To be competitive in today’s challenging market, it’s important to leverage support solutions that provide flexibility, maximize space and lower total installed cost.
Often when trying to find space for mounting items such as piping, duct, electrical conduits, cable trays, data cabling and equipment, the contractor must deal with shrinking cubic areas. Obstructions to attachments due to structure type or other architectural features can limit locations and/or increase the frequency of connections.
Limitations due to architectural design with a simultaneous increase in the complexity of systems commonly leave the contractor with fewer options. Building Information Management (BIM) modeling has aided in the coordination efforts; however, space is still at a premium. The fact remains that getting systems from one place to another is proving more difficult than ever.
Specifications, as well as guidelines and standards contained within the applicable building codes, often determine maximum support spacing. Care must be taken to help ensure the application of the specification does not conflict with the loading capabilities of the chosen products. There are instances that could occur where the specification may not fully address the loading of the supports or could lack the appropriate guidance regarding structural connections. These instances may require the contractor to increase the frequency of supports or change to a different structural connection.
While the design of the support itself is critical, the attachment to the structure can often limit the methods chosen as well as spacing of the supports.
To develop the proper design of the support, it is important to consider the desired spans between supports based on the applied loads anticipated and the connections available.
The responsibility of determining the correct loading calculation has shifted to the contractor in recent years. Design-build and assist has become the norm for building delivery systems. This requires more focus on the design and submission to the Engineer of Record and is paramount to the process.
Now more than ever, labor impact as well as product capabilities enter into the equation. The total installed cost of a product now determines a products’ long-term success in the marketplace.
Traditional strut configurations typically only allow support from the continuous slot side of strut channels. This can cause the number of strut channels and need for the back-to-back strut to increase, thus driving the cost up.
When considering low carbon steel strut channels, there are a variety of finishes and material types. The job site conditions will determine the material and finish required.
Coordination is one of the most important considerations contractors will make once the overall project scope has been determined. Deciding which product to use is a balancing act between performance and budget constraints. Cost of a product alone can no longer serve as the major focus.
Depending on the project configuration, labor can be up to 70% of the cost of mechanical, electrical and plumbing (MEP) systems. Coordination and product selection can assist in helping cut labor costs, while helping drive value for the contractor and ultimately the owner.
Strut channels are selected based on uniform loading or column loading needs. First, the support spacing minimums need to be determined based on specifications and guidelines. Then, the actual calculated loads will be determined.
With the contractor now armed with the calculations and the specifications for the project, the product selected for the application can greatly impact the need to reduce or increase the distance between supports.
Uniform loading of a strut channel is determined by the span between the hanger rods or distance between vertical members (floor stands) and the number and/or weight of the supported items. Reducing the span between vertical members can significantly improve the uniform loading capacities of the strut channel members.
Traditional strut solution
Using traditional strut channels, the maximum support uniform load capacity at 48" long would be 851 lbs. with .224" of allowable deflection. Using traditional strut would not work with these parameters; so spacing would need to be reduced to 6' 6" to accommodate the load. To avoid the reduced spacing, the contractor would need to change the configuration to back-to-back traditional strut channel. This would double the cost of the solution, may increase lead-time, and could significantly increase the overall installation cost.
Eaton’s B-Line series 4Dimension strut solution
By using Eaton’s B-Line series 4Dimension strut (4D22), the contractor can elect to utilize the multi-sided functionality and mount pipe over and under the channel. This will result in a 24" long strut channel versus the traditional 48" long strut channel; thus, reducing the material cost up to 55%. If compared to welded back to back 1-5/8" channel, 4D22 also reduces the vertical space taken by 1-1/8". This 24" long 4D22 strut channel has the load capacity of 1,872 lbs. with .10" of deflection; therefore, allowing the distance between supports to be the planned 10'.
A huge benefit is the ability to work on the entire trapeze from one location because the trapeze is half as long. This saves the installer trips up and down ladders or adjusting lift locations. The installer may even reduce rental costs by reducing the number of man lifts required to perform the work.
4Dimension cuts up to 10 x’s faster due to material thickness, which can also reduce cost of cutting materials (ie.: saw blades).
Traditional strut solution
The total length of the trapeze rack using Eaton B-Line series B22SH would be 24". The total load of the conduits can be up to 18 lbs. per foot at a 7' span the total load per support would be 126 lbs. The load rating for the strut channel is 1,702 lbs. far exceeding the requirement.
Eaton’s B-Line series 4Dimension strut solution
By using Eaton’s B-Line series 4Dimension strut (4D21), the contractor can elect to utilize the multi-sided functionality and EMT conduit over and under the channel. This allowed the contractor to reduce to a 12-inch trapeze length, while maintaining an acceptable load rating of 1,402 lbs. This reduced the cost by reducing the length of the channel required.
Adding the B-Line series 4Dimension turn & lock or Flip Clip™ with the 4Dimension strut allows installers to save up to 70% on labor cost vs. the traditional hex nut and flat fitting installation methods.
The ability to shrink the length of the trapezes and easily coordinate the total footprint of the pathways for conduit and piping runs, can have dramatic positive results in very tight installations.
4Dimension cuts up to 10 x’s faster due to material thickness, which can also reduce the cost of cutting materials (ie.: saw blades).
Installed method type | Strut strength :uniform load (lbs.)* | Installed cost % savings |
48 inch - 1 5⁄8 Strut 48 inch - 4D21 Strut with Flip Clip 48 inch - 4D21 Strut with turn lock |
851 351 351 |
42.43% 39.47% |
24 inch - 4D21 Strut with Flip Clip 24 inch - 4D21 Strut with turn lock 48 inch - 4D22 Strut with Flip Clip |
700 700 936 |
52.82% 46.76% 35.34% |
36 inch - 4D22 Strut with turn lock 18 inch - 4D22 Strut with Flip Clip 18 inch - 4D22 Strut with turn lock |
936 1872 1872 |
27.33% 49.45% 42.71% |
Load rating of 3⁄8" Flip Clip pair (lbs.) Load rating of turn lock pair (lbs.) |
770 1155 |
Traditional strut & accessories: | 4Dimension strut & accessories: | |
15⁄8" strut | 4D21 or 4D22 strut | |
3⁄8" ATR (threaded rod) | ATR (threaded rod) | |
Hex nut | 3⁄8" Flip Clip or Turn and Lock | |
Square washer | trapeze hangers | |
Lock washer |
* For slotted hole (SH) use 90% of Strut strength
** Information on chart is based on Bill of Material (BOM) shown above
With Eaton’s B-Line series 4Dimension™ strut system, owners, designers and contractors have an opportunity to save time and material, as well as lowering their overall total installed cost.
1) Space limitations and structural obstructions
2) Frequency of supports and load
3) Product selection
4) Labor costs
With 4Dimension strut system, owners, designers and contractors now have the product that will help minimize total installed cost, allowing the users be more competitive and ultimately more profitable.