Acetylene, ammonia, arsine, butane, carbon monoxide, cyclopropane, ethane, ethylene, ethyl chloride, hydrogen, isobutan, methane, methyl chloride, propane, propylene, silane; what do all of these gasses have in common? That’s right, they are all extremely flammable under the certain conditions. If your facility handles these materials, you already know that there are certain precautions you and your workers must take while performing your daily duties. You also know that the equipment you use can become a source of ignition. The U.S. Department of Labor knows this too, which is why the Occupational Safety and Hazard Administration has produced the National Electric Code (NEC) to classify the different kinds of hazardous locations that exist and the safeguards electrical equipment must have in place in order to be safe for use in these environments. There are also risk assessment agencies that run thorough testing on any product proposed for use in a classified hazardous environment. Without approval from one of these bodies, products will not be safe to use around flammable gases or any other incendiary materials.
Classifying Locations Where Flammable Gas is Present
The classification system for hazardous environments begins with three different class types, which define the general nature of the hazardous material in the surrounding atmosphere. Class II deals with combustible or conductive dusts while Class III deals with ignitable fibers or flyings such as wood chips or cotton. Flammable gases, however, are all placed in Class I. A Class I hazardous environment is any location where flammable gases or vapors are present in the air in such quantities sufficient to be explosive or ignitable. Common Class I locations are petroleum refineries, utility gas plants, paint manufacturing facilities, distilleries, and fuel servicing areas. Classes are then categorized as Division I or Division II. Division I means the substance referred to by Class is present under normal working conditions. Division II means that the substance is only present under abnormal conditions, such as a leak, container failure, or system breakdown. Locations are further segmented into groups, which define the hazardous material being handled. These are defined on the properties of various gases and vapors and how they will affect the likelihood and severity of an explosion. This includes flame temperature, minimum ignition energy, upper and lower explosive limits, and molecular weight. Class I includes Groups A through D. Group A is a rare classification since it only includes acetylene which is used by automotive manufacturers as a key component in low pressure carburizing to create a strong, wear-resistant surface layer on steel parts. ItÕs also used by welding and metal fabricators for oxy-fuel welding and cutting as well as brazing applications because it offers the hottest flame temperature of all commercially available fuel gases. Group B includes hydrogen, fuel and combustible process gases containing more than 30% hydrogen by volume or gases of equivalent hazard such as butadiene, ethylene, oxide, propylene oxide and acrolein. Group C includes carbon monoxide, ether, hydrogen sulfide, morphline, cyclopropane, ethyl and ethylene or gases of equivalent hazard. Group D is the most common and includes gasoline, acetone, ammonia, benzene, butane, cyclopropane, ethanol, hexane, methanol, methane, vinyl chloride, natural gas, naphtha, propane or gases of equivalent hazard.
Requirements for Electrical Equipment
Any electrical equipment installed in a hazardous location must be specially designed and tested to ensure that it does not become a source of ignition. Arcs and sparks, high surface temperatures, and equipment failure of standard equipment can all trigger an explosion. For example, a light switch may emit a small, harmless spark that’s visible when it’s turned on. However, in an area where a flammable gas or vapor is present, this “harmless” spark may actually cause a potentially deadly explosion. Equipment must either be designed to contain an explosion within the device, or it must not produce sparks with sufficient energy to produce an explosion.
Non-Incendive and Intriscially Safe Scales
In North America, the suitability of equipment for use in a specific hazardous area must be tested and approved by a nationally recognized testing laboratory such as UL, FM Approvals or MET. Scales are often used in hazardous environments as a safety precaution, for instance, to monitor the level of liquefied gas in a drum as well as a variety of other purposes. However, ensuring that a safety precaution doesn’t pose a safety risk requires approval by one of these bodies.
Our ArlynGuard B, C, F, and P scales have one or more components that have been tested and approved to be Intrinsically Safe for use in an impressive range of hazardous locations including:
• Intrinsically safe for use in Class I, II, III; Division I; Groups A through G
• Non-incedive for use in Class I; Division II; Groups A through D
• Suitable for use in Class II; Division II; Groups F & G
• Suitable for use in Class III; Division II
Each ArlynGuard scale is equipped with one or more of:
• Model MKE-5-IS(-C) Digital Weight Indicator System
• Load Cell Models 620-300-IS, 620-100-IS, 620-50-IS, 620-25-IS, 620-10-IS, 520-10000L-IS, 520-5000L-IS, 520-5000IS, 520-2500-IS, 520-1250-IS, 320-500-IS and 320-250-IS
which are FM Approved components as per Approval Standard 3600, 3610, 3611 and 3810.
An intrinsically safe rating means that any arcs or sparks produced do not have sufficient energy (or heat) to ignite a flammable substance. They’re also rated as non-incendive for use in Class I, Division II, Groups A through D. A non-incendive rating means that the equipment is non-sparking or not able to generate sufficient thermal or electrical energy to ignite a volatile atmosphere.
ArlynGuard Explosion Proof Scales: Intrinsically Safe
Our ArlynGuard line of scales features bench, cylinder, platform and floor scale models in a variety of capacities and platform sizes and can even be customized to meet your unique specs. All scales are equipped with industrial-grade stainless steel load cells, which provide more accurate measurements and increased durability and longevity as well as protection from shock and overloading. They also feature a large, graphical LCD digital display that is easy to read (even at a distance) and comes with more than 100 memory locations, net/gross, zero, and multiple units conversion.
Our ArlynGuard B, C, F, and P scales have one or more components that have been tested and approved to be Intrinsically Safe for use in an impressive range of hazardous locations including:
• Intrinsically safe for use in Class I, II, III; Division I; Groups A through G
• Non-incedive for use in Class I; Division II; Groups A through D
• Suitable for use in Class II; Division II; Groups F & G
• Suitable for use in Class III; Division II
Each ArlynGuard scale is equipped with one or more of:
• Model MKE-5-IS(-C) Digital Weight Indicator System
• Load Cell Models 620-300-IS, 620-100-IS, 620-50-IS, 620-25-IS, 620-10-IS, 520-10000L-IS, 520-5000L-IS, 520-5000IS, 520-2500-IS, 520-1250-IS, 320-500-IS and 320-250-IS
which are FM Approved components as per Approval Standard 3600, 3610, 3611 and 3810.
Don’t Take a Risk
If you are looking for precise scales that are safe to use in a Class I environment that has high concentrations of flammable gas, contact Arlyn Scales today. We can provide you with further details about our intrinsically safe and non-incendive ratings as well as our superior construction and factory-direct pricing. We can also discuss your options for data storage and transfer as well as custom sizes, capacities, and a range of other features.
