In our previous blog Wire Decking vs. Pallet Supports we discussed the pros and cons of using wire decking and pallet supports with your pallet rack system. In this post, we go one step further and dig in to the various properties that make up a particular wire deck and discuss what we look for when purchasing wire decking for your pallet rack. We believe there are three key items to consider when purchasing wire decking:
- Working load of the wire mesh deck
- Type of wire coating
- Mesh pattern
- Working Load of the Wire Mesh Deck
Work load capacities are highly dependent on the mechanical characteristics of a deck’s components, and knowing what you place into a deck will ensure that the deck performs as expected. Once you've determined what you are going to place in the deck and know how much weight you'll need, you should make sure the deck you are purchasing can support the weight.
This sounds rather straightforward, but quite a bit goes in to calculating the final 'capacity rating' you see on quotes for wire mesh decking. To determine the working load of a wire mesh deck the Rack Manufacturers Institute (RMI) designed and approved a specific test method. This is the American National Standard Institute’s (ANSI) standard MH26.2, entitled “Design, Testing and Utilization of Welded-Wire Rack Decking”.
This standard applies to uniformly loaded rack decking fabricated from welded-wire mesh with permanently attached reinforcements, for use in pallet rack. There is no other approved test method recognized by RMI that rates a wire deck’s load capacity. Only manufacturers that can prove conformance to this standard are certified by RMI with an R-Mark.
Testing to this standard provides the rating capacity by the lesser of either deflection (of the rack & channels), or total deck collapse. To test this, wire decking is placed on pallet rack beams that match the wire deck’s depth. A load is then uniformly applied while measurements of deflection and load are taken.
In summary, when ordering wire decking double check to make sure you aren't adding decks rated for 1,900 lbs to a pallet rack beam rated for 2,500 lbs. Matching weight capacity ratings will not only ensure you get the most out of your pallet rack system, it could save you money as a wire deck rated for 1,900 lbs is going to be cheaper than one rated to hold 2,500 lbs.
- Type of Wire Coating
The coating on a wire deck protects the base metal from the elements. There are three different wire coatings available for wire decking: paint, powdercoat, and galvanized (zinc) coated. The cost of each process is rather different which influences the final pricing. While galvanized is the premier coating for wire decking, it is significantly more expensive than paint or powdercoat.
When operating in humid or salty environments powdercoat wire coating can lose up to 11% of its working load capacity, while a galvanized finish loses only 2%. That said, galvanized coating can be up to 20% more expensive making it hard to justify if you aren't working in particularly harsh environments.
For most instances that involve indoor storage in the Midwest, we recommend you opt for the cheaper painted option. It will hold up for years and you'll save some money as compared to a galvanized finish.
That said, a galvanized wire deck is going to be much better for food or cleanroom applications since it doesn't flake.
- Mesh Pattern
Pallet rack wire decking also comes in a variety of mesh patterns, using different wire diameters and channel gauges, depending on desired appearance and working loads. Some of the more common configurations include: 2”x 2” (for retail or handpick situations) and 2½”x 4” (for standard pallets). Other patterns are available upon request. It is important to recognize that mesh patterns are essential in determining work load capacities, as well as enhancing the overall look and functionality of the decking.
For example, if you were to try and set a small box on a 2-1/2" x 4" wire pattern you'd find it tips over or otherwise wobbles. It may even get caught on the decking as you move it. While, a 2"x2" configuration would allow the box to easily slide in any direction. The trade-off for this tighter wire mesh pattern is cost. The smaller the holes, the more wire you must utilize to manufacture the wire decking, which increases the end cost.
Each deck is then reinforced with metal channels that are welded to the mesh pattern. The required capacity will determine the number of channels and gauge of steel required to support the mesh pattern you specify. You will typically see 3 to 6 channels depending on the width of the wire decking.
Conclusion
When shopping for wire decking there are a few key points you should check on your quote prior to purchasing. It might very well be you are otherwise getting material that won't do the job properly or you could have saved some money by buying wire decking with a lower capacity or cheaper coating.