This article is Part 1 of a 3-part blog series that will provide an overview of safe practices for the use of material handling equipment in hazardous environments. Today, we’ll discuss the need for spark resistance.
Across a variety of industries, ranging from upstream oil and gas and refining to agriculture and wood working, potentially flammable atmospheres can exist. These hazardous areas can present a unique set of challenges for material handling equipment and can pose a serious threat to materials, equipment and, most importantly, personnel.
In the U.S., NFPA 70, part of the National Electric Code (NEC), addresses the design and installation of electrical conductors and equipment in hazardous areas, but does not specifically provide guidelines for mechanical equipment used in these same hazardous locations.
The Importance of Spark Resistance
The NEC breaks down hazardous areas into different types of explosive atmospheres, two of which are those involving flammable gases and those involving dusts. These hazard Classes are further clarified by Group and Division as shown in Figure 1.
It is generally understood that friction between certain materials can cause sparks sufficient enough to ignite flammable gas or dust. A cigarette lighter or an antique flintlock musket are familiar examples of this. Obviously the type and concentration/dilution of gases in an area is one element that affects potential ignition from a mechanically generated source, but other key factors could include:
- The type materials making contact
- The speed/pressure with which the materials come into contact
- Corrosion on one or more of the contacting surfaces
As with our cigarette lighter and flintlock examples, it is understood that contact between steel surfaces can create sparks. Steel is commonly used in most hoists and cranes for load-bearing components such as hooks, lower blocks, load chain and trolley wheels, and therefore may not be suitable for some hazardous environments.
To address this potential risk, Columbus McKinnon uses materials such as copper, bronze, and austenitic stainless steel, which are generally considered non-sparking, for coatings or as material substitutions for enhanced spark resistance. Not only are these materials spark resistant, but they can also protect against corrosion. Since surface corrosion can increase friction between mating components, corrosion prevention is also important when using material handling products in hazardous environments.
We specially engineer a variety of products with spark-resistant components and finishes, including:
- Solid bronze hooks, bottom blocks and trolley wheels
- Bronze plated components
- Stainless steel load and hand chain
- Multi-coat epoxy finishes
- Zinc-aluminum corrosion-resistant finish
Regardless of your industry or where you do business. CMCO has the hoists and cranes to keep your people, materials and equipment safe in hazardous areas. Learn more about our spark-resistant products: