Glossary

The SCL Protocol's definition covers both achieving the planned scope of work in a shorter time than planned and fitting extra work into the original time. It is a kind of mitigation. It is not a cause of action: a claim for its cost needs a term of the contract or a breach. HHJ Hicks QC in Ascon asked the two questions that decide who pays: "earlier than what?" and by whose decision the relevant steps were taken.

If the employer wishes to investigate completing before the Completion Date, the Architect/Contract Administrator (under Design and Build, the Employer) invites the contractor's proposals (SBC/Q 2016 Schedule 2; DB 2016 Supplemental Provision 4). The contractor is under no obligation to accelerate until its quotation is accepted by a Confirmed Acceptance. NEC4's equivalent is clause 36.

NEC4 defines it as the programme identified in the Contract Data or is the latest programme accepted by the Project Manager. Delay to the Completion Date from a compensation event is measured against the Accepted Programme current at the dividing date.

It need not be a breach. Actions by the employer which are perfectly legitimate under a construction contract may still be characterised as prevention, if those actions cause delay beyond the contractual completion date (Multiplex [56]), such as ordering extra work. It must cause real delay: the prevention principle necessarily means prevention in fact (Adyard [264]). Where the extension clause covers the act, the completion date moves and time is not set at large.

A party to a construction contract can refer a dispute under it to adjudication (Construction Act 1996, s.108). The adjudicator must reach a decision within 28 days of referral. That can be extended by up to 14 days with the referring party's consent, or longer if both parties agree (s.108(2)(c)-(d)), and the decision binds until the dispute is finally determined by legal proceedings, arbitration or agreement (s.108(3)). The courts enforce decisions unless the adjudicator answered the wrong question or acted in an obviously unfair way (Carillion [85]).

Available in Scotland where two causes operate and neither is dominant: the decision-maker, approaching the issue in a fair and reasonable way, may apportion the delay. In England there is no general power to apportion responsibility for delay; the contractor gets a full extension for the concurrent period and no money. A contract can provide its own apportionment machinery, which must then be pleaded and used.

In England and Wales it is governed by the Arbitration Act 1996, as amended by the Arbitration Act 2025. The tribunal must act fairly and impartially as between the parties (s.33(1)(a)). The award is final and binding unless the parties agree otherwise (s.58(1)), subject to limited challenges in court (ss.67-69).

An as-built programme records actual start and finish dates rather than planned ones. It is often rebuilt after the event by a delay expert from the daily reports and other records. Under the TCC Guide, the part of an expert's evidence that establishes primary facts is to be treated as factual evidence.

The second of the SCL Protocol's windows methods (SCL 11.6(d)). The analyst finds the critical path in each window by a common-sense and practical analysis of the available facts and must explain how criticality was decided. It needs only a baseline and as-built data.

It keeps the main contract and the subcontract in step, so the main contractor does not owe its subcontractor time it cannot recover from the employer. The subcontract in Steria gave time for any circumstance which entitles the contractor to an extension of time under the main contract (Steria [95]). Notice periods often differ between the two contracts, and that is where back-to-back arrangements tend to fail.

The standard for every fact in a delay claim. For loss and expense, the contractor has to demonstrate on a balance of probabilities the events, that they caused delay or disruption, and that the delay or disruption caused its loss (Walter Lilly [486(a)]).

Usually the contractor's programme as first accepted by the certifier. In the SCL Protocol it becomes the Accepted Programme, which is then updated with actual progress. Delay is measured by comparing later versions, or the as-built record, with it.

The Design and Build 2016 wording is that the contractor shall constantly use his best endeavours to prevent delay in the progress of the works, however caused (clause 2.25.6.1). The SCL Protocol says it may place a higher burden on the Contractor than the normal duty to mitigate. How far it requires the contractor to spend its own money is not settled.

Where a loss has been proved but its amount cannot be measured exactly, a tribunal may make a sensible estimate rather than award nothing. The limit is that it does not relieve the Claimant of proving that a legally recoverable loss was suffered (Lumley Baxter v Aviva [124(v)], a County Court decision, persuasive only). In Cleveland Bridge the court assessed disruption at the minimum the evidence showed was probably caused.

