Hazardous Engineering Solutions by Michael Dominguez

MAY 2011

Maintenance & Inspection – Regular Inspection is a must.

Industry News

5-7 9-12

Lone Worker Protection

14-15

Product Spotlight – Atex Equipment & Services

16-19

Dealing with Atex

20-23

Product Spotlight – Atex Equipment & Services

24-25

Industry News

27-28

Maintenance & Inspection

REGULAR INSPECTION IS A MUST – EVEN ON FANS Repeated, rapid speed cycling over a period of years imposes severe stresses on the vanes of centrifugal fans, eventually leading to failure at values below their ultimate tensile strength. This can cause catastrophic failure and total destruction of the fan and the fan casing, which is not designed to withstand such failure, shutting down production until the fan is replaced.

suffers “brittle fractures”. Jim Curley, Oakland’s engineering manager, had to find a new fan quickly to get the plant back into production but enquiries to the original fan’s European supplier, and others, seemed to indicate

Oakland Glass, based in Dewsbury, is one of the UK’s leading

a minimum 10 week delay in providing a new fan at great cost,

independent glass processors and produces a range of energy

until Mr Curley was recommended to try Halifax Fan in nearby

saving and toughened sheet glass. It produces over 10,000 m2

Brighouse. “Fans aren’t something we buy every day and I’m not

of Oaktough® toughened glass per week, much of which is

that conversant with the fan market so I didn’t really know Halifax

used in-house to produce sealed glazing units such as are used

Fan” said Jim “Their service was exceptional. They were here

in conservatories. Because of its internal stress characteristics,

on site within hours of my phone call, discussed the application,

toughened glass shatters into small fragments and cannot be

measured up what was left of the old fan and provided a

reworked after tempering so sheets are cut to size before processing.

competitive quotation.”

Toughened or tempered glass is produced by heating the glass sheet up to 700oC, then cooling it rapidly using high pressure air from a chiller fan. The chiller fan, driven at up to 2970 rpm by a 250kW motor, is accelerated to full speed to cool the glass sheet within a few seconds then equally rapidly decelerated again. This demanding repetitive cycle, by its very nature, imposes a cyclic stress loading onto the impeller. Eventually failure will occur at stress values that are lower

“They built a bespoke fan to my exact specifications, with a matching impeller to maintain the correct glass tempering characteristics, and it was installed and operational within two weeks, saving a huge amount of production.”

than the UTS of the material. In effect the impeller work hardens and

HAZARDOUS ENGINEERING SOLUTIONS

Maintenance & Inspection

Halifax effectively reverse engineered the original fan to ensure the

replacement for a glass chiller fan on the point of failure.

replacement met Oakland’s production characteristics precisely. The 950mm impeller was built of Weldox® 700 steel. This high strength

Halifax Fan Technical Director Charles Halstead commented that,

steel was used to enable the high running speed of the fan to be

given a “clean sheet” of paper, designing for extreme fatigue

achieved whilst maintaining a good degree of toughness to withstand

life (essentially predicting the cycles to failure), is possible. By

the cyclic loading. The whole design was subject to detailed finite

designing a careful selection of fan size, speed and materials,

element analysis (FEA) before manufacture. The extreme cyclic stress

working stresses can be limited and this, combined with

will however demand regular inspection and maintenance in future.

information of the cyclic duty, allows a prediction of safe working

Other users of high-cyclic action chiller fans have been recommended

life to be made. In this case where the parameters were fixed, we

to inspect fans that have been in production for a few years and as

were able to produce a safe working fan, albeit with a finite, safe

a consequence, Halifax Fan has supplied at least one other similar

working life.

Ian Crum Halifax Fan Ltd Mistral Works Brookfoot Business Park Elland Road Brighouse, W Yorks HD6 2SD Tel:- 01484 475123 Fax:- 01484 475122 e-mail:- Ian@halifax-fan.com web:- www.halifax-fan.com 07

HAZARDOUS ENGINEERING SOLUTIONS

Product Spotlight - Gas Detection

CROWCON KEEPS WORKERS SAFE AT DOW CORNING’S BARRY MANUFACTURING PLANT -65 Triple Plus+ IR detectors used for pentane and hydrogen detection

