Standard of the International Organization for Standardization (ISO) that defines the quality of the product in the production, installation and service stages.
The standard title (quoted from its latest version of 1994): Model for quality assurance in production, installation, and servicing
This standard is not in use today as it was combined with ISO 9001 and ISO 9003 standards for ISO 9001 ().
An example of a cover that carries the standard on the "ultimate manhole covers" site. From this lid the picture that appears in the general section was taken.