Most people have heard the expression, The Devil is in the Details. It is commonly thought to be a play on the idiom God is in the Details, which had been used to exemplify the works of celebrated artists, architects, and engineers. It suggests that great reward can be found when consideration is given to the smallest details.
Alternately, The Devil is in the Details suggests that situations or plans that seem sound should be carefully evaluated because even the smallest detail can cause major problems if neglected. It is meant as a caution to pay attention.
Architects and engineers are often devoted to spending countless hours laboring over the finest details when preparing calculations, drawing packages and specifications. Indeed great reward awaits those who pay attention when their efforts are realized in the form of a building or innovative fabrication. Following traditional design phases, these projects can take many months and even years to design and document. Today’s projects usually follow three design phases: Conceptual Design, Basis of Design (BOD) and Detail Design.
Conceptual Design begins once a project is initiated with a goal of establishing the project scope and cost. Project parameters are defined and the design teams set out to create a facility which meets those requirements. Ultimately, conceptual design concludes with a Rough Order of Magnitude (ROM) estimate and a report which is often used to acquire project approval and funding for subsequent design phases.
The BOD phase begins where the concept left off and is also commonly referred to as Basic Design or Design Development. Project teams are increased and the scope is developed to approximately thirty percent completion. This phase is referred to as the Basis of Design because it sets the stage for Detail Design. At this point, all major scope items should be defined and coordinated so that detail design can commence. Another estimate is prepared with a slightly higher accuracy as the scope is better defined and documented.
Detail design follows, culminating in the development of construction drawings. At approximately sixty percent completion of project documentation, the final construction estimate can be developed. This estimate often carries a plus or minus (+/-) 10 percent accuracy and involves extensive material take-offs and pricing from external vendors and contractors.
This process depicts a more traditional approach to project execution. But, what happens when design teams are asked to reduce project schedules? As specialists, we willingly accept the challenge and draw from our experience to help our clients be first to market or to quickly rectify issues with aging facilities. When we challenge the execution of a project to go from the conventional to the unconventional, we should also challenge other aspects of the design phase.
In simple terms, shortening a design phase typically means something is not being evaluated to an extent that normally would have required more time. These tasks can be by-passed by making assumptions based on experience or known parameters, for example, “there will be no changes to the manufacturing process” or “existing utilities are adequate for future expansion”, etc.
These assumptions are often well informed; however, time is simply not allocated to provide the detailed analysis. The project, therefore, incurs more risk from this lack of detail. These risks have the potential to affect the project schedule, and in the most extreme case, its overall success. The most common impact, however, is increased cost.
There is no magic to cost estimating. The project scope is defined and project elements get assigned a value which can be based on vendor quotations, benchmarked data or a combination of both depending on the design phase. A plus or minus (+/-) accuracy percentage is included in the estimate to cover price fluctuation as the numbers may be preliminary and not be based on actual bids.
The accuracy percentage varies depending on the design phase with the highest accuracy (and lowest +/- percentage) occurring in detail design. It is important to note that the accuracy percentage is not meant to cover unforeseen scope additions. If the building gets bigger or more equipment is added, the base estimate must be adjusted to reflect the added scope. Managing scope creep is one of the biggest challenges during subsequent phases as new information unfolds and earlier assumptions are tested.
When schedules are challenged to be less than traditional, we should also challenge conventional estimate accuracy values or contingencies. The potential for missed scope goes up exponentially as schedule time is reduced and we should be realistic in our evaluations and acknowledge any shortcomings or uncertainty. We have to ask ourselves, “How well did we pay attention?” After all, if the costs go up, we cannot blame the Devil if there are no details and I am pretty sure we will not receive any great rewards.
(Source: IPS – Integrated Project Services, LLC)