Activity Duration Limits
Last reviewed 9 September 20261,881 words9 min read
How long is too long — and how short is noise
🟩 In one line: A Level 3 production activity is 5–20 working days; nothing incomplete on a Task activity exceeds 44 working days without a reason written down (DCMA Metric 8 allows 5% of them); procurement, fabrication and authority periods are the legitimate exceptions and are split into stages anyway; and nothing production-related is shorter than one shift — durations below that belong in steps, not activities.
👤 Who this is for: J/M. Prerequisites: schedule-levels-1-to-5, crew-and-manhour-formulas. Reference page; the argument is elsewhere.
First, let's be honest about why this page exists
Two questions arrive every review: "why is this activity 90 days?" and "why is this one half a day?" The first hides a sequence that can't be statused; the second hides 4,000 activities that can't be maintained. Both have numeric answers that come from the reporting cycle, the DCMA test and the level of the schedule — this page puts them in one table.
🟨 The standard — what "good" looks like
| Source | What it asks for (paraphrased) | Number |
|---|---|---|
| DCMA 14-Point, Metric 8 (High Duration) | Incomplete Task activities with baseline duration > 44 working days ≤ 5% of incomplete tasks; LOE and summaries excluded | 44 working days; 5% |
| GAO Schedule Assessment Guide, BP 1 and 4 | Activities detailed enough to be statused and managed within a reporting period; durations realistic and justified | ≈ ≤ 2 reporting periods |
| PMI Practice Standard for Scheduling, 2nd ed. | Activity duration proportionate to the update frequency | Same |
| AACE RP 27R-03; RP 38R-06 | Detail matches schedule class; basis per duration | L3 detail; basis in UDF |
| NEC3/NEC4 Cl 31.2 | Programme detailed enough to show order and timing and to assess CEs | Activities that can hold a fragnet link |
| Client schedule specifications (typical Gulf) | Frequently cap Task durations at 20–30 working days and require justification above | Adopt the spec's cap if lower |
| Convention (schedule-levels-1-to-5; weekly-vs-monthly-cycles) | L3 = contract baseline, monthly update; L4 = weekly look-ahead | Sets the ranges below |
🟢 Rule: L3 production activities 5–20 working days, none above 44 without a stated reason and never more than 5% of the incomplete count; long chains split by stage, zone or level, not shortened; exceptions (procurement, fabrication, authority periods, curing, LOE) named in the SBM; minimum one shift; and any activity spanning more than two monthly data dates gets a Notebook line explaining why it wasn't split.
How it actually works
1. The ranges
| Level | Typical duration | Upper limit | Lower limit | Update cycle |
|---|---|---|---|---|
| L1 | Months | — | — | Rolled up |
| L2 | 4–12 weeks | — | 1 week | Rolled up |
| L3 (baseline) | 5–20 working days | 44 (DCMA); 20–30 where the spec says) | 1 shift | Monthly |
| L4 (look-ahead) | 1–10 days | 15 | 0.5 day | Weekly |
| L5 (daily/shutdown) | Hours to 2 days | 3 days | 1 hour | Daily/shift |
The test for L3: could this activity be statused with a real percent and remaining duration on two consecutive monthly data dates? If it spans more than two, it should have been two or more activities.
2. Legitimate long activities — and how they are still split
| Activity | Why long | How to split anyway |
|---|---|---|
| Fabrication / shipping of long-lead equipment | Supplier lead 16–30 weeks | Stages: shop drawings → fabrication → FAT → shipping → customs → delivery; each ≤ 44 days, each with a milestone from the supplier's schedule |
| Authority approval period | Fixed by the authority | Apply → period → receive; the period activity may exceed 44 on a 7-day calendar — accepted, listed in the SBM exceptions |
| Curing | 3–28 days | Already short; on a 7-day calendar |
| Piling / earthworks on a large site | Continuous production | By zone, chainage or pile group |
| Commissioning of a large system | Weeks | By subsystem and stage (pre-comm, cold, hot, integrated) |
| Design of a package | 6–12 weeks | 30/60/90/IFC stages or steps (engineering-and-design-schedule) |
| Scaffold, hoist, crane, supervision | Whole span | LOE — excluded from Metric 8 by type, never a long Task |
Every remaining Task over 44 working days after splitting goes in an SBM exceptions table: ID, duration, reason, source of the figure. If the table has more than 5% of incomplete tasks on it, the schedule fails Metric 8 whatever the reasons say.
3. Too short — the other failure
| Symptom | Problem | Fix |
|---|---|---|
| Half-day and quarter-day activities across an L3 baseline | 6,000 activities nobody can status monthly; density and float noise | Combine into shift-length activities; put the sub-steps in P6 Steps with weights |
| Same activity repeated per room, per door | Detail that belongs in the L4 look-ahead | L3 per zone; L4 built with the site team (rolling-wave-planning) |
| Zero-duration Tasks that aren't milestones | Type error | Milestone or one shift |
An L3 baseline for a mid-rise is 1,500–3,000 activities; a hospital 3,000–6,000. Beyond that, the detail is L4 masquerading as L3 (logic-density-and-quality).
