Hazcon Inc.
Intrinsic Safety Systems
Hazcon Inc. provides a full suite of consulting services for manufacturers of electrical equipment for hazardous locations and explosive atmospheres.
Intrinsic safety is one of the safest ways to ensure that an electrical device installed in a hazardous location cannot result in a fire or an explosion. Intrinsic safety is a system concept.
Intrinsic safety might seem confusing and involves complex calculations and detailed assessments. But it is not that difficult if we understand the principles behind it. It’s important to understand what intrinsic safety is, the safety of each component in the system, and how an intrinsically safe system is achieved.
In the below intrinsic safety animation, Hazcon Inc. has simplified the concept by focusing on:
To demonstrate why it is critical that electrical equipment to be protected in a hazardous area lets look at an electrical installation in such an area without any protection. An electrical sensor is placed in a hazardous location power is fed to it from a safe area outside the hazardous location.
If a fault happens within the safe area a voltage of 250V or higher can enter the hazardous area. Furthermore if a fault happens within an electrical sensor located inside the hazardous area a high value short circuit current can flow into the hazardous location from the power supply.
In both of these fault conditions, excess temperature, arcs and sparks can ignite the explosive atmosphere present. Intrinsic safety is a highly affective protection technique bases on the principle of limiting the thermal and electric energy within the equipment and its interconnecting wiring.
Intrinsic Safety Systems contain 3 main components:
It is vital that the safety of each component is considered.
Information Courtesy
Behzad Nejad, P. Eng. (Hazcon)
Director & Consulting Engineer at Hazcon Inc.; Hazardous Locations Consulting Services; IECEx, ATEX, CEC & NEC
Specializing in the design, safety and approval of electrical equipment for hazardous locations.
Mr. Nejad has over 15 years of experience as an Electrical Engineer and is a sought after professional in the hzardous area and explosion protection industry. He is fully-qualified at the advanced level of all hazardous locations protection techniques including Intrinsic Safety & Non-incendive, Explosion Proof & Flame proof, Increased Safety, Non-arcing, Purging and Pressurization, Encapsulation, Optical Radiation, and Dust-tight enclosures. Mr. Nejad’s tenure in the industry includes six years at the CSA certification agency, working closely with manufacturers (Emerson, GE, ABB, Siemens, Endress-Houser, VEGA etc.) as a technical and certification engineer for Hazardous locations equipment.
Thorne & Derrick are leaders in the development and distribution of Product Innovations that deliver significant improvements to clients plant, people and operational safety in the explosive atmosphere industries.
Your proactive problem solvers experienced in succession planning for the replacement of obsolete, non-conformant and legacy equipment in hazardous areas.
Your first-choice provider of innovative and competitive solutions to ensure ATEX & IECEx Compliance for Hazardous Area Electrical, HVAC & Process Instrumentation Equipment to UK and international projects.
Control Panels | Plugs | Isolators | Enclosures & Junction Boxes | Lighting | Control Stations | Motor Starters | Heat Trace | Gas Detection | Flame Detection | Process Instrumentation | Process Heating | Ventilation Fans | Security Access Control
Competitive Prices | Extensive Stocks | Technical Support | Express Delivery
Nightstick: a global brand of professional lighting products including flashlights, headlamps and Intrinsically Safe lighting solutions
Portable LED Lighting Meeting or Exceeding Industry Standards
Special thanks to Derek Box at Nightstick for the kind permission to republish
The dangers of explosive environments are obvious in the petroleum and chemical processing industries, but many other industries can create explosive atmospheres that are not as obvious but still represent a serious danger.
Examples illustrating this are facilities that process grains, sugar, metal powders, and wood products. In 2018 grain handling facilities in Nebraska and eastern France were destroyed or seriously damaged by grain dust explosions. In 2008 an explosion wrecked a sugar refinery in Georgia, killing 14 people and injuring another 40. Five workers were fatally injured in an iron dust fire in Tennessee in 2011.
It is essential to understand the conditions that can create explosive environments and the proper equipment required to enter them safely.
