With a potential partial government shutdown only days away–federal agency spending authority expires Friday (December 8) unless extended–it’s time for federal managers to brush up on OPM guidance on the process.

That guidance, last updated two years ago, explains numerous management considerations related to “shutdown furloughs,” which agencies must order when appropriations lapse (except for agencies that are self-funding such as the USPS). Within agencies affected by a lapse, some employees are put on unpaid furlough while those designated as “excepted” are to continue working, unpaid for the meantime.

“Agency legal counsels, working with senior agency managers, determine which employees are designated to be handling “excepted” and “non-excepted” functions,” it says.

Employees to be designated as excepted are not necessarily the same employees as those who are designated as “emergency” employees who must report to work in severe weather and similar situations when agencies otherwise are closed.

Excepted occupations are defined in agency contingency plans, some of which date to about the same time period and others that have been updated since, are on the OMB site.