1️⃣ Purpose of X5 (Sectional Completion) — why it exists, who benefits
Plain-English purpose. X5 lets you break the works into defined “sections,” each with its own Completion and Completion Date. The contract then reads references to “the works,” “Completion,” and “Completion Date” as applying to the whole or any section, as appropriate (X5.1 in both editions). That single sentence is the “switch” that makes sectional time control work.
Why Clients/Employers use it.
- To open portions of an asset early (stations, units, track blocks) while the rest continues—takeover and benefit sooner. (NEC4 35.2–35.3; NEC3 35.2–35.3)
- To target delay damages per section (with X7) instead of one blunt project-wide rate. (Contract Data tables)
- To encourage earlier delivery via bonus per section (with X6). (Contract Data tables)
Why Contractors like it.
- Clearer priorities; you plan to hit the “money sections” first and protect the rest with float and access logic on the Accepted Programme (Core 31/32).
- If the Client/Employer takes over a part early, X7.3 proportionally reduces delay damages from that date—fairer risk. (NEC4/NEC3)
NEC3 ➜ NEC4—what actually changed?
- Text is almost identical; “Employer” becomes “Client” and some housekeeping around clause layout. (X5.1 unchanged in substance.)
- NEC4 keeps the X7.3 proportional reduction rule and strengthens usability by making the Contract Data layouts for X5/X6/X7 very explicit (per-section entries).
2️⃣ Breakdown of X5 — how to “switch it on” and wire it correctly
A. The operative sentence — X5.1
“Unless stated as the whole of the works, each reference and clause relevant to the works, Completion and Completion Date applies … to either the whole or any section.” (NEC3/4 X5.1)
This is why Completion certification, delay damages, bonus windows, and programme treatment can all operate at section level.
B. Contract Data entries (don’t skip these!)
- Define sections + dates: “If Option X5 is used, the completion date for each section is …” (tabular). (NEC4 CD; NEC3 CD)
- Bonuses per section if X6 used with X5. (NEC4 CD)
- Delay damages per section if X7 used with X5. (NEC4 CD; NEC3 CD)
C. What the Programme must show (Core Clauses 31–32)
You still show access, Key Dates, Completion Date(s), float, time risk allowances, and logic to meet each sectional milestone. (NEC3 31.2; NEC4 32.1–32.2). Keep section interfaces explicit.
D. Certification & take-over still run through Core Clauses
- Completion is decided and certified per 30.2/30.3—and thanks to X5.1, that can be for a section. (NEC4 30.1–30.3; NEC3 30.1–30.2)
- Take over of a part before Completion is under 35.2–35.3 (both editions). This certification date is pivotal for X7.3 reductions.
E. Don’t confuse Sections with Key Dates (Core 25.3)
A Key Date is cost-only: if you miss the Condition by the Key Date, the PM assesses the additional cost to the Client/Employer; that’s the only right. It is not delay damages. (NEC4 25.3; NEC3 25.3; note four weeks assessment timing)
3️⃣ Key interpretations & implications — reading the fine print like a pro
1) How exactly do damages/bonuses run per section?
- Delay damages (X7.1): run from the (sectional) Completion Date until the earlier of Completion of that section or the date the Client/Employer takes over the works (or part). (NEC4 text; applies via X5.1 to sections)
- Proportional reduction (X7.3): if the Client/Employer takes over a part before Completion, damages reduce from that date in proportion to the benefit of that part relative to the whole not yet taken over. (NEC4/NEC3 text is near identical.)
- Bonus (X6.1): if used, the Contractor earns a per-day bonus from the earlier of Completion or takeover until the (sectional) Completion Date—but only if the CD tables are filled for each section. (NEC4 X6.1 + CD)
2) What happens to retention and defects when we “go sectional”?
By default, X16 retention works off the whole of the works: it is retained until the earlier of Completion of the whole or takeover of the whole, then halved, and remains held until the Defects Certificate is due. That means no sectional release unless you draft it in Z-clauses. (NEC4 X16.1–X16.2)
3) Programme discipline matters more with sections
The PM can withhold acceptance if your programme doesn’t represent the plan realistically or doesn’t comply with the Scope (NEC4 32). With sections, that scrutiny usually increases—interfaces and Key Dates need to match each section’s path.
4) Key Dates vs Sections—remedy split
A missed Key Date = additional cost only (and the PM must assess within four weeks of the Condition being met). A missed Sectional Completion Date = X7 delay damages (unless reduced by early takeover under X7.3). Keep them conceptually separate.
