Hazardous Location Ratings identify the risk level associated with the presence of potentially dangerous substances in a specific location. In the case of Class I Div 2 Hazardous Location Ratings, they are locations where flammable gases and vapors might be present, usually in the case of a spill, ventilation system failure, or abnormal operations. Understanding these designations is essential for maintaining safety, especially in high-risk sectors like Oil & Gas, Chemical Manufacturing, and Pharmaceutical industries.
At Profire, our burner & combustion management solutions operate predominantly within Class I Div 2 Hazardous Locations, and we generally adhere to both the Canadian Electrical Code (CEC) and the National Electrical Code (NEC). In this article, we explore Hazardous Location Ratings and why understanding them is important.
The Canadian Electrical Code (CEC) & the National Electrical Code (NEC)
As mentioned, Profire predominantly follows the CEC and NEC guidelines when developing our burner & combustion management solutions. We always stay updated with the latest requirements to keep up with any revisions over time. It’s important to adhere to the code requirements in your area to stay safe and compliant. But what are these codes?
The National Electrical Code (NEC)
The National Electrical Code (NEC) is used by the National Fire Protection Association (NFPA) to set the standards for hazardous locations in the United States. Adhering to NEC guidelines is crucial for safe and legal operations. By following NEC standards for classification appropriately, you guarantee the use of the right safety measures, compliance with regulations, and the safeguarding of your business and staff.
The Canadian Electrical Code (CEC)
The Canadian Standards Association (CSA) uses the Canadian Electrical Code (CEC), enforced by the Authorities Having Jurisdiction (AHJs), to set the standards and regulations that govern electrical installations in Canada. The CEC’s main goal is to ensure electrical safety by establishing minimum requirements for installing, maintaining, and operating electrical equipment. [5]
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Understanding Hazardous Locations
Hazardous Locations consist of classes, divisions, and zones. Understanding the significant risks these locations carry, and what each class, division & zone signifies, is vital. When these hazards are present, and location ratings are given, specific safety measures and adherence to regulations are required. Understanding the different criteria for hazardous locations allows you to implement the appropriate safety protocols for your operations and, most importantly, your personnel.
Hazardous Location Classification
Hazardous locations are classified by the type of ignitable or explosive substance present in the atmosphere. There are three class levels for hazardous locations: Class I, Class II, and Class III. [3]
Class I Locations – gas and vapor environments: Any location with potential flammable gases or vapors prone to ignition. These locations require explosion-proof equipment and safety measures to prevent hazards. Please note that in Canada, Class I locations are further divided into divisions (pre-1998) and zones (post-1998). [3]
Class II Locations – dust environments: Any location with combustible dust particles. These particles become suspended in the air and create a risk of explosion. Ventilation and dust control are required in these locations. And equipment must be dust tight. [3]
Class III Locations – fibers and flyings environments: Any location with easily ignitable fibers like cotton, wool, and other similar materials. These locations require equipment enclosures and fittings to be constructed to minimize the entry of fibers or flyings. [3]
Hazardous Location Divisions
Hazardous locations are divided into two divisions that apply across all classes.
Division 1: Hazardous locations that contain ignitable hazards during normal operations on a continuous, intermittent, or periodic basis. [3]
Division 2: Hazardous locations with volatile, flammable liquids or gases, typically contained in closed containers or systems, where exposure only happens in the event of an accidental rupture or system breakdown. [3]
Hazardous Location Zones
In the NEC and CEC classification systems, zones are defined by the presence of gas or dust and the likelihood of ignition. NEC has six hazard levels for each material (Zones 0-2, 20-22), CEC has three (Zones 0-2), and the division system has two levels for all materials.
