ATEX & hazardous areas
Electrostatic discharge – Some normal equipment operations can generate static electricity, which can serve as an ignition source at certain levels.
Friction sparks – Equipment operation may also involve repeated contact between materials, resulting in friction that can produce heated sparks and material contents must be considered as a potential ignition source.
To be able to eliminate the potential ignition sources, which can include considered faults, prior to manufacture and installation, a pre- assessment is recommended to understand the equipment design, operation and desired location and environment. This can also be carried out for existing non-electrical equipment which was manufactured and installed prior to July 2003.
HAZARDOUS ENVIRONMENTS The UKCA Ex Regulation provides a detailed overview of the essential health and safety requirements applicable to equipment used in hazardous environments. However, the specific technical requirements to demonstrate compliance for various types of equipment and operating environments are found in nearly 100 individual designated standards. Depending on the equipment and its intended use, this means that more than one designated standard may be applicable to the evaluation and certification process. Under the provisions of the UKCA Ex Regulation, evidence of compliance is generally demonstrated by the issuance of a manufacturer’s, or supplier’s Declaration of Conformity, and the task of demonstrating compliance rests with the party responsible for introducing a product into the marketplace. External to Europe and the UK, the IECEx conformity mark is evidence that a manufacturer’s products have been independently assessed against the additional requirements of the IECEx conformity mark licensing system. The mark license number is issued to a manufacturer by an accepted IECEx certification body (ExCB) that has entered into a mark license agreement with the IEC.
The primary goals of the IECEx Scheme are to reduce testing and certification cost, speed up market access for new products and equipment, and increase international acceptance of product assessment results. The Scheme achieves these goals through the issuance of an International Certificate of Conformity based on:
Testing and assessment of equipment samples for compliance with applicable international standards.
Assessment and auditing of a manufacturer’s quality assurance system.
On-going surveillance audits to ensure continued compliance.
The UKCA Ex Regulation’s conformity assessment process provides a certification route for a broad range of equipment. It also offers significant latitude in the technical assessment of non-conventional equipment through the use of a technical construction file. This can be especially important to manufacturers of customised equipment, or equipment specifically designed for unique applications. However, as the IECEx Certified Equipment Scheme only assesses electrical equipment against TC 31’s IEC standards, this restriction can present an insurmountable hurdle for manufacturers of highly specialised electrical equipment, as relevant standards will not exist.
ENSURING COMPLIANCE The UKCA Ex Regulation’s conformity assessment process provides a certification route for a broad range of electrical and non- electrical equipment. Under the IECEx Scheme, equipment must be tested and certified by IECEx-approved Testing Laboratories and Certification Bodies. Evidence of prior testing conducted by an EU Notified Body or UK Approved Body is not acceptable.
The preferred conformity assessment path for many manufacturers has therefore traditionally involved first obtaining equipment certification under the IECEx Certified Equipment Scheme. The IECEx testing data must then be submitted to an EU Notified Body or UK Approved Body as part of the certification process. Equipment used in hazardous environments must be expressly designed to minimise risks, and manufacturers of electrical, non-electrical, electronic, mechanical equipment, protective systems and assemblies must ensure that their products meet the requirements of applicable regulations and standards. Although similar in scope and intent, it is clear that the UKCA Ex Regulation and the IECEx Scheme encompass different requirements and utilise different assessment approaches, complicating the regulatory approval process for equipment manufacturers that supply multiple regions.
Instrumentation Monthly June 2023 TÜV SÜD
www.tuvsud.com/uk
HIGH-RES POSITION FEEDBACK FOR INDUSTRIAL APPLICATIONS
P
ositek has expanded its range of rotary sensors with a new cost competitive model aimed at demanding industrial and scientific applications. Based on the leading
UK designer and manufacturer’s patented PIPS technology, the P530 offers an effectively infinite resolution and linearity of +/- 0.25 per cent FSO. Application flexibility is ensured with a wide choice of industry standard outputs calibrated to a customer specified angle from +/-50° to +/-160° in increments of one degree. Positek’s non- contacting technology, a major advance in displacement sensor design, is based on simple inductive coils and micro-electronic circuitry that provides an exceptionally long MTBF life of up to 350,000 hrs at 40°C as well as excellent durability against shock, vibration, and temperature extremes. The new P530 rotary sensor’s 35mm diameter housing is IP67 sealed and together with its flange mounting and shaft drive is finished in 316 stainless- steel. A machined registration mark identifies the mid-point of rotary travel. The comprehensive selection of supply and instrument-level signal outputs extends to input voltages of +/- 5V DC or +/- 24V DC with ratiometric and buffered voltage outputs as well as 4… 20mA current outputs. EMC performance conforms to EN 61000-6-2 and 6-3. A choice of M12 connector or cable gland connection is available with cable length specified by the customer. Positek’s PIPS technology (Positek Inductive Position Sensor) scores well when compared to other LVDT technologies. Its simpler coil design is more compact and utilises inexpensive magnetic materials - which makes for easier installation, competitive costs and lowered environmental susceptibility. The well proven ASIC technology simply decodes the absolute position of embedded inductive coils providing a proportional, high-bandwidth and readily useable high resolution analogue output that does not require further signal conditioning. Furthermore, in comparison to potentiometer-based displacement sensors, the non-contacting PIPS technology ensures an extremely long working life.
Positek
www.positek.com 21
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