In a delay claim the contractor must prove that the events it relies on critically delayed it (Obrascon [272]); a party alleging that a notice was late must prove that ([313]). A tribunal need not always choose between the parties' cases. It may find that the party with the burden has failed to discharge that burden (Rhesa Shipping, as quoted in Citylink [64]).

The ordinary test of causation. It cannot answer concurrency on its own, because removing either cause leaves the job just as late. English law keeps it for money: unless the contract says otherwise, a contractor recovers loss and expense for delay only where it satisfies the but-for test, since it would have suffered exactly the same loss from its own delay.

In the SCL Protocol's words, these methods start with the identification and description of an event (a cause) and thereafter seek to establish its impact. Impacted as-planned, time impact analysis and collapsed as-built work this way. They measure only the events the analyst chooses to model.

The SCL Protocol calls this person the contract administrator: the person responsible for administration of the contract, including certifying what extensions of time are due and what loss and expense is to be paid (App A). It may be one of the employer's employees, or the employer itself. The certifier has two functions. As agent it carries out the employer's wishes. When it decides between the parties its duty is to hold the balance fairly between employer and contractor (Scheldebouw [24], a case about a construction manager). It is not independent, but must act in an independent manner ([26]).

One of the SCL Protocol's six methods (SCL 11.6(f)). The programme it needs is rare, so the analyst usually adds logic to the as-built record, and that logic is open to attack. It measures only incremental delay, because the finish will not collapse past the next near-critical path.

The contractor must notify a compensation event within eight weeks of becoming aware that it has happened, unless it arises from the Project Manager's or Supervisor's own instruction or other communication (clause 61.3). The changes to Prices and dates are the parties' only rights in respect of a compensation event (clause 63.6).

Liquidated damages run from it. JCT and NEC4 call it the Completion Date; FIDIC works from the Time for Completion. An extension of time fixes a later completion date, so that liquidated damages run only from the new date.

The clause in North Midland provided that any delay caused by a Relevant Event which is concurrent with another delay for which the Contractor is responsible shall not be taken into account. The Court of Appeal upheld it as an allocation of risk which the parties were entitled to agree. Read the clause before the case law.

The working definition is John Marrin QC's, adopted by the Court of Appeal in North Midland, in a passage it called only tangentially relevant to the appeal: a period of project overrun which is caused by two or more effective causes of delay which are of approximately equal causative potency. Each cause must be driving the completion date; a delay that is not on the critical path cannot be a concurrent cause. In England the contractor gets time but not money for the concurrent period.

The court may direct that some or all of the evidence of experts from like disciplines shall be given concurrently (PD 35 11.1). The judge leads the discussion, then invites the parties' representatives to ask questions (11.4). The TCC Guide says the experts are generally cross-examined on general matters and key issues first (14.8.2).

A notice clause is a condition precedent when it makes the right to time or money depend on the notice. The Court of Appeal's test in DBS v Tata is that the clause needs something that makes the relief conditional upon the requirement. Clear words will usually be needed, but the clause need not use the label. An "if ... then" or "provided that" structure is the usual sign.

A United States concept. The SCL Protocol defines it and adds that it is rarely recognised under English law. The Protocol's advice is to take steps to have the dispute about the extension resolved first, and to give notice of the intended measures before spending money on them.

A record written as the work goes on, not afterwards. The SCL Protocol says records of progress and delay must be generated contemporaneously as the works progress, and not afterwards. FIDIC's 2017 Red Book calls them "contemporary records" and defines them as records prepared or generated at the same time, or immediately after the event behind the claim. Courts generally treat them as more reliable than a witness's memory, though that is not a rule of law.

The SCL Delay and Disruption Protocol (2nd edn, 2017) uses "CA" throughout. The guide calls the same person the certifier.

The SCL Protocol's term for an event or cause of delay or disruption which under the contract is at the risk and responsibility of the Contractor (Appendix A). Its opposite is an Employer Risk Event. Which side an event falls on depends on the contract actually signed, including its amendments.

