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Most American warehouses have at least one thing in common — the need for selective pallet racking. Racks, as they’re commonly called, are indispensable pieces of material handling equipment. They capitalize on space, safely store a multitude of products and make workers’ jobs easy for retrieving materials and merchandise.
But, not all racks have common designs. Racking has evolved over the years, and the main difference is in the beam connection slots built into the racking system’s vertical or upright members. Although there are many slot designs, there are two primary profiles commonly found within warehouses — teardrop pallet racks and double slotted pallet racks.
Both configurations get their name from their connection opening shape. Teardrop rack connections are pear-shaped. They look like inverted teardrops. Double slots, on the other hand, are vertical incisions in the metal members. As their name suggests, double slots have two vertical holes sitting side by side. Teardrops also have parallel perforations in most applications.
Why Are There Different Racking Slot Designs?
There are clear reasons why selective racking manufacturers offer two main slot designs. This dates back to World War II when massive manufacturing of war goods required pallets and related material handling equipment, including racking and shelving systems. Different companies produced rack systems, leading to non-uniformity in design. This made rack uprights, beams and decks incompatible with one another.
Following the war, the demand for warehousing and efficient racking didn’t slow down. As post-war production for civilian interests expanded, so did the demand for pallet racking components. This led to manufacturing competition and many unique vertical member slot designs showing up on the market.
The theory was that each racking system maker would hold proprietary patents on their systems through creative slot designs. That way, a warehouse business would have to buy additional racking components from the original manufacturer. This supposedly ensured continuous demand and not losing market share to the competition.
In practice, this led to incompatibility between systems. As pallet racking equipment aged and needed replacement, or as warehouses expanded and required additional racking, consumers became frustrated by the differences between competing rack components. Rather than adding on more verticals, beams and decks, the warehouse businesses had to replace entire systems at significant costs.
Rack manufacturers slowly responded to consumer demand. Industry-driven cooperative associations like the Rack Manufacturers Institute, Inc. (RMI) worked to streamline the rack options offered by a multitude of racking manufacturers. This led to uniformity in the bulk storage industry. As a result, today the most popular upright and beam connection point is the teardrop design. That’s followed by the less-popular, but still functional, double slot connection design.
What Is Teardrop Pallet Racking?
Teardrop pallet racking is the most popular rack design in the world. After decades of experimenting with several different vertical rack slot profiles, the simple teardrop configuration won out. That’s because the teardrop slot is simple, secure, steady and safe. It’s also due to the teardrop design being speedy to assemble and disassemble when rack configurations need changing.
From an engineering point, the teardrop racking design is superior to others in several ways. With the teardrop being similar to a V, the load transfer from the rack’s horizontal beam to the vertical support compresses the beam’s pin into the teardrop slot. As this force bottoms out, the pin’s head is well below the opening diameter at the top of the slot. This makes it impossible to slip out without an upward force lifting the beam and deck assembly.
The friction produced by squeezing the beam pin into the teardrop slot also strengthens the entire rack assembly. A tight fit prevents the rack from swaying and buckling. Teardrop slot racks are exceptionally stable. However, they are easy to loosen and disassemble if required. It’s the combination of easy use and dependable performance that make teardrop slotted racks the warehouse industry standard.
Safety is another critical issue with all selective pallet racking systems. To prevent accidental loosening and beam separation, the teardrop vertical members and beams have a locking device that keeps the pins inside the slot unless intentionally released. Accidental loosening could be caused by forklift mishandling where a deck and beam assembly is suddenly raised. Racking pins can’t be accidentally dislodged when held in with safety catches.
