Tent innovator Todd Dalland discusses what’s on the horizon for new clearspan technology and tent designs.
By Todd Dalland
With a 35–year history as a tent and temporary structure innovator, Todd Dalland has a resume that reflects the evolution of the industry. Professional highlights include contributing to wind and download criteria interpretation of the ASCE standard that is used today for tension and clearspan tents; contributing to tent design, engineering and manufacturing technology with support from leading tent manufacturers and installers; and helping to pioneer the use of solar technology in tents. He is co–founder of Pvilion and consults with Future Tents–Todd Dalland Consulting. Dalland received the Bruce W. Wodetzki Award, the tent industry’s most prestigious award, from the Tent Rental Division of IFAI in 2011.
Clearspan enhancements, more stringent engineering and certification requirements, stretch tent adoption in North America and airbeam and solar technologies are all areas that will shape the future of the tent and temporary structure industries.
Solar clearspan fabric panels:Â Clearspan fabric panels integrated with flexible solar panels that pull into the keder channels on aluminum clearspan rafters would allow a clearspan tent to provide power for an event as well as shelter. The challenges are that the solar clearspan panels weigh more, require special handling and cost more because they provide a double function.
Government subsidies and rebates are available for permanent solar panel installations, which helps to make them financially viable. Temporary clearspan installations with solar fabric panels provide the same renewable energy that permanent ones do, and should also be qualified to receive this type of support. Industry support would help in this pursuit.
Arched clearspan rafters:Â Clearspans with arched rafters are entering the marketplace as well as clearspans with inclined, straight rafters. They take up more space on a truck, and there is a premium in the purchase price. However, they are more elegant from engineering and visual standpoints, which should help expand the market.
and aircell tents
A current Pvilion project involves designing a new 20–meter–wide temporary clearspan tent for special events on the rooftop terrace of a prestigious cultural institution inÂ New York City. It uses fabric airbeam rafters for support instead of aluminum ones. Airbeams have been used for decades in military and rapid deployment applications. Standardized, high quality airbeams are now available at prices that are worth considering for tent rental applications. Airbeam rafters lift themselves into place, the fabric along with them, and hold the promise of faster installations with less labor. Fabric aircell tents are similar in this regard.
Other tent styles
Stretch tents: Stretch tent technology has been perfected largely in South Africa over the last decades and is ready to enter the North American market. It should find good application in certain niche markets to start. Stretch tents hold the promise of layouts that have greater flexibility and are more responsive to special site conditions, and installations that are faster and require less labor.
There appears to be little technical engineering information for stretch tents to establish building code conformance. Future Tents is performing material tests that provide the data needed for two–way stretch fabric behavior under load, developing new form–finding and analysis techniques to address larger acceptable fabric stretch and deflection and preparing layout drawings with engineering certification that address the most typical layouts.
Folding frame tents: 10–by–10–foot scissor action pop–up tents enjoy widespread application largely because they are easy and fast to install with little labor. More robust frame tents that fold out to 20 feet wide quickly are coming onto the market. Larger widths may be coming.
Enhanced Clearspan and tension tents
It’s been 25 years since the first tension tents were introduced with high peaks, curved fabric surfaces, fewer poles and engineering documentation, and since the first clearspans came out with rigid frames, no columns, flat fabric panels that pull into channels, tight fabric sidewalls and a greatly reduced need for staked guy ropes. Are there ways to further improve client satisfaction with these tents? Here are some ideas:
Fabric insulation panels and mechanical engineering calculations: This effort aims to improve comfort levels inside tents during events while reducing heating, ventilation and air conditioning costs, and to standardize fabric insulation components such as thermal liners, thermal sidewalls, thermal drop ceilings and thermal floor–to–ceiling partitions to segregate heated spaces. These components exist on a limited or ad hoc basis and can reduce event heating and cooling costs by 50 percent, as well as demonstrate sustainability awareness and reduced carbon footprint. Tent manufacturers can design their tents with standardized connections adapted for thermal fabric insulation components with dead air space.
Fabric vents and structure–mounted ventilation fans: Vents and fans at rafter peaks and pole tops can create a largely passive way to reduce heat inside tents during events. Very little work has been done in the area of fabric venting in tents. Operable or rain–shedding peak vents are a basic feature of permanent buildings in certain climates. The physical principles and advantages are much the same for temporary structures. Tents could be designed with operable fabric vents and clip–on fans. Mechanical engineers specializing in temporary tents can calculateÂ the amount of fabric vent “opening area” and fan required, and can generate standardized information regarding fabric insulation panels required to achieve comfort levels in different geographical regions as well as the amount of fuel saved.
Fabric skylights:Â This design innovation involves circular fabric tension ring openingsÂ (12 to 48 inches in diameter)Â in particular locations on main fabric surfaces. Openings are belt reinforced so skylights can be covered or open, removable, operable, clear, opaque or different colors. They can also serve as vents.
New engineering certification for non–engineered tents: Traditional “red and white stripe” or other pole tents that have not been engineered may be analyzed to determine what wind speed rating they conform to and certified to that effect. Often, minor changes to the tent materials or construction can result in certification to a higher wind speed.
Enhanced certification documents: When conducting an engineering study and certification, some of the steps Future Tents performs include:
- adding wording and sketches on certification drawings and reports showing ballasting layout and loads, as well as a layout with guys and stakes.
- adding standardized, generic life safety information on certification drawings geared to fire marshals, with architect’s stamp.
- requiring fabric suppliers to provide biaxial stress–strain information and testing using actual tent fabric design loads, and state it on the certification drawings. This improves tolerance on actual tent pull–out dimensions and tightness of fabric cutting patterns. It also establishes quality control and consistency of important fabric roll goods properties.
- adding wording describing sustainable and LEED characteristics of the tent, the tent manufacturing process and the tent installation.
Additional module shapes: Clearspan manufacturers offer a number of specialty modules to maintain market interest. Options for tension tent modules are not as diverse, but there is a variety of possibilities:
- Round end modules: for additional end option instead of rectangular end modules; also enables round tent installations.
- Coupler modules: a wedge–shaped module that would join, for example, a 40–foot–wide middle module to a 60–foot–wide middle module, or a single–pole module to a double–pole module.
- Crescent modules: a wedge–shaped module that allows a tent layout to be curved in plan or have bends in it.
- Center modules: a square or rectangular module that laces on all four sides to other end or middle modules.
- Bandshell end module: a module that has a high edge with a wider column spacing to serve as a bandshell for performances.
- Miscellaneous modules such as T–shaped modules and L–shaped modules.
Covered walkway module: a module with tensile or arched look that connects directly to tent eave with watershed connection.
- Add–a–room modules: 10–by–10–foot and 20–by–20–foot modules with tensile or arched looks that connect directly to tent eave with watershed connection.
Partial snow load ratings and/or increased wind speed ratings: Many tents have an inherent ability to carry a modest amount of snow, and this can often be increased with minor modifications to materials, construction and installation. This can be formalized with engineering certification, which can help extend the rental season in some locations. Similarly, wind speed ratings for tents that are already engineered can be increased for specific wind regions or requirements.
Solar fabric pole tents: Flexible solar fabric tent accessories that pull over and belt onto frame and pole tents will enable renters to take a first step into solar tents, without having to invest in new tents.