The equipment you are using must meet or exceed the standards for the most explosive environment you could face under known or unknown situations. In the United States, intrinsically safe products are tested to the UL 913 5th or 8th edition standards with the UL 913 8th edition being harmonized to the EN/IEC 60079 -01/-11 standard for European Union ATEX certifications and the remaining countries IECEx certifications.
For an explosion to occur, five components must be in place: oxygen, confined space, ignition source, dispersion, and a fuel source. These elements make up the explosion pentagon. The three elements needed for a fire — fuel source, oxygen, and an ignition source — can create a flash fire within a confined space, resulting in the ingredients for an explosion.
Eliminating one of these five elements will prevent an explosion, but eliminating these hazards is not a simple process. Oxygen in confined spaces typically cannot be eliminated. Therefore, managing fuel sources and the use of properly rated equipment to prevent ignition is essential.
As an example, using the ATEX classification system, a Zone 2 environment could quickly become a Zone 1 or even a Zone 0 environment, and your equipment must be rated appropriately as you may not be aware that the environment has changed until it is too late. If you are unsure, analyse the work environment, determine the worst-case scenario, and equip your workers based on that.
The quality of your equipment is vital in explosive environments. You must ensure it is manufactured by a reputable company with documented experience in creating intrinsically safe (IS) products.
The ideal situation would be to purchase all of your IS products from a single manufacturer rather than mixing and matching products from several companies. A single source manufacturer ensures consistent quality and safety across the entire product line. Because of the knowledge, time, and expense required to engineer and produce IS products, a very limited number of companies can achieve this.
Nightstick is a global brand of professional portable LED lighting products that meet or exceed industry standards. Our products are UL 913 certified for Class I DIV 1 (all gas atmosphere groups) and Class II DIV 1 (all dust atmosphere groups), many with a Zone 0 IIC equivalency rating for use in hazardous environments.
Most additionally carry a Zone 0 IIC ATEX and IECEx certification with T3 & T4 temperature rating, making Nightstick a truly globally intrinsically safe lighting company. From penlights to area scene lights, Nightstick leads with over 50 safety rated LED lighting products.
Contact:
Derek Box
Marketing Manager Industrial
Nightstick
Phone: 469-326-9470
Website: www.nightstick.com
Thorne & Derrick are leaders in the development and distribution of Product Innovations that deliver significant improvements to clients plant, people and operational safety in the explosive atmosphere industries.
Your proactive problem solvers experienced in succession planning for the replacement of obsolete, non-conformant and legacy equipment in hazardous areas.
Your first-choice provider of innovative and competitive solutions to ensure ATEX & IECEx Compliance for Hazardous Area Electrical, HVAC & Process Instrumentation Equipment to UK and international projects.
Follow our Showcase Page on LinkedIn to receive hazardous area product innovations, industry news, whitepapers, videos, technical tips and training webinars for professionals involved in the explosive atmosphere industries.
Register HERE for Raytec’s Latest Webinar
Hazardous Area Lighting
Thorne & Derrick International, based in the UK, are Preferred Distributors and Stockists for the Raytec SPARTAN range of ATEX lighting using LED technology for the illumination of hazardous area locations and potentially explosive atmospheres.
With the UK officially leaving the EU, the UKCA mark has been introduced for any hazardous area products being sold into the UK.
In Raytec’s latest webinar, they discuss what the changes mean and how they could affect you if you’re using hazardous area products in the UK, or if you’re purchasing them from a UK manufacturer.
Raytec will also be taking you through what their plans are for their hazardous area lighting range in response to the latest certification criteria, and the changes you can expect to see on SPARTAN LED luminaires in the coming weeks – this Webinar will answer all your questions about UKCA Lighting.
When: Tuesday 16th March 9.00am GMT (London)
Sign-up: 9:00 GMT (London), 10.00 CET (Berlin), 13:00 GST (Dubai), 14:30 IST (Mumbai), 18:00 JST (Tokyo), 20:00 AEDT (Sydney)
https://register.gotowebinar.com/register/5466132310721187856
See how Raytec have been working closely with UK notified body, Eurofins CML to ensure certificates are constantly updated to the latest edition of the standards for all hazardous area lighting in their range in the following Blog.