Uniformity is a significant advantage with teardrop racks. Today, the industrial racking industry has come together to ensure most brands using teardrop designs are compatible. Here are some of the common teardrop rack designs and their builders:
- Husky Rack & Wire: a standard teardrop design with safety clip
- Frick Gallagher: a combination of teardrop/keyhole design
- Lyon: a true teardrop configuration
- Mecalux: a leading brand name and design
- Spacerak: a new style teardrop and an older style teardrop
- Speedrack: a conventional teardrop indentation
- Bulldog: a teardrop design that’s slightly slanted
- Kingway: a standard and interchangeable teardrop
- Excel Storage Products: another conventional teardrop
- Ridg-U-Rak: a large opening teardrop with a single exposure
- Interlake: a teardrop design appearing like a question mark
- Prest: a dual-opening, mirror-image question mark shape
- Unarco: another dual-opening teardrop slot
- TP Rack: universal teardrop beams & uprights
Teardrop pallet racking profiles are highly flexible in matching and mixing different brand name components. However, although the teardrop slots might be universal in accepting beam pins, the beams might vary slightly from maker to maker.
For instance, a beam classified by one company as 8-feet might be longer or shorter than another manufacturer’s 8-foot rating. One beam might be exactly 96 inches between pin centers while a competitor’s true distance might be 95 ½ inches. While two slightly different length beams will fit a universal teardrop slot, the length variance will cause a rack to go out of square and be unstable.
The best method of interchanging components in a teardrop racking system is to make sure each vertical, beam and deck is from the same manufacturer. That way you can safely add additional beams to an existing system regardless of manufacturer.
Benefits of Teardrop Pallet Racks
The main benefit of using teardrop pallet racks is compatibility. This alone has led to teardrop connection profiles being universally accepted by the warehouse industry. There is no sign of this trend changing or being replaced by another upcoming improvement.
Teardrop racking systems have significant benefits for end-users. This design is a proven performer, and that’s clearly established by the number of teardrop racks in operation today. Here are some of the main benefits gained by using teardrop pallet racks:
- Versatility: Being interchangeable with different manufacturer brand names allows the user to source components from different makers and suppliers. That could be new, used or reconditioned racking components.
- Strength: Teardrop designs let beam pins lock into place by friction and gravity. The more weight placed on a teardrop vertical support, the more it compresses and strengthens.
- Installation ease: Teardrop verticals and beams are easy to install. They don’t require a high skill level, special tools or expensive fasteners.
- Customization: It’s simple to mix and match suitable components. Parts from one rack manufacturer used with another supplier’s product allow warehouses to customize their racking systems to suit their needs.
- Safety: Properly matched and assembled, teardrop pallet racks are entirely safe. The safety catches add extra protection to ensure a teardrop connection isn’t accidentally released.
What Are Double Slotted Pallet Racks?
Double slotted pallet racks are second in warehouse popularity to the teardrop style racking systems. The main difference between the two selective pallet racking structures is the beam-to-upright connection configuration. Slot systems have two parallel and elongated rectangular openings that accept the beam flanges and pins.
Double slotted pallet rack designs are older than the teardrop systems. The first commercially manufactured racks had slot designs, and that suited the purpose at the time. However, double slotted racks aren’t as compatible with different manufactured components as teardrop rack styles are. That’s the primary reason that double slotted racks have waned from warehouse popularity while teardrops have grown.
There is one area where double slotted pallet racks excel — in strength and durability. Modern racks that choose the slot designs are heavier and bulkier. Quite simply, today’s manufacturers choose double slotted racks because they can support the heaviest loads. Users of the double slotted pallet rack prefer its indisputable strength compared to the more universally accepted option of teardrop pallet racking.
Most double slotted rack uprights built today are called structural pallet racks. These slotted uprights are formed from molten iron cast to configurations. Teardrop-style uprights are usually lighter weight and made from cold rolled steel sheets.
Because double slotted uprights are iron rather than steel, they weigh more. That’s not a disadvantage when it comes to heavy-duty applications where strength is the issue, not speed in setup and takedown. Therefore, double slotted racks are more commonly found in large warehouse situations where the racks might have a double-duty purpose, forming part of the building’s structural integrity.
Some double slotted rack uprights require independent fasteners to secure the beams and platforms. Where almost all teardrop uprights simply snap together, many double slotted verticals need bolts, washers and nuts to secure connections. This adds assembly time and effort as well as additional expense.
