Global network and IT services provider Verizon has completed an airflow optimization project across a dozen US data centers, resulting in projected annual energy savings of 18.8m kWh.

Verizon contracted California-based provider of containment services Polargy, which designed the containment solutions for each of the facilities, secured local fire-marshal approvals, managed installation and helped with the commissioning process. The project started in 2010.

The data center containment solution is called PolarPlex. In Verizon's case, it included hot-air redirection, installation of solid or plastic panels for air containment and of blocking panels to fill empty rack spaces.

Mark Capurso, director of national technical operations at Verizon, said in a statement his company chose Polargy for the job because it "hit the mark" on both energy savings and reduction of environmental impact.

"The PolarPlex cold-aisle containment solution lowered our airflow requirements and our air-conditioning usage, moving us one step further in making our network more efficient and sustainable," he said.

Together, the 12 sites constitute about 1m sq ft of data center space. Once completed, Verizon has seen an aggregate 7.7% improvement in energy efficiency across all the facilities involved.

Overall Data Center Infrastructure Efficiency (DCiE) metric across the facilities went from 0.45 to 0.5. Developed by The Green Grid, the metric is derived by dividing power used by IT equipment in a data center by power used by the facility as a whole: