BS EN ISO 2692:2021

This standard BS EN ISO 2692:2021 Geometrical product specifications (GPS). Geometrical tolerancing. Maximum material requirement (MMR), least material requirement (LMR) and reciprocity requirement (RPR) is classified in these ICS categories:

• 17.040.40 Geometrical Product Specification (GPS)
• 01.100.20 Mechanical engineering drawings

This document defines the maximum material requirement (MMR), the least material requirement (LMR) and the reciprocity requirement (RPR). These requirements can only be applied to linear features of size of cylindrical type or two parallel opposite planes type.

These requirements are often used to control specific functions of workpieces where size and geometry are interdependent, for example to fulfil the functions “assembly of parts” (for MMR) or “ minimum wall thickness” (for LMR). However, the MMR and LMR can also be used to fulfil other functional design requirements.