➡ UKCA Certified Hazardous Area Lighting from Raytec SPARTAN
💡 Did you Know? Thorne & Derrick using latest software provide a FREE LIGHTING DESIGN SERVICE for the specification and supply of ATEX & IECEx Certified light fittings to provide safe and reliable lighting in explosive atmospheres and hazardous area locations.
SPARTAN is a full range of Ex LED luminaires and lighting approved for all ATEX and IEC Ex Zone 1 and Zone 2 hazardous area environments, including UL /CSA C1D2 installations. The hazardous area lighting products are designed for the most extreme environments – Flood, Linear, Bulkhead, Bay and Crane luminaires with emergency and industrial lighting versions are also available from Thorne & Derrick International.
➡ Further Reading: UKCA ATEX & Hazardous Area Equipment Certification
Thorne & Derrick are leaders in the development and distribution of Product Innovations that deliver significant improvements to clients plant, people and operational safety in the explosive atmosphere industries.
Your proactive problem solvers experienced in succession planning for the replacement of obsolete, non-conformant and legacy equipment in hazardous areas.
Your first-choice provider of innovative and competitive solutions to ensure ATEX & IECEx Compliance for Hazardous Area Electrical, HVAC & Process Instrumentation Equipment to UK and international projects.
Follow our Showcase Page on LinkedIn to receive hazardous area product innovations, industry news, whitepapers, videos, technical tips and training webinars for professionals involved in the explosive atmosphere industries.
Global Dust Safety Conference 2021 – REGISTER HERE
Dust Safety Academy
Dr. Chris Cloney, PEng is proud to announce the 2nd annual Global Dust Safety Conference which will take place digitally between March 1st- 3rd 2021 after the success of last years which saw 225 people registered from 25 countries and across 12 different time zones.
➡ Register today and watch replays until March 31st 2021 if time zone differences are challenging.
When registering for this conference you’re not only securing your seat for world-class combustible dust safety training, education seminars and research presentations you are protecting yourself and everybody around you.
💡 Did you know? There has been 726 Fires, 270 Explosions, 446 Injuries and 51 Fatalities recorded in our global database since 2016.
The goal for the 2021 Dust Safety Conference is to get your questions answered about combustible dust. We do this by bringing together the community of stakeholders involved in combustible dust. This includes equipment manufacturers, OEMs, safety system designers, safety system implementers and integrators, regulators, insurance companies and researchers.
Here’s What Makes #DSC2021 Different From Your Average Conference…
Have questions about
Get them answered at the event!
Meet your host, Dr. Chris Cloney, PEng.
Managing Director and Lead Research for Dust Safety Science.
Chris will be bringing together industry experts and researchers to cover combustible dust education from global and regional perspectives.
The purpose of holding the 2021 Global Dust Safety Conference is threefold:
Chris will be joined by over 40 speakers from around the world delivering live presentations including:
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| Reliable 24/7 Dust Detection in Industrial Environments John Korpi Sintrol |
Dust Collector Replacement – Overcoming Murphy’s Law Diane Cave Element6 |
Practical considerations when planning and implementing dust explosion protection Timothy Heneks Dustcon Solutions |
Inherently Safer Design Protocol for Process Hazard Analysis Kayleigh Rayner Brown Dalhousie University |
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| Difference Between Prescriptive and Performance-Based DHAs John Wincek DEKRA |
NFPA 69 – Chapter 12-Material Chokes-Rotary Airlocks Pablo Balan Boss Products |
New 2021 SIL Rating Requirements per NFPA 69 Burke Desautels IEP Technologies |
PPE and Combustible Dust – the often overlooked piece of protection Derek Sang Bulwark Protection |
Q: Who can attend the conference?
A: Anyone can attend the event with the purchase of a general admission ticket. Premium Dust Safety Academy members get access to the conference with their annual subscription.
