T H E E X T E C H N I C A L A S S O C I A T I O N O F A U S T R A L I A & N Z

O C T O B E R 2 0 1 5

John CurranCHAIRMAN

UPDATE FROM THE CHAIRMAN

Hello and welcome to our second ExTA newsletter. As all of you may already know, ExTA has been formed from members drawn from within the hazardous area industries groups.

We have now been in operation for just on 12 months and we are now planning our services expansion. Our AGM is on October 29th; refer to our Secretary’s News for further information. Our membership renewals have just gone out. I would like to thank all our members for their ongoing support. Your continuing loyalty and support is greatly appreciated.

We are currently negotiating with Standards Australia to achieve Nominating Organisation status. When complete, this will allow us to nominate representatives to Standards Committees to assist with the integration and correlation of issues affecting our industry.

Our forum, which is accessible from our web site has been in operation some 6 months and is showing a continuing increase in usefulness to the industry. Members can start topics and request assistance from others in the industry. The forum is monitored by members of ExTA to ensure topics are relevant etc. The rules of the forum are located on the website.

THERE IS STILL A HIGH LEVEL OF UNCERTAINTY SURROUNDING THE FUTURE OF THE ANZEX

SCHEME. EXTA HAS FORMED A SUBCOMMITTEE WHOSE ROLE IS TO MONITOR PROGRESS IN THIS AREA AND KEEP EXTA’S INTEREST IN THE

FOREFRONT.

I trust that you all enjoy our second issue of our ExTA newsletter which we plan to publish two to three times per year.

Membership of the Association is available to anybody who has an active interest in the industry. Details for membership are available on our web site, www.exta.org.au.

Regards to all and enjoy the read.

John Curran, Chairman

NEWSLETTER 2

The processes of developing mechanical explosion-protection techniques and standards started within v [ATmospherique EXplosive] with a generalised EU Directive (1993) requiring the management of ignition risks in hazardous areas. There was no distinction made between electrical, mechanical, chemical or natural ignition sources.

The Directive imposes requirements on the entirety of the supply chain including designers, manufacturers, importers/agents, end-users.

The Directive applies to all equipment brought into the EU, including second hand equipment from overseas countries.

The Directive needed a series of standards to guide stakeholders as they attempted to meet the Directive requirements.

These were produced as EN (European Normative) Standards. In 2005 the decision was taken to internationalise the standards and ISO/IEC SC31M was established as a joint IEC & ISO committee to produce a suite of mechanical Ex Standards. This work is ongoing. The chart (following) outlines the activity in the development of the new standards.

We now have three (3) vacancies on our Management Committee, due to retirements for business and family issues.

The elections for these positions will be held at the AGM.

If you, or another member you know, would like to become a member of the Management Committee, please send me your details and a short resume by Friday October 9th.

We would prefer that one of these vacancies be filled by a Group I manufacturer and another by a Group II / Group III manufacturer.Marketing skills would be a definite advantage.

We would love to see as many as possible members attending and if you cannot attend, please send your Proxy, on the attached form.

Please Note: If you nominate an individual, other than the Chairman of the meeting as your proxy, please ensure:

1. They will be attending the meeting2. They agree to be your proxy

MANAGEMENT COMMITTEE VACANCIES PROXIES

THE BRAVE NEW WORLD OF MECHANICAL EXPLOSION PROTECTION

Our AGM is scheduled for October 29th 2015. It will be held at the Christie Conference Centre, Level 4 - 100 Walker Street North Sydney. 10-30am to 2.30pm. In addition to our AGM, we will be having a Workshop with three speakers including a question time and discussions at the end.The topics are:

► The ANZEx scheme, Now and in the future ► Mechanical Ex Systems ► Non-Conforming Product

UPDATE FROM EXTA SECRETARY AND NOTICE OF ANNUAL GENERAL MEETING (AGM)

UPDATE FROM EXTA SECRETARY AND NOTICE OF ANNUAL GENERAL MEETING (AGM)The development of the standards required to satisfactorily address mechanical Ex techniques, EPLs (Equipment Protection Levels), ignition hazard assessments and ignition sources is ongoing. It may be many years before a suite of standards similar to the AS/NZS(IEC)60079 series is available for the management of Ex mechanical issues.

The development of these new standards has been undertaken in a “parallel universe” to the similar Ex electrical standards. The Ex mechanical standards are so closely aligned that they share common elements and even common standards with electrical Ex standards and requirements.

