24/7 Staffing Coverage Model

SHIFT STRUCTURE — 8-HR CONTIGUOUS SHIFTS

DAY SHIFT

0600–1400

All regular pay.
0 hrs night differential.

EVENING SHIFT

1400–2200

4 hrs night differential
(1800–2200, +10%).

NIGHT SHIFT

2200–0600

8 hrs night differential
(all hours qualify, +10%).

Three contiguous 8-hour shifts cover 24 hours exactly with no overlap — each shift starts precisely when the previous ends. Each person works 5 shifts per week × 8 hours = 40 hours, with 2 days off per week (pattern varies by rotation cycle).

CONTINGENCY BUFFER (SICK / LEAVE / EMERGENCIES)

25%

0% (theoretical) OPM RECOMMENDS ~25% 40% (extreme)

THE ACTUAL MATH

HOURS TO COVER (1 POSITION x 24/7/365)

8,760 hrs/yr

GROSS FTE HOURS (40 hrs/wk x 52 wks)

2,080 hrs/yr

OPM MANDATORY LEAVE (PER PERSON)

Annual Leave (avg)20 days / 160 hrs

Sick Leave13 days / 104 hrs

Federal Holidays11 days / 88 hrs

TOTAL MANDATORY LEAVE 44 days / 352 hrs

NET AVAILABLE HOURS (BEFORE BUFFER)

83% availability

1,728 hrs

EFFECTIVE HOURS AFTER 25% BUFFER

62% of gross FTE time

1,296 hrs

PEOPLE NEEDED PER POSITION

8,760 / 1,296 = 6.76 -> round up

7 FTE

RESULT AT 25% BUFFER

OPERATORS

21

3 positions x 7

SUPERVISORS

7

1 position x 7

TOTAL STAFF

28

full 24/7 coverage

OPM SHIFT DIFFERENTIAL RULES (GS EMPLOYEES)

NIGHT DIFFERENTIAL

+10%

6:00 PM - 6:00 AM

5 CFR 550.122

Modest. Many prefer nights (fewer supervisors, lifestyle fit). Not a strong staffing pressure.

SUNDAY PREMIUM

+25%

Regularly scheduled Sunday work

5 CFR 550.171

Significant. Attractive financially, but opt-outs create backfill problems without a solid rotation policy.

In a properly structured rotating schedule, every crew shares nights and weekends equally -- so preference issues largely self-resolve. Shift attractiveness does not change your headcount math unless you allow opt-outs. A fair rotation makes this a morale and recruiting problem, not a staffing number problem.

BOTTOM LINE

CONSERVATIVE (25% BUFFER)

Operators: 21

Supervisors: 7

Total: 28

ROBUST (30% BUFFER)

Operators: 24

Supervisors: 8

Total: 32

This is the number of people dedicated to shift coverage for a 4-person rotation (3 operators + 1 supervisor) running 24/7/365 under OPM federal leave rules. At a 25% contingency buffer the math lands at 28 people; at 30% it rises to 32. Your total headcount will be larger — personnel who carry other primary duties (admin, training, projects, ancillary ops) are also qualified on the rotation and step in when a shift rotator is on leave or unavailable. Those dual-role personnel are doing productive work the rest of the time; they are not idle buffer.

EXAMPLE: TWO-WEEK ROSTER — 80 HRS PER PERSON

DAY 0600–1400

EVE 1400–2200

NGT 2200–0600

BUF On-call buffer

OFF Rest day

5 TEAMS · 20 ACTIVE ROTATORS · 10 SHIFTS EACH · 80 HRS EACH · 4 REST DAYS EACH

This roster shows the active rotation only. Your full headcount will be larger. Personnel carrying other primary duties — training, administration, ancillary operations — are also qualified on the rotation and step in when a rotator is on leave or unavailable. They are doing real work the rest of the time, not sitting idle. When the calculator shows 24–28 people, that figure covers dedicated rotators; your broader qualified pool is on top of that.

	— WEEK 1 (APR 6–12) —							— WEEK 2 (APR 13–19) —
TEAM	MON 6	TUE 7	WED 8	THU 9	FRI 10	SAT 11	SUN 12	MON 13	TUE 14	WED 15	THU 16	FRI 17	SAT 18	SUN 19
ALPHA 3 OPS · 1 SUP	OFF	DAY	EVE	NGT	OFF	DAY	BUF	NGT	OFF	DAY	EVE	BUF	OFF	NGT

BRAVO 3 OPS · 1 SUP	DAY	OFF	NGT	EVE	DAY	OFF	DAY	BUF	EVE	OFF	NGT	EVE	NGT	OFF

CHARLIE 3 OPS · 1 SUP	OFF	EVE	OFF	DAY	EVE	NGT	OFF	DAY	NGT	BUF	OFF	NGT	DAY	EVE

DELTA 3 OPS · 1 SUP	EVE	OFF	DAY	OFF	NGT	EVE	NGT	OFF	DAY	EVE	BUF	OFF	EVE	DAY

ECHO 3 OPS · 1 SUP	NGT	NGT	OFF	BUF	OFF	BUF	EVE	EVE	OFF	NGT	DAY	DAY	OFF	BUF

ALPHA

Op A-1

Op A-2

Op A-3

Sup A

BRAVO

Op B-1

Op B-2

Op B-3

Sup B

CHARLIE

Op C-1

Op C-2

Op C-3

Sup C

DELTA

Op D-1

Op D-2

Op D-3

Sup D

ECHO

Op E-1

Op E-2

Op E-3

Sup E

Each team works exactly 10 of the 14 days (80 hours), with 4 rest days spread across both weeks. On the 8 days where 4 teams are active, the 4th serves as on-call buffer — immediately available if someone calls in sick or a shift overruns. When a rotator takes annual leave or goes TDY, a qualified person from outside the active rotation fills their slot — someone who spends most of their time on other duties but maintains rotation currency. The rotation stays intact; the broader qualified pool absorbs the variance.

8-HOUR SHIFT COVERAGE ANALYSIS