Q: What if I can’t view the conference live?
A: Replays of the conference presentations will be available for one month after the event for general admission. Premium Dust Safety Academy members have unlimited access to the conference replays from 2020 and 2021.
Q: Are the tickets refundable?
A: No, the tickets are non-refundable. However, they can be reassigned to another individual before February 15, 2021. We will try our best to help you find someone to take the ticket before this date.
Q: How long are the presentations?
A: Live technical presentations are 40 minutes in length (30-minute presentation and 10 minutes of Q&A). Live research sessions are 20-minutes followed by a 5-minute question period. Keynotes are 40 minutes followed by a 15-minute question period. On-demand sessions will vary in length.
Thorne & Derrick are leaders in the development and distribution of Product Innovations that deliver significant improvements to clients plant, people and operational safety in the explosive atmosphere industries.
Your proactive problem solvers experienced in succession planning for the replacement of obsolete, non-conformant and legacy equipment in hazardous areas.
Your first-choice provider of innovative and competitive solutions to ensure ATEX & IECEx Compliance for Hazardous Area Electrical, Heating, Lighting & Process Instrumentation Equipment to UK and international projects.
Control Panels | Plugs | Isolators | Enclosures & Junction Boxes | Lighting | Control Stations | Motor Starters | Heat Trace | Gas Detection | Flame Detection | Process Instrumentation | Process Heating | Ventilation Fans | Security Access Control
Competitive Prices | Extensive Stocks | Technical Support | Express Delivery
When electrical equipment is used in, around, or near an atmosphere that has flammable gases or vapours, flammable liquids, combustible dusts, ignitable fibres or flyings, there is always a possibility or risk that a fire or explosion might occur.
Those areas where the possibility or risk of fire or explosion might occur due to an explosive atmosphere and/or mixture is often called a hazardous (or classified) location/area. Currently there are two systems used to classify these hazardous areas; the Class/Division system and the Zone system.
The Class/Division system is used predominately in the United States and Canada, whereas the rest of the world generally uses the Zone system. However, the United States and Canada are trending more towards the Zone System.
Class/Division System for Hazardous Area Locations
Hazardous locations per the Class/Division system are classified according to the Class, Division, and Group.
Hazardous Area Zone System
Hazardous locations per the Zone system are classified according to its Zone which can be gas or dust. For gas atmospheres electrical equipment is further divided into Groups and Subgroups.
Zone—The Zone defines the probability of the hazardous material, gas or dust, being present in sufficient quantities to produce explosive or ignitable mixtures.
Group—Electrical equipment is divided into three groups.
Various protection techniques and methods have been developed and employed, thus reducing or minimising the potential risks of explosion or fire from electrical equipment located in hazardous locations. Not all methods are listed.
Class/Division System for Hazardous Area Locations
Hazardous Area Zone System
The below concepts are high-level protection concepts. There are also sub-levels of protection that may or not be applicable to each type. Also, some equipment may combine multiple types of protection such as hazardous area lighting:
Equipment Protection Level (EPL) Markings
The EPL marking indicates the level of protection that is given to equipment based on the likelihood of its becoming a source of ignition and distinguishing the difference between explosive gas atmospheres, explosive dust atmospheres, and the explosive atmospheres in mines susceptible to firedamp.
Temperature Code (T Code)
A mixture of hazardous gases and air may be ignited by coming into contact with a hot surface. The conditions under which a hot surface will ignite a gas depends on surface area, temperature, and the concentration of the gas. The same can be said about combustible dusts. The T code or T class rating of a product denotes the maximum surface temperature that a given product will not exceed under a specified ambient temperature. For example, a product with a T code of T3 means that its maximum surface temperature will not exceed 200°C provided it is operated in a ambient temperature defined by the manufacturer.