Cost is all expenditure reasonably incurred (or to be incurred) by the Contractor, including overheads, but not profit (FIDIC 2017 Sub-Clause 1.1.19). Cost Plus Profit adds the percentage in the Contract Data, or 5% if none is stated (1.1.20). Each Sub-Clause that gives money says which of the two it gives. Variations are valued separately.

In court, the general rule is that the unsuccessful party will be ordered to pay the costs of the successful party (CPR r.44.2(2)(a)), though the court may order otherwise and looks at the parties' conduct. An arbitral tribunal applies the same principle unless it is inappropriate (Arbitration Act 1996, s.61(2)). The rule is about legal costs, not damages.

The SCL Protocol has no separate entry for the term. It defines it within the critical path: a delay to progress of any activity on the critical path will, without acceleration or re-sequencing, cause the overall project duration to be extended (App A). Delay elsewhere first uses up float.

The longest sequence of activities through a project network from start to finish, the sum of whose durations determines the overall project duration. There can be more than one. A delay to an activity on the critical path will, without acceleration or re-sequencing, delay completion; a delay to any other activity uses up float first.

The SCL Protocol describes it as the technique that, through the use of calculation rules, determines the critical path and calculates float. The rules are a forward pass (earliest dates) and a backward pass (latest dates); the difference between them is float.

The SCL Protocol notes it as an expression sometimes used to describe what the Protocol calls Contractor Delay. An employer event arriving during culpable delay gets an extension only for the delay it actually causes, added to the existing completion date.

The SCL Protocol says particular care is needed because of the risks of a global claim, but the approach may be valid if all causes of disruption can genuinely be said to be the Employer's responsibility and their financial effects cannot practicably be separated.

Under FIDIC 2017 disputes shall be decided by a DAAB (Sub-Clause 21.1). Its decision binds the parties at once, even if one of them gives a Notice of Dissatisfaction. If no Notice of Dissatisfaction is given within 28 days, the decision becomes final and binding (21.4.3, 21.4.4). The DAAB is not an arbitral tribunal.

The main progress record on a project. The SCL Protocol suggests a daily report for each work area recording weather, labour, deliveries, adverse conditions, working hours, plant and the work under way (Appendix B 2.2(a)), and that it state facts only (1.12). A report that men or machines stood idle is a matter of fact that belongs in it.

What counts depends on the main Option chosen. Under Options C, D and E it is the cost of the components in the Schedule of Cost Components less Disallowed Cost (NEC4 cl 11.2(24)); Options A and B use the Short Schedule of Cost Components, and Option F has its own definition. A compensation event is priced as its effect on Defined Cost plus the Fee, a percentage applied to Defined Cost (cl 11.2(10), 63.1).

The SCL Protocol says that when it refers to delay it is concerned with time: work activities taking longer than planned. Its focus is largely on delay to the completion of the works, which it calls critical delay (Part A para 2). Work can run late without causing the contract completion date to be missed; the Protocol calls that delay to progress (App A). Delay is different from disruption, which is about lost productivity.

The SCL Protocol describes six methods in common use and lists other methods that may suit particular cases. No method is required by law. A tribunal asks whether the method fits the case and was properly applied (Thomas Barnes [109]-[110]).

NEC4 provides for them in Option X7: the contractor pays them at the rate in the Contract Data for each day from the Completion Date until Completion, take-over or a termination certificate. FIDIC's 2017 Red Book calls them Delay Damages (Sub-Clause 8.8) and says they are the only damages due for late completion, except on termination for the contractor's default.

Also called a programming expert. The delay expert's duty is to help the tribunal, not the client (CPR r.35.3). The tribunal, not the expert, decides as a matter of fact what delayed the Works and for how long. The delay expert's periods of delay are what the quantum expert prices.

In common usage the phrase can mean delay to the contractor's planned finish or to the contract completion date. The SCL Protocol uses it for delay to a contract completion date, and that is the date extension clauses and liquidated damages look to.

The SCL Protocol's term for a delay that holds up the contractor's progress without causing a contract completion date not to be met. Work can run late without the job finishing late, usually because the delayed work had float. A delay to progress may still push back the contractor's own planned finish. On its own it gives no extension of time.

