1

How to perform Time Impact Analysis (TIA)

Amr M. Morsy, Consolidated Contractors Company, April 2017

The planned project completion date usually cannot be achieved in construction projects, due to

unexpected delays that were not planned for before the project commencement. Those delays

can be considered excusable delays if they were attributable to the Employer, while they can be

considered non excusable delays if they were attributable to the Contractor. To avoid the

application of Liquidated Damages on the Contractor, the Contractor shall prove his entitlement

to Extension of Time for Completion through confirming that the dominant delays are excusable

delays. There are many delay analysis methods that can be used to analyze the project delays

and quantify the entitlement for the Extension of Time for Completion.

Time Impact Analysis (TIA) method in one of the most reliable methods to analyze and quantify

the entitlement for the Extension of Time for Completion during the project, as stated by AACE,

it is recommended that the TIA method to be used “forward looking” or “ prospective analysis”

approach.

The benefit of using the TIA method is that it is a dynamic method, which shows the status of

the project in the period of occurrence of the delay. So, the concurrent delays can be viewed to

calculate the correct entitlement for EOT for the Contractor, if those concurrent delays were

attributable to the Contractor and overlapped with the Employer’s delays, those delays period

shall be deducted from the Contractor’s entitlement as shown in figure 1.

2

Figure 1

3

To start performing the TIA on delay event, the forensic planner (delay analyst) needs to identify

the fragnets to be incorporated in the schedule, and that can be achieved through acquiring all

the correspondences, RFIs, VORs, etc.… related to that delay event.

It is essential to have an approved or consented programme to insert the fragnets in. the next

step in performing the TIA is selecting the suitable updated programme for progress. This step is

one of the most important steps in the TIA, as it depends on the type of delay whether it is due

to additional works, change in the type of materials, installation method, suspension of works by

the employer, etc.….

To select the suitable updated programme for progress, the delay analyst needs to identify the

delay start date, and then select the last updated programme for progress prior to the delay

start. In case there was an activity in the P6 Programme for receiving instructions to start works

in specific location, receiving the IFC drawings, or receiving materials delivered by the Employer,

the delay start date will be the late start date for that activity. In case of receiving an instruction

to change the type of material, check the late dates for the activities related to that material

(Engineering, Procurement, and Installation), then check the date of instruction. If the date of

instruction is earlier than the dates of those activities, then there is no need to perform the TIA,

as there will be no time impact from that delay event. While, if the date of instruction is later

than the late dates of those activities, then the delay analyst needs to select the last updated

programme for progress prior to the late start of those activities.

After selecting the suitable updated programme for progress, use two copies of that updated

programme, rename one of them “before impact”, and the other one “after impact”. Insert the

prepared fragnets in the “after impact” programme, and link them to the related impacted

activities. Create new activity code and rename it with the delay event and assign that code to

the fragnets and the impacted activities. Run the programme, then check the new longest path,

assign that activity code to the activities on the new longest path and then assign the “before

impact” as a baseline to the “after impact” programme. Compare between the two programmes

on the impacted path to see the extent of the delay on the impacted activities, using the filter of

the “used activity code”.

After performing those analyses, now the delay analyst has the expected impact from that

delay, also the delay analyst needs to transfer the “used activity code” and check the longest

path in the “before impact” programme, to view the actual delay till the data date of that

programme, and to check if the impacted activities filtered by “used activity code” are on that

4

longest path to justify that delay. In case those impacted activities are not on the longest path,

the delay analyst shall try to relate the delay in the “before impact” programme to another

delay event caused by the Employer, to avoid the deduction of that delay period resulted from

the “after impact” programme. If he could not find justification to the delay or relating it to the

Employer delays, then the overlapped period between the two delay paths will be deducted

from that delay period resulted from the “after impact” programme.

TIA method proved that it is a reliable method to use to identify the impact of the delays on the

project completion, but it is recommended to be used during the occurrence of a delay event

and it’s impact, not after the end of that delay event and it’s impact.