AS/NZS(IEC)60079.0 – 1 – 2 – 31 & 34 apply to both to Ex mechanical and Ex electrical devices and systems.

The chart (preceding) illustrates the interaction and applicably of current “electrical” standards to both electrical and mechanical Ex.

We are able to use three of the “electrical” techniques from the AS/

NZS(IEC)60079 series of Standards and apply the techniques equally to either “electrical” or “mechanical” devices or systems.

The techniques are; ► Exd - Flameproof – AS/NZS(IEC)60079-1 ► Exp - Pressurisation (gas) - AS/NZS(IEC)60079-2 ► Ext - Enclosure (dust) – AS/NZS(IEC)60079-31

AS/NZS(IEC)60079.0 – 1 – 2 – 31 & 34

This standard adds detail to AS/NZS(ISO)9001 and provides Quality Management System guidance to the manufacturers of Ex equipment. It does not differentiate between Ex Electrical and Ex mechanical.

AS/NZS(ISO)80079.34 : Explosive Atmospheres – Application of quality systems for equipment manufacture.

ISO80079.36 is the “core” standard for Ex mechanical devices and systems but it also relies on many of the provisions of AS/NZS(IEC)60079.0. This standard should be published early in 2016 and be available for use. It may be applied to couplings, pumps, gearboxes, brakes, hydraulic and pneumatic motors and any combination of devices to realise a machine, fan, engine, compressor, assemblies, etc.

Part 36 applies to Group I (methane), Group IIA, IIB & IIC (typically; propane, ethylene and hydrogen) and Group IIIA, IIIB & IIIC (dusts & flyings).Part 36 applies ignition hazard assessments to mechanical devices and systems and identifies;

► Possible ignition sources (any type of ignition source, hot surfaces, flames & hot gasses, mechanically generated sparks etc)

► Equipment related ignition sources (by the equipment – regardless of its ignition capacity)

► Potential ignition sources (by the equipment with the capability to ignite an explosive atmosphere)

► Effective ignition sources [a potential ignition source, able to ignite an explosive atmosphere with consideration of when? Normal operation, expected malfunction or rare malfunction. (This determines the EPL)]

While EPLs and Zones overlap – they are different. Equipment Protection Levels (EPLs) consider not just likelihood, but also consequence – that is RISK.

ISO 80079.36 provides good guidance and some worked examples as to how ignition hazards are assessed and what the (EPLs) really mean in mechanical explosion protection.

► We need to decide what is tolerable in a given situation? Do we need to provide effective controls for malfunctions in normal operation, expected malfunctions and rare malfunctions? – If so, then we must aim for the top – for Group I that is EPL Ma and for Group II that is EPL Ga …. Or Da for dust & flyings.

► Or can we provide a sufficient assurance of operational safety if we do not cater for rare malfunctions and just deal with malfunctions in normal operation and expected malfunctions?

- for Group I that is EPL Mb and for Group II that is EPL Gb …. Or Db for dust & flyings.

► Perhaps the consequence of an ignition is low enough that we can live with providing controls for malfunctions in normal operation? - for Group II that is EPL Gc …. Or Dc for dust & flyings.

ISO80079.36 : Non-electrical equipment for explosive atmospheres – Basic method and requirements

We then move to the mechanical (only) explosion-protection techniques that are available in order to achieve the pre-determined EPL. ISO 800079.37 introduces and applies three specific, new, mechanical techniques.

► Ex h(c) - Constructional safety ► Ex h(b) - Control of ignition source ► Ex h(k) - Liquid immersion

This part of ISO/IEC 80079 specifies requirements for the constructional features of equipment and components that may be an individual item or form an assembly, to enable them to be used in mines, or parts of mines, susceptible to explosive atmospheres of firedamp and/or combustible dust.

Both non-electrical equipment and the interconnection of electrical/non-electrical equipment require an ignition hazard assessment.

This standard should be published early in 2016 and be available for use.

ISO80079.37 : Non-electrical equipment for explosive atmospheres – Non electrical type of protection constructional safety ”c”, control of ignition source ”b”, liquid immersion ”k”

ISO80079.38 Equipment and components in explosive atmospheres in underground mines

This International Standard covers the technical requirements necessary to avoid or minimize the significant hazards identified, which could occur during normal operation, maintenance or foreseeable malfunction of reciprocating internal combustion engines intended for use in explosive atmospheres including;

► Group I EPL Mb for use in underground workings susceptible to firedamp and/or combustible dust, ► Group II EPL Gb and Gc for use in potentially explosive atmospheres of flammable gas and vapour and ► Group III EPL Db and Dc for use in potentially explosive atmospheres of combustible dust.

