Citable answer: Under FIDIC 2017 Sub-Clause 3.7, the Engineer has 42 days to help the parties agree a Claim or matter, then a further 42 days to issue a determination — 84 days in total. Either party then has 28 days from receiving that determination to serve a Notice of Dissatisfaction. Miss the 28 days and the determination becomes final and binding, however wrong it is.
Most construction teams know the notice deadlines at the front of a claim. Far fewer watch the deadline at the back of one. The determination arrives, it awards a fraction of what was claimed, it goes into the commercial manager's pile marked "respond properly when the programme calms down" — and four weeks later the argument is over. Not lost on the merits. Simply closed, because nobody served a piece of paper.
This is what Sub-Clause 3.7 actually requires, what happens when the Engineer says nothing at all, and the four dates worth putting in a diary the moment a claim is submitted.
What is an Engineer's determination under FIDIC?
It is the Engineer's formal decision on a Claim or a matter that the contract requires to be agreed or determined — an extension of time, additional Cost, a valuation, a reduction in delay damages. It is not advice and it is not a negotiating position. Once issued it binds both parties, who must give prompt effect to it, unless and until it is displaced by a Dispute Avoidance/Adjudication Board (DAAB) decision, an agreement or an arbitral award.
Two features of the 2017 editions matter here. First, the Engineer is not required to obtain the Employer's consent before exercising authority under Sub-Clause 3.7, and must act neutrally between the parties when doing so — a deliberate change from the 1999 wording, as Victoria Tyson of Howard Kennedy sets out in her commentary on Clause 3. Second, under Sub-Clause 3.4 the Engineer may not delegate the Sub-Clause 3.7 function to an assistant. The determination has to come from the Engineer.
The two clocks: 42 days to agree, then 42 days to determine
Sub-Clause 3.7 runs in two stages.
Stage one — consultation (Sub-Clause 3.7.1). The Engineer consults both parties and tries to get them to an agreement. The window is the time limit for agreement: 42 days. If the parties agree, the Engineer gives notice of the agreement and, under Sub-Clause 3.7.4, it binds them.
Stage two — determination (Sub-Clause 3.7.2). If no agreement is reached, the Engineer has a further 42 days from expiry of the agreement period to give notice of a fair determination, with reasons.
That is 84 days end to end, and it is the outer limit rather than a target. The periods can be changed, but only if the Engineer proposes it and both parties accept — not retrospectively, once the deadline has already gone.
Where does the clock start? Under the 2022 reprints, Sub-Clause 3.7 separates (a) matters to be agreed or determined from (b) Claims. Matters are tied to thirteen specific sub-clauses, and each of those sub-clauses states its own date of commencement for the time limit for agreement. Claims run from the claims machinery in Clause 20. The practical consequence: on an amended contract you cannot assume a single start date across every issue. You have to read the clause that generated the matter.
What happens if the Engineer never determines?
This is the gap the 1999 editions left open, and it is now closed. Under Sub-Clause 3.7.3, if the Engineer does not give the notice within the time limit, one of two things happens:
- Where there is a Claim — the Claim is deemed rejected. It is resolved against the claiming party by default.
- Where there is a matter to be agreed or determined — a Dispute is deemed to have arisen, and either party may refer it straight to the DAAB under Sub-Clause 21.4 without needing a Notice of Dissatisfaction first.
Read that first bullet again, because it is counter-intuitive. Engineer silence is not neutral and it is not a free extension. For a Claim, silence is a rejection — and the 28-day clock described below starts running against you anyway. A contractor waiting politely for a determination that is never coming can lose the entitlement while doing nothing wrong on the merits.
The 2022 reprints also added a fast track at Sub-Clause 21.4 for a narrow set of situations — broadly, non-payment of a Payment Certificate, non-payment of financing charges, and termination — where a Dispute is deemed to have arisen and can go directly to the DAAB without a Sub-Clause 3.7 determination and Notice of Dissatisfaction at all.
The 28-day Notice of Dissatisfaction: the deadline that quietly ends it
Under Sub-Clause 3.7.5, a determination becomes final and binding unless a dissatisfied party gives a Notice of Dissatisfaction (NOD) to the other party, copied to the Engineer, within 28 days after receiving the determination or a corrected version of it.
Three details decide whether that notice works.
It must be labelled. The notice has to state that it is a "Notice of Dissatisfaction with the Engineer's Determination". A letter that merely disagrees, however forcefully, is not obviously the thing the clause requires.
It must give reasons. The NOD sets out why the party is dissatisfied. A bare reservation of rights does not do the job.
It runs from receipt, not from issue. On a project where the determination is issued in one office and read in another, the difference is real days off an already short window.
The 28-day limit is not waivable under Sub-Clause 20.2.5. And it is not the last deadline either: under Sub-Clause 21.4.1 the Dispute must then be referred to the DAAB within 42 days of the NOD, failing which the NOD lapses and the determination becomes final and binding after all. Again, no waiver. Two hard deadlines, back to back, after the determination lands.
If a party simply fails to comply with a final and binding agreement or determination, the other party can refer that failure directly to arbitration under Sub-Clause 21.7 — it does not have to go back round the DAAB loop first.
