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1 Bulletin No. CO 3 Revised (Replaces 2005 version). File: Change Orders Bulletin Time Impact Analysis . Measuring Project delay Introduction specifications carefully before any work Schedule delays are a frequent is performed on the project. It is not occurrence on many construction unusual to find terms and conditions projects and can have immense cost such as: consequences. Without the remedy of a time extension, mechanical contractors Contractor's failure to submit its time are often forced to work overtime and impact analysis, with all supporting may be required to increase crews and documentation and within the time supervision to mitigate delays, even period provided for in this contract, when caused by others. Mechanical will constitute a full and final waiver contractors may also be assessed of the contractor's right to an liquidated damages for delay , along with extension of time arising from the possibly having to defend against delay alleged changed condition. Absent claims from the prime contractor or the timely and complete submission other trades.

2 In some instances, a of the contractor's time impact mechanical contractor is not made analysis as required by this contract, aware of delaying events until it is too it is mutually agreed that the alleged late to remedy the delay without changed condition has no effect on incurring added costs that can be the critical path of the project substantial. schedule. The purpose of this bulletin is to alert The method of delay impact analysis mechanical contractors to several of the described in this bulletin is known as the key elements of schedule usage and the contemporaneous windows method of development of time impact analyses to analysis. The windows method identify and quantify project delays. An measures delay at specific time important first step in this process is the windows throughout the project. The mechanical contractor's thorough review contemporaneous windows in time used of the contract documents. The for this type of analysis are usually the specifications generally contain the dates of the monthly update of the scheduling requirements for the project.

3 Project schedule. While there are other Within this section of the specifications methods of construction delay analysis, is often found the provisions governing such as the impacted as-planned, the timely notice and the requirements for a as-built, or the collapsed as-built . schedule impact analysis. Read the methodologies, none offer the ability to general conditions of your contract evaluate the project at specific windows Copyright, Mechanical Contractors Association of America, Inc., Revised 2011. 1. of time throughout the duration of the activities are analyzed to determine how work. Moreover, some methodologies, each interrelates to other activities on including the impacted as-planned the overall project with regard to technique, have been generally performance dates. Logic restraints are discredited or strongly critiqued by created between the activities to create courts and boards in reported cases. the CPM schedule network, which is the Many modern contract specifications graphic representation of the overall require the contemporaneous windows schedule showing the activities and the method of delay impact analysis.

4 This interconnecting logic restraints. The bulletin will describe this method of CPM schedule should demonstrate the analysis using the terms employed by most efficient and profitable means of contract specifications that are completing the project within the encountered on many public and private performance time set forth in the construction projects. contract. Terms and Concepts Used in Critical Path the longest connected delay Analysis chain (or chains, in the case of multiple Activity the basic unit of work in a critical paths) of activities in a CPM. construction schedule. The activity is the schedule that, if delayed, will have an unit of work1 into which the overall equivalent impact on the end date of the project is divided for the purposes of project. tracking and managing time and labor during the construction process. The Total Float the number of days an overall project is divided into activities activity can be delayed from its earliest during the job planning phase.

5 Each start date, or its earliest finish date, activity is defined by specific geographic without causing delay to the completion or contract boundaries such as phase, of the project. Activities on the critical building, floor, and sectors; and by other path have zero (0) total Total float designations, such as column lines, is a computation that is derived from the systems, rooms, crew codes, or other CPM schedule network and is definitions that will allow specific dependent on the duration of the identification of the work on the contract activities and the logic restraints that are drawings. Each activity is given an input by the scheduler. Total float can estimated duration and is linked to other Change with each progress update or activities in the schedule by the use of modification made to the original logic restraints. Logic restraints ( , schedule. finish to start, start to start, finish to finish, and start to finish) define the Most contract specifications contain a relationship between activities in a shared total float clause.

