After a successful hydrostatic test, water must be removed from the pipeline prior to the introduction of product. While this is sometimes performed by displacing the water directly with product, in most cases, the water is removed separately by dewatering with air. This is particularly the case where complete drying is required.

GNS provides a wide variety of air compressors to suit the project requirements. These project requirements are usually met using primary screw compressors, but if high pressure is required positive displacement booster compressors will be added to provide pressure up to 5,000 psig.