4️⃣ Cross-references you’ll actually use (and how X5 reshapes them)
- Core 30 (Start, Completion, Key Dates): PM certification of Completion applies to a section through X5.1. Keep the programme in lockstep.
- Core 35 (Take Over): Taking over a part triggers PM certification of that date; that date feeds X7.3 for damages reduction. (Both editions)
- X6 / X7 Contract Data: Populate the per-section tables; otherwise your clever sectional strategy won’t cash-flow as intended. (Both editions’ CD layouts)
5️⃣ “What-if” scenarios (realistic and a bit messy—like projects) 🏗️
Scenario A — Two sections (A & B). A is late; B is on time.
- Damages: X7 damages bite only for the section that misses its Completion Date (A). B is clean. (Drive this with per-section X7 rates in the CD.)
- Early partial use of A: If the Client takes over a part of A on (say) 15 June, X7.3 reduces A’s damages from that date by the assessed proportionate benefit.
Scenario B — Key Date missed in Section B, but B still meets its Completion Date.
- No X7 damages. The PM assesses additional cost under 25.3—and that’s the only right. (Assess within four weeks after the Condition is met.)
Scenario C — Early Completion of Section B with X6 on.
- Bonus runs from the earlier of Completion or takeover until B’s Completion Date, at the per-section rate you entered in the CD. (Check the “remainder of the works” line too.)
Scenario D — Acceleration to save a slipping sectional date.
- Use Clause 36: PM instructs a quotation for acceleration; when accepted, the PM changes Prices, Completion Date(s) and Key Dates, and accepts the revised programme. (NEC4 36.1–36.3)
Scenario E — Retention expectations vs sectional handovers.
- Client wants retention halved on Section A Completion? Not by default. X16 halves after Completion (or takeover) of the whole. Add a Z-clause for sectional retention release if that’s the intent. (NEC4 X16.1–X16.2)
6️⃣ Drafting & management tips (to avoid arguments later) ✍️
- Name sections like you mean it. “Section A—Station Box; Section B—Fit-out L1–L3” beats “Phase 1/2.” Put the description + Completion Date in the CD.
- Wire the money: Fill X7 (per-section damages) and X6 (per-section bonuses). If you forget, you’ve undermined the whole sectional strategy.
- Define likely partial takeover points in the Scope so X7.3 reductions don’t turn into a battle over “benefit proportions.” (Core 35.2–35.3 + X7.3)
- Key Dates ≠ Sections. If you truly want time pressure (damages) on a utility availability, consider making it a micro-section with a Completion Date (plus an X7 line) rather than only a Key Date (which is cost-only).
- Programme hygiene. Show section interfaces, test windows, access logic and float clearly. PM acceptance hinges on realism and Scope compliance. (NEC4 32; NEC3 31/32)
- Retention expectations. If the commercial deal expects section-wise retention release, write a Z-clause mirroring NEC4 X16 mechanics at section level. Otherwise, default is whole-of-works.
7️⃣ Final takeaways (sticky notes for your folder) ✅
- X5 makes time obligations work per section—because X5.1 tells the whole contract to read “the works/Completion/Completion Date” at section level where relevant.
- The Contract Data is where X5 breathes: list sections + Completion Dates, and wire X6 bonuses/X7 damages per section.
- Partial takeover (Core 35.2–35.3) can fairly reduce damages under X7.3—but only from the takeover date and only in proportion to benefit.
- Key Date misses (25.3) don’t trigger delay damages; they trigger additional cost only, assessed within four weeks after the Condition is met.
- Retention (X16) is whole-of-works unless you Z-clause it into sectional release.
Quick reflection prompts 💬
- Can it be interpreted that you can take over a section without its tests? You can take over a part (Core 35.2) before Completion; just plan how that affects X7.3 reductions and any acceptance/testing criteria for Completion.
- Would a Key Date suffice for “substation energized by June”? If you want a time-risk remedy (damages), consider a small section with its own Completion Date + X7 rate—Key Date alone gives cost-only recovery.
Perfect—here’s a clean, copy-paste-ready package you can drop into your tender/contract. I’ve given you:
- a Contract Data (Part one – Client) block that wires X5 sections with Completion Dates, plus X6 (bonus) and X7 (delay damages) lines per section, and
- a tight Z-clause that implements sectional retention release in line with the logic of NEC4 X16.