Class/Division System
Approved equipment is marked according to which Class (I, II, or III), Division (1 or 2), Group (A, B, C, D, E, F, or G), and temperature code (T1 through T6) that it is rated for. For intrinsically safe equipment the words “Intrinsically Safe” or “IS” will precede the actual approval marking to indicate it as being intrinsically safe. Examples are listed below:
Class I Division 1 Group B,C,D T5
CL I Div 2 GP ABCD T5
IS CL I,II,III Div 1 GP ABCDEFG
CL II,III Div 1,2 GP EFG T4
Zone System for Hazardous Area Locations
Approved equipment is marked according to the protection concept for which it has been designed (Ex i, Ex d, Ex n, and etc.), the group (I, IIA, IIB, IIC, IIIA, IIIB, or IIIC), and temperature code (T1 through T6) that it is rated for. For the United States it will be preceded by which Class and Zone it is approved for. Examples are listed below:
Ex ia IIC T5
Ex d IIB+H2 T6
Ex nA IIC T6
Class I Zone 2 AEx nC IIC T5
Additional Terminology
Although the following terminology is not permitted for markings it is commonly used to describe the various types of approvals or when speaking of them.
XP—Flameproof approval for Class I Division 1
EXP—Flameproof approval for Class I Division 1
NI—Non-incendive approval for Class I Division 2
DIP—Dust Ignition Proof approval for Class II Division 1
S—“Suitable For” for Class II Division 2
IS—Intrinsically Safe
Generally speaking, most countries require that products intended for installation in a hazardous location be approved by a recognized authority or approval agency (governmental or independent) which that country has established by various laws, regulations, or codes. See table 1 for an overview of approvals and approval agencies.
North American Approvals
Of the 15 national testing laboratories (NRTL’s) in the United States, only a few are qualified to approve products for use in hazardous locations. Two such agencies are; Factory Mutual (FM) and Underwriters Laboratories (UL). In Canada, products are approved by the Canadian Standards Association (CSA).
European Approvals
Each country belonging to the European Union has established one or more “Notified Bodies” for product approval. Notified Bodies not only approve products for use within their own country, commonly called national certifications/approvals, but also for any other country within the union, known as CENELEC certifications/approvals. CENELEC is the acronym for European Committee for Electrotechnical Standardization. A product which has been CENELEC certified or approved by any of the Notified Bodies is automatically accepted for use within all of the participating union countries. In July 2003 a European Directive, called the ATEX Directive, which pertains to equipment for explosive atmospheres, was adopted. All equipment intended for use in explosive atmospheres must comply with the ATEX Directive in order to be sold into the European Union.
International Approvals for Hazardous Area Locations & Explosive Atmospheres
Countries participating in the IECEx Scheme (International Electrotechnical Commission on explosion protected equipment, known as “Ex”) can issue either an international certification or a national certification of explosion protected equipment. Each country within the IECEx scheme establishes an ExCB (Ex Certification Body) which can approve products. ExCB’s can issue the national certification for their country based upon the IECEx standards (including any national deviations) and the international certification. Currently, Australia is the only country accepting international certifications for use in their country.
