Enclosures for hazardous areas: understanding the differences

When it comes to specifying enclosures for hazardous area electrical applications, engineers must ensure they fully understand IP protection ratings, as well as the implications of modifying an Exd or Exe enclosure prior to or after installation, says Gary Johnson, Technical Manager at COOPER Crouse-Hinds UK.

As a manufacturer of enclosures for harsh industrial and hazardous environments, we often deal with customers who don't fully understand what they require in terms of the IP protection rating of an enclosure and whether what they are asking for meets the end users' technical specification.

The function of an enclosure is to protect the internal components from excess heat, humidity, dirt, dust or water. The customer could be sourcing an enclosure for a hazardous gas environment such as an oil platform or petrochemicals plant, or for a dusty environment such as a flour mill or sugar production plant.

In either case, it is crucial that the customer fully appreciates the differences between the IP ratings along with the requirements for one that is fully certified for use in a hazardous gas or dust environment. Also, in terms of modifying an enclosure - either prior to or after installation - it is equally important that the installer and end user fully appreciates what they are allowed to do with that Exe or Exd enclosure so as not to adversely affect its protection rating or invalidate the certification.

With an Exd enclosure, the box cannot be modified once it has been manufactured and assembled; otherwise the protection rating will be affected. For example, drilling new cable entries must only be carried out by the manufacturer or by an approved local assembler (distributor). Once an Exe enclosure leaves the factory, although this is in a certified state, end users may then modify that box prior to or after installation within certain guidelines. Any alterations need to be communicated to the manufacturer or local assembler to ensure that the correct certification is given or maintained. These modifications normally involve adding some extra cable entries or terminals. This is why Cooper Crouse-Hinds normally supplies a range of standard hazardous area Exe enclosures to its network of approved local assemblers, who are then able to carry out modifications to those enclosures to suit the application, without adversely affecting the certification or protection rating.

Enclosures for hazardous gas or dust environments are normally manufactured from stainless steel or GRP, but also painted steel for some indoor, sheltered applications. Many customers don't fully appreciate that an Exd or Exe enclosure has been put through a series of arduous tests. These include thermal conditioning (to represent rapid ageing), which simulate 20-plus years of operation in the field. In addition, hazardous enclosures are also subjected to a series of mechanical impact tests, in places that are considered to be the weakest points of the enclosure (the test houses are experts in finding these!). If the material is considered to have a reduction in resistance to impact at lower temperatures, the box is also impact tested at the lower end of the box's operating temperature range. These tests are important because once installed in a harsh hazardous area, it is often difficult to service an enclosure due to the hazardous area or it could get inadvertently knocked or bashed in a working environment, so the enclosure must remain intact in order to continue performing the intended function for protection.

In recent years, European and International standards for hazardous area enclosures have become even stricter in terms of impact and thermal tests. In the latest standards, all openings on the enclosure are tested (opened and closed) prior to their IP test. Many companies can offer industrial-grade enclosures with an IP66 rating, but for hazardous areas, customers need to be absolutely certain that the enclosures they source are fully certified boxes that have been tested in terms of temperature ratings and impact protection.

It is generally accepted in the oil & gas industry that hazardous area enclosures need to be manufactured from 316L stainless steel as a minimum. Most of our hazardous area enclosures are made from electro-chemical polished 316L high-grade stainless steel as standard, as this offers enhanced corrosion resistance over other finishes.

GRP enclosures also offer technical advantages. The material is often graphite-loaded in order to avoid a build up of electrostatic charge, which is important for hazardous area applications. Moulded, non-metallic enclosures also enable the manufacturer to construct very modular or flexible design features for the customer, including quick-fitting of components such as pushbuttons, switches, lamps, and so on. Non-metallic enclosures also enable you to design low-sided enclosures for easier, faster wiring. With stainless steel fabricated boxes, it is a little more difficult to offer these features, but fabricated steel enclosures are very flexible in the size ranges offered, special sizes can be quickly included, and they can also be provided in much larger sizes if required.

For further information, view website: www.ceag.de or e-mail: Gordon.Low@CooperIndustries.com

Empowering energy solutions with EPLAN Platform

Russia relies a great deal on localised heat and power generation. For Impuls Industrial Boiler Plants, the opportunities for building or rebuilding large boiler houses that provide heat and power to communities, including remote industrial installations, represents a major growth market. Founded in 2002, the company has pioneered development of modular, fully automated industrial boiler houses that don´t require a human operator. A key reason for choosing EPLAN as the new design tool was the ability of the software to support electrical, process control and enclosure design on a shared platform. As a result, projects that typically took  three months or more are now being completed in 5-6 weeks.

Design plays a crucial role at Impuls; over half the 100 staff are engineers. The company recognised that its old software tools were too constraining. Engineers were using AutoCAD to design power equipment, automated heating systems and instrument and control (I&C) systems, and using MS Excel to draw up bills of materials and other lists and tables. Engineers had to connect assemblies and control devices manually. There was no way for the different engineering disciplines to share content or work collaboratively and no way to archive commonly used content. "With so much manual processing, it wasn't unusual for major errors to creep into projects that were a challenge to fix, especially when projects were to deadline" says Alexey Soloviev, head of the engineering department at Impuls

Attracted by the EPLAN Platform concept
"Seeking to optimise design productivity, Impuls selected EPLAN for its vast automation features, and because its database-driven suite of products was unique - it being the only computer aided engineering product that supported electrical, process control and enclosure design on a shared platform. That meant data generated by one discipline could be shared by all" comments Soloviev.

