Intrinsically Safe (IS) Circuit Design for Hazardous Locations

Engineers, designers, installers, and others who need to understand the complexities of intrinsic safety and who wish to apply the concepts involved to real-life scenarios.

Day 1:

Section A: Introduction to Intrinsic Safety Circuits

• What is intrinsic safety
• Applications of IS, advantages and disadvantages of this protection technique
• How intrinsic safety helps protect circuits in hazardous locations
• Ex markings and applicable Standards
• Levels of protection (Ex ia, Ex ib, Ex ic)
• Equipment Protection Level (EPL) achieved by intrinsic safety
• Definition of important terms in intrinsic safety

Section B: Power Supply Analysis

• Types of power supply
• Linear Resistively Limited Circuit
• Fused Limited Circuits
• Combined Fuse and Resistive Circuits
• Characteristics of Non-linear (rectangular) power sources
• Trapezoidal power source characteristics
• Maximum open circuit output voltage (Uo)
• Calculation of Maximum output short circuit current (Io)
• Calculation of Maximum output power Po (linear, trapezoidal, and rectangular)

Section C: Spark Ignition Assessment

• Safety factors and fault conditions
• Resistive assessment
• Capacitive assessment
• Inductive assessment
• Combined capacitive and inductive assessment
• Determination of Ci, Li, Co and Lo
• Spark ignition test
• Spark test apparatus and its limitations
• Infallible components & safety components
• Spark ignition assessment/ testing for dust application

Section D: Thermal Ignition Assessment

• Temperature evaluation
• Fault applications
• Thermal ignition test
• Small components surface temperature evaluation
• Surface temperature and service temperature determination under fault
• Thermal ignition assessment/ testing for dust application

Close of Day 1 – Questions and Answers; definition of terms and concepts introduced in Day One

Self-Administered Day One Test: Application of terms, definitions, and concepts

Day 2:

Section A: Physical Construction

• Creepage and Clearance distancing
• PCB Assessment
• Track layout assessment
• Infallible tracks, wires and connections
• Application of conformal coating
• Use of enhanced distancing and its restrictions
• Application of encapsulation
• Application of solid insulation
• Enclosure requirements for gas and dust applications

Section B: Characteristics of Specific IS Components

• Rating requirements, failure of components, countable and non-countable faults
• Fuses
• Semiconductors
• Current-limiting resistors
• Transformers & relays
• Galvanically separating components/ Opto-couplers
• Electrochemical cells
• Blocking capacitors

Section C: Cells and Battery-operated Equipment Used in IS Systems

• Cell construction requirements
• Cell restrictions and protections
• Spark ignition and surface temperature
• Electrolyte leakage test
• Mechanical test
• Battery pack and protective components
• Charging batteries in hazardous and non-hazardous locations
• Things to consider when your equipment is a battery-operated device

Section D: Zener Diodes & Galvanic Isolators

• Fundamentals of associated apparatus
• Basic circuitry and its functions
• Safety components
• Earthing requirements
• Comparison of Zener Diodes & Galvanic isolators
• Entity Parameters
• Fault consideration
• Testing and verification

Close of Day 2 – Questions and Answers; definition of terms and concepts introduced in Day Two

Self-Administered Day Two Test: Application of terms, definitions, and concepts; Case Study

Day 3:

Section A: Certification Process for IS Equipment

Section B: Installation and Maintenance of IS Systems

• Intrinsically safe systems
• Entity Concept verification and connection of the IS barrier and IS field device
• Cable inductance calculation & cable capacitance calculation
• Control Drawing and Descriptive System Document
• Wiring installation and separation from other non-IS wiring
• NEC, CEC and IEC 60079-14 wiring installation requirements for intrinsic safety systems
• The importance of earthing and grounding
• Practical rules for maintenance and inspection of IS assemblies

Close of Day 3 - Questions and answers; definition of terms and concepts introduced in Day Three

Self-Administered Day Three Test: Application of terms, definitions, and concepts; Case Study that incorporates topics covered over the three days of the course

This three-day course provides everything you need to know about the challenges related to designing an intrinsically safe (IS) system for an Ex location (Explosion protected location). It is intended for persons with little or no knowledge of and experience with hazardous locations and this protection concept. Even the smallest design error can have catastrophic results, so careful attention to all the topics covered in this course is critical. Topics include system and component design, relevant Standards, compliance for certification, installation, and maintenance.

