What should be maintained if inert gas, such as nitrogen, is used in the boiler during dry lay-up?

Maintaining an adequate level of pressure, such as 35 kPa, when using inert gas like nitrogen during the dry lay-up of a boiler is essential for several reasons. This pressure helps to prevent the ingress of atmospheric air, which could introduce moisture and potentially harmful gases that can lead to corrosion or other forms of deterioration within the boiler.

By keeping the pressure at 35 kPa, it ensures that a protective blanket of nitrogen is maintained throughout the boiler system. This creates an inert atmosphere that is less reactive than air, significantly reducing the oxidation process that could harm the metal surfaces. It also aids in Displacing moisture that might not have been fully removed during initial drying processes, further protecting the integrity of the boiler materials.

Choosing a pressure of 35 kPa reflects a balance between ensuring safety and avoiding excessive pressurization, which could pose its own set of risks. Therefore, maintaining this specific pressure during a dry lay-up with inert gas can enhance the longevity of the boiler and maintain its operational readiness when it is eventually put back into service.