In the Business and Property Courts, which include the TCC, disclosure is governed by PD 57AD. A "document" includes any record of any description containing information, in any form, and extends to metadata. Electronic documents are provided in the documents' native format, in a manner which preserves metadata.

The SCL Protocol calls it a disturbance, hindrance or interruption to the contractor's normal working methods that lowers efficiency. It is about hours, not dates, so it can happen with or without delay to completion. It is not a cause of action by itself: the money has to come through the contract or a claim for breach.

For an event that arises from the Project Manager or the Supervisor giving an instruction or notification, issuing a certificate or changing an earlier decision, it is the date of that communication. For other compensation events, the dividing date is the date of the notification of the compensation event (NEC4 cl 63.1). Delay is measured against the Accepted Programme current at the dividing date (cl 63.5).

The test Scots law uses for delay claims (City Inn [42]; John Doyle [15], drawing on Leyland Shipping, a House of Lords insurance case). If a dominant cause can be identified, effect is given to it and the other causes are left out of account. Only where neither cause is dominant may a Scottish decision-maker apportion. English law does not use the test for loss and expense (Thomas Barnes [118]), and English courts have no general power to apportion (Tata v DBS [229]); a contract may provide its own machinery.

Under PD 57AD the duty arises for anyone who knows it is or may become a party to proceedings. It must take reasonable steps to preserve documents in its control that may be relevant, including documents a retention policy would otherwise delete, and must suspend relevant document deletion or destruction processes. Sometimes called a litigation hold.

The Contractor and the Project Manager give an early warning by notifying the other as soon as either becomes aware of such a matter (clause 15.1). If the contractor fails to give one it should have given, the compensation event is assessed as if it had been given (clause 63.7).

The SCL Protocol describes it as comparing the amount of man-hours reasonably included in the tender allowance with the actual hours for the same work. It is simple, but it assumes the tender was achievable, and the Protocol warns that tender assumptions are not automatically a realistic baseline.

These methods start with identifying critical delay (an effect) and thereafter seek to establish what might have caused that delay. Time slice windows, as-planned versus as-built windows and retrospective longest path work this way. After completion the Protocol regards them as generally more forensically reliable, because they consider every potential cause.

For concurrent delay to exist, each event must be an effective cause of delay to completion, not merely incidental to it. Hamblen J's test in Adyard is that both events in fact cause delay to the progress of the works and their delaying effect is felt at the same time.

The SCL Protocol sets out three steps. The last is to multiply the figure resulting from Step 2 by the number of days compensable delay. The Protocol prefers it, with Emden, and suggests cross-checking one formula against another.

The percentage is the contractor's head office overheads and profit percentage (actual), taken from its accounts rather than its tender. The SCL Protocol prefers it, with Eichleay, where a formula is used at all.

The SCL Protocol's term for an event or cause of delay or disruption which under the contract is at the risk and responsibility of the Employer (App A). A Contractor Risk Event is the same for the contractor. Which side an event falls on depends on the contract signed. An Employer Risk Event may give the contractor time, money or both.

JCT Design and Build 2016 makes the Employer itself the decision-maker on extensions (cl 2.25.1). Article 3 gives the Employer's Agent full authority to act for the Employer under the conditions unless the Employer gives notice otherwise, so in practice the agent usually decides.

In Tata v DBS both parties had proceeded on precisely the same assumption that a five-day notice requirement had fallen away. The assumption was communicated and relied on, so the employer could not rely on the missed notice ([148], [159]-[163]).

The SCL Protocol's glossary calls it additional time granted to the contractor to provide an extended contractual period or date by which work is to be completed, and to relieve it from liability for damages for delay. Any extension is added to the existing completion date.

A head of loss, not interest awarded by statute. The SCL Protocol says such interest is recoverable as damages where the loss was actually suffered and was within the parties' reasonable contemplation when they contracted; in construction contractors therefore need only establish that the loss was actually suffered.

The SCL Protocol's glossary defines float as the time available for an activity in addition to its planned duration. Generally, float has to run out before a delay reaches the completion date, which is why float can decide whether two delays were concurrent. Who owns float is argued in chapter 2.

The SCL Protocol defines it as the time an activity can be delayed beyond its early start/early finish dates without delaying the early start or early finish of any immediately following activity. Free float belongs to the activity alone; total float belongs to the chain.

