Availability

Running Equipment Availability as a Daily System

Availability is the first gate on everything you promised the customer. This playbook covers the loss tree, benchmark ranges, changeover and minor-stop levers, and the tiered cadence that adds 5 to 8 points in a year.

Equipment availability is the first gate on everything you promised the customer. Schedule a line for 20 hours a day at 85 percent availability and you get 17 productive hours; drop to 70 percent and you get 14, which is 3 lost hours a day and 90 a month. At 300 units an hour and $12 contribution per unit, that gap is $324,000 a month before anyone talks about speed or scrap. Availability also multiplies: in an OEE stack of availability times performance times quality, a 10 point availability loss cannot be bought back by running faster, because you cannot run at all during downtime.

The math is runtime divided by planned production time. Plan 480 minutes, lose 45 to a breakdown and 30 to changeovers, and availability is 405 over 480, or 84.4 percent. Layer on performance and quality for the OEE view: at 84.4 percent availability, 92 percent performance, and 98 percent quality, OEE is 76.1 percent. The Equipment Availability calculator stacks those three for you. The definitional fight is planned time: exclude no-demand time and planned shutdowns, include changeovers and breakdowns. If you let changeovers escape into planned downtime, availability inflates 5 to 10 points and the improvement pressure disappears.

Ranges to calibrate against: world-class discrete plants run 90 percent plus availability; typical plants sit at 75 to 85; anything under 70 means the schedule is fiction. Process industries with continuous assets should see 92 to 97. Read the number with its loss pareto. In most plants changeovers take 8 to 12 percent of planned time, breakdowns 5 to 10, and minor stops another 3 to 8 that never get logged because each one is under 5 minutes. A plant reporting 88 percent with no minor-stop tracking is usually an 82 percent plant with bad data.

The levers rank by loss size, not by preference. SMED programs routinely cut changeover time 40 to 60 percent; taking a 45 minute changeover to 20 minutes across 3 changeovers a day returns 75 minutes, roughly 5 availability points on a 24 hour schedule. Planned maintenance compliance above 90 percent typically cuts breakdown minutes 25 to 40 percent within two quarters. Operator-run cleaning and inspection routes catch 30 to 40 percent of failures before they stop the line. And attack minor stops with a 2 week stopwatch study; a stop of 90 seconds happening 20 times a shift is a silent half hour.

The metric fails in predictable ways. Overstated planned time punishes crews for demand gaps they do not control; understated planned time hides losses. Averaging across lines hides the constraint: 90 percent fleet availability with 72 percent on the bottleneck means the plant runs at 72. Manual downtime logging typically captures only 60 to 70 percent of actual lost minutes, so reconcile logged downtime against counted output monthly; a gap above 5 percent means your log is decorative. And beware availability bought with speed: slowing a line 15 percent to avoid stops moves the loss to performance and fools nobody who reads the full OEE.

Deploy on a cadence. Every shift: the operator logs stops over 2 minutes with a reason code from a list of no more than 25 codes. Daily: a 10 minute tiered meeting on yesterday's availability versus an explicit target, with the top loss named and one action assigned. Weekly: pareto of downtime minutes by code, pick the top bar, and run a structured problem solve; one closed countermeasure per line per week is a realistic pace. Monthly: recalculate the loss tree, verify planned time definitions, and reset targets. Plants running this rhythm typically gain 5 to 8 availability points in the first year.

World-class is 90 percent plus availability on constraint equipment, changeovers under 10 minutes on the majority of products, breakdown losses under 2 percent of planned time, and automatic stop capture on every asset that matters. Loss data is trusted enough that nobody argues about the number, only the countermeasure. Targets step up 2 to 3 points a year and each line can show the three projects funding that step. Most importantly, availability is reviewed where it is lost: at the line, within 24 hours, by the people who can fix it, not in a month-end report nobody can act on.

Published 2026-07-02.