Crowcon has provided 65 of its portable gas detectors to protect personnel at Dow Corning’s manufacturing plant in Barry, south Wales. The Triple Plus+ IR detectors are used by maintenance contractors during crucial operational site shutdowns. As silicone is present in the manufacturing process and can interfere with conventional sensors, it was necessary for the detectors to have infrared (IR) capability as IR sensors are unaffected by silicone. In addition, Crowcon provided linearization of the IR sensor for pentane and also provided a bespoke hydrogen sensor. According to Kevin Reid of Dow Corning’s analyser Group, ruggedness was a key factor in the company’s choice of gas detector supplier. “We issue the instruments to off-site contractors, which means they pass through many pairs of hands in a short space of time,” he explained. “Without a sense of ownership on the part of the user, they can get some pretty rough treatment. The Triple Plus+ units are hardwearing and require little maintenance – they also have an extremely reliable IR sensor. They performed exceptionally over the first shutdown period without a single detector exhibiting a fault or failure.” The Triple Plus+ IR version differs from traditional detectors because it does not require the presence of oxygen, making it ideal for use in silicone manufacturing processes or in purge monitoring of hydrocarbon storage tanks such as in petroleum processing facilities or oil and gas carriers.

Favoured by the chemical and oil and gas industries because of its toughness, and with around 100,000 units in use worldwide, the Triple Plus+ is arguably the world’s most popular full function multi-gas gas detector. It can monitor up to four toxic and flammable gases at once from a list of over 15, is almost unbreakable and uses 7-series sensors which have been shown to be the most reliable sensor type available. It is housed in a shatterproof polyamide/ABS casing, making it shock-resistant and water-proof to IP65. It will also float if dropped in water. A large backlit display shows all gas levels simultaneously and a loud audible alarm and extremely bright visual alarm warns the operator when gas levels reach dangerous levels. 100 hours of datalogging capacity is available as standard and a PC interface through an RS232 serial port allows all data to be downloaded for permanent storage. Dow Corning’s 160-acre Barry site employs approximately 600 people and manufactures silicon-based products and intermediates for use globally. The process starts with elemental silicon which is chemically reacted and changed to make siliconbased fluids, gums, rubbers and specialty polymers. Crowcon company contact and reader enquiries: Louise Early Crowcon Detection Instruments Ltd 2 Blacklands Way, Abingdon Business Park Abingdon OX14 1DY United Kingdom Tel: +44 (0)1235 557700, Fax: +44 (0)1235 557718 E-mail: sales@crowcon.com Website: www.crowcon.com

HAZARDOUS ENGINEERING SOLUTIONS

Latest News & Products

ENSURE RELIABLE GAS DETECTION WITH NEW DRAEGER WIRELESS SAFETY NET Operating as an all-round safety network, the new Draeger X-zone 5000 uses wireless technology to automatically connect multiple monitors for reliable, continuous detection of toxic, combustible and explosive gases. Ensuring that personnel have the confidence to work worry free, even in the most dangerous environments, these transportable units are quick to deploy and easy to set up. Issuing a loud alarm as soon as a gas is detected, they also change colour to clearly identify the alarm status. The areas where gas has been detected are indicated by red visual alarms. Safe atmospheres and, therefore, a safe escape route are confirmed by green visual alarms. By simply placing Draeger X-zone 5000 units around potentially dangerous areas or where maintenance or shutdown work is being carried out, these robust, waterproof units will ensure increased levels of safety in any application. As soon as one of HAZARDOUS ENGINEERING SOLUTIONS

the units detects a gas it immediately transmits an alarm to each of the others, warning everyone in the area that a danger exists. At the same time, a loud evacuation alarm is emitted and a patented 360ยบ alarm amplifier ensures that it is heard with the same intensity in all directions. Up to 25 Draeger X-zones can be used at any one time, forming a complete wireless network to suit the specific application, including those where an explosion hazard might exist. In addition to Zone 0 ATEX performance, they also offer a lower cost of ownership by combining flexible monitoring capabilities with a long sensor life and enhanced battery performance. Allowing gas ingress from every side, it can be fitted with up to four sensors to detect as many as five gases at once. The Drager X-zone 5000 provides simultaneous measurement of gases and vapours such as hydrocarbons, hydrogen and other explosive, combustible or toxic gases. Unlike portable instruments which usually leave the scene with the wearer, the Draeger X-zone 5000 can be left in situ for up to 120 hours continuous operation, issuing an alarm as long as the danger exists. For further information contact Customer Service, Draeger Safety UK Limited, Ullswater Close, Blyth Riverside Business Park, Blyth, Northumberland, NE24 4RG. Tel: 01670 561200, fax: 01670 356266, www.draeger.com.

