Let’s address the elephant in the room. Google "ISO 3691-4 PDF" and you will find Chinese rehosters, Russian translation sites, and obscure document libraries.

The risks of free PDFs:

Red-Flag Warning: If the PDF does not have the ISO copyright footer on the bottom left of every page, it is fake.


The standard mandates that AGVs must have two distinct types of protective equipment:

In most industrialized nations, following harmonized standards like ISO 3691-4 provides a presumption of conformity with machinery directives (e.g., EU Machinery Directive 2006/42/EC). Without the official PDF, proving compliance during a legal audit or insurance claim is extremely difficult.

If you are downloading the ISO 3691-4 PDF to implement AGVs in your facility, use this checklist:


You cannot rely on random forum links for safety standards. Here is the legitimate supply chain for the document:

Warning on "Preview" PDFs: Many sites offer a red-lined "Preview" PDF. This is legal but useless for engineering. It lacks the normative references (the calculations for safety distances). You cannot certify a machine with a preview.