The is more than a document; it is a liability shield. If your product catches fire or fails in the field, one of the first questions a forensic engineer will ask is: "Was the PCB designed to IPC-2221 standards?"
Vias and interconnections
Common Best Practices (Practical Tips)
IPC-2221, titled "Generic Standard on Printed Board Design," is the cornerstone document developed by the Association Connecting Electronics Industries (IPC). It establishes the generic requirements for the design of organic printed boards and their forms of assembly. Ipc-2221 Pcb Design Pdf