Industry News

PETROFAC COMMITS TO STRATEGIC FUTURE IN ABERDEEN The Company has invested considerable time, money and people

Petrofac, the international

to move its freefall lifeboat capability from Dundee to the Quay

oil & gas facilities

Training Services business, but help to position Aberdeen and

service provider,

operations.

today announced

The investment sees Petrofac bring together all of its Marine

in Aberdeen Harbour. This move will not only enhance Petrofac’s the North Sea as a strategic centre for the development of its UK

training to one location, to offer more efficient, flexible training

significant investment in the Aberdeen region, cementing its strategic commitment to the city and the future of safety in the oil & gas industry.

to delegates. The Aberdeen harbour area is less exposed to strong winds than the Dundee location so the site is expected to experience less restrictions due to weather conditions. The site will also add two fast rescue boats as well as pontoon and davits and a number of upgrades have been made to current facilities at the Quay, which will mean a total of 15 boats and 21 staff delivering competence training and maintaining the facilities in the area. All Dundee staff are being transferred to the new Quay facility.

For additional information, please refer to the Petrofac website at www.petrofac.com.

COMPANY AWARDED CONTRACT WORTH £45MILLION Dron & Dickson has secured longterm contract renewal with an oil major valued at up to £45million. The five-year deal, with options to extend by up to a further four years, involves supplying electrical equipment and cabling, inspecting hazardous area certified equipment, and provision of additional electrical and inspection services to meet operational requirements in the North Sea.

with our clients to offer bespoke solutions incorporating the very latest industry and safety legislation. As a result, we are winning record levels of business and have added to our team of electrical

Dron & Dickson has held the contracts since 2004 and

technicians, the majority of whom are IRATA Qualified.’’ He added:

operations director Colin Maver said: “Our experienced

“Dron and Dickson provides a unique service to the oil industry

team has a reputation for providing quality products and

in that we are a combined electrical wholesaler / contractor. We

a high-calibre service for operators across the North Sea.

have explored the synergies between the two sides of the business

“We have invested heavily in developing exceptional QHSE

and through this cross-fertilisation of disciplines are able to offer

standards and a competency-assured workforce and work

prospective clients an even more competitive service.’’

HAZARDOUS ENGINEERING SOLUTIONS

An Interview With SBES

AN INTERVIEW WITH SBES LIFESAVER......... THE EFFORTLESS WAY TO CHOOSE A LONE WORKER ALARM SYSTEM There’s often a lot to think about when choosing a Lone Worker Alarm System – Ex Certification, Environment, Operation/Functionality, Design, Site Layout, Installation, Alarm Notifications, User Training, System Support and Service. SBES LifeSaver offers an innovative way to create a Lone Worker Alarm System specifically to fulfil the customers requirements. SBES know from experience that companies work and operate in different ways. The SBES LifeSaver team of expert designers, surveyors, project managers and installers will create a truly individual system that has been designed to reflect your requirements.

Quality Systems Of all the lone worker alarm providers to choose from, it’s surprising how few offer a complete all-inclusive service. SBES is different. As a company SBES take care of everything, from initial design, installation, through to full on-site User Training and

System Servicing. The SBES Lifesaver range of lone worker alarm systems which include ATEX/Ex Certified systems are individually designed for you using only the highest-quality materials and all systems are installed by their own installation teams. SBES are proud to have a first class global client base with many of them offering testimonials; and unlike some lone worker companies vanishing overnight, SBES has a proven track record of over 12 years. SBES are a proven global service provider.

Getting it right from the start SBES can arrange for one of their surveyors to visit your premises at a time to suit you, to see your lone worker environment first hand. They will discuss how you (the Client) would like the system to operate and then provide complete and sound advise on how they can deliver your system utilising the latest technologies.

Looking after you every step of the way SBES’s highly skilled staff will look after you every step of the way – from initial consultation right trough to the finished installation and of course – Post installation Support & Service, so you don’t have to worry about a thing.

For further information on the SBES LifeSaver range of Lone Worker Products, please visit their web site: www.sbeslifesaver.com where you can find product information, virtual demonstrations, client list and product literature. HAZARDOUS ENGINEERING SOLUTIONS

Product Spotlight – Lone Worker Protection

STAFF PROTECTION FROM CALL SYSTEMS TECHNOLOGY Multiple alarm alerts, accurate location tracing, text and voice messaging in a robust, IP65 rated DECT handset provides maximum staff protection. The C-3115 handset protects workers with automatic alerts from site safety systems, tilt, man down and ‘snatch’ alerts, periodic checks, a large user-operated button and extra

C-3115 DECT Handset

user-selected alarm. Precise location positioning instantly give the exact location of the person needing help. The C-3115 can be integrated with access control systems, fire alarm panels, building maintenance systems (BMS), machine operation and hazard alarms. Handsets receive alphanumeric text alerts and display colour graphics.

