Contractors can't let problems like zero-degree temperatures and frozen ground get in the way of jobsite deadlines. Luckily for them, ground-heating products can save the day and help them stay on schedule.
In order to recommend the right ground-heating and thawing equipment, rental company personnel should know the basics about the contractor's job. What is the timeline for the thaw? What's the soil type? What is the purpose: excavation, concrete placement or frost prevention? Does the contractor have adequate power and heat-retention materials such as vapor barrier and insulation blankets?
According to Ed Jaroszewicz, senior vice president of sales and marketing for Ground Heaters, understanding the soil is critical to understanding thaw performance because different soils have the capacity to hold large amounts of water — or ice. For every pound of ice that is present, 143 Btu are required to thaw the ice. More ice means that more Btu are required or contractors will experience longer thaw times. Soils that have large amounts of ice, such as clay and silt, usually require more Btu because speed is so important for contractors (see chart).
Most hydronic surface heaters, according to Jaroszewicz, can do both thawing and concrete-curing applications. When choosing a heater, both contractors and rental companies need to consider operation costs, including installation and labor, equipment control features and if more heat transfer hoses can be added. Thawing typically requires more Btu per square foot, so the tighter the hose spacing and more concentrated the Btu, the better the performance for the user. Curing though, can be done with less Btu per square foot. To maximize the benefits of the Btu output, the contractor must spread the Btu by using more heat transfer hoses. Having the ability to add accessories to a hydronic surface heating system gives the contractor more flexibility for multiple applications. Temperature-monitoring devices and temperature-controlling features are also helpful to contractors, especially for curing applications.
Different applications have different thawing requirements and knowing that is the key to maximizing the capabilities to the application. For example, when placing concrete, all frost must be removed from the ground for effective substrate material preparation. When excavating however, it is not necessary to remove all frost. Ultimately, rental companies should try to maximize the machines' capabilities to the application, which allows the contractor to minimize thawing costs per square foot.
