Estimating Aligned with Work Packaging for Planning and Scheduling

Modern project controls — including those on Advanced Work Packaging (AWP) projects — have evolved toward highly effective performance management using Control Accounts at both the Work Package (WP) and Planning Package (PP) levels. (AACEI RP 125R-22 Developing Work Packages and Planning Packages in support of Performance Management).

The critical missing link is granular estimates that can be rolled up to any PP level — and ultimately to the WP level — as Installation Work Packages (IWPs) are developed.

Why does this matter? When the hours and schedule durations assigned to WPs and PPs are misaligned with the Control Budget, the effectiveness of project controls is significantly diminished. Divergent trends will not be detected early unless the schedule and the control base are kept in sync.

The Problem: Conventional estimating methods typically aggregate details across item groups, with many items factored at summary levels. This leaves project planners and schedulers with no choice but to notionally split total estimated hours into various buckets for schedule development. Only a handful of EPCs and owner companies have begun evolving their estimating systems to close this gap and achieve better alignment between schedule and estimate.

A further challenge is that Class 3 Estimates — which typically serve as the basis for the Final Investment Decision (FID) and project budget — are sometimes prepared with lower-than-ideal levels of engineering maturity. Yet a Class 3 Schedule is required for the FID stage gate, meaning it becomes the first “control schedule” for the project phase until a more detailed schedule is available.

The Work Process

Top-down planning and semi-detailed scheduling methods are generally used to develop the Class 3 Schedule.

Even at this stage, the schedule must be aligned with the accompanying Class 3 Estimate — not only at the total budget hours level, but across the various “Construction Work Package (CWP)” including the Cost Breakdown Structure (CBS) by Account as well.

The Class 2 Control Baseline Schedule is developed at a later stage using a bottom-up, detailed approach. (AACEI RP 27R-03 Schedule Classification System).

Rolling Wave Planning Detail from early stages to defined IWPs

Planning and scheduling begin with top-down planning, progressing through Planning Packages (PPs) at higher levels, with each PP later broken down into IWPs as field construction approaches.

(AACEI RP 125R-22 Developing Work Packages and Planning Packages in support of Performance Management).

Estimating Aligned to Support Integration with PPs and IWPs

The solution is a granular estimate that can be rolled up to any desired level of PPs or IWPs — at any stage of schedule planning or construction — using a dynamic mapping table that links PPs and IWPs to their constituent elements by spool/isometric number, cable ID, and other applicable identifiers.

For this to work, the estimate details must incorporate WBS structure — including spool or isometric numbers — along with additional coding that enables roll-up to discrete labor operations such as spool installation, field welding, bolt-up, and similar activities.

Granular Estimate Examples

See interactive reports and an example project detail estimate designed to support planning and scheduling fully aligned to the control base, with ongoing mapping to PPs and IWPs through a dynamic mapping table.