Call Systems Technology 0800 389 5642

020 8381 1338

solutions@call-systems.com

www.call-systems.com

HAZARDOUS ENGINEERING SOLUTIONS

Product Spotlight - Atex Equipment/Services

AXAIR ‘ATEX’ FANS – CORROSION RESISTANT Axair Fans UK Limited manufactures ATEX Category 3 Zone 2 plastic centrifugal fans for corrosive fumes, also suitable for outdoors installation. Two ATEX ranges are available, including a wide variety of motor types, rated outputs and speeds. The SA range is designed for airflow up to 10,000m³/h for systems with moderate pressure loss, whereas the STA range has lower flow characteristics for systems up to 2000pascals. In general the fans comply with ATEX Ex-II-3G-II-T3 for surface industries. Installation is permitted in Category 3 gas (Zone 2) areas, for Group II gas. The maximum motor surface temperature T3 (200°C) will prevent spontaneous combustion of most gasses. The fans can be installed where an explosive atmosphere is not expected to exist in normal operation. Axair SA and STA fans are made of carbon-loaded semiconducting moulded polypropylene, to earth static electricity. ATEX fans construction depends on the electric motor selection, the first choice for Category 3 being the non-incendive type EExnA, designed to prevent internal sparking. The explosion-proof EEx-d option provides extra security (with thermistor if used with variable speed drive). Unlike metal fans, polypropylene fans are unaffected by outdoors installations and Axair offers a semi-conducting polypropylene weather pedestal for electric motors.

Axair manufactured ATEX fans have inlet and discharge spigots matching standard ductwork diameters and are sealed to prevent explosive gasses and fumes escaping in the air-stream. For the widest selection of ATEX fans – AXAIR FANS UK LIMITED Telephone : 01782 349430 - Website : www.axair-fans.co.uk

WHEN AND WHERE QUALITY AND PERFORMANCE MATTERS

Introducing AVEX CCTV’s innovative AXIPTZ-5 & 5IR Stainless Steel Explosion proof PTZ

for day or night surveillance in complete darkness or low

CCTV Camera Stations.

light conditions. Meeting stringent ATEX Zone 1 standard for potentially explosive and extreme environmental conditions

Both models are fully integrated all-in-one PTZ units

(certified by Sira Certification UK), Avex CCTV provides

which combines pan/tilt, housing, telemetry receiver

some of the most durable and reliable CCTV camera

(Pelco D/P & Vicon protocols), wiper system and Day/

stations & housings around.

Night CCD Camera into one fully integrated easy to install and maintain unit. The AXIPTZ-5IR incorporates a LED or Laser IR Illuminator making it the ideal choice

HAZARDOUS ENGINEERING SOLUTIONS

For More Details Web : http://www.avexcctv.com

Product Spotlight - Atex Equipment/Services

HIGH-PERFORMANCE DIRECTIONAL SOUNDER FROM CLIFFORD & SNELL Leading manufacturer of audible and visual alarms, Clifford & Snell, Member of the R. Stahl Group, has extended its Yodalex range of Explosion Proof signalling devices with the introduction of a high-performance directional sounder – Type Y09. This new series of High Output Sounders features a lightweight painted GRP Exd enclosure with a sound output of 115Db and independentlyselectable 2nd stage, 32 Internationally-recognised sound tones. YO9 is finished in high performance red paint, as standard. ATEX and IECEx Approved for Gas & Dust, Zones 1 & 2 Listed and available in Gas Groups IIB & IIC, these sounders offer a certified temperature range extending from an exceptional -60oC to +60oC. Operational voltage ratings are 24Vdc and 48Vdc with a single AC unit covering a range from 115Vac to 230Vac. An adjustable stainless steel ratchet bracket is provided along with stainless steel fixings. Dual cable entry enables ease of installation and the facility to safely loop to the next device.

For further details, contact: Clifford & Snell, TEL: 0121 767 6400 FAX: 0121 767 6490 WEBSITE: www.cliffordandsnell.com or Karen Mascarenhas, Mascarenhas PR TEL: 020 8305 0650 FAX: 020 8305 9520 EMAIL: karen@kmpr.co.uk WEBSITE: www.kmpr.co.uk

8 variable FOUNDATION™ fieldbus Indicators can be Nodes or Listeners BEKA associates eight variable FOUNDATION™ fieldbus indicators can now be configured on-site as fieldbus Nodes or as fieldbus Listeners. As a Node the indicator is configured via the fieldbus host, the instrument push buttons being used to select which preconfigured variable is displayed and, if required, to return operator acknowledgements to the host. As a fieldbus Listener, the indicator is not visible to the host, does not use any valuable macrocycle time and may not be subject to a Node Licence Fee thus reducing operating costs. Configuration is performed via the instrument’s push buttons. All the models have an easy to read 20mm high 5 digit display plus a 31 segment bargraph.

