Engineers have a moral and ethical obligation to use accurate and unaltered information in their designs. Modifying or using a "patched" standard that has been altered, even unintentionally, represents a direct opposition to professional codes of conduct. If a calculation or specification derived from a patched standard leads to an accident, the responsible engineer can be held personally liable.
In technical circles, searching for a "patched PDF" or a pre-cracked standard document typically stems from two motivations: bypassing digital rights management (DRM) or seeking a file that bypasses payload security blocks. 1. Bypassing Official DRM Safeguards IEC 60099-5:2018
If you are an engineer or student, your company or university library likely has subscription access to these standards.