From The Nuclear War File: Weaponry, Strategy, Flashpoints, and the Balance of Power. Chant, Christopher and Ian Hogg. London: Nomad Publishers Ltd, 1983.
Or just duck and cover under your desk.
On this topic, my mother has vivid memories of one of her school teachers assuring the kids that there was room for the students in the school’s fallout shelter. But not enough room for the parents and other town folk. This teacher vowed he would guard the door from the outside and shoot anyone who tried to compromise the shelter. Even the kids’ parents.