| Table 1. Approval Agencies | ||
| Approvals¹ | Approval Agencies Used² | Approvals Accepted |
| FM | FM—Factory Mutual | North America |
| CML | CML—Certification Management Limited | Japan |
| CSA | CSA—Canadian Standards Association | North America |
| ATEX | Baseefa—British Approvals Service for Electrical Equipment in Flammable Atmospheres KEMA—NV tot Keuring van Elektrotechnische Materialen LCIE—Laboratorie Central des Industries Electriques |
European Union |
| IECEx | CSA—Canadian Standards Association Baseefa—British Approvals Service for Electrical Equipment in Flammable Atmospheres |
International |
| SAA | SAA—Standards Association of Australia | Australia |
| NEPSI | NEPSI—National Supervision and Inspection Centre for Explosion Protection and Safety of Instrumentation | China |
| TIIS | TIIS—Technology Institution of Industrial Safety | Japan |
| INMETRO | INMETRO—National Institute of Metrology, Quality and Technology | Brazil |
| CUTR | FGUP Certification Centre: SC VSI VNIIFTRI Certification Body: OS VSI VNIFFTRI |
Russia, Belarus, Kazakhstan & America |
| ¹ Fisher™ products may carry additional approvals. Contact T&D for additional approval information. ² Fisher product approvals may be certified by other agencies. Contact T&D for additional information. |
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Figure 1. Typical I.S Installation
Selecting an intrinsic safety barrier with the required entity ratings depends upon the combined effects of the instrument, its cabling, and any instrument accessories such as the AMS Trex™ Device Communicator. Determine the barrier entity ratings using the following guidelines:
Voc ≤ Vmax
Isc ≤ Imax
Ca ≥ Ci + Ccable
La ≥ Li + Lcable
where:
Voc = Barrier open circuit voltage
Vmax = Instrument Vmax
Isc = Barrier short circuit current
Imax = Instrument Imax
Ca = Barrier acceptable connected capacitance
Ci = Instrument total unprotected internal capacitance
Ccable = Signal cable total capacitance
La = Barrier acceptable connected inductance
Li = Instrument total unprotected internal inductance
Lcable = Signal cable total inductance
The values Voc, Ioc, Ca, and La are specified by the barrier manufacturer for any given barrier. The values of Ccable and Lcable for the signal cable must be determined for the specific cable used.
Example barrier entity ratings calculation
A system is comprised of a FIELDVUE™ DVC6200 digital valve controller (FM approved), a Device Communicator (FM approved), and 1000 feet of cable with 60 pF/ft capacitance and 0.2 μH/ft inductance. Calculate the barrier entity ratings.
Figure 1 shows a typical I.S. installation.
Calculate Ccable and Lcable
Ccable = 60 pF/ft x 1000 ft
= 60 nF
Lcable = 0.2 μH/ft x 1000 ft
= 0.2 mH
Determine Ca and La for the barrier
Ca ≥ Ci (DVC6200) + Ci (TREX) + Ccable
≥ 5 nF + 0 nF + 60 nF
Ca ≥ 65 nF
La ≥ Li (DVC6200) + Li (TREX) + Lcable
≥ 0.55 mH + 0 mH + 0.2 mH
La ≥ 0.75 mH
Determine Voc and Isc of the barrier. Note that in this example the output of the Trex (Voc (TREX) and Isc (TREX)) must also be considered because it can also add energy to the loop besides just the barrier itself. Voc of the barrier plus any additional voltage that could be added to the loop from each device must be subtracted from Vmax for each device. Isc of the barrier plus any additional current that could be added to the loop from each device must not exceed Imax for each device.
Voc of the barrier must meet all of the following conditional requirements.
Voc ≤ 28.1 VDC
Isc of the barrier must meet all of the following conditional requirements.
Isc ≤ 200 mA
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. All sales are governed by our terms and conditions, which are available upon request. We reserve the right to modify or improve the designs or specifications of such products at any time without notice. Emerson.
Thorne & Derrick are leaders in the development and distribution of Product Innovations that deliver significant improvements to clients plant, people and operational safety in the explosive atmosphere industries.
Your proactive problem solvers experienced in succession planning for the replacement of obsolete, non-conformant and legacy equipment in hazardous areas.
Your first-choice provider of innovative and competitive solutions to ensure ATEX & IECEx Compliance for Hazardous Area Electrical, Heating, Lighting & Process Instrumentation Equipment to UK and international projects.
Control Panels | Plugs | Isolators | Enclosures & Junction Boxes | Lighting | Control Stations | Motor Starters | Heat Trace | Gas Detection | Flame Detection | Process Instrumentation | Process Heating | Ventilation Fans | Security Access Control
Competitive Prices | Extensive Stocks | Technical Support | Express Delivery
Published 13 Mar 2020
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Published 04 Jul 2019
Press Release Date: 04.07.2019 uploaded by Chris Dodds (T&D Sales + Marketing Manager) Category: Stockist Distributor Agreement Announcement Thorne & Derrick International announce that they have signed a Preferred Distributor Agreement with Raytec, the world leading manufacturer of LED...