An employer claims general damages for delay where there is no working LD clause, where time is at large, or for losses after termination. It must prove its loss, subject to the ordinary rules of remoteness; the contractor must prove any failure to mitigate. In Energy Works the burden was on the employer to plead and prove its losses.

Akenhead J described it in Walter Lilly as a claim which identifies numerous potential or actual causes of delay and/or disruption, a total cost on the job, a net payment from the employer and a resulting loss. It is not wrong in principle, but it is harder to prove. The SCL Protocol says that failing to keep records is unlikely to justify one.

The SCL Protocol defines them as the incidental costs of running the Contractor's business as a whole. A claim for them after delay is a claim for lost opportunity: the contractor must prove that, without the delay, it would have won other work that paid a contribution to those costs.

One of the three formulae in the SCL Protocol's Appendix A. Its percentage is head office overheads and profit percentage in tender. The Protocol does not support its use, although Walter Lilly described a formula "such as Emden or Hudson" as legitimate once the lost work is proved.

The simplest of the Protocol's six methods (SCL 11.6(a)). It does not consider actual progress, so it can show more delay than the event actually caused. The Protocol treats it as enough to assess an extension of time only in limited circumstances.

It records the issues on which the experts agree and those on which they disagree, with a summary of their reasons for disagreeing (CPR r.35.12(3)). The TCC Guide calls it a critical document. The lawyers must not engage in negotiating, drafting, or revising it (14.6.3). What the experts say in their discussion stays private unless the parties agree (r.35.12(4)); what they sign in the joint statement can be used at trial.

A Key Date is the date by which work is to meet the Condition stated (NEC4 cl 11.2(11)). A compensation event can move a Key Date as well as the Completion Date, and delay to a Key Date is assessed in the same way as delay to Completion (cl 63.5).

Under PD 57AD a document is adverse if it contradicts or materially damages the disclosing party's contention or version of events on an issue, or supports the other side's. A party must disclose known adverse documents, unless they are privileged, at the times the practice direction sets, whether or not any disclosure order is made.

The SCL Protocol says it would not be correct to compare work carried out in the learning curve part of a project with work executed after that period. A second learning curve can follow a shutdown, when crews are laid off and brought back.

Where no clean period exists, the SCL Protocol suggests using a period of least disruption as the measured mile. The result is conservative, because it cannot capture the loss already inside the chosen period.

Part of the penalty test in Cavendish v Makdessi. For a straightforward damages clause, such as an LD clause, the interest will rarely extend beyond compensation for the breach.

Agreed in advance, so the employer need not prove its loss. They run from the completion date as extended, which is why an extension of time for concurrent delay costs the employer its damages for that period.

The ordinary link is finish-to-start: activity B cannot start until activity A has finished. Start-to-start and finish-to-finish links also exist, and any link can carry a lag, a required wait such as the curing time of concrete.

Recovered under the contract's own machinery rather than as damages, but proved the same way: event, causation and loss. Unless the contract says otherwise, the contractor recovers nothing for a period of concurrent delay, because it would have suffered exactly the same loss from its own delay.

The SCL Protocol's preferred method: subject to the availability of the necessary records, the measured mile analysis is the most widely accepted method of calculating lost productivity. It uses the contractor's own rate on the job as the baseline, so arguments about the tender fall away. The mile must be like work, outside the learning curve and long enough to be a reliable sample.

PD 57AD defines it as data about data and extends disclosure to metadata and other embedded data which is not typically visible on screen or a printout. In a programme file it can show when each change was made.

Acceleration is a subset of mitigation. At common law mitigation limits the damages a claimant can recover: it cannot recover loss it could reasonably have avoided, but it can recover the cost of reasonable attempts to avoid loss. Leggatt J said in Thai Airways that mitigation is not in truth a duty but an assumption, in the absence of a contrary agreement. Construction contracts often add express duties to reduce delay.

The Inner House in John Doyle described the term as showing that the global technique need not be applied to the whole of the contractor's claim. The SCL Protocol recommends the same two stages for the rare case where the effects of the causes cannot be separated: price what can be linked, then claim the rest as a composite whole (17.2).

