companies to implement tough cost-cutting measures, we should be seeing an end to the more costly 'fix it when it breaks' maintenance and a shift towards prevention and prediction. 

Schneider Electric in profile
As a global specialist in energy management with operations in more than 100 countries, Schneider Electric offers integrated solutions across multiple market segments, including leadership positions in energy and infrastructure, industrial processes, building automation, and data centres/networks, as well as a broad presence in residential applications. Focused on making energy safe, reliable, and efficient, the company's 114,000 employees achieved sales of more than 18.3 billion euros in 2008, through an active commitment to help individuals and organisations "Make the most of their energy™".

For further information, view website: www.schneider-electric.co.uk  Refer to page 182

Custom service and maintenance equipment for hazardous
areas improves efficiency and safety of process plants

The servicing and maintenance of electrical equipment in hazardous areas can be time-consuming and costly, particularly if engineers are not provided with the right tools to carry out the job quickly and safely. Custom designed equipment is now available to assist, says Gordon Low of Cooper Crouse-Hinds.

As industrial processing plants become more complex and safety requirements more stringent, these plants have to become more efficient in terms of their maintenance and servicing activities. The objective is to minimise costly production downtime and to guarantee the safe operation of plant, machinery and other electrical equipment at all times.

However, when it comes to the repair, replacement, servicing and maintenance of electrical equipment in hazardous areas, the challenges facing servicing and maintenance personnel can be daunting, time-consuming and costly, particularly if the engineer is not provided with the appropriate tools.

Furthermore, in hazardous gas or dust areas, before any electrical apparatus - such as electric motors, variable speed drives, valves, actuators and sensors - can be installed, repaired or maintained, the technician needs to ensure that the electrical connection or disconnection procedure is carried out safely, with all electrical apparatus isolated from the power supply. These measures are necessary because the explosion-protection of the apparatus becomes ineffective once the enclosure is opened. Ensuring that all appropriate fire protection and safety fencing procedures are carried out is also important here. This type of preparation requires a Hot Work Permit, which can take 24 hours to be issued. Even if the permit arrives in a couple of hours, costly production downtime may already have been incurred.

Therefore, when engineers look at selecting the most appropriate electrical equipment for their plant, the most important factors to consider are the life of the equipment, the likely maintenance effort required, how easy the equipment will be to use, and whether the equipment has any smart maintenance features and support options.

Selecting electrical equipment on the basis of price alone can have far more damaging effects on the business in the medium to long term. A higher frequency of product failures and breakdowns may occur after installation due to inferior quality design and manufactured components. Companies should therefore consider the complete product lifecycle cost of the electrical equipment - including purchase price, initial installation costs, maintenance life costs, scrap costs (due to failure of pumps, valves and instrumentation) and the cost of any unforeseen production downtime - before making any purchasing decisions. Often, this is referred to as th Total Cost of Ownership of a product.

In a typical hazardous area plant such as an offshore oil platform or onshore petrochemical plant, selecting the right portable lamp, cord reel, plug distributor or repair socket to work with, will have a significant positive impact on the efficiency of the maintenance and servicing activities - and therefore on how productive the business is.

Engineers should therefore start by ensuring that all their existing electrical equipment and new purchased products comply with the relevant European safety regulations and quality standards. Companies also need to conduct proper risk assessments on equipment located in hazardous gas or dust areas. This must comply with the latest Health and Safety and European ATEX Directives (ATEX 137 or ATEX 118a, 1999/92/EC).

The minimum requirements stipulated in Directive 1999/92/EC (ATEX 137) are that "all necessary measures shall be taken to ensure that the workplace, the work equipment and the associated connection devices…are maintained and operated in such a way as to minimise the risks of an explosion…"

While a wide range of standard, off-the-shelf explosion-protected electrical equipment is now available to help engineers minimise service and maintenance costs, some of this equipment can now be customised to suit the individual requirements of a plant or offshore oil platform.

On the lighting side for example, portable Ex-lamps and torches, including LED versions, can be activated using one hand. Spotlights can be provided with displays showing the user how much operational time is remaining. Single and double-lamp machine lights can be provided with rugged pipe made from polycarbonate and protected to IP68. 

For high power lighting in Zone O hazardous areas, Ex tank inspection lights can be provided to check oil or gas storage tanks, quickly and safely. These lights can also be integrated with a custom designed transport trolley if required. Other lighting products for hazardous areas include emergency lights, pendant light fittings, floodlights, and lamps for outbuildings and mast bases. …./ Continued on the next page