Like teardrop configurations, there are different brands and sub-styles of double slotted pallet racks. Each type has individual features to offer warehouse organizers. Here are the most popular double slotted rack designs and manufacturers:
- Paltier 50: an old style keystone slot design
- Penco: a double slot with tapered openings
- T-Bolt: heavy-duty application requiring bolts
- Speedrack Selective: oval-shaped double slots
- Ridg-U-Rak: elongated slots with deep openings
- Lynx: conventional double slots from Wireway Husky
- Redirack: one of the most common rack styles
- Master Rack: a square hole design from Buckley
- M-I-Rack: lighter weight design by Inca
- Interlake New Style: unique slots slightly resembling teardrops
Benefits of Double Slotted Pallet Racks
The main benefit warehouse businesses receive from double slotted pallet racks is their strength. Because speed and versatility aren’t as important as support in certain cases, many warehouse owners and managers choose double slotted racking systems. When weight retention is a big issue, they forgo a speedy process in favor of maximum security.
Many structural racks are double slotted configurations. These simple and straightforward designs aren’t intended for continuous change of deck heights and widths. Structural racks with double slots are meant for permanent or semi-permanent locations. They’re installed by professionals using specialized knowledge and tools.
Double slotted pallet rack systems have other benefits besides brute strength. They’re not intended to compete head-on with teardrop designs, and there’s a definite marketplace for them. Here are more benefits delivered by double slotted pallet racks:
- Impact resistance: Because most double slotted uprights are made from cast metal, they’re far more impact resistant than cold rolled steel. This makes them ideal for areas with aggressive forklift and truck traffic.
- Structural support: Double slotted verticals can act as structural supports to the building. Engineers can certify the racks as load-bearing structural members that serve a dual purpose.
- Longevity: Because most double slotted rack systems are so durable, they last longer than other products. Needing to replace a double slotted system is unlikely.
- Return on investment: Most double slotted pallet racks are more expensive than teardrop rack systems. However, because they tend to last longer in industrial settings, support heavier loads and guarantee against failing, double slotted racks deliver an excellent long-term return on investment.
Choosing Teardrop vs. Slotted Pallet Rack Uprights
Choosing teardrop vs. double slotted pallet rack uprights might sound difficult, but it doesn’t have to be. For most warehouse applications, fast and easy teardrop systems are a better choice. The fact that teardrops are the most popular style in America and around the world speaks volumes to their serviceability. For many people in a decision-making role, that’s proof enough that teardrop pallet racks work.
Teardrop pallet rack systems are best for warehouses that need flexibility. Teardrop designs allow for quick changes to deck heights and widths. They’re also best-suited where add-ons are expected, and the work can be done by existing staff. There’s no need for contracted help just to make rack changes with teardrops.
However, there are situations where double slotted pallet racks are a better buy. When load capacities exceed teardrop system ratings, there’s no choice but to invest in rugged cast-metal uprights with double slot designs. This is normally a matter of safety rather than economics.
Double slotted pallet rack systems are ideal for heavy-duty applications. That includes warehouses with permanent or semi-permanent rack intentions. It also includes placement where material handling machinery risks are high, and the budget for having professionals install the rack systems are flush. For large loads in heavy traffic, nothing beats a double slotted pallet rack design.
Contact T.P. Supply Co for Pallet Racking
T.P. Supply is one of America’s leading suppliers of teardrop and double slotted pallet rack components. As our slogan goes, “We’re not the biggest, just the best.” We’ve been the best pallet rack and material handling equipment supplier since 1979. Today, we’re an international distributor for storage racks, shelving solutions and material handling products.
At T.P Supply, we also offer professional pallet rack installation. We use our own teams to deliver and set up both teardrop and double slotted systems. That’s part of our customer commitment for outstanding service and unparalleled choice.
For more help in choosing teardrop vs. double slot pallet racks, call T.P. Supply today. We’re at (877) 302-2337. Or, we can be reached anytime through our online contact form.