Racking: Safety and Storage Density
|Copyright 2014 by Virgo Publishing.|
|By: Cary F. McGovern|
|Posted on: 05/01/2004|
Your choice of records-storage racking can improve your yield per square foot, long-term revenue and operational efficiency. The single most expensive mistake many records-storage operators make is buying “cheap” racks. Racking is a commodity and can be found anywhere, but rack design and planning requires professional assistance from expert resources.
Choosing the right racking is not easy. Racking choices affect storage density, profitability, operational efficiency and safety. Let’s review these issues:
Catwalks vs. Order Pickers
I will attempt to be unbiased here, though it may be difficult, since I am convinced the foremost issue in rack design must be employee safety. There are also issues of insurance and employer liability to consider. For now, let’s look at the design density and efficiency of each racking system.
Order-Picker Systems.Order-pickers are forklift-like vehicles that move around a warehouse, usually under the control of a warehouseman. Since the width (base) of the order-picker is relative to the height of its mast (upright reach), it requires wider aisles than a catwalk. Wider aisles (45 to 48 inches) generally translate into less storage density. The argument for the picker’s use is usually relative to speed. However, I have information that shows well-designed catwalk systems with well-trained and supervised warehousemen may provide faster retrieval throughput.
The most innovative new method used to attain greater storage density in picker systems is a four-deep, three-high, box-bin configuration. These require the picker operator to reach deeper into the racks at heights that may exceed 30 feet. This opens the door for huge safety and liability concerns. Pickers are large, heavy pieces of equipment that can attain speeds and force capable of toppling racks. Rack collapses are not uncommon and deaths have occurred as a result.
The force required to crimp uprights and topple racks is not difficult to achieve. Records-storage racking supports heavy boxes in configurations that may meet or exceed the strength limitations of its uprights and steel-gauge expectations, particularly if the rack design is amateur.
Catwalk Systems.In catwalk systems, aisles are predominantly between 30 and 32 inches, and racks are made from metal grids designed to hold the weight of warehousemen and their box loads. These systems use ladders, walkways, elevators, gates and box slides. There may be multiple levels of catwalks depending on ceiling height.
The height of each walk is usually between 8 and 9 feet, or three shelf levels of three-high, three-deep boxes. The most common depth of racking uprights is 48 inches. This depth computes equally to three letter/legal-size boxes or two 24-inch storage-transfer boxes. Safety and storage density are the prime reasoning for the catwalk system. To achieve or exceed the order-picker retrieval throughput, the operations manager should have a well-trained and managed workforce.
Personally, I prefer catwalks. Shelving options are always arguable, since design is an art as well as an engineering science. There are certainly reasons pickers may be a good choice. It has been my experience that these usually relate to odd ceiling heights or unusual circumstances. Regardless of your choice, make sure your warehousemen are trained and safety is always a mandate. Following are some other warehouse musts.
I could and may write a book on racking and safety, but for the moment, let these general guidelines be sufficient. In the words of comedian Dennis Miller, “This is my opinion and I’m sticking to it.”
Regular columnist Cary McGovern, CRM, is the principal of FileMan Records Management, which offers full-service records-management assistance for commercial records storage startups, marketing assistance, and sales training in commercial records-management operations. For assistance in feasibility determination, operational implementation or marketing support, call 877.FILEMAN; e-mail email@example.com; www.fileman.com.