Construction Delay and Claims Glossary: 20 Terms Explained

November 5, 2026
Articles, Delay & Claims

In brief: Short, plain definitions of the terms used most often in construction delay and claims work, from extension of time and critical path to measured mile and time bars. Each definition links to a longer guide.

Terms: Extension of time (EOT) · Delay analysis · Time impact analysis (TIA) · Windows analysis · As-planned vs as-built analysis · Critical path · Longest path · Total float · Free float · Concurrent delay · Prolongation costs · Disruption · Measured mile · Acceleration · Liquidated damages (delay damages) · Time bar · Fragnet · Baseline programme · Quantum · Global claim

What is Extension of time (EOT)?

An extension of time is a contractual adjustment to the completion date because of a delay the contractor is not responsible for under the contract. It protects the contractor from delay damages for that period. Whether it also carries money depends on the event and the contract.

What is Delay analysis?

Delay analysis is the process of working out which events delayed a project’s completion, by how much, and who was responsible. It is usually done in a scheduling tool such as Primavera P6, using the baseline and update programmes and the project records.

What is Time impact analysis (TIA)?

A time impact analysis adds a fragnet for a delay event to the programme update current before the event, reschedules it, and measures the change in the completion date. It is mainly used prospectively, at the time of the event. AACE Recommended Practice 52R-06 describes the method.

What is Windows analysis?

Windows analysis divides the project into periods, usually between programme updates, and measures the delay to the critical path in each period. It uses contemporaneous updates, so it shows how the critical path moved over time. It is a common retrospective method.

What is As-planned vs as-built analysis?

An as-planned versus as-built analysis compares the planned programme with what actually happened to identify where and why the work slipped. It needs a reliable baseline and good as-built records. It is often used when programme updates are missing or unreliable.

What is Critical path?

The critical path is the longest chain of logically linked activities that determines the earliest finish date of a project. A delay to an activity on the critical path delays completion unless it is recovered. In Primavera P6 it can be shown by total float or by longest path.

What is Longest path?

Longest path is a Primavera P6 setting that shows the chain of activities driving the project finish date through driving relationships. It is not affected by constraints on other activities, so it often gives a truer critical path than total float on complex schedules.

What is Total float?

Total float is the amount of time an activity can be delayed without delaying the project completion date or a constrained milestone. Activities with zero or negative total float are usually treated as critical. Who owns float is a common point in delay disputes.

What is Free float?

Free float is the amount of time an activity can be delayed without delaying the early start of any of its successors. It is always equal to or less than total float.

What is Concurrent delay?

Concurrent delay is where two or more delay events, one the employer’s risk and one the contractor’s, affect the critical path in the same period. Under the approach common in the UK, the contractor usually gets time but not money for the concurrent period. Other countries and contracts treat it differently.

What is Prolongation costs?

Prolongation costs are the time-related costs a contractor incurs because the project takes longer, such as site staff, site facilities, plant and head office overheads. They are claimed for the period of excusable and compensable delay and must be linked to that period.

What is Disruption?

Disruption is a loss of productivity caused by events such as late information, changes or restricted access, so the same work takes more labour or plant hours. It can happen with or without delay to completion, and is claimed separately from prolongation.

What is Measured mile?

The measured mile is a method of proving lost productivity by comparing output in an unaffected period with output on similar work in an affected period of the same project. The difference, applied to the affected quantity, gives the lost hours.

What is Acceleration?

Acceleration is extra effort, such as added shifts, labour or plant, to finish earlier than the contractor otherwise would. Directed acceleration is ordered by the employer. Constructive acceleration arises when a valid extension is refused and the contractor is held to the original date.

What is Liquidated damages (delay damages)?

Liquidated damages are a pre-agreed amount, usually a daily or weekly rate, that the contractor pays the employer for each period of late completion. An extension of time moves the date from which they run.

What is Time bar?

A time bar is a contract clause that removes the right to an extension or payment if a notice or claim is not given within a set period. FIDIC’s 28-day notice and NEC4’s 8-week notice are examples.

What is Fragnet?

A fragnet is a small network of activities, with durations and logic, that represents a delay event or change. It is inserted into the programme to model the event’s effect, for example in a time impact analysis.

What is Baseline programme?

A baseline programme is the accepted plan for the works, against which progress and delay are measured. A clear, logic-linked baseline accepted by the employer side is the starting point for most delay claims.

What is Quantum?

Quantum is the money part of a claim: the amount claimed and how it is calculated and proved. It is assessed separately from entitlement, which is the right to be paid under the contract.

What is Global claim?

A global claim is a claim that links a total loss to a group of events without showing the effect of each one. Tribunals treat global claims with caution, and they can fail entirely if part of the loss is the claimant’s own responsibility.

These definitions are general guidance, not legal advice. Contract wording and the governing law can change how a term applies.

Need support with this topic?

Solvix prepares delay analyses, extension of time claims and quantum assessments for contractors, employers and legal teams. Book a free 30-minute call to talk through your project with us.

Ahmed Elsayed

Managing Director

Managing Director of Solvix International. Ahmed leads the firm's delay analysis, construction claims and project controls work, and holds an MSc with a specialism in delay analysis. He has prepared delay analyses, extension of time claims and Primavera P6 programmes for contractors, employers and legal teams on projects across the Middle East, Africa, Europe, North America and Australia.