The Maximum Storage Amount setting caps how much of any item can be placed in a stockpile on a project. You set it as a percentage of each item's authorized quantity. Leave it at zero for no cap, which allows up to 100% of an item to be stockpiled.
For example, if a contract authorizes 100 units of Item #1 and 200 units of Item #2, and you set Maximum Storage Amount to 75%, you can stockpile at most 75 units of Item #1 and 150 units of Item #2.
How to set the Maximum Storage Amount
An administrator or project manager sets this in the project settings, and only while the project is in Draft. Once the project moves to Under Construction, the stockpiling settings lock.
Open the project's settings and find the Stockpiles section. You can also reach these settings from the gear icon on the Stockpiles page.
Make sure Enable Stockpiling is on.
Enter a percentage for Maximum Storage Amount. Leave it at zero for no cap.
Note: To change this after construction has started, move the project back to Draft, update the setting, then return it to Under Construction.