I’ve included both a blank template and a worked example so you can see exactly how to fill it.
Contract Data – Part one (Client)
Options in use: X5 (Sectional Completion), X6 (Bonus for early Completion), X7 (Delay damages), X16 (Retention)
✅ Tip: Keep section names crystal clear (Scope references help). Where a part of the works isn’t in a named section, use “Remainder of the works” lines for X6/X7.
A) X5 – Completion Date for each Section
Template (fill in):
If Option **X5** is used, the Completion Date for each section is:
| Section ref | Section name/description | Scope/Drg ref | Completion Date (dd mmm yyyy) |
|-------------|--------------------------|---------------|--------------------------------|
| S-__ | | | |
| S-__ | | | |
| (Remainder) | Remainder of the works | | |
Worked example (illustrative):
If Option **X5** is used, the Completion Date for each section is:
| Section ref | Section name/description | Scope/Drg ref | Completion Date |
|-------------|---------------------------------------|-----------------------|------------------|
| S-A | Station Box & Base Build | Sec 4, Drgs SB-100.. | 15 Dec 2025 |
| S-B | Fit-out Levels L1–L3 (Public Areas) | Sec 7, Drgs FO-200.. | 31 Mar 2026 |
| (Remainder) | Remainder of the works | — | 30 Jun 2026 |
B) X6 – Bonus for early Completion (per section)
The bonus runs from the earlier of Completion of the section or take over of that section until that section’s Completion Date. State a rate per day (or a lump sum per whole week) and, if desired, a cap.
Template (fill in):
If Option **X6** is used, the bonus for early Completion is:
| Section ref | Bonus basis | Bonus rate | Bonus cap (if any) |
|-------------|-----------------------------|-------------------------------|--------------------|
| S-__ | per day earlier | [₹/$/£] ___ per day | [₹/$/£] ___ |
| S-__ | per day earlier | [₹/$/£] ___ per day | [₹/$/£] ___ |
| (Remainder) | per day earlier | [₹/$/£] ___ per day | [₹/$/£] ___ |
Worked example (illustrative):
If Option **X6** is used, the bonus for early Completion is:
| Section ref | Bonus basis | Bonus rate | Bonus cap |
|-------------|-----------------|------------------------|--------------------|
| S-A | per day earlier | ₹ 200,000 per day | ₹ 20,000,000 |
| S-B | per day earlier | ₹ 150,000 per day | ₹ 12,000,000 |
| (Remainder) | per day earlier | ₹ 100,000 per day | ₹ 10,000,000 |
C) X7 – Delay damages (per section)
Damages run from a section’s Completion Date until the earlier of Completion of that section or take over of the works/part, with proportional reduction if the Client takes over part benefiting them (per X7.3). State daily rates and, if used in your market, a cap.
Template (fill in):
If Option **X7** is used, the delay damages are:
| Section ref | Delay damages basis | Daily rate (₹/$/£ per day) | Cap (if any) |
|-------------|---------------------|-----------------------------|--------------|
| S-__ | per day late | [₹/$/£] ___ per day | [₹/$/£] ___ |
| S-__ | per day late | [₹/$/£] ___ per day | [₹/$/£] ___ |
| (Remainder) | per day late | [₹/$/£] ___ per day | [₹/$/£] ___ |
Worked example (illustrative):
If Option **X7** is used, the delay damages are:
| Section ref | Damages basis | Daily rate | Cap (if any) |
|-------------|---------------|--------------------|---------------|
| S-A | per day late | ₹ 350,000 per day | ₹ 35,000,000 |
| S-B | per day late | ₹ 250,000 per day | ₹ 25,000,000 |
| (Remainder) | per day late | ₹ 180,000 per day | ₹ 18,000,000 |
Optional helper line (keeps disputes away)
Add this note beneath B and C in Contract Data:
Note to X6/X7: Where the Client takes over a part of a section under Clause 35, the Project Manager assesses the proportionate benefit for X7.3 against the section’s defined outputs in the Scope (e.g., areas, systems, or capacities). The proportion is recorded in a PM communication within 7 days of takeover for clarity.
Z-Clauses – Sectional retention release (tracks NEC4 X16 logic)
Goal: Retain the familiar X16 mechanics but allow halving and final release per section, not just for the whole of the works. These Z-clauses override the standard triggers in X16 to the extent of any inconsistency.
