Design Change Notice — Companion Article

What this tool does

The Design Change Notice records a change to the approved piping base case, and the labour effect of that change. The base case is the approved scope of work. A change is anything that moves that scope, the estimate that was built from it, or the schedule that was built from the estimate.

The method distinguishes two kinds of change:

• Client change orders. The client has asked for work that was not in the approved scope, or has changed work that was.
• Trends. Creep that starts inside the piping effort: the scope was thin, the estimate is proving light, or the schedule is slipping, and nobody outside the team has issued a change yet.

Both kinds affect hours. Both are written down against the base case. They are not the same approval path, and they are not mixed into the original hours without a trace.

When to use it

Use it as soon as you can see that the work in front of the team is not the work the approved scope described. Do this before the extra hours are absorbed into the weekly plan.

A client request that is already inside the approved scope is not a change. A client request that is outside it is a change order, and the work waits until that order is approved. An internal trend is raised when the lead can see creep coming, so it can be accepted, reduced, or rejected while it is still a forecast.

Inputs

Bring:

• The approved scope item the change is measured against, or a clear statement that no scope item covers it.
• What is changing: facilities, services, deliverables, quantities, or dates.
• Whether this is a client change order or an internal trend, and which kind of trend: scope, estimate, or schedule.
• The piping labour hours you propose to add or remove, built the same way as the original estimate.
• The schedule effect: which activities move, and whether the hours are approved, or still unapproved but required.

If the project also tracks cost, it applies its own rates to these hours. The notice identifies the change and the hours.

How it works

Raise and close a notice in this order.

• Compare the request or the creep with the approved scope. If the work is already included, do not open a change. If it is not, open one.
• Class it. Client-originated work is a change order. Creep that starts in the piping team is a trend.
• Estimate the hours the same way you estimated the base scope: from the added or deleted deliverables and quantities, using your own history, and say which activities on the schedule are affected.
• Keep the status of the hours visible. Approved change hours are added to the plan as change. Hours that were not approved, including work the client rejected but the plant still needs, stay in their own place on the schedule. They are not dropped into the original total.
• Update the forecast of hours still to complete from that split. The schedule carries the forward hours. This notice is the reason those hours changed.

Understanding the result

The result is a notice a reviewer can accept or refuse: what changed relative to the approved scope, whether the client or the piping team originated it, and the proposed piping hours.

On the schedule, approved change hours and hours that are still unapproved stay separate from the original plan. The forecast to complete moves only by the hours that belong in the forward plan. The original estimate stays readable.

Engineering considerations

Write the change against a specific scope statement. “Extra piping” is not a base case. “Tank-farm tie-ins, which Part I of the scope excluded” is.

Estimate the added hours the same way as the original estimate, and calibrate them against your own history. A round allowance with no deliverable behind it will not survive a review. Keep trends visible. A model that is quietly absorbing unplanned hours is a trend whether or not it has been written down, and writing it down is what lets the project manager decide.

The piping lead identifies the technical change and the hours. The project manager and the client decide approval under the contract.

Example

Illustrative example. Figures are not benchmarks.

The approved scope covers one process unit and excludes the tank farm. The approved estimate is 500 piping hours. The client asks for 15 tank-farm tie-in isometrics. That work is not in the scope, so it is a client change order. For this illustration the added isometrics are 80 hours. Until the order is approved they sit as unapproved change. Once approved, the schedule shows them as 80 change hours on isometrics, inside the forecast to complete, while the original 500 stays visible.

Separately, the model is overrunning. The lead expects about 40 hours of creep with no client request behind it. That is an internal estimate trend. It stays in the unapproved column until the project decides to accept it, cut scope, or reject it. It is not added to the 500 in the meantime.

Standards and references

Based on the project-controls methodology of James O. Pennock, Piping Engineering Leadership for Process Plant Projects. Change orders and trends in that method are identified against the approved scope, and their hours are carried separately on the control-level schedule. It is a practical method for a piping engineering lead. It is not an ASME or API code, and it is not a substitute for the contract change procedure or your company procedure.

Limitations and disclaimer

This tool records piping changes and their labour-hour effect against an approved scope. It does not set a universal rate for extra work, and it does not replace the contractual change procedure or your company’s approved procedure. It does not, by itself, approve a change or authorise the team to start out-of-scope work. The piping lead judges the technical impact. Approval sits with the project, under the contract.

Use the tool

Calculate now: Design Change Notice

How this calculation works: Design Change Notice

Related tools

• Scope of Work is the approved base case this notice is written against.
• Piping Man-Hour Estimator is how the added or deleted hours are built up.
• Piping Estimate Summary shows approved change hours beside the original total.
• Control Level Schedule carries approved and unapproved change hours, and the forecast still to go.
• Physical Progress Calculator measures the approved work, including approved change, not unapproved trends.
• Historical Data Log records the hours the job actually took, change included, once it is finished.