Engineering and Design Schedule
Last reviewed 9 September 20262,666 words12 min read
IFC drawings, review cycles — the schedule that decides when construction can actually start
🟩 In one line: Design is scheduled as a chain per deliverable — produce → check → submit → review (on the contract's review calendar) → respond → resubmit → approve → issue for construction — linked forward to the procurement or site activity that needs it, with progress earned on deliverable stages rather than time; on most Gulf projects the first six months of the critical path run through this chain, and it is the part of the schedule most often drawn as a single bar.
👤 Who this is for: M/S, with J reading for the chain. Prerequisites: milestones-and-key-dates, procurement-and-long-lead-items, calendar-setup-and-holidays, progress-measurement-and-rules-of-credit.
First, let's be honest about why this page exists
"Design — 16 weeks" as one activity, followed by "Approvals — 8 weeks", is how design appears in most contractor programmes, whether the design is the employer's, the contractor's or a subcontractor's shop drawings. Neither bar can be statused, neither shows which package is late, neither links to the pile that can't start without it, and neither records the review period the contract actually allows — so when the consultant takes 31 days instead of 14, there is no activity to point at.
Design scheduling is repetitive, not difficult. The chain is the same for every deliverable; the numbers come from the contract; the links go to the site. What takes the time is the deliverable register — and that is the document the design team should already have.
🟨 The standard — what "good" looks like
| Source | What it asks for (paraphrased) | Consequence |
|---|---|---|
| FIDIC 1999 Cl 1.9 / 2017 Cl 1.9 (delayed drawings or instructions) | Contractor gives notice when a drawing or instruction is needed by a date; failure to issue in time is an EOT/cost ground | Every employer-issued drawing package is a milestone with a "needed by" date the notice can cite |
| FIDIC 1999 Cl 4.1 (Red Book, contractor-designed parts) / Yellow Book 1999 Cl 5.2 / 2017 Red Cl 4.1, Yellow Cl 5.2 | Contractor's Documents submitted for review; Engineer's review period stated in the contract (21 days in the Yellow Book unless amended — verify) | Review period is a contract number; goes on the review calendar |
| FIDIC 1999 Cl 8.3 / 2017 Cl 8.3 | Programme shows order and timing of design (where applicable), Contractor's Documents, procurement | Design chains are required programme content |
| NEC3/NEC4 Cl 21.2, 21.3 | Contractor submits design particulars; Project Manager replies within the period for reply (Contract Data); Contractor does not proceed until accepted | Review period = period for reply; proceed-after-acceptance is a hard link |
| NEC3/NEC4 Cl 27.1, 31.2 | Contractor obtains approvals from Others as required; programme shows dates for information from the Client | Authority approvals as chains; client-information milestones |
| SCL Protocol 2nd ed., Core Principle 1; Guidance Part B (records) | Programme reflects design and approval periods; records of submissions and responses kept | Submittal log dates are the actuals |
| AACE RP 38R-06 | Basis records design assumptions, review periods, resubmission allowance | SBM design section |
| GAO Schedule Assessment Guide, BP 1 and 2 | All work — including design and approvals — captured and logically linked to what depends on it | Design links forward to procurement and construction |
| DCMA 14-Point, Metrics 1, 8 | No open ends; no incomplete Task > 44 days | Every design activity has a successor; no 16-week design bars |
| Convention (calendar-setup-and-holidays; multiple-calendars-and-float) | Review periods stated in calendar days go on a 7-day calendar; working-day periods on the consultant's 5-day calendar | Applied to every review activity |
🟢 Rule: one chain per deliverable or logical package; review durations from the contract on the calendar the contract counts in; one resubmission cycle allowed unless the SBM says otherwise; every chain linked forward to the activity that needs the IFC; employer-issued information as milestones with a needed-by date; and progress earned on deliverable stages (30/60/90/IFC or submitted/approved), never on elapsed weeks.
How it actually works
1. Three kinds of design, one chain
| Kind | Who produces | What the contractor schedules | Contract hook |
|---|---|---|---|
| Employer's design (traditional build) | Employer's consultant | Milestone per package: "IFC structural — Podium — issued"; needed-by date from the site logic; notice under Cl 1.9 when at risk | FIDIC 1999/2017 Cl 1.9; NEC Cl 31.2 (information from the Client), Cl 60.1(3) |
| Contractor's design (D&B / EPC) | Contractor's designer | Full chain per deliverable, including internal checks and authority approvals | FIDIC Yellow Cl 5; NEC Cl 21 |
| Shop drawings, submittals, samples, method statements | Subcontractors and suppliers | Chain per submittal package, linked to fabrication and site | Employer's Requirements / spec section on submittals |
2. The chain
| Step | Activity | Duration | Calendar | Notes |
|---|---|---|---|---|
| 1 | Produce (30% / 60% / 90% where staged) | From designer's deliverable schedule; manhours ÷ team | Office 5-day | Steps in P6 for staged design (progress-measurement-and-rules-of-credit) |
| 2 | Internal check / IDC | 3–5 days | Office | Often skipped and always needed |
| 3 | Submit | 0 (milestone) | — | Actual = transmittal date from the submittal log |
| 4 | Review period | Contract figure (14 / 21 calendar days; NEC period for reply) | 7-day where the contract says calendar days; consultant 5-day only if it says working days | The contract number, not last month's experience |
| 5 | Response received | 0 | — | Actual from the log; code A/B/C/D or accept/not accept |
| 6 | Revise and resubmit | 5–10 days | Office | One cycle allowed in the baseline; SBM states it |
| 7 | Second review | Contract figure | 7-day | |
| 8 | Approved / no objection | 0 | — | |
| 9 | Issue for Construction | 2–5 days | Office | Or 0 if IFC = approval |
| 10 | Successor | Procurement (order placement) or site activity | FS, hard |
Steps 4–8 collapse to a single review if the contract or the SBM assumes first-time approval — write the assumption down; most Gulf projects average 1.5–2 cycles on structural and MEP packages.
