Frequently Asked Material Handling Questions Phoenix | Custom Material Handling 480-829-7232


Which Is Stronger? Structural Or Roll Formed Columns?

What determines the amount that a braced column section will bend when a load is applied is called the moment of inertia. It is expressed with reference to the bending axis, and in forklift impact, deeper columns will have much greater bending resistance. Column depths more important than the material thickness or the column width, and as a result, if a structural and roll formed column of equivalent capacities have these loadings applied, the structural will temporarily bend, or deflect, up to seven times as much as would the roll formed section. In terms of failure caused by overload, this relationship holds. A roll formed column of an equivalent capacity is approximately four times as strong in failure as the structural section, meaning that the structural column will tolerate only one-quarter of the force of the roll formed column before the deflection above becomes permanent deformation. It is obvious that that the roll formed column dents more easily than the structural, it isn’t considered “damaged” until significant deformation of the material has occurred. Because of its inherent advantages over structural, it would take significant damage of the roll formed column before it would be brought to the same weakness level as the structural column. This is a huge surprise to many of our customers because they have experience with denting only, and have never really experienced rack failure. To sum it all up, Structural is designed to hold more weight, but is more likely to fail with permanent damage if hit. Racking failure should be of greater concern and the safety hazards it represents.

Which Design Resists Impact Damage Better?

Closed sections have certain structural advantages, but not in the area of impact resistance. The moment of inertia about the bending axis in a frontal impact situation for a closed section column and an open section column are virtually identical, so their bending resistance levels are equivalent. In fact, if all else is equal, because of the structural advantages of closed sections, a closed section column of a given load-carrying ability will have a thinner wall than will an open column of the same load-carrying ability. This would decrease impact resistance. Only if the capacity of the closed section is greater (or thicker) would you gain any structural advantage – but this holds true when comparing almost any two columns. We don’t see many manufacturers produce this shape because of usability. Attachment of accessories is much more difficult with closed sections, because through-bolts would have to be used, and proper tightening without column crushing would be a problem without a special type of fastener. Also, accessories attached in opposition (on each side of the column) can create an attachment problem. Because of these problems and the fact that there are no real advantages, very few companies still offer closed roll formed column sections.

What Does RMI Stand For? 

The Rack Manufacturers Institute (RMI) is a firm put together in 1997 to assure customers that manufacturers are producing up to code materials.

What Are The Aisle Requirements For A Standard Sit Down Propane Forklift?

The following clear aisles are required for the associated lift equipment. Keep in mind, this is WSN’s suggested aisle widths. Prior to purchasing any materials or lifts, confirm the data with your supplier.

Sit Down counterbalanced Lifts typically require a 12’ aisle. A Wave order picker is 3’ clear. Stand Up Single Reach Truck is 8’6”. Stand Up Double Reach Truck is 9’ spacing. (NAOP) Narrow aisle order pickers are 5’ clear. Turret Trucks are 5’6”.

How Should I Secure My Racking? 

Racks must be structurally attached to the following if the overall height from the floor to the top load beam exceeds six (6) times, but no more than eight (8) times the depth of the frame. Example: 42” deep frame with top load beam at 288” = 6.86 to

1. Chose from the list below.

A. Replace standard frame footplates with oversized seismic footplates requiring two (2) anchors per footplate or four (4) anchors per frame.

B. Tie frames to a concrete wall using wall ties that do not exceed 10’-0” (vertically) from each other.

C. Tie frames to adjacent row frame using cross aisle ties.

D. Tie frames to another row (create back to back row) using row spacers that do not exceed 10’-0” (vertically) from each other.

When Does a Storage Rack System Need To Have Approval For Seismic Zones? 

Any System that is in Seismic Zones 2A, 2B, 3, or 4 with loads above 8’-0” must be designed to resist seismic forces. Special requirements will have to be met in order to achieve compliance in your local municipalities. Prior to designing a Seismic Zone System, an analysis must be performed by a seismic engineer to determine the exact materials that will be required in the System. You will need to fill out the engineering worksheet to get preliminary calculations from WSN.

