Char Blisters : Convex segments of carbonized material separated by cracks or crevasses that form on the surface of char, forming on materials such as wood as the result of pyrolysis or burning
Ingenieurbro Frank Markmann, Fire, Arson & Explosion Investigation in Germany and Europe, Fire Investigators Dictionary (The English definitions 1995 Edition of NFPA 921 Guide for Fire and Explosion Investigation), Wald, Germany (Revised 2008), http://www.fmfire.de/fidicteg.html, (FrInv - Brit) {94}