4. Checking it — two filters
| Filter | Layout | Result |
|---|---|---|
| Type = Task Dependent; Status ≠ Completed; Original Duration > 44 (or spec cap) | 03 Review | Count ÷ incomplete Task count ≤ 5%; each row in the SBM exceptions table |
| Type = Task Dependent; Original Duration < 1 | 03 Review | Zero |
Also, once a year or at every baseline revision: group by Original Duration in bands (1–5, 6–10, 11–20, 21–44, >44) and read the distribution. A healthy L3 has most activities in 6–20.
5. Durations in hours
Remember the storage: 44 working days on a 10-hour calendar is 440 hours; on an 8-hour office calendar 352 hours. The DCMA test is in working days of the activity's own calendar, which is what the Original Duration column shows when Admin Preferences → Time Periods uses the assigned calendar (hours-per-day-and-duration-display). On a received file with that tick off, check the hours before failing an activity.
🟥 Where people go wrong
- Shortening durations to pass Metric 8. The 90-day façade becomes 44 days with the same quantity. Split by elevation or level band; the total stays.
- Crane and supervision as long Tasks. They fail the metric and mean nothing. LOE by type.
- Fabrication as one 180-day bar. Cannot be tracked; the supplier's slippage is invisible until delivery. Five stages with supplier milestones.
- Every door and socket at L3. 9,000 activities, unmaintainable, and the float sorts are noise. Zone-level at L3; room-level in the L4 look-ahead.
- Spec cap ignored. The client's spec says 20 working days; the schedule is built to DCMA's 44. The spec wins; the exceptions table covers what can't meet it.
- No exceptions table. Thirty activities over 44 days, each with a good reason nobody wrote down. SBM table, ID by ID.
⚖️ When you're challenged
"Twelve activities over 44 days. Fail." Twelve of 2,140 incomplete tasks is 0.6% — the metric allows 5%. All twelve are in the SBM exceptions table: four authority periods on the 7-day calendar, six fabrication stages at the supplier's stated lead, two piling zones on a continuous rig. Each has its source next to it. Splitting them further would add milestones without adding information.
"Why can't you break the structure down to every column?" Because it would be 4,000 activities on a 14-floor tower, and none of them can be honestly statused on a monthly data date. Level 3 is per zone per floor — that's what the payment and the update cycle work at. Column-by-column lives in the weekly look-ahead the site team builds.
📄 Related pages
- Schedule Levels 1 to 5 — which level sets the range
- Crew and Manhour Formulas — where the duration comes from
- Justify a Duration — the basis behind each number
- DCMA 14-point assessment — Metric 8 in context
- P6 Activity Types Explained — LOE for the long support activities
- Procurement and Long-Lead Items — staging the fabrication chain
- Logic Density and Quality — the activity-count side of the same question
- Hours per day and duration display — reading the days correctly on a received file
✏️ Worked example
Duration audit on a Dubai mid-rise L3 baseline draft, 2,410 Task activities, spec cap 30 working days:
| Band (working days) | Count | Share | Action |
|---|---|---|---|
| < 1 | 38 | 1.6% | 26 converted to milestones (type error); 12 combined into shift activities with steps |
| 1–5 | 612 | 25% | — |
| 6–10 | 890 | 37% | — |
| 11–20 | 640 | 27% | — |
| 21–30 | 178 | 7% | — |
| 31–44 | 34 | 1.4% | 19 split (façade elevations, MEP risers by band); 15 in exceptions table with reasons |
| > 44 | 18 | 0.7% | 3 converted to LOE (crane, hoist, supervision); 9 fabrication bars split into stages; 6 remain (authority periods, utility energisation) — exceptions table |
After the audit: 2,398 Task activities, 21 over the 30-day spec cap (0.9%), 6 over 44 (0.25%), zero below one shift, exceptions table of 21 rows in SBM section 6. Time: three hours.
📖 References
- DCMA 14-Point Schedule Assessment, Metric 8
- GAO Schedule Assessment Guide (GAO-16-89G), Best Practices 1, 4
- PMI Practice Standard for Scheduling, 2nd ed.
- AACE International RP 27R-03, Schedule Classification System; RP 38R-06, Documenting the Schedule Basis
- NEC3 / NEC4 Engineering and Construction Contract, Cl 31.2 (check the edition in your contract)
- Oracle Primavera P6 Professional User Guide — Activity Details; Filters; Admin Preferences → Time Periods
From the field
Experience from working planners. Unreviewed — read it as experience, not guidance.
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