PD 57AD defines native format as the original form in which it was created by a computer software program. For a programme, the native file holds the logic links, durations, calendars, constraints and progress from which the dates, float and critical path are calculated. A PDF shows only the resulting bars. The SCL Protocol asks for the programme in native form, not just as a PDF.

The Court of Appeal held in Amec that the rules of natural justice bind judges and arbitrators but not an Engineer giving a decision under the ICE conditions. A certifier must still act fairly: honestly, with skill and without favouring the employer.

The SCL Protocol uses the phrase without defining it. AACE says the purpose of quantifying near-critical paths is to reduce the effort of identifying and analyzing potential concurrent delays, and offers four criteria for choosing a threshold. Whether experts should rely on them is contested: in Santos v Fluor (Queensland, 2025) referees were entitled to reject an expert's reliance on them under an agreed method that did not call for them.

The SCL Protocol notes that negative float only occurs when an activity on the critical path is behind programme. Once float goes negative, the critical path is the chain with the lowest float value, not the one showing zero.

The approach the court adopted in Balfour Beatty v Chestermount, as described in Walter Lilly: the "net" method was correct. The SCL Protocol says the same: any extension should simply be added to the contract completion date.

Under JCT Design and Build 2016, if the contractor fails to complete the Works or a Section by the relevant Completion Date the employer must issue one (cl 2.28). A new Completion Date fixed later cancels it, and a further notice is needed. It is the first of the notices the employer gives before recovering LDs.

The power comes from the court's full power to determine by whom and to what extent the costs are to be paid (Senior Courts Act 1981, s.51(3)). In Thomas Barnes (costs) (2026) the family who funded a failed claim were ordered to pay the Council's outstanding costs, jointly and severally.

Either party gives it as soon as practicable, and no later than 28 days after it became aware, or should have become aware, of the event or circumstance (Sub-Clause 20.2.1). A fully detailed claim follows within 84 days. A late Notice of Claim bars the claim, subject to the Engineer's 14-day response and the review of late notices in Sub-Clause 20.2.5.

Under the FIDIC Red Book 2017, if no NOD is given within 28 days of the Engineer's determination, the determination shall be deemed to have been accepted by both Parties and becomes final and binding (Sub-Clause 3.7.5).

Described in Tata v DBS as a non-critical activity prolonged deliberately in the face of delays caused to a critical activity; whether it happened is a question of fact. The SCL Protocol recommends that a contractor who intends to pace tells the employer and the contract administrator, with reasons.

JCT reduces the rate by the same proportion as the value of the Relevant Part bears to the Contract Sum (cl 2.34). NEC4 reduces it by the Project Manager's assessment of the benefit to the Client of the part taken over (X7.3). FIDIC reduces the daily rate by value but leaves the maximum unchanged (Sub-Clause 10.2).

The Construction Act 1996 lets the payer give a notice of the payer's intention to pay less than the notified sum (s.111(3)). JCT Design and Build 2016 reminds the employer that it needs one to withhold or deduct liquidated damages.

The Supreme Court restated the test in Cavendish v Makdessi (2015): the question is whether the provision imposes a detriment out of all proportion to any legitimate interest of the innocent party. For a clause fixing damages, Lord Hodge's yardstick is the highest loss that could possibly arise. Between properly advised parties, the court starts from a strong presumption that a negotiated clause is valid. The name the contract gives the sum does not decide the point.

The SCL Protocol defines the contractor's planned completion date as the date shown on the Contractor's programme as the date it plans to complete. It warns that contractors sometimes call this the "completion date", and uses contract completion date for the contractual date to avoid confusion. NEC4 measures delay from a compensation event by how far planned Completion moves (cl 63.5).

JCT does not define it. The Court of Appeal in Mears v Costplan (2019) said it is easier to recognise than define, and summarised it as a state in which the works have been completed free from patent defects, other than ones to be ignored as trifling. Latent defects do not prevent it. NEC4's equivalent is Completion; FIDIC's is taking-over.

