31 Oct 2017

Keeping jobsites ahead of schedule during cold winters

Aggreko team at a construction jobsite suring winter
 

Keeping jobsites ahead of schedule during cold winters

Cold temperatures and snow may seem like a threat to jobsites during the winter. Regardless of the construction phase, low temperatures often lead to more costs and delays. That is why our experts design and deploy the best-fit portable heating solution for the construction industry. We’re always focused on your schedule and budget, total operating costs, equipment efficiency, site productivity and enhanced product quality and safety. 

In the video below, you can find the five main heating applications we usually deliver to construction projects:


Rental heaters for concrete pouring

When we get deeper into the applications discussed in the video, concrete pouring and curing is a prime example of success. In a typical concrete curing schedule, the onus is on maintaining a 60°F curing surface temperature, regardless of freezing ambient air temperatures. 

During the winter months, the challenge is to maintain and manage the quality of poured concrete throughout a typical 14-to-21 days curing process. One of the benefits from fuel-efficient ground heater technology is the fact that the units are capable of continuous operation. Contractors want to guarantee very precise temperature control of the curing process, and this allows them to do so.

For instance, when a car dealership in Manitoba needed a foolproof heating solution to cure concrete in winter ambient conditions as low -40°F, Aggreko was called to help with a well planned insulation strategy while the poured concrete was cooling. 

In order to reduce costs and fuel consumption, we heated the concrete using expendable heat transfer tubes embedded within the concrete pours. In this application, a propane-fired boiler was found to be the most fuel-efficient system with minimal power draw while connected to a grid of tubing spaced 1 to 1.5 feet apart. This ensured uniform heating of the poured concrete in a confined area and kept the project on schedule and under budget. 

Another example to share is that of an underground shaft for a subway was being expanded in North Toronto. It was not feasible to pour cement during the winter months since the cold and damp weather prevented the concrete from properly pouring. Waiting until springtime was not an option due to schedule commitments along with the increased overall costs related to delays. That is when Aggreko was called to provide a heating solution, so the contractor could continue to pour concrete throughout the entire year. 

A number of significant challenges arose for this project. The biggest being the sheer size of the jobsite. Nine different areas required cement to be poured, covering one-half mile. On top of that, placing the heaters 150 feet below ground was also a challenge. Once underground, all cables had to be hung to avoid placing too much weight on the heaters. After everything was finally placed, connected and grounded, ductwork was routed to provide heated air at strategic points throughout the shaft. Once in the shaft, the heaters were able to be maneuvered by a forklift after being placed on skids. All generators used were equipped with our Aggreko Remote Monitoring solution, so alarms would notify the Remote Operations Center if servicing was required to perform proactive maintenance and keep everything running despite subzero conditions. 

Heating the construction site in subzero weather

The need to heat the interior of a building during construction is driven by concerns of freezing temperatures and worker safety and productivity. When a commercial construction site faced heating challenges with the -40°F Canadian winter, our team was once again called. We provided two 1.2 million BTU natural gas boilers with 12 points of radiant heat dispersed throughout the project area. 

The hoses connecting the boilers with the fumeless, radiant heaters were run under crawl spaces, essentially making the floors function like a huge radiator and keeping the building temperature above 53°F. While much of the building was covered by tarps, a heating airflow was maintained to balance heat flow loss. The heat flux was remotely monitored to ensure temperature would be kept despite different trades introducing cold building materials and equipment previously stored in the open air.

Compared to conventional heating typically employed during the construction phase of commercial buildings, radiant systems transmit heat on average 15% more efficiently and are an ideal strategy when space is limited. The optimal space-heating envelope was developed after a mutual collaboration between the contractor and our climate control experts. 

Boiler Bypass for potable and non-potable water

As a final example, boiler bypass is a typical application when heating is mandatory to overcome harsh winters. Existing buildings, especially older ones, have planned maintenance from time to time on their heating systems.  Often times an emergency heating solution arises when there is a unplanned failure with the equipment. 

Our hydronic heaters provide reliable and cost-effective temporary heating for both potable (domestic hot water) and non-potable water applications. The open atmosphere ventilation eliminates the need for an on-site technician. The heaters interface directly with the building’s permanent distribution systems, vents &/or radiators. Smart controls optimize temperature control and minimize fuel burn emissions and heaters can run on either propane, natural gas or diesel. Along with these features, the rapid response and expert knowledge from our team makes us go beyond the rental and deliver an all-in-one solution for existing buildings or construction projects.