The range includes panel and field

mounting ATEX, IECEx and FM certified intrinsically safe, Type n,

For further information please visit:

nonincendive and safe area indicators.

http://www.beka.co.uk/ff

Single variable FOUNDATION™ fieldbus and PROFIBUS PA

or phone: 01462 438301

indicators are also available.

HAZARDOUS ENGINEERING SOLUTIONS

Product Spotlight - Atex Equipment/Services

DETECTION INSTRUMENTS Detection Instruments (Northern) Ltd has been a leading supplier of fire and gas detection equipment to the oil & petrochemical industries for over 30 years. Our extensive experience of designing and supplying fire and gas systems for the offshore oil & gas sectors, and of problem solving in an offshore environment, has given our engineers an unparalleled understanding of the unique requirements of gas detection in these industries, and of high-reliability systems destined for harsh environments.

INTRINSICALLY SAFE VIBRATION SENSORS OPERATING UP TO 250Â°C Hansford Sensors Ltd manufacture and supply a range of ATEX and IEC Ex certified intrinsically safe vibration sensors which are suitable for use in areas of very high temperatures. This enables maintenance engineers to monitor vibration levels of large pumps, diesel engines, fans, compressors, motors, drilling rigs and all types of rotating machinery, located in a potentially explosive working environment. The sensors are constructed in stainless steel and have the ability to withstand tough operating conditions, offering reliability, optimum performance and long service. They are supplied with a separate charge amplifier module positioned within the braided cable run allowing this to be positioned outside the high temperature area and are available with a wide choice of cable lengths and mounting options. Hansford Sensors Limited Artisan, Hillbottom Road, Sands Industrial Estate, High Wycombe HP12 4HJ. UK Tel:0845 680 1957 Fax:0845 680 1958Â www.hansfordsensors.com HAZARDOUS ENGINEERING SOLUTIONS

We can provide solutions to all your gas and fire detection needs: bespoke system design - hazardous and safe area detectors - control equipment - portable and personal gas monitors - repair of flammable detectors and control cards. For more information call: +44 (0)1563 525525 or email info@di-northern.com

Editors Choice - Dealing with ATEX

DEALING WITH THE ATEX DIRECTIVE REQUIREMENTS IN EU Negotiating the maze of national and international rules and regulations

The devil is, as always, in the detail(s), though. Sometimes changes have to be made to meet ATEX requirements. Compliance issues and legislation are becoming increasingly complex and detail-oriented, hence more of a burden to manufacturers. We cannot describe all the minor differences between ATEX and other requirements in this article, but we will review some of the fundamental differences between North American and European requirements.

on hazardous area approvals is a minefield, and can extend product development project costs and times considerably

HAZARDOUS AREA CLASSIFICATIONS. Industrial operations often involve using, processing or storing hazardous (flammable) materials. Among the many protection techniques commonly used to annihilate, purge or drastically minimise the risks of explosion are Intrinsic Safety and Flame/Explosion-Proof apparatus, which are highly common in the process instrumentation industry. Such methods must be embedded in the initial engineering design and subsequent testing of electronic devices, and maintained through installation and commissioning.

This article was provided by Gus H Elias, Senior Certification Engineer at Moore Industries International, in the USA, and provides an American perspective on the ATEX approvals that are needed for the safe and legal installation of electrical equipment in hazardous areas in Europe. One of the new minefields for a product manager is the mandatory European Community (EC) Harmonised Safety Compliance Directives and Standards, with the most current being ATEX directive 94/9/EC. ATEX stands for “Atmosphere Explosive” (in French) and it is the law in the EU. Only EU certification agencies are allowed to certify products in accordance with the ATEX directive. Despite the fact that ATEX compliance testing has been mandatory in Europe since 1 July, 2003, many manufacturers are still not integrating the time, labour and cost implications of ATEX compliance into their R+D project planning and resource allocation. It has become almost impossible to complete product design and secure its timed launching into the marketplace without considering all of the compliance issues necessary for the global marketplace. Clearly, a product should first and foremost be designed to conform to all the compliance requirements for all the targeted marketplaces, national and international. This may sound obvious, but many large and multi-national firms have lost huge contracts, big orders and even had to scrap designed products because they could not meet the ATEX compliance requirements. In some cases, the instrumentation was perfectly adequate for the task and met nearly every other safety directive; but, because it had not yet been ATEX-certified, it was unacceptable. HAZARDOUS ENGINEERING SOLUTIONS

In general, an instrument that can meet most international safety directives can probably meet ATEX requirements, but it first must pass the ATEX certification process.