3. Packaging — how many chains
| Project | Chains | Basis |
|---|---|---|
| Mid-rise building, contractor shop drawings only | 40–80 | Per discipline per zone: structural shop drawings by level band; MEP coordinated drawings per floor group; façade; finishes schedules; major equipment submittals |
| D&B hospital | 150–300 | Design deliverable register by discipline and stage, plus authority approval chains (civil defence, municipality, utilities) |
| EPC process plant | 500+ | Per document from the master document register; engineering progress measured on it (oil-gas-and-epc) |
One chain per drawing is too many; one per discipline is too few. Package at the level the reviewer responds at — the transmittal.
4. Linking forward — the need date
Every chain ends in the activity that cannot proceed without it. Working backwards from that activity's early start gives the need date; the chain's finish must sit on or before it. Where it doesn't, the design is on the critical path and the programme says so. Employer-issued packages get a Start On or After milestone at the contract or agreed release date with the reference — and the need-date comparison is the basis of the Cl 1.9 notice.
| Chain ends in | Typical need-date logic |
|---|---|
| Structural IFC (level band) | Rebar procurement (bar bending schedule) and formwork fabrication for that band |
| MEP coordinated drawings (floor group) | Sleeve/embed setting-out before the slab pour of the first floor in the group; first fix |
| Façade shop drawings | Façade fabrication order — the 26-week chain (tender-programme) |
| Equipment submittal (chillers, switchgear, lifts) | Purchase order release; fabrication lead |
| Authority approval (civil defence, building permit) | Mobilisation, or the inspection stage it gates |
5. Measuring design progress
Design does not earn progress by the week. Two acceptable methods (progress-measurement-and-rules-of-credit):
| Method | Steps and weights | For |
|---|---|---|
| Deliverable stage | Started 10 / IDC issued 30 / Submitted 60 / Approved 90 / IFC 100 | Shop drawings and submittals |
| Design stage | 30% 25 / 60% 30 / 90% 30 / IFC 15 | D&B design packages |
Each step earned on a transmittal or log entry. Remaining durations re-forecast from the achieved review cycle: if the consultant is returning packages in 24 calendar days against 14, the remaining review activities are 24 (with the deviation recorded as a notice-able event, not silently absorbed).
6. The submittal log is the actuals
The design/document controller's submittal log — submission date, response date, code, resubmission date — is the quantity sheet for design. Actual starts and finishes on the chain come from it; the monthly reconciliation compares log dates to P6 dates; the trend in consultant review duration is reported like any other achieved rate.
7. SBM design section
Review periods per document type with clause references; resubmission allowance; authority approval periods as numbered assumptions; deliverable register revision; need-date table for the top 20 packages.
📜 Late information — the record
Under FIDIC Cl 1.9 the contractor must give notice stating when the drawing is needed and the consequences; the schedule's need-date table is that statement, and the milestone with its Start On or After and reference is the record. Under NEC, information from the Client later than the date on the Accepted Programme is a compensation event under Cl 60.1(3) — the programme has to show the date first. A design chain that exists only as a 16-week bar cannot support either.
🟥 Where people go wrong
- One bar for design, one for approvals. Cannot be statused, linked or argued. Chain per package with the contract's review period.
- Review period from experience, not contract. 21 days shown because that's what the last consultant took; the contract says 14. The baseline carries 14 (the entitlement); the achieved 21 is recorded as a deviation and noticed. Doing it the other way round gives the review time away.
- Review on the consultant's 5-day calendar when the contract says calendar days. 14 calendar days becomes 20. 7-day calendar for calendar-day periods (multiple-calendars-and-float).
- No resubmission cycle. Every package approved first time in the baseline; the first B-code adds two weeks nobody planned. One cycle allowed and stated in the SBM.
- Design not linked forward. The IFC milestone dangles; the pile starts regardless. Every chain FS into the procurement or site activity that needs it — the need date is the whole point.
- Employer's packages missing. Structural IFC assumed at week 6 with no milestone; week 10 it hasn't arrived and there is nothing in the programme to cite. Milestone, reference, needed-by, Cl 1.9 notice.
