Used to identify pipe and fitting sizes in plumbing. Refers to the inside diameter of the pipe which can vary by thickness of the pipe. The outside is a constant size. For copper pipe the outside diameter is always 1/8 larger than the nominal size. Example: 1/2 nominal is always 5/8.
Competency-based learning or Competency-Based Education and Training is an approach to teaching and learning more often used in learning concrete skills than abstract learning. It differs from other non-related approaches in that the unit of learning is extremely fine grained.
From its beginnings, special education had championed the cause of children with learning problems. It is as the advocates of such children and of the concept of individualization that special education can come to play a major creative role in the mainstream of education. The special competencies of special educators are more than a collection of techniques and skills.