Tunnel Boring & Heavy Civil Equipment worked example

Maintenance Interval at 12% access, lockout, and delay allowance: a worked example in tunnel boring & heavy civil equipment

What does the result look like when access, lockout, and delay allowance reaches 12%? The full calculation is worked below with real intermediate numbers. Use it when maintenance interval in tunnel boring and heavy civil equipment is changing rate or allowance and you want to see the impact.

The inputs for this scenario

  • Scheduled service work volume per interval: 120 units (unchanged)
  • Crew service completion rate: 12 units / min (unchanged)
  • Access, lockout, and delay allowance: 12 % (raised for this scenario; the documented default is 10)

Working through the calculation

  • Applying the documented formula (Base maintenance interval time = maintenance interval workload รท maintenance interval completion rate) to the inputs above produces each figure below.
  • At this operating point the engine returns 11.2 hr for required maintenance interval time, the number this scenario is built around.
  • At this operating point the engine returns 10 hr for base maintenance interval time.
  • At this operating point the engine returns 12 % for maintenance interval allowance applied.
  • At this operating point the engine returns 12 pieces / min for maintenance interval completion rate.

How this compares with the baseline

  • Against the tool's baseline example, where access, lockout, and delay allowance sits at 10% and the headline result is 11 hr, this scenario comes in 1.82% above the baseline at 11.2 hr.
  • A figure at this level is achievable when access, lockout, and delay allowance is genuinely sustained, not just peaked for a shift. A single allowance percentage cannot capture a hyperbaric intervention or unexpected ground condition, so treat the output as a planning estimate rather than a guarantee for atmospheric-work-under-pressure entries.

Results at a glance

  • Required maintenance interval time: 11.2 hr (headline result)
  • Base maintenance interval time: 10 hr
  • Maintenance interval allowance applied: 12 %
  • Maintenance interval completion rate: 12 pieces / min

Run it with your numbers

  • Every input above is editable in the live Maintenance Interval calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.