- Progress by elapsed time. "Design 60%" because ten of sixteen weeks have passed; nothing submitted. Steps on deliverable stages, earned on the log.
⚖️ When you're challenged
"Why are there 70 design activities on a build-only contract? The employer designs." Sixty of them are our shop drawings and submittals — structural, MEP coordination, façade, equipment — each with the 14-day review the Employer's Requirements allow and one resubmission. The other ten are milestones for the Employer's IFC packages with the dates we need them. Without those ten there's nothing to give notice against when a package is late.
"The consultant has 21 days. You've shown 14." The contract says 14 calendar days, section 4.1 of the ER. Fourteen is the entitlement and the baseline shows it. The consultant has averaged 23 on the first six packages — that's in the narrative as an achieved rate, remaining reviews are forecast at 23, and the notices are in. If I baseline 21, I've given a week away on every package.
"Design is 45% complete — ten weeks of twenty-two are done." Twenty-two percent by deliverable stage: 8 of 36 packages submitted, 2 approved. The manhours may be 45% spent, but the site can build from approved drawings, not from weeks. The stage-weighted figure is the one in the report, and the forecast is from the achieved submission rate.
📄 Related pages
- Procurement and Long-Lead Items — the chain the design feeds
- Milestones and Key Dates — employer-information milestones
- Calendar Setup and Holidays — the 7-day review calendar
- Multiple calendars and float — why calendar-day reviews break float sorts
- Progress measurement and rules of credit — deliverable-stage steps
- Notice Requirements and Records — the Cl 1.9 / Cl 60.1(3) record
- Rolling Wave Planning — design detail near, construction detail far
- Oil gas and epc — engineering progress at document level
✏️ Worked example
Design-and-build clinic in Abu Dhabi, FIDIC Yellow Book 1999-based, review period 21 days (Cl 5.2, unamended — verify), authority approvals: municipality building permit, civil defence, health authority. Deliverable register: 42 design packages, 3 authority approvals, 18 subcontractor submittal packages.
| Chain (extract) | Produce | IDC | Review 1 (7-day cal) | Revise | Review 2 | IFC | Successor | Need date | Finish vs need |
|---|---|---|---|---|---|---|---|---|---|
| STR-01 Foundations 90% → IFC | 15 d | 4 d | 21 cd | 7 d | 21 cd | 3 d | Rebar BBS / piling order | C+11 wk | C+12.3 wk → critical, 1.3 wk late |
| STR-02 Superstructure L1–L3 | 20 d | 4 d | 21 cd | 7 d | 21 cd | 3 d | Formwork fabrication L1 | C+19 wk | C+17 wk, 2 wk float |
| MEP-04 Coordinated L1 | 18 d | 5 d | 21 cd | 8 d | 21 cd | 3 d | Sleeves before L1 slab pour | C+22 wk | C+21.6 wk, 0.4 wk float → near-critical |
| AUTH-01 Building permit | — | — | 6 wk (A03, municipality) | — | — | 0 | Mobilisation / piling | C+8 wk | C+8 wk, on need date |
| AUTH-02 Civil defence design approval | — | — | 4 wk (A04) | 2 wk | 4 wk | 0 | MEP fabrication orders | C+26 wk | C+24 wk |
| SUB-07 Chillers submittal | 10 d | 2 d | 21 cd | 5 d | 21 cd | 0 | PO release; 22-wk fabrication | C+14 wk | C+13.4 wk |
Findings at baseline: foundations design 1.3 weeks late to the piling need date — resolved by splitting STR-01 into pile design (IFC first) and pile cap/raft (second package), which brought the piling order inside the need date and put the raft design on Float Path 2. Progress on all 42 packages by design-stage steps; submittal log as the actuals; consultant review trend reported monthly. Month 4: average review 26 calendar days against 21; four Cl 1.9-style notices issued citing the need-date table; remaining reviews re-forecast at 26 with the entitlement at 21 recorded in the narrative.
📖 References
- FIDIC Conditions of Contract for Construction, 1999, Cl 1.9, 4.1, 8.3; 2017, Cl 1.9, 4.1, 8.3; FIDIC Conditions of Contract for Plant and Design-Build, 1999, Cl 5.2; 2017, Cl 5.2 (check the edition in your contract)
- NEC3 / NEC4 Engineering and Construction Contract, Cl 21.2, 21.3, 27.1, 31.2, 60.1(3) (check the edition in your contract)
- SCL Delay and Disruption Protocol, 2nd ed. (2017), Core Principle 1; Guidance Part B
- AACE International RP 38R-06, Documenting the Schedule Basis
- GAO Schedule Assessment Guide (GAO-16-89G), Best Practices 1, 2
- DCMA 14-Point Schedule Assessment, Metrics 1, 8
- Oracle Primavera P6 Professional User Guide — Activity Steps; Calendars; Milestones
From the field
Experience from working planners. Unreviewed — read it as experience, not guidance.
Add what you know about engineering and design schedule. What worked, what the consultant pushed back on, what you would do differently next time. A paragraph is plenty.
Contributors get their name and one link on the site — your own templates, course or consultancy. We take nothing and hold nothing.
Add your experience