What Does The Permitting Process Consist Of And How Long does it take? 

*This is a very brief description on the permitting process*

Here Is The Procedure For Obtaining Pallet Rack Permits:

Have a layout and material detail sheet approved by the customer, with an engineering worksheet filled out. Submit information to an Arizona State licensed engineer to have structural calculations performed. After having the stamped calculations, floor plans and detail sheet returned from the engineer, they will be submitted to the city for permit.

There Are Two Factions Of The City That Will Be Reviewing The Permit.

One is the building department. They will review the seismic calculations and any other structural related issues.

The other is the city fire department, which will review the commodity stored in relation to the style and design of the sprinkler system. They will also look at safe passages out of the building, and any other life/ safety issues.

After we receive the approved permit back from the city, we are able to start the building process. Upon completion of building the rack system, there will be a building inspection, and a fire inspection with the racks empty and in certain circumstances there can be a commodity inspection also. Once everybody has signed off, the racks are then approved for loading.

After we have decided on a functional Rack System, the local ordinances will require the following information at the time of the plan review.

1. The physical address of where the Rack System is to be installed.

2. The complete floor plan layout (preferably an AutoCAD file) of the entire facility that includes dimensions of aisle widths and distances from permanent structures.

3. Pallet and load data that will be stored in the Rack System:

• Pallet depth and width.

• Load depth, width, and overall height (including the pallet).

• Maximum and average weights.

• Maximum and average utilization of the pallets stored.

4. Carton data that will be stored in the System:

• Carton depth, width, and height.

• Maximum and average utilization of the cartons stored.

• Maximum and average weights.

5. Floor slab thickness and concrete strength in pounds per square inch (PSI).

6. Soiling bearing pressure in pounds per square foot (PSF).

7. Drawings that indicate the maximum and average weights to be stored in the Rack System, the model numbers for each segment of the Rack System, and an elevation view of each segment of the Rack System.

8. Calculations noting the approved materials that are to be used in the Rack System itself.

9. Attachment method details of the Rack System that indicate the anchor size, quantity, and embedment per frame.

10. Drawings, calculations, and details that have a wet seal and signature accepting compliance by a registered Professional Engineer (normally from the state where the rack is to be installed).

What Is A Starter Bay And Add On Bay?

A starter bay is a full bay of pallet rack consisting of 2 frames (or uprights) and a chosen amount of beams and decks. An add on bay is the connecting bay to the starter with 1 frame and a chosen amount of beams and decks.

Not So Frequently Asked Customer Question’s And Company Answers:

Q: I have some damage in the bottom of one of my pallet rack uprights. It was lightly hit by a forklift last week but is visually damaged. Do you fix them or do I have to replace it? What can you guys recommend?

A: Because of the size and weight of most pallets, important safety factors have to be considered at all times. Always pay attention to any loose and damaged components in pallet rack systems. Write down things you see that could pose a problem with your storage solutions throughout the warehouse; if this is severe enough, such frame damage could cause the pallets to fall or cause entire rack to collapse. Call us at 480-829-7232 to schedule a safety inspection ASAP. We would be more than happy to walk through your warehouse with you and make some suggestions concerning your racking system. Depending on the size and style of the upright, sure we can probably fix it. If not we can get it replaced for you. Regardless, it needs attention. For the time being, unload the damaged racks and throw some caution tape around the bay with a “Damaged Do Not Use” sign.

It is important to have highly visible warning signs if the pallet rack system is a potential safety hazard, especially in retail environments, such as wholesale centers, where the public will be present.

It is your legal responsibility to communicate all important warnings to those who will be around your storage racks.

Q: Do you guys carry mesh wire decking? Our pallets are not always the nicest and we would like a little bit more stability under them. The pallets weigh about 640#’s a piece give or take. We are currently setting them 3 pallets per level. Our cross members are 144” long. I have attached some pics.