In the past, industries typically classified hazardous locations as Division 1 or 2 based on NEC or CEC, whichever code they adhered to. Now, post amendments, locations with gases or vapors (Class I) adhering to the CEC should be reclassified as Zone 0, 1, or 2. [4]
Comparing Divisions and Zones
Division 2 aligns with Zone 2, while Division 1 corresponds to Zone 0 or 1. The key difference lies in their treatment of terminations. In the International Electrochemical Commission (IEC) Zone System, which the CEC adopted in 1998, terminations rated for increased safety aren’t seen as ignition sources, and undergo testing for resistance to heat and vibration. In contrast, the Division System views wire terminations as potential ignition sources due to the risk of loosening, short circuits, and arcs. See a breakdown of the zone system below. [4]
The NEC and CEC Zones
It’s worth noting that Zones 0-2 apply to both the NEC and CEC, while Zones 20-22 are strictly for the NEC. Additionally, Zones 0-2 are reserved for gases, vapors, and mists—while Zones 20-22 are reserved for dusts, fibers, or flyings. [4]
NEC & CEC Zone 0: Flammable gases or vapors that persistently exist or linger for extended periods in ignitable concentrations.
NEC & CEC Zone 1: Flammable gases or vapors can be present in ignitable concentrations likely to occur under normal operating conditions.
NEC & CEC Zone 2: Flammable gases or vapors may be present in ignitable concentrations unlikely to occur under normal operating conditions and are only transient.
NEC Zone 20: Flammable dusts, fibers, or flyings consistently present or remain in ignitable concentrations for extended periods.
NEC Zone 21: Flammable dusts, fibers, or flyings that may be present in ignitable concentrations that could occur under normal operating conditions.
NEC Zone 22: Flammable dusts, fibers, or flyings that may be present in concentrations that could ignite, though such conditions are unlikely during normal operations and occur briefly.
Class I Locations Divisions & Zones in Canada
As mentioned, Class I Locations in Canada are divided into divisions and zones based on the year of construction. Before 1998, hazardous locations followed the pre-1998 version of the Canadian Electrical Code (CEC). In 1998, the code adopted the “three zone area” system from the International Electrotechnical Commission (IEC) for Class 1 Hazardous Locations, aligning Canadian standards with international ones. While division systems are maintained for pre-1998 CEC facilities, new constructions follow the IEC zone classification. [3]
Hazardous Location Class Groupings
The classification of groupings is based on the hazardous materials found within the surrounding atmosphere. [1] Class I groups apply to both CEC and NEC standards, while Class II groups are NEC specific. [4]
Class I Groups [1]:
Group A: Acetylene
Group B: Acrolein, Butadiene, Ethylene Oxide, Hydrogen, Propylene Oxide, and similar gases or vapors.
Group C: Acetaldehyde, Carbon Monoxide, Cyclopropane, Ether, Ethyl, Ethylene, Hydrogen Sulfide, Isoprene, and Morpholine.
Group D: Acetone, Ammonia, Benzene, Butane, Ethanol, Gasoline, Hexane, Methane, Methanol, Naphtha, Natural Gas, Propane, Toluene, and Vinyl Chloride.
Class II & III Groups [1]:
Group E: Combustible metal dusts: Aluminum, Magnesium, Bronze, Chromium, Titanium, Zinc and their Commercial Alloys.
Group G: Chemicals, Grain Dust, Flour, Plastic, Starch, Sugar, and Wood.
The Differences Between Class I Div 1 & Class I Div 2
The presence of flammable gases or vapors, prone to ignition, determines a Class I Hazardous Location Rating. When it comes to the divisions within the class, the differences are clear:
Class I Div 1: Hazardous locations that may contain ignitable hazards, such as flammable gases or vapors, during normal operations.
Class I Div 2: Hazardous locations where ignitable hazards, such as flammable gases or vapors, can be present under abnormaloperations.
With Class I Div 2 Hazardous Locations, the concentrations of ignitable hazards are generally not present under normal operating conditions. Understanding the classification of your operation allows you to equip your personnel with the proper safety training and personal protective equipment (PPE).
Classifying Class I Div 2 Hazardous Areas requires checking off the following items:
Is there a presence of flammable gases or vapors in the atmosphere?
What’s the likelihood of these hazards being present under abnormal operations?
What is the ignition temperature of the hazards?
What’s the energy level of electric and mechanical equipment used in the area?
Answering these questions and adhering to the classification requirements ensures that your applications and equipment follow the regulations laid out within the National Electric Code (NEC). Understanding these regulations cannot be overstated.
