If you open the IPC-2221 PDF, three tables and two figures will dominate your daily work:
IPC-2221 works in tandem with IPC-2222 (Rigid Organic Boards), IPC-2223 (Flexible Boards), and IPC-2226 (High-Density Interconnect – HDI). Where IPC-2221 provides the "what" and "why," the subordinate standards provide the "how" for specific board constructions. ipc 2221 standards pdf
Specifies properties of base materials (CTE, dielectric constant Dk, dissipation factor Df), metal cladding (copper weight: ½ oz to 2 oz typical), and solder mask requirements. If you open the IPC-2221 PDF, three tables
The IPC 2221 PDF makes this distinction clear with side-by-side diagrams. Using clearance values for a creepage path (or vice versa) leads to arcing and field failures. If you open the IPC-2221 PDF