This standard is intended to cover all reciprocating internal combustion engines regardless of the fuel used and the means of ignition. (i.e. “spark” and “compression” engines are included)

This standard is in the early stages of preparation and it may be 3-4 years before publication.

GeneralIt is not a requirement that any of the standards listed mandate certification under the provisions of the ATEX, IECEx or ANZEx Schemes. Generally standards provide reference to certification schemes as being one of the means of demonstrating compliance.

Many manufacturers may choose to test their device/equipment to the requirements of relevant standard(s) within a Testing Laboratory (TL) and have a Certificate of Conformity (CoC) issued by a Certifying Body (CB) under one or more of the Schemes. They may do this to demonstrate that the device/equipment is

“fit-forpurpose” and that they are managing all inherent risks in an appropriate manner. “Regulators” in some jurisdictions may mandate certification under one of the Schemes in Acts, Regulations or legal instrument. (e.g. a Gazette Notice.)

ANZEx SchemeWork is progressing to include provisions for the testing and certification of mechanical Ex devices and equipment under the provisions of MP087.1.

Similarly, the probability is that the “Recognised Service Facility” program in

MP087.2 will be extended to include both electrical and mechanical workshops. This may be particularly important when workshops wish to expand their scope to include both disciplines?

Under the ANZEx Scheme mechanical Ex devices and equipment may be certified to relevant AS standards, AS/NZS standards, IEC standards or ISO standards.

DisclaimerThe foregoing very brief summary of the current status, progress and interaction ofstandards and schemes as they relate to mechanical explosion-protection was written by Phil Berriman to better inform stakeholders and interested persons and at the request of some interested groups.

Any persons or organisations requiring more detailed or definitive information should contact the relevant organisations or bodies.

The views expressed are those of the author only. They do not purport to represent the views of Standards Australia (SA), Standards New Zealand (SNZ), International Electrotechnical Commission (IEC), International Electrotechnical Commission System for Certification (IECEx), International Standards Organisation (ISO) or any other organisation.

The Australian & New Zealand Standard, Diesel Engine Systems for Underground Coal Mines is well advanced – it should be out for “Publiccomment” soon. This new revision adopts and adapts the new mechanical Ex standards by;

► Requiring an ignition hazard assessment from ISO 80079.36 ► Adopting and adapting the new Ex Techniques – Ex c, Ex k, Ex b, Ex d from ISO 80079.37 ► Using the Equipment Protection Level concept for EPL Mb (+ consideration of rare malfunctions ► Requiring a QMS – AS/NZS9001 + AS/NZS80079.34 ► Using functional safety analysis (SIL 2 min) for control systems where the control system is the

prime or only barrier preventing an effective ignition source ► Going from simple regulatory concentrations for emissions to gravimetric determinations (g/kW/Hr) to EU Directives (EU Stage III min) ► Making certification possible under the ANZEx Scheme

This standard should be published early in 2016 and be available for use.

ISO80079.41 : Non-electrical equipment for explosive atmospheres – Ex Reciprocating internal combustion engines

CERTIFICATION

AS/NZS3584.1:2015 Diesel Engine Systems for Underground Coal Mines

PNEUMATIC OVERPRESSURE TESTING OF EX D ENCLOSURES

Overpressure testing is an integral part of the verification of new or overhauled Ex d enclosures. Pneumatic testing presents a potentially effective way to complete overpressure testing and may provide some advantages over hydrostatic alternatives.

This paper looks at the process of pneumatic testing of Ex d enclosures including risks and hazards, as well as the advantages of carrying out such testing.

1. OVERPRESSURE TESTING

1.1 Purpose of Overpressure TestingOverpressure testing is an important part of verification testing as part of new, overhauled or repaired equipment. Overpressure testing forms part of two forms of enclosure validation:

► Type Testing – One of two principal tests used for validating Ex d enclosure:

- Flame propagation test – used to check efficacy of flamepaths

- Peak pressure test – used to establish peak (reference) pressure resulting from optimised CH4 ignition.

► Routine Testing - Used to validate the structural integrity of new, overhauled or repaired Ex d enclosures using 150% of the reference pressure.

1.2 Safety Considerations in Overpressure TestingThe risks to personnel, plant and equipment when fluid is compressed and when failure of the pressure vessel (enclosure) or fittings may occur is potentially catastrophic. This is because compressible fluids can store significant amounts of energy.