Key Considerations for Equipment in Hazardous Locations
Equipment in Hazardous Locations must meet strict standards to prevent incidents. When making decisions on the equipment for your applications, adhering to the following requirements will safeguard your personnel and assets.
Intrinsically Safe Equipment
Intrinsically Safe Equipment mitigates the risk of igniting hazardous atmospheric mixtures by restricting thermal or electrical energy levels. By limiting energy levels, you can prevent sparks, heat, or other ignition sources from causing explosions, ensuring safe operation with flammable gases, vapors, or dust. This equipment is often designed with components that control the energy released to ensure safety, even under fault conditions. Intrinsically safe equipment is commonly used in industries where explosive atmospheres may be present. [6]
Explosion-Proof Ratings
Explosion-Proof Ratings are essential, as they indicate the equipment’s ability to contain explosions within its enclosure. Opting for higher-rated equipment ensures compliance with regulations and minimizes explosion risks. Understanding Explosion-Proof classification is key to accurately evaluating safety conditions and adhering to worksite safety rules. [7]
T-Code/Temperature Class
T-Code, or Temperature Class, denotes the peak surface temperature an electrical device can achieve during normal use. This classification is vital for safety in areas with flammable gases, vapors, or dust. Why do T-Codes matter? They prevent ignition, ensure safety compliance, and enhance system versatility. [8]
Preventing Ignition: Flammable substances have auto-ignition temperatures—the point at which they ignite without a flame or spark. That’s why understanding the T-Code is crucial. Because it ensures your equipment’s surface temperature stays below this threshold, averting potential explosions.
Safety Compliance: Your equipment in hazardous locations must comply with specific safety standards. With the T-Code, you know what equipment is needed to meet these standards. Ensuring you’re compliant and achieve safe operation in potentially explosive atmospheres.
Versatility: Lower T-Codes, like T6 with a max surface temperature of 85ºC, can be used in environments requiring higher T-Codes, such as T5 or T4. However, the reverse isn’t possible. This adaptability is necessary to ensure safety across hazardous locations.
It’s important to note these factors when choosing the most suitable equipment for your operations to ensure safety, compliance, and efficiency in hazardous environments.
Regulators, Certifications and Standards
Being aware of the industry regulators and acquiring the appropriate certification to adhere to the correct standards is fundamental for your operational success.
National Fire Protection Association (NFPA): Adherence to the key standards established by the NFPA are vital for fire safety, asset protection, and employee well-being. Following NFPA guidelines minimizes fire hazards, providing strict safety protocols for your operations.
Canadian Standards Association Group (CSA): Following the Canadian Electrical Code standard published by the CSA is vital for proper installation and maintenance of electrical equipment in buildings, structures, and premises in Canada.
Occupational Safety and Health Administration (OSHA): Compliance with OSHA regulations will minimize injury risks. Adhering to OSHA guidelines helps avoid penalties and legal troubles. Doing so can raise employee morale and productivity, through a dedicated focus on safety.
Atmosphères Explosives (ATEX) Certifications: These vital certifications are European Union directives for global hazardous location safety compliance in the EU. Understanding and obtaining ATEX certification can streamline compliance and boost reputation, creating growth opportunities.
Installation and Maintenance Best Practices
Following proper guidelines helps ensure safety in your installation and maintenance practices. With Hazardous Location Ratings, adhering to specific procedures can help prevent hazards and protect facilities and personnel in challenging environments.
Preventative Maintenance supports safe and efficient operations. Staying on top of your operational needs helps avoid unexpected failures, prolong the lifespan of company assets, and experience fewer interruptions. This strategy fosters a secure working environment for your team.
A regular 12-point inspection schedule supports equipment maintenance and allows you to easily identify and resolve issues to stay compliant with standards.
Understanding and adhering to Hazardous Location Ratings is crucial for supporting safety and operational efficiency in hazardous environments. By ensuring compliance, you not only adhere to legal requirements, but also understand how to mitigate risks and protect your personnel and equipment.
To make sense of these classifications, we’ve created an easy-to-use info sheet that simplifies Hazardous Location classification just for you!
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