A: Yes we carry mesh wire decking in all sizes but that’s not always the best solution. First off, only use quality pallets that are not damaged to store your product on. Greatly inspect your pallets for broken boards, nails, and missing support blocks. This is essential as far as I am concerned. 9 times out of 10, pallet damage will cause you loading and unloading problems. Usually, loose stringers get hung up on the pallet racks, and cause loads to fall. Those pallets in the pics do look pretty run down. If I could make a suggestion, have you considered a common wood or steel pallet support (crossbar) by any chance? They will probably be just as functional, but a heck of a lot cheaper. For your specific application they should give you the added support you feel you need. You should definitely put something under there one way or another. I carry them both so I can provide you with pricing on both and let you decide is best for your application.

Q: I have some 8’ beams I bought from your competition a while back. I am not sure if they are capable of holding the weight I am now planning to put on them. They are about 5” thick and my pallets are close to 2k a piece. Any Recommendations?

A: You should never overload the recommended load specs for the rack system. Without seeing this beam in person or knowing the specifications on the beam, I cannot give you a definite answer Larry. What I can tell you is overloading that beam may cause a catastrophic failure of your storage rack system. It sounds like you should be safe though. A standard 8’ beam can usually hold approximately 1000 Lbs per inch of face value, therefore your beam should be able to hold 5000 LBS. Keep in mind that is a Static capacity and not a Seismic capacity. Depending on where you are located, you may need to have it engineered to confirm the true seismic capacity of the beam.

Q: I have a large section of rack that has 3 pallets loaded on it and my warehouse manager just pointed out to me it has a bit of sag to it. Is this a normal thing or should we be worried?

A: I am going to assume you are talking about the deflection in the load beams. Sir, depending on the length and thickness of the beam, all beams are going to deflect with a load on them. Some are designed to deflect more than others even up to a ¼ of an inch or more in some cases. If you are seeing more than that, let me know. I will stop into your facility tomorrow and take a look at it myself. Deflection is very common especially on the longer beams but too much can be very dangerous.

Q: We just moved into a new facility and installed some pallet racking. The facility had some pre-existing pallet racking when we moved in that we added on to. The old stuff is permitted, our stuff isn’t. Do we need a permit and do you help with the permit process? We are located in Kent, WA. Thanks.

A: Joel, to answer your question’s; Yes we can help you with any permit issues you may have. Do you need to permit it? Probably yes. Unless your Rack System configurations are all less than 12’ tall, in most of the local municipalities you will be required to permit your storage rack. In your case you will have to apply for a pre-existing permit. We can help with the drawings and engineering of them if need be. Let’s set up a good time to meet so I can discuss this in further detail. Once the permits are done and dusted, we should also set up an Audit (safety check) to be performed on a regular basis by Warehouse Solutions Northwest to make sure all aspects of the system are 100% operationally safe at all times. We are qualified professionals familiar with RMI design and the local safety standards. This should help keep you from any confrontation with the city inspectors and the fire department in the future.

Q: I have some long pipe that I need to store along the back of my store along with some fittings and other misc things. I am a small outfit out in Buckley with a small budget. What type of racking is suitable for me and do you have anything used in stock? I was thinking a tree rack with some small pallet racking.

A: There are a number of things to consider when purchasing any type of storage rack. What will you be storing? How is it currently being stored? What is your budget like.. etc? I think you hit the nail on the head when you mentioned cantilever. Technically, you could make any type of rack work for what you are trying to do. Although a cantilever racking system tends to be a bit more pricey, the open capabilities of the rack make it so much more functional. I think I just might have something that will work perfect for you. It’s a structural furniture cantilever set up. It can be used for light pipe and lumber storage as well as your shelving needs. I’ll send one of my reps to your facility tomorrow so she can offer you some of her recommendations and explain a little bit more about the cantilever set up.

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