⚖️ House view: This is commercially common on phased/sectional jobs; it protects the Contractor’s cashflow for finished sections while keeping sensible carve-outs for shared systems and latent defects.
Z.16 Sectional retention release
Z.16.1 Definitions (for these Z-clauses only)
a) Section means a section of the works identified in Contract Data under Option X5.
b) Sectional Takeover Date means the date the Client takes over a Section under Clause 35 or, if earlier, the date the Project Manager certifies Completion of that Section under Clause 30.
c) Sectional Retention Maximum means the maximum amount of retention to be held for a Section, if stated in Contract Data (otherwise none).
d) Shared System means any plant, system or area in the Scope which serves more than one Section such that defects in that system would materially impair the operation of another Section (e.g., primary power, common BMS backbone, smoke extract, life-safety).
Z.16.2 Retention percentages and maxima
X16 applies, except that the retention percentage and any retention maximum may be stated per Section in Contract Data. If not stated per Section, the percentages and maxima stated for the whole apply to each Section pro-rata to that Section’s Prices for Work Done to Date.
Z.16.3 Halving of retention at Sectional Takeover
Notwithstanding X16, the amount of retention held for a Section reduces by half on its Sectional Takeover Date. The reduction is applied in the next assessment for payment following that date.
Z.16.4 Final release of retention per Section
The balance retention held for a Section is released at the earlier of:
i) the Project Manager’s confirmation that no notified Defects remain to be corrected in that Section and that all tests on Completion for that Section have been passed, or
ii) the Defects Certificate for the whole of the works.
The Project Manager does not unreasonably withhold confirmation under (i).
Z.16.5 Carve-outs for Shared Systems
Where a Shared System serving a Section is incomplete or has notified Defects that materially affect that Section’s operation, the Project Manager may withhold an amount of the Section’s balance retention which is no more than a fair estimate of the cost risk attributable to the Shared System defect or incompletion. The Project Manager states reasons and the withheld amount in a communication under Clause 13.
Z.16.6 Retention bond (optional)
If a retention bond is provided in the form and amount stated in Contract Data for a Section, retention is not deducted for that Section from the date the bond is accepted by the Project Manager, and any retention already deducted for that Section is repaid at the next assessment.
Z.16.7 No cross-default between Sections
Outstanding Defects in one Section do not prevent retention halving or final release for another Section unless those Defects are within a Shared System which materially affects the other Section’s operation.
Z.16.8 Interaction with X5/X7
The date of Sectional Takeover used under this Z-clause does not change the operation of X7; if the Client takes over a part of a Section earlier under Clause 35, X7.3 (proportionate reduction) still applies from that earlier date.
Contract Data add-on for Z.16 (to keep it explicit)
Add this little table to Part one next to your X16 data:
Template (fill in):
If Z.16 applies, the retention details per Section are:
| Section ref | Retention % | Sectional Retention Maximum | Retention bond allowed? (Y/N) | Bond amount/terms (if Y) |
|-------------|-------------|------------------------------|-------------------------------|--------------------------|
| S-__ | __ % | [₹/$/£] ___ | Y/N | |
| S-__ | __ % | [₹/$/£] ___ | Y/N | |
| (Remainder) | __ % | [₹/$/£] ___ | Y/N | |
Worked example (illustrative):
If Z.16 applies, the retention details per Section are:
| Section ref | Retention % | Sectional Retention Maximum | Retention bond allowed? | Bond terms |
|-------------|-------------|------------------------------|-------------------------|-------------------------------------|
| S-A | 5% | ₹ 60,000,000 | Y | 100% of retention, on-demand form |
| S-B | 5% | ₹ 40,000,000 | Y | 100% of retention, on-demand form |
| (Remainder) | 5% | ₹ 50,000,000 | Y | 100% of retention, on-demand form |
How to use this (quick playbook)
- Populate A/B/C tables with your real sections, dates, and rates.
- Drop Z.16 into your Z-clauses and add the retention per Section mini-table to Contract Data (Part one).
- In the Scope, list each Section’s tests on Completion and any Shared Systems so the X7.3 proportion and Z.16.5 carve-out are easy to administer.
- Remind bidders: Key Dates (Core 25.3) are cost-only; sectional Completion Dates trigger X6/X7 time-risk.
If you want, I can tailor the example to your live project (with your real section names, dates, and appropriate market rates) or generate a one-page PM checklist for administering X5/X6/X7/X16 day-to-day.