6 Such clauses construction schedule and are input by state that total float is a commodity to be the scheduler to develop the overall shared between the parties to the Schedule Network. contract. In the case of a delaying event, a time extension will be granted only to Change Orders Critical Path Method the extent that the delay first consumes (CPM) Scheduling a formalized, and the entire available total float and, usually computerized, method of thereafter, causes a delay to the critical construction scheduling. This dynamic path. Impact events, which only construction management tool requires consume positive float when analyzed in the development of activities and the CPM schedule, will usually not result interconnecting logic restraints. The in the granting of a time extension. Copyright, Mechanical Contractors Association of America, Inc., Revised 2011. 2. Time Impact Analysis (TIA) a series schedule should not pose a problem. of activities and logic restraints that The prime mechanical contractor is define what is known about a changed usually tasked with the same type of condition,3 such as work added by a overall scheduling responsibilities as scope Change or work occasioned by a would a typical general trades contractor differing site condition.

7 As the conditions or construction manager. In such cases, Change , or as more information is the prime mechanical contractor will be known about the potential delay , the TIA fully aware of the requirements of the must be modified (evolved). The TIA project schedule and will know when has become a term of art in the industry TIAs are required to be developed and and is referenced in many contract input into the overall project schedule. specifications regarding project scheduling, notice, and delay analysis. The majority of mechanical contractors, TIAs are input into the CPM schedule as however, are in the role of subcontractor soon as the changed condition is to a prime contractor or construction recognized and are inserted into the manager. In such cases, the mechanical CPM schedule update with a status, or subcontractor may not have unfettered data date, closest in time to the date of access to the prime contractor's the initiation or discovery of the potential schedule. When that is the case, the impact event.

8 Mechanical subcontractor must take some affirmative steps regarding Fragnet another term of art in the participation in the scheduling process. construction industry having the same It is recommended that the following definition as the TIA. The fragnet is a minimum steps be followed on every fragmentary portion of an overall project project: CPM schedule network that depicts the activities and logic associated with a Request the opportunity to potential schedule impact. The gapless participate in the development of evolving fragnet is a term of art that the project schedule. describes a process of identifying, defining, and developing over time, the It is essential that the mechanical discrete activities that form a potential subcontractor request that it be given a impact to the project schedule. full and complete opportunity to Maintaining contemporaneous participate in the development of the documentation supporting the details of overall project schedule prepared by the each delay activity is important in prime contractor or construction developing and supporting the TIA, or manager.

9 Furthermore, the mechanical gapless evolving fragnet. The terms subcontractor may, from time to time, be TIA and fragnet will be used asked by the prime contractor to review, interchangeably herein. or to provide input into, the overall project schedule. The mechanical The Project Schedule contractor should respond competently, While this bulletin does not cover the comprehensively, and in a timely means and methods of CPM schedule fashion to such requests. development, updating, and maintenance, some commentary Request electronic copies of the concerning the scheduling process is project schedule and all updates. useful. If the mechanical contractor is also the prime contractor on the project, It is often difficult, if not impossible, to the development and control of the conduct a meaningful schedule review using only a paper copy of the project Copyright, Mechanical Contractors Association of America, Inc., Revised 2011. 3. schedule or updates thereto. Thus, the of the CPM schedule.

10 The absence of mechanical subcontractor should these vital logic restraints can create request in writing a magnetic media false float5 which, in the event of a copy4 of the prime contractor's baseline delay , may improperly consume the schedule and each progress update impacts when a TIA is inserted into the thereto. The mechanical subcontractor project schedule. When mechanical is then able to perform a much more crew and equipment restraints are detailed and thorough review of the missing, a delay impact may show no prime contractor's schedule. On public delay computation in the project projects, when requests for the schedule due to false float. In fact, electronic scheduling files are denied by because of the lack of crew and the owner, construction manager, or equipment restraints, the mechanical prime contractor, such files can subcontractor's activities may become sometimes be obtained through a improperly stacked in the schedule in a Freedom of Information Act (FOIA) or manner that was totally unanticipated, in public information act request filed by turn, leading to unplanned increases in counsel.