There are a great number of potential ignition sources such as unauthorised smoking and use of naked flames, hot surfaces from the process itself, frictional sparking from rusty metals and static electricity, including problems from clothing. Most of these sources, at least to some extent, can be controlled and minimised, and this comes under the heading of sound engineering designs, good plant management and effective control systems. There is however, an additional problem. The electrical apparatus necessary to operate the plant pumps, lights, instrumentation, and other equipment is itself a potential source of ignition. Thus, the very apparatus which should be serving to provide better control over the plant and process may be making the site more, rather than less, dangerous. The identification of Hazardous “Classified” Locations in a plant is usually carried out by experts or highly qualified personnel, such as process, industrial or chemical engineers. The possibility of a hazardous atmosphere being present and its condition and duration must be established. If an area is known to not contain hazardous materials or potentially explosive atmospheres, then it is classified as a non-hazardous area or a safe location. In the United States, the classification of hazardous locations is based on the National Electrical Code (NEC), while in Canada the Canadian Electric Code (CEC) applies. In Europe, Asia and Australia, the tendency is to follow the recommendations of the International Electrotechnical Commission (IEC). In Europe, compliance with ATEX Directive 94/9/EC is mandatory when installing and commissioning electronic or mechanical devices in hazardous locations. Once an area is classified as potentially explosive, a risk analysis will

Editors Choice - Dealing with ATEX normally dictate that only suitably certified electrical and qualified mechanical equipment can be installed. These regulations force manufacturers to gain certification of electrical and/or mechanical products that can be used in a potentially explosive atmosphere. In many cases, legal requirements will not allow non-certified products to be placed in the field, whether mandated by the company, the enduser or by specific legislative requirements (i.e, ATEX in the European Union) and even possibly by insurance policy underwriters. In Europe, hazardous areas are classified into three zones which are directly related to the predicted occurrence of when and the duration that an explosive atmosphere may be present in the area.

THESE ZONES ARE: ZONE 0: Where an explosive atmosphere is continuously present, or present for long periods of time. ZONE 1: Where an explosive atmosphere is likely to occur in normal operation. ZONE 2: Where an explosive atmosphere is not likely to occur in normal operation and if it does occur, it will exist only for a short time. The differences to North American practice can be seen from the following: Continuous hazard present: CEC/NEC=Division 1, IEC/Europe=Zone 0. Intermittent hazard: CEC/NEC=Division 1, IEC/Europe=Zone 1. Abnormal to be a hazard: CEC/NEC=Division 2, IEC/Europe=Zone 2. It is important to note that Zone 2 (IEC/Europe) and Division 2 (North America) are similar to a great extent but are not identical, while Division 1 includes the corresponding Zones 0 and 1. An instrument designed for Zone 1 cannot necessarily be directly used in Division 1, and no quantifications of the expressions “long period of time” for Zone 0, “can be present” for Zone 1 and Division 1, and “not normally present” for Zone 2, are given. In common practice, for Zone 0, a level of probability of a dangerous mixture present more than 1% of the time is generally accepted. Locations classified as Zone 1 have a level of probability of a dangerous mixture between 0.01% and 1% (maximum 100 hours per year), while Zone 2 locations can be considered dangerous when said mixture is present for no more than one hour per year. The main difference between the North American and the European classification of hazardous locations is that there is currently no direct equivalent to the European Zone 0 in the North American system; however, existing standards may be revised to allow an equivalent representation. Zone 0 is therefore the most dangerous. An instrument designed for Zone 0 must be incapable of generating or accumulating sufficient energy to ignite the fuel mixture. Furthermore, European standards require that apparatus be subdivided into two groups: I and II. Group I is for apparatus to be used in mines where the danger is represented by methane gas and coal dust.

Group II is for apparatus to be used in surface industries where the danger is represented by gas and vapour that has been subdivided into three groups: A, B and C.

SAFETY METHODS: To minimise the risk of explosion, elimination of one or more of the components of the ignition triangle is necessary. There are three basic methods of protection: 1) Explosion Containment: The only method that allows the explosion to occur but confines it to a well defined area, thus avoiding the propagation to the surrounding atmosphere. Explosion/Flame-Proof enclosures are based on this method. 2) Segregation: A method that attempts to physically separate or isolate the electrical parts or hot surfaces from the explosive mixture. This method includes several techniques such as pressurisation and encapsulation. 3) Prevention: A method that limits energy, both electrical and thermal, to safe levels under both normal operation and fault conditions. Intrinsic Safety is the most representative technique of this method, it being a protection concept employed in potentially explosive atmospheres. It relies on the electrical apparatus being designed so that it is unable to release sufficient energy, by either thermal or electrical means, to cause an ignition of a flammable gas. The energies required to ignite various gas groups have been proven by experimentation. Electrical equipment that has been assessed, tested and found to be in compliance with the ATEX Directive and the relevant European Harmonised Standards must be marked with the certification coding as described in the standards. The ATEX label and markings on the product should include information stating that it is: • • • • • •

In compliance with the relevant and applicable safety standard/directive. Intended for use in hazardous or explosive atmospheres. Approved for certain defined gas groupings. Operational in a specific ambient temperature range. Assigned a certain (quoted) temperature coding. Meeting all the Directives.

