Delay Analysis Methods under FIDIC 1999 and 2017: A Review of Contractual Fit and Method Selection for Extension-of-Time Claims

An extension-of-time (EOT) claim under the FIDIC Red Book succeeds or fails on three things: whether the notice was given in time, whether the delay is shown to affect the Time for Completion, and whether the method used to show it fits the records that exist. This review compares the claims procedures of the 1999 and 2017 editions of the Red Book and maps them to the nine forensic schedule analysis methods in AACE International Recommended Practice 29R-03, using the SCL Delay and Disruption Protocol (2nd edition) as the guidance on method choice. The 28-day notice period is retained in 2017, but the period for the fully detailed claim doubles from 42 to 84 days, the Engineer must now challenge a late notice within 14 days or the notice is deemed valid, and the 2017 form sets no express rule for concurrent delay. The review argues that no single method suits every claim. It sets out a selection matrix based on the quality of the programme updates and as-built records, and a practical workflow that a planning engineer can follow from the first notice to the final claim. The review is based on the published forms, the cited standards and published commentary, and is not legal advice.