Emphasis is on understanding the concepts, the specific requirements of system components, and achieving compliance with safety requirements, given the gas- or dust-hazardous nature of the environment. A self-administered multiple-choice test is provided at the end of each day, so participants can test their own understanding of the concepts presented and their application in real-life scenarios.

Day 1 is an introduction to the intrinsic safety protection technique, the advantages and disadvantages of this method and how intrinsic safety helps protect circuits in hazardous locations. Levels of protection that can be achieved are covered, as well as the characteristics of types of power sources and their outputs. Two critical concepts of IS system design, spark ignition and thermal ignition assessments are covered in detail. The goal of IS system design is always to achieve a safe system that complies with relevant Standards. Day 1 addresses the Ex-markings that indicate compliance with these Standards.

A glossary is provided at the end of the day that clarifies the meaning of each term covered in Day One. A self-administered evaluation is provided that covers terms, concepts and their application in real life scenarios.

Day 2 of this course begins with a detailed explanation of the components on which an intrinsic safety system depends, as well as their main safety requirements – their physical requirements and layout considerations such as creepage and clearance. Emphasis is placed on specific and accurate calculations for proper and effective design.

The enclosure requirements for IS devices for dust and gas applications are compared. Because some IS products use cells and batteries as the power source, these systems are addressed in detail, along with the tests used to ensure their safety. For those IS products that need to be powered by an external safety barrier, the two common types of barriers (“associated apparatus”) are compared (Zener Diodes & Galvanic isolators).

A glossary is provided at the end of the day that clarifies the meaning of each term covered in Day Two. A self-administered evaluation is provided that covers the terms, concepts and their application from Days One and Two in real life scenarios.

Day 3 prepares the learner for the certification process for intrinsically safe devices. Certification systems available around the world (European, International and North American) are all covered, as are the related legislative authorities. We will discuss the major obstacles that may be encountered as well as best practices to achieve IS certification with the minimum cost and time. Certification of a safe design is no guarantee of safety if the system is installed incorrectly. This course therefore concludes with a discussion of the installation and maintenance requirements of an intrinsically safe system. Topics include Entity Concept verification, Control Drawing and Descriptive System documentation and field wiring against NEC, CEC and IEC 60079-14 (code of practice), inspection and maintenance requirements.

A glossary is provided at the end of the day that clarifies the meaning of each term covered in Day Three. A self-administered evaluation is provided that covers terms, concepts and their application. The evaluation at the end of Day Three challenges the learner to demonstrate an understanding of what has been covered over the three days and apply it to real life scenarios.

This is course covers a wide range of topics related to intrinsic safety for persons with a variety of backgrounds who design and work with equipment in potentially hazardous environments. It is focused specifically on this one protection technique and all the specific aspects that are critical to its effectiveness.

Instructor-led training in a virtual classroom. This means the course is Live Online. Participants will learn through online teaching. Lectures, case studies, group exercises, discussions, problem solving, examples with explanation, assignments and/or quizzes happen in the virtual classroom training. Delivery provides a blend of theoretical knowledge and real-life examples of theory at work when designing an intrinsically safe system. Case studies are used to encourage application-oriented thinking to hazardous environments. Participants need to connect to the class from any internet accessible location. Each module is delivered live using webinar technology, creating a virtual classroom learning environment. Live sessions provide you with direct access to the trainer so you can ask questions, understand complex concepts and share ideas with peers. Webcam and microphone are REQUIRED to interact with the instructor and/or other participants.

The course content and structure are designed by the domain experts from TÜV SÜD.

With immense experience and knowledge in the relevant standards, our team of product specialists and technical experts at TÜV SÜD, developed the course content based on current business landscape and market requirements.

Three, self-administered tests that test theoretical knowledge as well as the ability to apply it to case scenarios.

Access to Standards and codes is helpful but not mandatory. A calculator is required.