For decades, the Tent Rental Division (TRD) of IFAI has been an industry leader in the development of tools that promote the safe installation of tents for the rental marketplace. In 2012 the division launched its TRD Ballasting Tool—a calculator that determines the required amount of ballast for commercial tents. Here’s a closer look at the Ballasting Tool, why and how it was developed, and how it benefits the industry.
The goal of the TRD Ballasting Study was to determine the friction coefficient of the various types of ballast on different surfaces to develop a systematic approach to ballasting tents. According to Jim Reyen, business director at Eureka! Tents and TRD chairman at the time of the study, TRD conducted a multi-year educational and research campaign with TRD members before the study was taken to explain the goals of the study and gather feedback on what the study should entail. “After two years of educating and gathering information, the study moved forward with a 90 percent approval from membership and full support from renters and suppliers,” he says.
Goals and the study
The industry needed a tool that could quickly and accurately convert the recommended staking loads required by manufacturers and/or codes into the equivalent ballast weights. “At the time, the only way to obtain approved ballast requirements was through expensive site-specific engineering or from tent manufacturers,” says Reyen.
The study, conducted by Clemson University, established the following:
- What are the most common ballast configurations? The study identified four and named them A–D.
- What are the most commons types of ballast used? Cement, barrels, blocks, etc.
- What are the most common surfaces ballast is used on? Grass, asphalt, concrete, dirt, gravel, etc.
- How will the ballast be attached to the tent? Guylines, plates, etc.
- What are the dimensions of the ballast and what is its proximity to the tent? This plays an important role in the way ballast functions and its holding power.
The team that collected these requirements included renters, suppliers, engineers and IFAI staff.
The study defined failure modes for each of the ballast configurations. These included any sliding, uplift or tilting of the ballast. A ratio was identified between the recommended stake requirements of tents and how much ballast it takes to achieve them. It is critical to understand that when ballasting, one pound of dead weight will not equal one pound of load resistance rate. Because ballast can slide, tilt, tip or be lifted, a factor must be applied to identify the amount of dead weight required to achieve the load resistance. As a result, the study calculations accounted for all of these variables to determine the ballast weight required. Ballast weight will always be higher than the load requirements.
The TRD Ballasting Tool
After testing thousands of scenarios using the established criteria, the Clemson team developed formulas for the Ballasting Tool, and the tool was launched for TRD members. “The tool was set up with lots of input and requires the minimum inputs you need to calculate the conversion,” says Reyen. “It does not take long to learn how to use the tool, and once you are a TRD member the use is unlimited.”
The tool had two immediate implications. It revealed that:
- The industry was not using enough ballast.
- The coefficient of friction and the basic geometry of ballasts such as water barrels made them unsafe.
As a result, the tool raised the bar in terms of how tents are ballasted, and it has largely eliminated the use of water barrels as ballast.
To clear up a few misconceptions, TRD emphasizes the following:
- The Ballasting Study was not pursued with the goal of achieving a favorable result for the installers, but rather to produce results that would provide the public with safe tents.
- The study does not provide the installer with the input for the stake holding requirement. That comes from the manufacturer and/or a code requirement.
- The tool does not add any additional factors of safety to the calculations unless the user adjusts it to do so.
“The TRD Education Committee is always on the cutting edge when it comes to safe tent installations,” says Michael Tharpe, TRD Steering Committee chairman. The committee is currently working on Best Practices for Ballast Attachment. This has become more prevalent as the weight and size of the ballast has an effect on the overall application of
TRD members can also look forward to the introduction of the Non-engineered Ballasting Study, which will be integrated into the current TRD Ballasting Tool and will be used to calculate the ballasting requirements for tents that are not engineered or for applications that do not require full engineering for installation. This additional research will show the requirements for tents with and without sidewalls, and will take into account the various styles of frame tents, widths, lengths, heights, anchor points down each side and wind load criteria that must be met. “Hopefully with this new tool we can eliminate the most common failure of ballasting, which is ‘not using enough ballast,’” says Tharpe.