As a result of the combination of company installation policies, public legislation and safety requirements, many manufacturers and end-users must deal with issues with which they are somewhat unfamiliar. New directives and amended directives in the European Union can be introduced at any time. It is the manufacturer’s sole responsibility to identify the mandatory directives and qualify their applicable products for full compliance. The degree of expertise and specialised equipment required to meet all the various directives and requirements is beyond the reach of most companies.

HAZARDOUS ENGINEERING SOLUTIONS

Editors Choice - Dealing with ATEX Indeed, it is often not cost effective to hire and retain a full-time inhouse specialist to handle a task or a function that may be only called on several times a year. Moore Industries, which builds instrumentation for use worldwide, has such a full-time specialist because of the multitude of products it makes and the markets it serves. Companies may prefer to concentrate on their core business rather than having to deal with the constantly changing legislative world of compliance, approvals and certifications. Instead, they outsource their compliance requirements. Outsourcing is a long term relationship between the manufacturer and the compliance service. This sort of relationship is ideally suited for complex and on-going problems of product design and safety compliance. Both outsourcing and subcontracting are costly, time-consuming and may require substantial material and human resources. Design and compliance firms that provide such services must know products, marketplaces, and current and future compliance requirements so they can fully assist clients from the initial design specifications to the final listing or certification by a third party. A third party is an independent certification agency, neutral to both the consumer/end-user and the manufacturer. Some of the well-known and reputable testing approval agencies for ATEX compliance include ISSeP (Belgium), SIRA (UK), LCIE (France), KEMA (Holland) and Factory Mutual (USA and UK). Certification is the process of assessing the design to the specification set down in an applicable Standard or Directive. Approval or certification agencies are generally not the standardswriting bodies (although they often have a strong presence on those bodies) but are rather independent services which give a third party attestation that a certain design complies with the requirements of a particular standard.

THE CHANGING INTERNATIONAL SCENE. Many countries publish their own National Standards concerning hazardous and electrical apparatus. Some of these standards still exist and others have become superseded. Dealing With The ATEX Directive. There are differences from country to country in the way in which the standards and certification procedures are implemented. Within Europe, the Committee for Electrotechnical Standardisation (CENELEC) produced a series of standards aimed at harmonising the technical approach of its member countries. On the other hand, North American approval agencies adhere to the guidelines and constraints stated by both the National Electric Code (USA) and the Canadian Electric Code (Canada). Although Canada follows the classification of North America, it has close links with the IEC and CENELEC. In Australia, the Standards Association of Australia (SAA) produces National Standards, and offers a certification/approval service by which its main requirements are very similar to the European Standards.

Also, there exist reciprocal arrangements assuring the acceptance of test results between European bodies and North America and Australia. ATEX is required in Europe, of course, but because many countries follow Europeâ&#x20AC;&#x2122;s standards, ATEX is being increasingly required across Asia and other regions. In summary, the field of industrial safety is broad and very detailoriented. Manufacturers are forced to adhere to numerous standards, regulations and directives in order to compete in the global marketplace and avoid liability and monetary losses caused by faulty designs and un-safe products. Government agencies as well as insurance companies have strict guidelines on industrial facilities to integrate their procedures into the highest possible methods of protection. The first and primary precaution to be used is to avoid placing electrical apparatus in hazardous locations. When designing a plant or a factory, this aspect needs to be considered and only when there is no other alternative should such applications be allowed. The size of the apparatus, the flexibility of the system, and its cost of operation and maintenance are secondary but also important facts that need to be considered. Manufacturers of pneumatic and electrical/electronic devices that are intended for use in potentially explosive atmospheres must invest substantial monies in research and development, design and third party agency approvals in order to stay in business and compete. Products designed and intended for installation and commissioning in hazardous locations in the European Community and many other regions must be tested and certified in accordance with the mandated ATEX Directive 94/9/EC, else they cannot be sold to the European marketplace. It is that simple: use ATEX-certified products for hazardous locations, else youâ&#x20AC;&#x2122;ll break the law in the EU.