For example: one cubic metre of water at 1MPa stores approximately 200J, and one cubic metre of air at 1MPa stores approximately 2 000 000J of energy. This energy is in addition to the energy created due to the elasticity of the enclosure itself.

Based on these examples, hydrostatic testing appears ‘safer’ than pneumatic testing, as the potential energy stored is significantly less. Pressure vessels are, however, commonly used for gaseous substances and are generally operated safely by non-experts on a regular basis (gas bottles, SCUBA gear, etc).

Regardless of the substance used, it is critical that demonstrably competent practitioners and sound testing methodology are adopted when performing any overpressure testing to ensure it is carried out safely.

1.2.1 The consequences of a failure of overpressure testingA few examples of the serious consequences of a failure of enclosures during overpressure testing are described below.

Figure 1 shows the result of a failure due to overpressure during preparation of hydrostatic testing. The tank top blew off due to high water filling rates coupled with a low capacity relief valve.

Figure 1: Failure of tank during preparation of hydrostatic testing

A KC-135 aircraft was being pressurised at ground level. The outflow valves which are used to regulate the pressure of the aircraft were capped off during a 5 year overhaul and were not reopened. As a result the rear hatch was blown a distance of over 70 yards, behind a blast fence. Figure 2 shows the resulting damage to the aircraft.

Figure 2: Failure of rear hatch on aircraft

The damage sustained to a tank which collapsed during the emptying of water following hydrostatic testing is shown in Figure 3. A plastic sheet blocked the air inlet and created a vacuum.

Figure 3: Collapse of tank after completion of hydrostatic test

1.3 Considerations for Overpressure TestingA number of criteria for overpressure testing should be defined, documented and understood prior to starting tests. This will ensure that the results are accurate and relevant. Some questions that may be considered include:

► What event is being emulated in testing? A gaseous CH4 ignition for example?

► What test method best emulates this event: - Transient (impulse) testing with gas - Static testing with gas - Static testing with liquid?

► What deformation and/or damage is acceptable as a result of overpressuring the Ex d enclosure?

► Is it necessary to identify leaks in the enclosure? Can those leaks be between compartments and/or to outside the enclosure?

► When is the most relevant time to measure (flamepath) deformation - under load or after relaxation?

1.4 Standards Applied to Overpressure TestingThere are many standards which can be applied to overpressure testing depending on the application. In Australian underground coal mining applications there are three principal references:

► AS/NZS60079.1:2007 (IEC60079.1:2007) ► AS/NZS 3800:2012 (IEC60079.19:2010) ► HB239:2011 (IECEx OD 315-5:2013)

NOTE: the term “hydrostatic” only appears in HB239. All other documents use the term “overpressure” when referring to this type of testing.These standards outline the performance criteria of an enclosure during and following overpressure testing, and the way such testing should be completed. The relevant sections of the above mentioned standards are highlighted below.AS/NZS 60079.1 – Ex d EquipmentRoutine overpressure test – First method (static):

► 1.5 times reference pressure for at least 10 seconds (Clause 15.1.3.1)

► Test criteria:15.1.1 Type Test …the enclosure suffers no permanent deformation or damage affecting the type or protection…the joints shall in no place have been permanently enlarged15.1.3.1 Type Test15.1.1 and there is no leakage through the walls of the enclosure16.1 Routine Test Routine tests intended to ensure that the enclosure withstands the pressure and also that it contains no holes or cracks connecting to the exterior.16.3 Routine Test …the enclosure withstands the pressure without suffering permanent deformation of the joints or damage to the enclosure…16.3.1The individual parts…can be tested separately…such that stresses are comparable to complete enclosure

AS/NZS 3800 – Repair and Overhaul5.2.1.2An overpressure test shall be conducted where structural repairs of the enclosure have occurred or the integrity of the enclosure is in doubt:

► …1.5 times the reference pressure and held for at least 10 secs ► Pass/fail criteria shall include assessment of structural

damage measured at the geographical [sic] centre of an enclosure panel…flamepath joint surfaces shall be measured

to verify that there is no permanent deformation. ► Where overpressure tests are carried out on multi-

compartment enclosures the tests shall be done on individual compartments separately.

► HB 239 provides practical assistance…for verifying the integrity of explosion protected equipment.

HB239 Guidance on Repair and Overhaul6.5

► Major repairs include…any action that brings the enclosure integrity into doubt…and be verified by pressure test.

