Pt100 - Temperatur Sensors

IECEx

Every operator based outside the EU who wants to measure the temperature of explosive substances with Pt100 RTD temperature probes has already dealt with the subject of “explosion protection” and has come across the term IECEx.
IECEx stands for the International Electrotechnical Certification System for the certification of equipment used in potentially explosive atmospheres.
It is a global certification system that ensures uniform standards for explosion protection and is recognized worldwide.
In contrast to ATEX, which is based on European directives, IECEx offers an internationally recognized alternative that is particularly relevant for companies outside the European Union.
IECEx is not a legally binding “directive”, but uses technical standards that are internationally recognized as the basis for explosion protection.
These standards are primarily part of the IEC 60079 series of standards, which deals with the safe operation of electrical equipment in potentially explosive atmospheres.

IECEx system specifications

• IECEx Equipment Certification Scheme
  Certification of devices used in potentially explosive atmospheres.
• IECEx Certified Service Facilities Scheme
  Certification of services, e.g. for the maintenance or repair of devices.
• IECEx Personnel Competence Scheme
  Certification of the competence of persons working in potentially explosive atmospheres.
• IECEx Conformity Mark
  Marking that confirms conformity with IECEx certificates.

Key points

• Legal basis
  Not a law, but a voluntary, global certification system.
• Scope of application
  IECEx is recognized by many countries worldwide, e.g. Australia, New Zealand, Canada, USA, Brazil and some Asian countries.
• Standards basis
  Based on international IEC standards (e.g. IEC 60079 series).
  (IEC = International Electrotechnical Commission).
• Certification system
  The device must have an IECEx certificate, which is issued by an accredited testing body (ExCBs, e.g. DEKRA, TÜV Nord,...) after testing using a standardized procedure for tests and assessments.
  The manufacturer needs a suitable quality management system (e.g. according to ISO 9001) that monitors that the devices comply with the certified specifications and that there are no deviations between the delivered devices and the tested sample.
  No CE marking is required.
  All certificates can be viewed in a transparent online database.
  Link to IECEx-Certifications

When will the explosion occur?

An explosion is a sudden and violent release of energy that can be triggered by various physical or chemical processes.
It occurs when a rapid transformation of matter or energy takes place, resulting in a sudden increase in pressure. This usually produces shock waves, heat and sometimes light.
Chemical explosions often result from a rapid reaction of flammable substances with oxygen, such as the detonation of explosives or flammable gases.
An explosion occurs when three conditions are met:

Explosion protection zones acc. IECEx

Areas with potentially explosive atmospheres, also known as explosion protection zones, occur wherever flammable substances in the form of gases, vapors, mists or dusts can occur in hazardous concentrations. These play a central role when working with flammable substances.
In order to minimize risks for people, systems and the environment, explosion protection zones are divided into different categories, each of which requires different safety requirements. The classification is based on the probability and duration of the occurrence of a hazardous explosive atmosphere.
This systematic classification is the basis for the selection of suitable protective measures, such as explosion-proof devices and safety-conscious operating procedures, and ensures operational safety in potentially hazardous environments.

Device labeling of Pt100 resistance thermometers according to IECEx

Device marking in accordance with IECEx is a crucial prerequisite for the safe use of Pt100 - resistance thermometers in potentially explosive atmospheres.
IECEx stands for the EU directives that regulate the requirements for devices and protective systems for use in environments with a potential explosion hazard.
The marking provides important information about the suitability of a device for certain zones and substances as well as the protective measures that the device offers.
The marking must be permanently attached to the device.
Manufacturers, operators and maintenance personnel must understand the marking to ensure the correct selection, installation and maintenance of Pt100 resistance thermometers.
Pt100 resistance thermometers without correct labeling must not be used in potentially explosive atmospheres as they can pose a significant safety risk.
In addition to labeling, regular inspections and maintenance are also required to ensure long-term safety.

Main elements of the device labeling:

• Characteristics of the device
  The marking specifies the areas for which the Pt100 resistance thermometers may be used (device group, device category) and how the explosion protection has been designed (explosion protection type).
  Furthermore, the maximum surface temperature of the device is specified (temperature class).
• Property of the explosive product
  The marking specifies how dangerous the product to be measured (explosion group) may be. The system operator must ensure that the ignition temperature of the product is not lower than the maximum surface temperature of the appliance (temperature class).
  The explosion group and temperature class many products can be found at:
  
  • Gases: https://gestis.dguv.de
    
  • Dusts: https://www.dguv.de/ifa/gestis/gestis-staub-ex/index.jsp

Example for the marking of electrical devices according to IECEx:
(The colored background is only for the assignment to the following explanation).