Breather valves can be installed to either vent to atmosphere or be piped away for recovery (nitrogen systems). Piping that connects nitrogen blankets from tank to tank needs to be heat traced/insulated to avoid plugging up over time (in case of cold climates and hard products). Careful engineering needs to be undertaken to propery size vent systems that do not dump to atmospheric pressure. Breather Valves can be designed with different over pressure and under pressure within the same unit.For additional information, refer to the Refinery Layers of Protection document on the MTL Sharepoint.