1 Scope
This document describes how to calculate the work performed by a person’s respiratory
muscles with and without the external respiratory impediments that are imposed by
RPD of all kinds, except diving equipment. This document describes how much additional
impediment people can tolerate and contains values that can be used to judge the acceptability
of an RPD.
NOTE These calculations are explained in some textbooks on respiratory physiology (in the
absence of an RPD), but most omit them or are incomplete in their explanations.