This class consists of units of military defence (including those staffed by civilian personnel) stationed at home or abroad. Included are units mainly engaged in defence administration; the administration of defence research and development policies and associated funds; contingency planning; and carrying out military exercises in which civilian institutions and populations are involved.
- Armed forces unit operation (except manufacturing or educational)
- Civil defence operation (military)
- Government administration (defence)
Units mainly engaged in operating military academies or research schools are included in the appropriate classes of Division P Education and Training.