: Small fragments from the protected side of the barrier must not break off with enough force to injure someone standing directly behind it. Reference: Classic Level Breakdown
Be extremely cautious of any website offering a "free PDF" of the UL 752 standard. These are often outdated versions, incomplete documents, or, in some cases, potentially malicious files. For legal and professional applications, you must obtain the official, copyrighted document from an authorized source. ul 752 standard pdf new