I've seen the famous pyramid picture several times showing the four tiers of documentation. My question is, should the pyramid contain all documents within the company or just the ones associated with quality? For example, our company typically creates requirements, design and test plan documents for each project or program. These are a fundamental part of what we do and I'm certain that ISO requires that these types of documents be written and controlled. However, from the typical description of the Tiers I do not see to which tier these belong.