Many preliminaries are time-related, so they grow when the job runs late; this is the usual core of a prolongation claim. They can also be thickened, where more staff or resources are needed during a period rather than the same resources for longer. In Walter Lilly the court held that a claim for thickened preliminaries, linked to events and costed from the contractor's records, was not "total" or "global" ([491]).

Where the contract has a working extension of time clause, the principle is not engaged: time is not set at large because the contract provides for an extension on the occurrence of those events. In what Coulson LJ called perhaps the most important reason of all, the Court of Appeal said that nothing in the authorities suggests parties cannot contract out of some or all of its effects. Its relationship with concurrent delay is open at appeal level.

A gang can hit its planned production and still lose productivity, by using more hours to do it. AACE's example is a pipe crew accomplishing 100% of planned production but operating at 50% productivity. Lost productivity is the difference between the productivity the contractor would realistically have achieved and what it actually achieved.

The SCL Protocol wants the contractor to prepare, and the certifier to accept, a programme showing the manner and sequence of the works, updated for progress, variations and extensions. It can then be used as a tool for managing change and deciding extensions (Core Principle 1). It should be kept in its native electronic form, and no version should be overwritten (1.43, 1.59).

AACE's term. Its recommended practice treats project float, absent contrary contract terms, as owned solely by the contractor. That is US practice. In England the wording of the extension of time clause usually decides who has the benefit of it.

The SCL Protocol defines it as the extended duration of the works during which time-related costs are incurred as a result of a delay (App A). Prolongation costs are the costs of keeping the site and its staff running for longer. Whether the contractor recovers them depends on the contract and on proof that the employer's event caused them.

The SCL Protocol says a prospective delay analysis identifies the likely impact of historical progress or delay events on a completion date (11.4(e)). It is the natural frame for an extension of time decided during the works, such as the JCT interim decision. Its answer may differ from what later happened, because the contractor may accelerate or re-sequence the work.

On a project, quantity surveyors value the work as it goes. In a dispute, each side often instructs one to value the claim, and at trial they may give evidence as quantum experts. In Thomas Barnes each side's quantity surveyor put a maximum value on the claim before trial (Thomas Barnes (costs) [22]).

The quantum expert usually prices the periods of delay the delay expert finds, so the two reports stand or fall together. The duty to the court is the same as the delay expert's. Two of the leading English cases on experts who forgot that duty, Van Oord and ICI v Merit Merrell, concern quantum experts.

The employer alleging the breach must prove what a reasonable time was, leaving out delays the contractor caused. In Shawton v DGP (2005) the Court of Appeal said it has to be judged as at the time when the question arises, in the light of all relevant circumstances.

Listed in the JCT forms (for example clause 2.26 of the Design and Build Contract 2016). Some Relevant Events, such as variations, also carry money; others, such as bad weather, carry time only. NEC calls the equivalent a compensation event; FIDIC lists causes of delay in Sub-Clause 8.5.

Listed in clause 4.21 of the JCT Design and Build Contract 2016. The list is not the same as the list of Relevant Events, which give time: some events, such as bad weather, give time but no money.

On the end-of-job review under JCT Design and Build 2016, the Employer may fix an earlier Completion Date only having regard to any instructions for Relevant Omissions (cl 2.25.5.2). Otherwise an extension once granted stays.

A dated log of requests for information shows when the contractor asked for each piece of information and when it arrived. The SCL Protocol lists requests for information and responses among the correspondence records to keep (1.31).

The SCL Protocol says a retrospective delay analysis identifies the actual impact of the delay events on the identified actual or as-built critical path (11.4(e)). Courts assessing damages use it, and the JCT final review after practical completion is one. It still has to trace what critically delayed the works as they went along, not blame the last event for the whole overrun.

One of the SCL Protocol's six methods (SCL 11.6(e)). The path it finds should not be confused with the contemporaneous or actual critical path, and the method has a more limited capacity to recognise and allow for switches in the critical path.

If a contract does not comply with the Act's adjudication requirements, the adjudication provisions of the Scheme for Construction Contracts apply (s.108(5)). The Scheme is a statutory instrument (SI 1998/649). Its provisions take effect as implied terms of the contract (s.114(4)).

