Intrinsically Safe (IS) Circuit Design for Hazardous Locations

This course is designed for engineers, technical professionals, and decision-makers involved in the design, assessment, installation, maintenance, certification, or approval of electrical and electronic equipment used in hazardous (Ex) locations. It is particularly valuable for professionals who need to understand not only the principles of intrinsic safety, but also how to apply them in real-world industrial environments.

This training is recommended for:

• Electrical Engineers
• Electronics Design Engineers
• Instrumentation and Control Engineers
• Process Control Engineers
• Product Development Engineers
• Hardware Design Engineers
• Functional Safety Engineers
• Compliance and Certification Engineers
• Explosion Protection (Ex) Specialists
• Hazardous Area Engineers
• Technical Managers
• Engineering Managers
• Maintenance Engineers
• Reliability Engineers
• Project Engineers
• System Integrators
• Instrument Technicians
• Certification and Regulatory Affairs Professionals
• Quality and Compliance Personnel
• Product Managers responsible for Ex-certified products

Industries Served

The course is especially relevant to professionals working in:

• Oil & Gas
• Petrochemical
• Chemical Processing
• Hydrogen Production and Storage
• Renewable Energy
• Pharmaceutical Manufacturing
• Mining and Minerals Processing
• Food and Beverage Processing
• Water and Wastewater Treatment
• Power Generation
• Industrial Automation
• Process Instrumentation Manufacturing
• Hazardous Area Equipment Manufacturing

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.

What You Will Gain

Upon completion of this course, participants will be able to confidently design, evaluate, install, and support intrinsically safe systems while understanding the technical and compliance requirements that govern their use in hazardous locations.

Key Benefits

Participants will learn how to:

• Understand the principles of intrinsic safety and their practical application in hazardous environments.
• Perform intrinsic safety assessments including spark ignition, thermal ignition, power source, and entity parameter evaluations.
• Select and evaluate safety-critical components used in intrinsically safe circuits.
• Design intrinsically safe systems in accordance with IEC 60079-11 and related standards.
• Interpret Ex markings, Equipment Protection Levels (EPLs), temperature classes, and hazardous area classifications.
• Apply best practices for PCB layout, creepage, clearance, insulation, grounding, and fault analysis.
• Properly evaluate batteries, associated apparatus, zener barriers, and galvanic isolators.
• Verify intrinsic safety loops using the Entity Concept.
• Develop and review documentation packages required for certification.
• Understand IECEx, ATEX, and North American certification frameworks and approval processes.
• Identify common design, installation, and certification mistakes before they become costly project delays.
• Improve communication with certification bodies and regulatory authorities.
• Apply concepts to realistic engineering scenarios through discussions, case studies, and practical examples.

Organizational Benefits

Organizations benefit from:

• Reduced design and certification rework
• Improved compliance readiness
• Faster time-to-market for hazardous-area products
• Enhanced engineering competence
• Improved installation quality and documentation practices
• Reduced operational and safety risks
• Stronger understanding of international certification requirements

This highly interactive instructor-led training combines theory, engineering practice, and real-world application to ensure participants can confidently apply intrinsic safety principles in their own projects.

The course is delivered live online in a virtual classroom environment and includes:

• Expert instructor-led presentations
• Guided engineering examples
• Real-world industrial case studies
• Interactive group discussions
• Design review exercises
• Problem-solving activities
• Practical calculation workshops
• Daily knowledge assessments
• End-of-day glossaries
• Peer learning and experience sharing
• Comprehensive capstone case study integrating concepts from all three days

Throughout the program, participants progressively build their knowledge from fundamental concepts to system-level design, installation, maintenance, and certification considerations.

The training emphasizes practical decision-making and application rather than theory alone, helping participants understand not just what the requirements are, but why they exist and how they are applied in actual projects.

Participants receive direct access to the instructor throughout the course and are encouraged to ask questions, participate in discussions, and share real-world challenges from their own industries.

Webcam and microphone are required to participate in discussions, exercises, and collaborative learning activities.

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

Participants who attend at least 90% of the total training duration will receive a Certificate of Attendance from TÜV SÜD Academy.

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

No prior experience with intrinsic safety is required.

Participants should have:

• A basic understanding of electrical or electronic systems
• Familiarity with common electrical components such as resistors, capacitors, power supplies, and wiring systems
• An interest in hazardous-area equipment, industrial automation, process instrumentation, or product certification

The course starts with foundational intrinsic safety concepts and progressively advances toward design assessment, installation requirements, and certification considerations, making it suitable for both newcomers and experienced professionals seeking a deeper understanding of intrinsic safety.

Recommended

The following knowledge is helpful but not mandatory:

• Basic electrical engineering principles
• Industrial instrumentation
• Control systems
• Hazardous-area classifications
• IEC, ATEX, NEC, or CEC environments

Required Materials

Participants should have access to:

• Calculator
• Stable internet connection
• Webcam and microphone
• Access to course materials provided during training

1. What is intrinsic safety (IS) and why is it important?
Intrinsic safety is a protection technique that limits electrical and thermal energy to prevent ignition in hazardous environments. It is critical in industries like oil & gas, chemical, and mining where explosive atmospheres may be present.

2. Who should attend this training course?
This course is ideal for engineers, designers, technicians, safety professionals, and anyone involved in the specification, design, installation, or maintenance of equipment used in hazardous locations.

3. Do I need prior experience in hazardous area classification?
Basic electrical knowledge is recommended, but the course typically covers foundational concepts such as hazardous area classifications and protection methods, making it accessible to those newer to the topic.

4. What standards and regulations are covered in the course?
The training introduces key international standards such as IEC, ATEX, and other relevant certification frameworks that govern intrinsically safe system design and compliance.

5. Will the course include practical examples or real-world applications?
Yes, the course incorporates real-world scenarios and examples to help participants understand how intrinsic safety principles are applied in actual industrial environments.

6. What skills will I gain from this course?
Participants will learn how to design intrinsically safe circuits, select appropriate components, evaluate safety parameters, and ensure compliance with industry standards.

7. How is this training beneficial for my organization?
It helps reduce safety risks, ensures regulatory compliance, improves system reliability, and equips teams with the knowledge to design safer systems in hazardous environments.

8. Is this course focused on theory or practical application?
The course combines both theoretical foundations and practical design approaches, ensuring participants can apply what they learn directly to their work.

9. Can this training help with certification or compliance projects?
Yes, it provides the knowledge needed to support intrinsically safe system design and documentation required for certification and audits.

10. What industries benefit most from this training?
Industries such as oil and gas, petrochemical, pharmaceuticals, mining, and manufacturing benefit most due to their exposure to hazardous environments.

11. Will I learn how to select and verify IS barriers and devices?
Yes, the course covers proper selection, integration, and evaluation of IS barriers, field devices, and associated apparatus.

12. How does this course differ from general electrical safety training?
Unlike general electrical safety training, this course focuses specifically on preventing ignition risks in explosive atmospheres through intrinsic safety design principles.

TÜV SÜD is a leading provider of training and certification in hazardous locations (HazLoc) safety and compliance. Its programs are widely recognized in the United States and internationally. The experts at TÜV SÜD Academy possess in-depth knowledge of global standards such as IECEx, ATEX, and North American requirements, and are committed to delivering practical, application-focused training. Professionals responsible for equipment and systems in explosive atmospheres play a critical role in ensuring operational safety and compliance, and their competence is essential for the safe and efficient functioning of industrial facilities.