What is the time limit on a sodium nitrite wet lay-up?

The time limit on a sodium nitrite wet lay-up is considered to be indefinite. This method is used primarily for corrosion protection in systems where the water content needs to be maintained. When a sodium nitrite wet lay-up is properly implemented, it can help in preventing rust and corrosion in the internal surfaces of the system for an extended period without any stringent time constraint.

This is particularly useful in marine environments or during maintenance periods when systems may not be in use for some time. The effectiveness of sodium nitrite as a corrosion inhibitor allows for flexibility in scheduling maintenance and repairs without the immediate requirement to flush or drain the system, making it an advantageous choice for long-term lay-ups.

Other options that imply specific time limits are not applicable in this context since the sodium nitrite wet lay-up effectively provides ongoing protection beyond set time frames.