Equipment Inventory Audits:

You should be able to identify what equipment you have in your plant, and where it is.

Expansion Planning:

If you have layout and "equipment as built drawings" your expansion plans can be quickly reviewed to see what will fit where.

Egress Routes:

This is becoming a standard in the industry, and is required in many cases.

Facility Drain Locations:

If you are using water you need to document where the drains are.

Fire Department / City:

They want and need to know where things are in your plant, fire riser locations, egress maps, hazardous material locations.

Maintenance Up Keep:

Help out your maintenance department by locating motors, electrical outlets, power sources.

Electrical Panel Locations:

Need to know where the power is in your facility.