A review of the difference between engineered and non-engineered tent systems
A co-worker’s grandfather was a train engineer in the 1920’s. He passed away before she was born, but she once told me that trains must be in her DNA, because she loves to hear the long, low whistle of a train as it winds past. There’s a certain nostalgia that rides along with train engineers when we think about them today. A bit of Wild, Wild West meets gypsy spirit crisscrossing the country in an iron horse mounted on a set of steel rails.
Sadly, for those of us in the tent rental industry, Old West nostalgia and gypsy wanderings mercilessly collide with cold, hard facts when the topic shifts to an engineer of a different kind – the kind you need to certify that your tent will meet the code requirements in your municipality for your next important install.
Engineered vs Non-Engineered Tents
Simply put, an engineered tent means that the manufacturer has paid a structural engineer to conduct a Finite Element Analysis. That means the engineer has conducted a series of mathematical formulas based on the design of the tent and provided documented data that proves the tent system – as designed – is able to withstand certain forces such as wind loads and/or snow loads. Some engineers are licensed for only one state. Others are licensed for all 50 states or even globally. But in order to meet the standards of the codes official, that engineer MUST be licensed for the state in which the tent is scheduled to be installed.
On the other side of the tracks, non-engineered tents have not been tested or rated to withstand certain levels of force. That means they typically do not contain the structural elements needed to withstand higher wind loads or snow loads. That’s generally OK. Many places don’t require engineered tents, and when they do, it often pertains to tents greater than 400 square feet.
Non-certified tents are used in a wide variety of venues and can be sourced from a wide array of manufacturers. Frame tents and pole tents can both be acquired without wind load certification and are generally less expensive than their certified counterparts due to the materials and level of construction of those tent systems. Non-engineered tents can be used as long as they meet the regulations of the local municipality of your event site.
Engineered tents have to play by different rules. In order for a frame tent to withstand the paces of an FEA that an engineer will put it through, the structural design must to be up to the task. For a frame tent, that can mean more rigid extrusions and bracketry, at a minimum. Pole tents are also offered with engineering certification. Those FEA’s usually revolve around specific requirements for the types of webbings and hardware, as well as the pole and out guy systems.
Engineered tent systems are only as strong as the sum of their parts. And in order for the tent SYSTEM to meet the engineered tent standards, all parts of the SYSTEM must be used as dictated. The standards set down by the structural engineer in meeting the criteria of the certification means there can be no substitutions or reductions. Tension tents have to maintain a specific number of anchor pounds at given locations around the perimeter to stay erect, but they also must maintain higher values at wind load.
Your manufacturer should be able to provide you the submittal documents your municipality requires for your certified tent. Those documents will contain several important items, including a stamped seal that proves that a structural engineer has reviewed the contents and certifies that they are legitimate. The engineering documents will spell out the criteria by which the system was certified, including specific wind loads. The documentation will also show reactions at specific places around the tent. The installer can use this information to determine at what level the tent needs to be secured to be sure it stays in place in the worst of conditions. It’s ultimately up to the installer(s) to be sure the tents are anchored to meet the values contained in the document, but that’s a topic for a future article.
Hopefully, this overview sheds some light on the difference between an engineered tent and a non-engineered tent, so that you’re prepared with all of the information and documentation your local codes official will need to approve your next important install without delays. To view an example of engineering documents that TopTec provides for our FutureTrac engineered tents, you can go here to learn more.