Shelving systems are a sturdy and economical solution to storage needs in the garage at home and in the workplace. They are a simple and effective tool that provides “visible” storage for just about anything from small nuts and bolts, to heavy storage boxes, to fully loaded palates weighing thousands of pounds. The variety of uses and applications for shelving systems leads to a huge number of styles and configurations that can sometimes be overwhelming when trying to decide on an appropriate shelving system for your needs. This article will focus on design and selection of free standing, industrial grade, metal shelving units and how to determine what products are appropriate for your specific applications.
Shelving units in their basic form consist of a frame and decking material. The frame can be constructed out of a variety of materials with the most common being steel sheet. The thickness of sheet metal is called its gauge and the lower its gauge number is, the thicker the steel is. Steel sheet ranges from about 30 gauge to 8 gauge, with thinner 30+ material called foil and thicker 8+ material called plate. The steel sheet is formed into structural members with various shapes for different applications and load carrying capacities. The capacities can range anywhere from a couple hundred pounds to 30,000 pounds or more.
The shelving support structure or frame will vary in gauge and shape depending on its intended use. The structural members consist of uprights, front & side supports, center supports, cross braces, and some type of fastening system. Not all of these support structure members will be present on every design, but at a minimum will have uprights and front/side supports. The steel support members can be formed into many shapes with the most common being tubular, punched “L” angle, or punched “C” channel. Light tubular style supports are very typical for use in wire shelving systems for light duty to medium duty loads. “L” angle is used for medium duty to heavy duty loads, and “C” channel supports are used for extra heavy duty loads. The “L” and “C” support member steel is punched with square, round, triangular or teardrop shaped holes which allow a variety of fastening systems to be used to join them together.
The fastening system is also very important in determining the maximum load capacity of shelving. Light duty wire shelving with tubular steel uprights typically utilizes a plastic collar fastening system. Medium and heavy duty shelving systems utilize a boltless design that incorporates single or double rivets to join the front/side supports to the uprights via the punched holes. Extra heavy duty or high capacity shelving is either bolted or permanently welded together, or may utilize special high strength, boltless fastening systems designed for extra heavy duty applications.
The decking is the final component in a shelving system and also comes in a variety of styles and materials. The most common materials include wire, steel, plastic, particleboard and solid wood. Again the strength of the material is governed by its thickness. Both wire and steel decking is measured in gauge while plastic, particleboard and solid wood is measured in thickness, usually in inches. It is important to note that a shelving system may only be rated for its support frame and the material used for the decking may not support the stated load capacity.
The shelving manufacturer will measure the load carrying capacities of each individual component and together as a shelving system to come up with a maximum shelf capacity and rating. It is very important to note that the rating given to a shelving system is based on slowly adding weight, evenly distributing it over the entire shelf. It will not support that weight if concentrated on one part of the shelf. The manufacturers rate their shelves as light duty, medium duty etc. Do not to let these ratings determine your design selection as every manufacturer rates their shelves differently and there is no commonly adopted rating system. Only careful consideration of the shelf’s intended use should be given when choosing a shelving design to prevent catastrophic structure failure.
Examples of light duty storage might include storing boxes of clothing, shoes, Christmas decorations, or anything that is less than around 200 pounds. Medium duty shelving ranges anywhere from 300 to 500 pounds and might include heavier boxes, tools, paint cans, automotive fluid containers and typical garage junk. Heavy duty shelving systems range from 500 to 1500 pounds and examples are fertilizer bags, large tools, tool chests, and multiple heavy boxes. Extra heavy duty capacities range from 1500 to 10000 pounds with examples including tire racks, document storage, machine parts, engine blocks, and bulk liquids or solids storage. Anything over 10000 pounds is usually classified as bulk racks or palate racks, and they are typically found in mechanic shops, storerooms or warehouses and have capacities that can exceed 30000 pounds.
It is important to design a shelving system around the maximum possible scenario. As an example, based on the criteria above an average homeowner may want to choose medium to heavy duty shelving for the garage that may include storing fertilizer or cement bags, tools, paint cans or cases of oil. A “Gear Head” might choose heavy duty or extra heavy duty shelving allowing engine part storage, tires and heavy shop tools. Whatever the required storage capacity is, there will be a shelving system to suit the application. When in doubt you should contact your supplier and discuss your application with them. They can help determine what capacities, sizes, and styles suit your needs and can provide multiple options that you may not have considered.