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Product Spotlight - Atex Equipment & Services

INMOCO LAUNCHES EXLAR ATEX/ CSAus- RATED EXPLOSION-PROOF LINEAR ACTUATORS FOR MOST DEMANDING PROCESS ENVIRONMENTS Inmoco’s new Exlar EL 100 series of explosion-proof linear actuators improve loop performance and reduce process variability in critical valve and damper applications. The actuators integrate features specially developed for use in process applications: sophisticated velocity and positioning control, high speeds and forces, and the ability to carry heavy loads, reliably, for thousands of hours. In addition, the fully sealed, iP66 design of the EL100 series ensures highly reliable and trouble-free operation, even in the most severe and demanding environments. The EL100 Series actuators are both ATEX – (Ex d II B T3 Gb IP66) and CSA -USA (Class I, Div 1, Groups B, C, D & T3) approved for use in potentially explosive environments. They are based upon a unique design that integrates a highly efficient planetary roller screw mechanism with a high torque servomotor in a single self-contained package. The roller screw outperforms rival ballscrews by a factor of 15, in terms of travel life and load carrying capacity. It consists of multiple threaded rollers assembled in a planetary arrangement around a threaded shaft. This highly robust design is designed to provide reliable and precise operation over thousands of hours. The combination of the planetary roller screw and servomotor produces an all-electric actuator which is extremely compact, yet delivers similar performance to hydraulic actuators in terms of force (907 Kilograms max) and torque capability, while surpassing them in speed (up to 635mm/s), efficiency, positioning performance, operating life and environmental impact.

where the actuators continuously hold the position of the valve stem, or shaft, allowing extremely fast response to the smallest command signal changes, without overshoot, even when friction is present. This results in improved loop performance and reduced process variability. Also optimising the EL100 series actuators for process applications is their excellent contamination protection. In conventional rotary to linear devices the critical mechanisms are exposed to the environment and therefore require frequent inspection, cleaning and lubrication. In contrast, all converting components in the EL-100 series actuator are mounted within the sealed motor housing, which is IP66 rated. The explosion-proof rating, high performance and environmental packaging of the EL 100 series actuators mean that they are ideally suited to the widest range of applications. In addition to Valve and Damper control, these include: Shipboard fuel management systems, Fuel skids, Refineries, Engine test stands, Paint booths and Printing presses. In all of these applications the performance of the EL 100 Series actuators can be optimised with Exlar’s EXP Series of explosion proof positioners. These units also offer CSA Class I Division 1 and ATEX conformity: SIRA 10ATEX1037X Ex d II B T3 Gb IP66.

Reader contact: INMOCO : Gerard Bush Tel: +44 (0)1327 307600 Fax: +44 (0)1327 300319

In demanding process applications, the EL100 actuator offers a unique combination of high speed, performance and accuracy in a compact package, plus the flexibility of compatibility with almost any resolver- based servo amplifier. The optimised performance features of the EL 100 Series actuators are evident in valve and damper control applications, HAZARDOUS ENGINEERING SOLUTIONS

Web: www.inmoco.co.uk Email: GerardB@inmoco.co.uk Address: 4 Brunel Close, Drayton Fields, Daventry, Northamptonshire, NN11 8RB, UK

Product Spotlight - Atex Equipment & Services

ATEX APPROVED INDICATOR FROM AVERY WEIGH-TRONIX Accurate weighing and process automation in hazardous areas is essential for maximising efficiency and productivity. The Avery Weigh-Tronix E1250 intrinsically safe configurable weight indicator is trade approved to 10,000 divisions and ATEX approved for use in hazardous areas rated Zone 1, 2, 21 or 22. The intrinsically safe system comprises of an ATEX approved indicator, power supply or battery pack and is suitable for use in a variety of applications and industries, including: • liquid gas cylinder filling • mixing and batching volatile chemicals • mixing and batching bulk solids, including food processing, grain stores, pharmaceutical and any potential explosive area

Suitable for hazardous gasses and dusty atmospheres Housed in a rugged IP67 stainless steel enclosure, the E1250 indicator can be used with a wide range of Avery Weigh-Tronix ATEX floor scales. In addition, vessels in virtually any application involving volatile materials or hazardous dusts can be weighed, displayed and controlled, both locally or remotely through optional safe area interfaces.

Special applications included as standard Gas bottle filling, Liquid filling and multiingredient Recipe batches can all be tailored to meet specific requirements and then stored for easy recall in the future.

Power supply to suit your needs The indicator can be powered via a hazardous area approved AC power supply for permanently connected installations, or approved DC rechargeable battery pack for mobile or portable applications. This, including the range of push buttons and solenoid valve, make the product suitable for installation in the hazardous area for local process control where it is needed. With more than 250 years in the Weighing Industry, we have the expertise to meet your business requirements.

For more information, contact: 08453 66 77 88 or visit: www.averyweigh-tronix.com Email : info@awtxglobal.com

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