The industry's standard guidance on programmes, extensions of time, delay analysis and the valuation of delay and disruption. It is not a contract document and does not state the law: it gives way to the contract and governing law (Introduction, para B). The first edition was published in 2002.

Used where the employer needs parts of a project before the whole, such as the first block of a school. The machinery has to work: some older clauses that tried to reduce one rate across parts could not be operated and failed.

One of the knock-on effects of disruption the SCL Protocol lists, alongside crowding of labour, dilution of supervision through fragmented work gangs, excessive overtime, repeated learning cycles and poor morale. It usually follows late or piecemeal access, out-of-sequence work or acceleration.

The SCL Protocol calls it a sub-network: a group of activities or durations, logically linked, used to show the work flowing from an Employer Risk Event. "Fragnet" (fragment network) is the common trade name.

Labour, productive plant and fuel are the usual examples. Disruption money is made mainly of these costs. Like "time-related cost", it is a working label used in this guide, not the SCL Protocol's own term.

In Walter Lilly Akenhead J held that a claim for thickened preliminaries is not a global claim. Once the link between the event and the extra resource is proved, the costing of it is established by showing how many man weeks were consequently needed, multiplied by the salary cost ([491]).

When time is at large, the obligation to complete by a fixed date is replaced with an implied obligation to complete within a reasonable time, and liquidated damages cannot run. The usual cause is an act of prevention by the employer for which the contract gives no extension. English first-instance decisions hold that a contractor's own failure to give a notice does not set time at large.

A time bar enforces a notice requirement that is a condition precedent. FIDIC 2017 Sub-Clause 20.2.1 (28 days) and NEC4 clause 61.3 (eight weeks) are the standard examples. A bar removes only what its words reach: it may take away money but leave the extension, or leave the contractor free to defend itself against the employer's delay claim.

The method the SCL Protocol recommends for a contemporaneous analysis of delay, described at SCL 4.12 and 11.6(b). Because it forecasts, it usually does not capture the eventual actual delay. Often shortened to TIA.

The SCL Protocol's glossary describes it as additional time included by the Contractor within the allocated duration for an activity to allow for risks that are its own responsibility. The Protocol's guidance also accepts contingency shown as separate activities, and says either is perfectly acceptable and prudent planning practice. Allowance inside a duration does not show up as float.

The first of the SCL Protocol's two windows methods (SCL 11.6(c)). The series of updates reveals the contemporaneous or actual critical path in each time slice period. It is only as reliable as the updates it uses.

Site managers, cabins, security and welfare are the usual examples. Prolongation money is made mainly of these costs. The label is a working tool used in this guide; the SCL Protocol itself classifies costs as direct and indirect.

The American name for the commonest form of global claim. The contractor takes its total cost on the job, subtracts the payment it received, and attributes the balance to the employer's events by inference. Akenhead J said in Walter Lilly that "global" and "total cost" are not terms of art, and that there is nothing in principle wrong with such a claim. The contractor must still show the loss would not have been incurred anyway.

The SCL Protocol measures it to the contract completion date: the amount of time that an activity may be delayed beyond its early start/early finish dates without delaying the contract completion date. Planning software usually measures it to the programme's own planned finish, so check which date a float figure uses. Total float is shared along a chain of activities. It is also called slack.

The SCL Protocol's term for the strict case: two or more delay events at the same time, one an Employer Risk Event and one a Contractor Risk Event, whose effects are felt at the same time. The Protocol says it will be a rare occurrence. The more common usage covers events that arise at different times but whose effects are felt together.

In the SCL Protocol, the Accepted Programme updated with all progress achieved and any revised logic or constraints. Each update is a snapshot of where the critical path ran on that date, so no version should be overwritten.

A party may waive a notice requirement, but a party that relies on waiver must plead it and prove it with clear evidence. Only the parties, or someone with authority to act for them, can waive a contractual requirement; a FIDIC Engineer usually cannot (Uniform Building Contractors [72], [79], [84]).

The SCL Protocol has two windows methods: time slice, and as-planned versus as-built. AACE says usage of method names is loose and undisciplined and lists "windows analysis" as a common name for five of its nine methods. An English judge adopted the view that windows are not methods of analysis in themselves.