► Minor repairs [include] a window lens replacement…

6.8 Hydrostatic Pressure Tests: ► Over pressure testing (static testing) of enclosures is required…

where repairs are of a structural nature… [or] where the structural integrity is in doubt.

► It is only necessary to test individual compartments… ► Repairs of a minor nature may not require overpressure testing

Other considerations from Clause 6.8: ► Seal the test piece and fill with the testing fluid… (6.8.3.d) ► Note: Air…is recommended only for pressurised enclosures

where relatively low pressures are involved. (6.8.3.d) ► …particular attention to flamepaths…flat sections…may show

minor deformation but this may not take away from the structural strength of the enclosure. (6.8.3.j). Cf: AS/NZS 3800 5.2.1.2

► The test should be considered satisfactory if the enclosure has not suffered damage or permanent deformation that may affect its explosion protected properties. (6.8.4)

NOTE: Hydrostatic testing using water is the conventional approach, but it is not the only approach permitted under AS/NZS 3800 and HB 239. An example of overpressure test rigs is shown in Figure 4.

Figure 4: Excerpt from HB239

2 PNEUMATIC TESTING2.1 Why Pneumatic Testing?There are a number of reasons why pneumatic testing may be considered an effective means of overpressure testing for Ex d enclosures:

► Static forces imposed on an enclosure are independent of fluid used

► Disassembly requirements are significantly reduced ► Errors introduced on re-assembly are minimised ► Turnaround times can be reduced

Pneumatic testing as a method of testing is not new; several testing facilities have the capacity to conduct pneumatic testing. TestSafe established a facility at Londonderry under Jim Munro 30 years ago, and Simtars are believed to have a similar facility.

2.2 Undertaking pneumatic testingWhen undertaking pneumatic testing the relevant standards must be considered:

► AS 1210:1989 Unfired Pressure Vessel Code ► AS 4047 Pressure Piping

Furthermore a comprehensive risk assessment should be completed. The results of this assessment will determine additional safety considerations that may be required such as remote monitoring and measurement, and exclusion of personnel from test area.Minimum test pressures need to be maintained while compensating for leakages through deflected flamepaths.

3 CONCLUSIONPneumatic testing is an effective and compliant means of overpressure testing of new, overhauled or repaired Ex d enclosures. This form of testing simplifies the preparation and reassembly of the enclosure being tested.

Irrespective of substance used, it is critical that safety considerations associated with compressible fluids be addressed, including ensuring the competency of personnel working with pressure vessels.

Since the 1990s there has been a significant expansion in the standards and an array of regulatory changes related to hazardous areas. Not just in Australia but overseas as well. These changes are set to continue for many years to come. In North America , UK and Europe there are associations and forums focussed on hazardous areas but there has been nothing in our region. The issues we face are not just ours. In a global environment, we need to meet the challenges with the right momentum and industry understanding in the ANZ region and be able to influence global developments.

Challenges ► Standards Australia seeking to divest itself of management of

the ANZEx certification scheme for certification of explosion –protected electrical equipment and services. The ExTA will also make a case to be considered to take over the management body function of the ANZEx scheme if it can prove itself as sustainable body.

► The development of future mechanical standards and certification of mechanical equipment for hazardous areas. This has even more potential to change the face of installations in hazardous areas than electrical equipment. For example in the Oil, Gas and Petrochemical industry the non-mechanical content is in the order of 90% balance of plant compared to

electrical. The cost factor for equipment to the new standards and certification of mechanical equipment could far outweigh the electrical component.

► ‘Experts’ at all levels and from all sectors needing to reach a common ground to avoid rework, confusion and cost.

► Streamlining Australian practices to remain competitive. Already our industries are known as more expensive in this space than other countries, (sometimes up to 3 times more expensive than comparable overseas installations either due to initial costs or rework on imported items to meet out standards).

► Maintaining and developing a knowledge and skill base based on both current and future developments in this field.

► Linking all of the areas that are affected by hazardous areas i.e. all onshore Groups I, II and III, all offshore fixed and mobile oil and gas installations and other industries such as aviation which may have North American hazardous area equipment.

► Australia & New Zealand accepting international standards other than IEC/ISO for specialised applications

► Rising influence of countries with low cost of manufacture, where there are ongoing issues with quality control and competency.

EXTA

NSW REGULATOR SAFETY ALERTS

► Electrical workers sustain fatal injuries following switch failure ► Electrician injured after making contact with live high voltage conductor ► In-service failure of safety critical steering component ► Fire ignites after worker drills into sealed void