Demolition of old FA components, wire, etc.

Hello Fire Alarm Folks.

I have always believed that any old fire alarm equipment (components, wired, etc.) must be removed from a building if it has been renovated with a new FA system and the old components/materials are no longer being used. I have also always thought that this is CODE that mandates this.

We have found this info in NFPA-70 (sec. 270?) but I cannot seem to locate this info anywhere in NFPA-72.

Does anyone have thoughts on this and where I can specifically reference this in case I need documentation support? IFC maybe?

Thank you.