Class 1 Div 1 vs. Class 1 Div 2

Attribute	Class 1 Div 1	Class 1 Div 2
Definition	Area where ignitable concentrations of flammable gases, vapors, or liquids can exist under normal operating conditions	Area where ignitable concentrations of flammable gases, vapors, or liquids are likely to exist occasionally under normal operating conditions
Frequency of Hazardous Atmospheres	Regular presence of hazardous atmospheres	Occasional presence of hazardous atmospheres
Equipment Requirements	Explosion-proof or intrinsically safe equipment required	Non-incendive or explosion-proof equipment required
Installation Requirements	More stringent installation requirements	Less stringent installation requirements

Introduction

When it comes to hazardous locations, it is crucial to understand the different classifications that are used to designate the level of safety required for electrical equipment. Two common classifications are Class 1 Div 1 and Class 1 Div 2. While both are designed for hazardous environments, there are key differences between the two that are important to consider when selecting the appropriate equipment for a specific location.

Definition and Scope

Class 1 Div 1, also known as Division 1, is a classification used for locations where flammable gases, vapors, or liquids are present in quantities sufficient to produce explosive or ignitable mixtures. This classification requires equipment to be designed and certified to prevent the ignition of these substances. On the other hand, Class 1 Div 2, or Division 2, is used for locations where flammable gases, vapors, or liquids are present but in lesser quantities that do not pose an immediate threat of explosion. Equipment for Class 1 Div 2 locations must still be designed to prevent ignition, but the requirements are less stringent compared to Class 1 Div 1.

Equipment Design and Certification

One of the main differences between Class 1 Div 1 and Class 1 Div 2 is the level of design and certification required for electrical equipment. In Class 1 Div 1 locations, equipment must meet strict standards to ensure that it is explosion-proof and capable of preventing the ignition of flammable substances. This often involves the use of specialized materials and construction techniques to minimize the risk of sparking or overheating. On the other hand, equipment for Class 1 Div 2 locations still needs to be designed to prevent ignition, but the requirements are not as stringent as those for Class 1 Div 1. This means that equipment for Class 1 Div 2 locations may be less expensive and easier to obtain compared to Class 1 Div 1.

Installation and Maintenance

Another important consideration when comparing Class 1 Div 1 and Class 1 Div 2 is the installation and maintenance requirements for electrical equipment. In Class 1 Div 1 locations, equipment must be installed and maintained by qualified personnel who are trained in working with hazardous materials. This is necessary to ensure that the equipment is properly installed and functioning correctly to prevent any potential ignition sources. On the other hand, equipment for Class 1 Div 2 locations may have less stringent installation and maintenance requirements, as the risk of explosion is lower compared to Class 1 Div 1. However, it is still important to follow manufacturer guidelines and industry best practices to ensure the safety and reliability of the equipment.

Cost and Availability

Cost and availability are also important factors to consider when choosing between Class 1 Div 1 and Class 1 Div 2 equipment. Due to the more stringent design and certification requirements for Class 1 Div 1, equipment for these locations is often more expensive compared to Class 1 Div 2. Additionally, there may be fewer options available for Class 1 Div 1 equipment, as manufacturers must meet specific standards to ensure compliance with the classification. On the other hand, equipment for Class 1 Div 2 locations may be more readily available and cost-effective, making it a more practical choice for locations where the risk of explosion is lower.

Conclusion

In conclusion, while both Class 1 Div 1 and Class 1 Div 2 are designed for hazardous locations, there are key differences between the two that must be considered when selecting electrical equipment. Class 1 Div 1 is intended for locations with a higher risk of explosion, requiring more stringent design and certification standards, as well as specialized installation and maintenance procedures. On the other hand, Class 1 Div 2 is suitable for locations with a lower risk of explosion, offering a more cost-effective and readily available option for electrical equipment. By understanding the attributes of each classification, individuals can make informed decisions to ensure the safety and compliance of their electrical installations in hazardous environments.