Pictures (left to right): 1) Boiler-house designed by Impuls. 2) Boiler-houseboiler houses designed by Impuls.

Pictures (left to right): 3) Electrical cabinet design with EPLAN ProPanel designed by Impuls. 4) Boiler plant of Yamburgskoye gas field in West Siberia designed by Impuls.

5) Boiler plant of Zapolyarnoye gas field in the Southern part of the Tazovsky region.

Major time-savings
"This was a capability the company wanted. Before we decided to use EPLAN for our engineering, working in AutoCAD and MS Office meant all product stages were executed by the same engineer, because functions like cross-discipline designing and multiple users sharing data were lacking. Now, with EPLAN, the electrical and process control engineers have the chance to collaborate together on projects" states Soloviev.

With the switch to the EPLAN Platform - Impuls acquired EPLAN Electric P8, EPLAN PPE and the 3D mounting panel layout module. Projects that typically took three months or more are now being completed in 5-6 weeks, and that was achieved within six months of switching to EPLAN. "Engineers are making the maximum use of EPLAN's vast automation functionality, like automated error-checking and cross-referencing. Error rates are down, and it's not unusual to have projects that are completely error-free" remarks Soloviev. An archive was created in EPLAN and now contains over 1,500 component macros and 2,000 function macros shared by all disciplines. Impuls expects that over time it can accelerate projects further by increasing the number of archived macros and recognising more ways to take advantage of EPLAN functionality during project development.

Customers benefit from EPLAN results
"With EPLAN, there should be a maintenance benefit over time for both Impuls and customers since the documentation generated by EPLAN for each installation is a high quality. We have noticed that our customers now have far fewer questions with regard to completed projects and tend to grade the ones done in EPLAN very well." says Alexey Soloviev, head of the engineering department at Impuls.

EPLAN Software & Service in profile
EPLAN Software & Service develops engineering solutions that accelerate the product engineering process. Interdisciplinary expert systems ensure a maximum of productivity and data continuity. The solution provider develops tailor-made PDM and PLM concepts and provides comprehensive services such as customising, consulting and training. Success factors are innovative development competence, a consistently practical approach and international presence. EPLAN is a subsidiary of Rittal International and thereby part of the Friedhelm Loh Group, with 11,500 employees worldwide, and an expected revenue of 2.2 Bn. € for 2011. EPLAN represents continuity and investment security. The seven German EPLAN branches and a presence in 50 countries support 19,500 customers with 65,000 installations worldwide. 'Efficient Engineering' - the corporate motto, underlines the proficiency of optimised, efficient processes, which support companies in their quest to stay competitive in the long term.

For further information, view website: www.eplan.co.uk or e-mail: kchristie@eplan.co.uk

Carbolite oven accelerates Formula 1 aerofoil development

An increasingly important aspect of many Formula 1 racing teams' engineering operations are sister companies focused on commercializing and developing Formula 1 spin off technologies and IP into the wider automotive and aerospace engineering sectors, as well as other advanced high performance engineering applications.

Carbolite is proud to count many  Formula 1 teams amongst its customers so when the company was  approached by one the most successful Formula 1 teams on the grid to help 'give their car wings' it was taken as read that Carbolite would have a product to solve the racing team's requirements.

Large General Purpose Oven.

Excellence in engineering is required to stay ahead in Formula 1 and demands that the Milton Keynes based company is continually designing, developing and refining prototype components and sub-assemblies that need to be built, assembled, tested and then re-engineered to meet specific high performance requirements.  As part of this challenging development cycle Carbolite has supplied them with a customized version of the company's LGP3-1500 high specification Large General Purpose Oven to implement post curing drying of composite moulds and moisture extraction for adhesives used for a variety of component parts such as carbon fibre composite body parts and aerofoils. 

The customised oven ensures reproducibility in the curing cycles by incorporating a controller option which enables five different programmable temperature profiles to be stored and recalled and also includes RS232 communications. The operator can easily select the correct ramp rate and heating duration for the job at hand. The valuable loads and oven are protected by the addition of an independent over temperature protection thermostat and a further option in the form of a top-mounted moisture / fume extraction fan was also installed, enabling process fumes to be ducted away from the work area.

Based upon Carbolite's standard design the 1500 litre capacity, Large General Purpose Oven has an operating temperature range 50°C to 300°C with a uniformity of ±5°C control accuracy and ±5°C. 

An additional requirement was customisation of the standard design so that the control panel was side-mounted rather than in the conventional front mounted position.  Relocation of the control panel module required the oven's air circulation fans and baffle assembly to be mounted into the oven base rather than into the side or rear.               

"The ability to take our well tried standard designs and where necessary customise them to customer's precise requirements, seems to be a key factor in persuading so many of the winning teams in Formula 1 to buy Carbolite products," said Carbolite's Product Manager, Alan Street. "It is also quite a compliment that advanced engineering teams who are themselves striving for the very best performance choose to use Carbolite to help them achieve their goals."

For further information, e-mail: info@carbolite.com or view website: www.carbolite.com