The federal Security Guard Series, numbered 0085, covers jobs whose main duty is protective service work. People in these positions guard buildings and property that the federal government owns or rents, and they watch over government equipment and material.
Part of the job is controlling who may enter a federal installation. Some positions in the series supervise protective service work rather than carry it out directly, so the series includes both guards and the people who lead them.
The reason for the work is preventing loss. Some of what guards protect supports national defense. Some of it matters to public health or safety. Some of it is valued as a national treasure.