The four dates worth diarising
| Step | Clause (2017) | Period | What happens if you miss it |
|---|---|---|---|
| Time limit for agreement | 3.7.1 / 3.7.3 | 42 days | Moves to determination stage |
| Engineer's determination | 3.7.2 / 3.7.3 | 42 days more (84 total) | Claim deemed rejected; matter becomes a deemed Dispute |
| Notice of Dissatisfaction | 3.7.5 | 28 days from receipt | Determination becomes final and binding |
| Reference to the DAAB | 21.4.1 | 42 days from the NOD | NOD lapses; determination becomes final and binding |
Under Sub-Clause 21.5 in the 2017 editions, the parties then have a 28-day amicable settlement period before arbitration, reduced from the 56 days in the 1999 forms.
How this differs from FIDIC 1999
If your project runs on the 1999 Red, Yellow or Silver Book, the shape is different and the exposure sits in a different place.
Sub-Clause 3.5 of the 1999 editions was two paragraphs. The Engineer consulted each party to try to reach agreement and, failing that, made a fair determination — with no time limit on the determination itself. Sub-Clause 20.1 required the Engineer to respond to a claim or further particulars within 42 days, but there was no deemed-rejection safety valve if the determination never came. A contractor could sit in procedural limbo indefinitely.
The practical translation: on a 1999 contract, chase the determination, because nothing forces it. On a 2017 contract, watch your own clocks, because the contract will resolve the silence against you.
Employer claims go through the same door
The determination process is not a contractor-only mechanism, and the leading authority on that point is an Employer case. In NH International (Caribbean) Ltd v National Insurance Property Development Company Ltd [2015] UKPC 37, the Privy Council considered Sub-Clause 2.5 of the FIDIC Red Book 1999, which requires the Employer to notify a claim as soon as practicable and in particularised form, after which the Engineer agrees or determines it under Sub-Clause 3.5.
The Privy Council held that Sub-Clause 2.5 barred the Employer from bringing claims, counterclaims or set-offs outside that contractual framework: having failed to raise the claim as the clause required, the back door of set-off was as firmly shut as the front door of an originating claim. Abatement — arguing the work was so poorly done that it is worth less than claimed — survived. Everything else did not.
For an Employer, the lesson is that the determination machinery is a condition of recovery, not paperwork. For a contractor, it is that a set-off appearing without a notified, determined claim behind it is worth challenging.
Why the deadline gets missed
None of this is difficult to understand. It is difficult to hold — which is a different problem.
A determination is one document arriving in one inbox on a project generating hundreds of documents a week. The 28 days are consumed by getting the commercial team, the planner and often an external adviser to agree a position on a technical decision. Nobody is tracking the deadline as a deadline, because it is buried in a clause rather than sitting in the programme. And on a heavily amended contract, the period may not even be 28 days — the particular conditions may have changed it, and the person reading the determination may be working from memory of the standard form.
The failure is almost never ignorance of the clause. It is that the clause and the calendar live in different places.
What Aven-AI does about it
This is precisely the gap the platform is built for. Aven-AI reads the project's actual contract — FIDIC, NEC4, or heavily amended versions of either — and extracts the clauses that carry deadlines, including the amended periods rather than the standard-form ones. It ingests the programme from Primavera P6 or MS Project so that contractual dates and construction dates sit in one view.
When a determination is logged, the platform works forward from the date of receipt: the Notice of Dissatisfaction window, then the DAAB referral window, and it warns the named person who owns the response before either lapses. It can draft the notice, with the clause and the relevant dates cited so the reader can check the reasoning rather than trust it.
What it will not do is send anything. The platform is advisory: it flags, it drafts, it cites. A human reads the draft, decides, and signs. On a decision this consequential, that is the right division of labour.
Related reading
- Clause 20.1, plainly: the 28-day time-bar and how teams lose entitlement to it
- Extension of time under FIDIC, plainly: how to protect your delay entitlement
- Contemporaneous records: the evidence that decides whether your claim survives
Sources & further reading
- Victoria Tyson (Howard Kennedy), FIDIC 2017: Clause 3 — The Engineer — the two 42-day periods, deemed rejection, and the non-waivable 28-day NOD: PDF
- Victoria Tyson (Howard Kennedy), FIDIC 2022 Reprints: 10 Key Areas of Change in the FIDIC Red Book 2017 — the split of Sub-Clause 3.7 into matters and Claims, and the new deemed-Dispute fast track: PDF
- Gowling WLG, A guide to dispute resolution under FIDIC (2024) — the 42-day DAAB referral bar and the shortened amicable settlement period: gowlingwlg.com
- CMGuide, The Engineer's Role in Dispute Prevention: Agreement and Determination under FIDIC Sub-Clause 3.7 (2017): cmguide.com.au
- AfiTaC (Jan Bouckaert), Determination in Sub-Clause 3.7 of FIDIC 2017 YB and RB (and 3.5 of SB) — the sub-clause-by-sub-clause structure: afitac.com
- CMS, Termination and set-off risks for employers under the FIDIC Red Book — case note on NH International (Caribbean) Ltd v National Insurance Property Development Company Ltd [2015] UKPC 37: cms.law
This article is general information, not legal advice. Clause numbering and time periods vary between FIDIC editions and are frequently amended in the particular conditions — always read your own contract and take professional advice on your own facts. Sources are linked above so you can verify every point for yourself.