Pureheat delivers on-time arrival at Copenhagen Airport

The cut-throat international airline industry has forced many airports to come up with creative approaches to attract travellers and business. The Nordic’s oldest and most travelled airport, Copenhagen Airport (CPH) in Denmark, recently opened a new, low-cost terminal designed to lower airfares by about 35%, so it could remain competitive.

The Swift terminal project was completed by Brdr. A. & B. Anderson (BRA), Gadstrup, Denmark, with construction beginning in October 2009. Contract timing required much of the concrete, sewer and utility to take place during the winter months.

Prior to construction, demolition contractors removed an old terminal and lined the 72,118 ft² (6,700 m²) construction zone with gravel in preparation for the new terminal. The gravel base for the excavated site served as a sponge, soaking up the deluge of rain Copenhagen received in November, which was six times the historic average.

Next came the subfreezing temperatures, which resulted in a frozen subgrade that brought concrete, excavation and sewage construction to a halt. The region experienced one of the coldest winters in more than 20 years with abnormally high precipitation. This jeopardized completing the 97,950 ft² (9,100 m²) expansion project within the contracted 10-month time frame.

Pureheat Rescue

Frost had permeated the entire 72,118 ft² (6,700 m²) area to a depth of 28-39 in (70-100 cm) at a time when BRA’s crews were in full swing with concrete and sewage system work. The frost penetration made it impossible to excavate the gravel. Facing a very tight construction schedule, it was impossible for BRA to simply wait for the temperatures to warm enough for the ground to thaw. The company needed a solution to quickly thaw the frozen ground.

Initially, BRA considered employing thermal mats to thaw the ground. However, the sheer size of the construction site rendered this idea impractical. The amount of electricity consumed by the mats would have required special power arrangements for the jobsite, making it financially unfeasible.

BRA broke with tradition and tried an alternative approach. The project’s chief engineer had experience with using a new heating system from Wacker Neuson, which consisted of a hydronic heating solution that runs through a series of hoses. He successfully used the Pureheat hydronic air or surface heater for a ground thawing application during the winter of 2008.

Pureheat from Wacker Neuson Climate Technology quickly thaws frozen ground at a depth rate reaching 12 in (30.5 cm) per day. Connected to an oil-fired boiler, the unit’s hydronic hoses are placed directly on the surface to be thawed. For insulation, the hoses are covered with vapour barrier and Red Wave heating blankets. The blankets are then covered with a material to keep them in place.

The versatile Pureheat system can operate on diesel fuel, natural gas or propane to fit jobsite needs. Operating at 83% heater efficiency, the heating system delivers 714,000 BTU/hr 209 (kW) heat output. When equipped with Wacker Neuson Heat Xchangers, the Pureheat heating system also delivers clean, dry air heat for heating inside spaces.

BRA equipped the Pureheat unit with auxiliary hoses and thawed approximately 30,149 ft² (2,800 m²) at a time. Once a section was thawed, the hoses were moved to another part of the construction zone, while digging and levelling commenced in the thawed area. Due to the extremely cold temperatures, crews often moved the heating system tubes back to a completed section or covered the area with insulating mats to prevent new frost from developing.

Employing the Pureheat system allowed BRA’s crews to dig the indoor sewer, build and level the foundation for floors, and install 8 mi (13 km) of electrical conduits under the floors during the winter months. While these measures entailed additional work and expenses, BRA officials reported that it was highly unlikely that they could have completed the entire project by the end of 2010 without using Pureheat.

Within a month after the cold winter temperatures subsided, crews had the terminal building with roof constructed and were working to finish the facade and installation work. Thanks to the help of Wacker Neuson and the Pureheat hydronic air or surface heater, BRA finished the project by the contracted completion date.

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