---
title: "Forced outage"
description: "A forced outage is an unplanned shutdown of an industrial unit, triggered by equipment failure (typically boiler tube failure) or by pressure-vessel safety conditions that cannot be tolerated in continued operation. Forced outages are tracked as a percentage of operating hours (forced outage rate, FOR) and contrast with planned outages scheduled in advance."
canonical_url: "https://sylio.co/glossary/forced-outage"
last_updated: "2026-06-28T02:29:31.982Z"
---

A **forced outage** is an unplanned shutdown of an industrial unit, triggered by equipment failure (typically [boiler tube failure](/glossary/boiler-tube-failure)) or by pressure-vessel safety conditions that cannot be tolerated in continued operation. Forced outages are tracked as a percentage of operating hours (forced outage rate, FOR) and contrast with planned outages scheduled in advance.

## Economic cost

Forced outages dominate the economic cost of poor cleaning practice:

- **Coal-fired utility (500 MW)** — typically $0.5–1.5 million per day of forced outage, depending on power-market price
- **WtE plant (40 MW + tipping-fee revenue)** — $0.3–0.7 million per day including lost gate fees
- **Pulp-mill recovery boiler** — typically $0.4–1.0 million per day of mill production interruption
- **Cement plant (5,000 t/day)** — $300–600k per day of lost clinker

## Fouling-driven forced outages

- [ESP hopper pluggage](/glossary/esp-hopper) forcing the field offline
- [Baghouse ΔP](/glossary/differential-pressure-baghouse) tripping the ID fan
- [Cement kiln-inlet snowmen](/glossary/kiln-inlet-ring-snowman) requiring manual cleaning
- [Recovery boiler superheater pluggage](/glossary/recovery-boiler) demanding chill-and-blow
- [HRSG ΔP](/glossary/heat-recovery-steam-generator) excursion derating the gas turbine

[Sonic horns](/glossary/sonic-horn) attack the root cause — early fouling — before it reaches the level that forces outages.

## Related terms

- [Boiler tube failure](/glossary/boiler-tube-failure)
- [Fouling](/glossary/fouling)
- [Derate (capacity)](/glossary/derate-capacity)
- [Sonic horn](/glossary/sonic-horn)