Reference data
Shutdown KPI Definitions and Turnaround Intervals: Reference Data with Sources
This reference set gives 10 shutdown KPIs with their formulas and basis, and published turnaround intervals, durations and windows for five sectors, each tied to a named source. Both tables can be downloaded as CSV. KPI worked examples use illustrative numbers; the intervals are published figures, not MaintWiz measurements.
How MaintWiz helps: The MaintWiz shutdown module calculates these KPIs from the live plan, so cost, schedule, scope and safety indices update as work is reported.
By Jai Balachandran · Technical review: Murali Nerur Pasupathy · Published · Last reviewed
What MaintWiz adds:Critical path and floatEarned value indicesCost and schedule KPIsSafety measures
KPIs
Which shutdown KPIs should you track, and how is each calculated?
Ten shutdown KPIs cover cost, schedule, scope, safety and permit quality; each has one formula and a named basis.
| KPI | Formula | Worked example (illustration) | Basis |
|---|---|---|---|
| Cost variance (CV) | BCWP - ACWP | 392 - 441 = -49 (over budget) | GAO cost guide |
| Cost performance index (CPI) | BCWP / ACWP | 392 / 441 = 0.89 | GAO cost guide |
| Schedule variance (SV) | BCWP - BCWS | 392 - 435 = -43 (behind plan) | GAO cost guide |
| Schedule performance index (SPI) | BCWP / BCWS | 392 / 435 = 0.90 | GAO cost guide |
| Estimate at completion (EAC) | ACWP + (BAC - BCWP) / CPI | 441 + (870 - 392) / 0.89 = about 979 | GAO cost guide |
| Duration variance, % | (actual days - planned days) / planned days x 100 | (11 - 10) / 10 = 10% | Agreed definition |
| Scope growth, % | (final work scope - frozen scope) / frozen scope x 100 | (940 - 870) / 870 = 8.0% | Agreed definition |
| Recordable injury rate | cases x 200,000 / hours worked | 7 x 200,000 / 400,000 = 3.5 | BLS incidence rate |
| Planned outage factor (power plants) | planned outage hours / period hours x 100% | 480 / 8,760 = 5.5% | NERC GADS Appendix F |
| Permits issued with hazards and controls adequately specified, % | permits judged adequate / permits sampled x 100 | 47 / 50 = 94% | Indicator example in HSE HSG254 |
Worked examples are illustrations with round numbers, not results from a MaintWiz customer. See Shutdown KPIs: formulas, worked examples and a calculator.
Intervals
How often, how long and when do plants shut down?
Published figures vary widely by sector; the table shows what each source states and where.
| Sector | How often | How long | Usual window | Source |
|---|---|---|---|---|
| Refining (US) | Routine turnarounds on key units every 3 to 5 years | A unit offline for several weeks to several months, after 1 to 2 years of planning | Spring or fall | EIA, AFPM |
| Nuclear power (US) | Refueling every 18 or 24 months of full-power operation | About two months on average; as short as 10 days | Spring and fall | EIA |
| Power generation (reporting definition) | A planned outage is described as occurring once or twice a year | Several weeks, of predetermined duration | Spring and fall in New England data (2011) | NERC GADS, EIA |
| Iron and steel (blast furnace) | Campaigns of 15 to 20 years between relines are the aim | One 2008 reline took 70 days, against over 80 days in 1996 | Around furnace and mill demand | EU study, AIST |
| Pressure plant (statutory) | India: a boiler certificate runs for no more than 12 months (Boilers Act 2025, in force from 1 May 2025). Great Britain: examinations follow a written scheme | Typically 1 to 3 weeks for a boiler or pressure plant inspection stop | Set by the certificate or scheme date | Boilers Act 2025, HSE PSSR, HSE INDG178 |
Sources list the original statements. Other sectors (cement, chemicals, pharmaceutical, food and beverage, mining, water) have no single published interval and are left out. See when to schedule plant shutdowns.
Download
Can you download and reuse the data?
Yes: both tables are available as CSV and may be reused with attribution.
Download: shutdown-kpi-definitions.csv (10 KPIs) · turnaround-intervals-by-sector.csv (5 sector rows). Free to use, modify and distribute with attribution to MaintWiz (www.maintwiz.com).
FAQ
Frequently asked questions
What does this reference data contain?
Ten shutdown KPIs with formulas, a worked example and a basis, and published turnaround intervals, durations and windows for five sectors with their sources.
Are the worked examples real results?
No. The worked examples use round illustrative numbers to show how each formula is applied. They are not MaintWiz customer results.
Where do the intervals come from?
From named public sources such as the US Energy Information Administration, AFPM, NERC, EU and AIST steel studies, HSE and the Indian Boilers Act. Each row cites its source.
Can I reuse the CSV files?
Yes. Both files are free to use, modify and distribute with attribution to MaintWiz at www.maintwiz.com.
Why are some sectors missing?
Where no single published interval exists, the row is left out rather than filled with an estimate.
Sources
Sources
Public sources behind both tables.
- U.S. Energy Information Administration, Refinery Outages: Description and Potential Impact on Petroleum Product Prices
- American Fuel & Petrochemical Manufacturers, Refinery turnarounds 101: What are turnarounds and why do we need them? (17 October 2023)
- U.S. Energy Information Administration, Nuclear power plants undergo seasonal scheduled outages (23 May 2011)
- North American Electric Reliability Corporation, Generating Availability Data System (GADS) Data Reporting Instructions, effective 1 January 2026
- U.S. Energy Information Administration, Seasonal maintenance helps keep power online during summer and winter peaks (22 April 2011; ISO New England data)
- Publications Office of the European Union, An in-depth study into prolonging blast furnace campaign life (2001)
- Association for Iron & Steel Technology, ThyssenKrupp Steel to Restart Blast Furnace 1 at Duisburg-Schwelgern (20 March 2008)
- Government of India, The Boilers Act, 2025 (Act No. 12 of 2025), Gazette text as published by PRS India
- UK Health and Safety Executive, Pressure Systems Safety Regulations 2000 (PSSR)
- UK Health and Safety Executive, Written schemes of examination (INDG178, rev 2, 2012)
- U.S. Department of Energy FEMP / Pacific Northwest National Laboratory, O&M Best Practices: Maintenance Approaches
- PRS Legislative Research, The Occupational Safety, Health and Working Conditions Code, 2020
- DLA Piper, Government of India notifies the Labour Codes (November 2025)
- US Government Accountability Office, GAO Cost Estimating and Assessment Guide (GAO-20-195G, March 2020)
- US Government Accountability Office, GAO Schedule Assessment Guide: Best Practices for Project Schedules (GAO-16-89G, December 2015)
- US Bureau of Labor Statistics, How to compute your firm's incidence rate for safety management
- North American Electric Reliability Corporation, GADS Data Reporting Instructions, Appendix F: Equations (2025)
- UK Health and Safety Executive, Developing process safety indicators: a step-by-step guide for chemical and major hazard industries (HSG254, 2006)
- US Chemical Safety and Hazard Investigation Board, Investigation Report: Refinery Explosion and Fire, BP Texas City (Report No. 2005-04-I-TX)
Calculate these KPIs on your own shutdown
Book a demo and bring last year's cost and schedule figures. We will show the indices on the live plan.