Can PPDs Be Used as Contract Documents?

Is this a trick question? Everyone knows that construction contract documents consist of the agreement, the conditions of the contract, the specifications and the drawings. Just check all the standard AIA agreements. Of course, preliminary project descriptions (PPDs) cannot be used as contract documents. Why even pose the question?

Well, think again. The limitation is only by name. PPDs are written requirements just as specifications are. The difference is only a matter of form and organization.

Broaden your horizon and consider other applications and other forms for contract documents to meet the ever changing project delivery systems. Even better imagine the possibilities with today's and future electronic capabilities.

Make the Connection

Architect's building models (BIM) assemble systems to form a building design. The exterior wall in BIM is not a collection of lines, but rather an element representing the complete wall construction. The BIM object can be generic - just a volume between two surfaces - or detailed showing every material layer used in the wall. Still, the wall remains a single object and is identified as a single assembly.

Open a Revit BIM object properties window and you will find a key data point. The Assembly Code is an 8-digit alphanumeric entry. The first five digits are a UniFormat number. The last three digits are "user" defined to permit multiple object definitions of the same basic type.

Review a preliminary construction estimate to see the data arranged by UniFormat, too. It was the estimators who first brought UniFormat to the construction industry as an alternative organizational method to permit better value analysis during early design stages. UniFormat allows entire assemblies to be easily compared for both cost and performance.

PPDs are arranged by UniFormat. So the data describing the BIM graphics and the quality required to determine the project costs are arranged identically to the BIM and the cost estimate. What a novel concept to have all project data arranged by the same organizational tool.

PPD Basics

PPDs are an effective tool for describing project performance for each functional element within the project. PPDs are organized by systems and assemblies rather than custom used for construction specifications organizations. Because of PPDs organization, the final designed solution need not be known to specify the performance.

Consider the level of detail suggested by CSI's PPDFormat. The content within a PPD for all levels of detail is not mandatory. The content is built as the design progresses: broad brush at first and more finite later.

Initially the information may be performance requirements only. The project team may be able to identify an overall thermal performance for the building envelope, but may have no idea what the materials of construction may be. And that is okay. Include what you know, when you know it. Do not pretend to know what has not been determined, yet.

New Think

Taking a page from Edward De Bono and his book New Think, consider the desired result and then consider how to best get that result. Why must the quality requirements of the construction documents be traditional specifications? Specifications are used as a matter of convention, not because they are the only or even the best solution.

The PPD organization matches the BIM and the estimate. Think of the advantages if the contract documents also matched the model and the estimate. Improved coordination among the documents controlling the ultimate construction should be advantage enough to consider a new approach. Why should a dissimilar specification organization be force fit as a contract document simply for the sake of the status quo?

Consider specifying the system and assembly requirements in a PPD. Specify the individual project's quality and performance requirements for the entire assembly. Specify the interfaces between the components that form the assembly. Specify the interfaces between the specified assembly and the adjacent assembly. Collect all the requirements for each assembly with the affected assembly.

Specify products used as assembly components by a simple reference to an external standard. Manufactured products are already governed by industry standards. Multiple assemblies are likely to contain the same products. So there is no need to continue repeating standard product information in every assembly description. Take CSI's mantra of "say it once and in the right place" to the next logical level and completely segregate the product specifications.

PPDs as Construction Contract Documents

PPDs can be an effective contract document. After all, the contractor is building systems and assemblies. And assembly interfaces are where building performance difficulties and ultimate failures begin. The current specifications organization does not consistently accommodate systems specifications - making addressing the interfaces awkward at best and impossible at worst.

PPDs are organized by systems and focus on performance and design criteria. PPDs can name the required components and reference the external product specs, keeping each assembly description about the completed assembly and its interfaces.

So PPDs may well be the next preferred contract document, directly connecting the BIM with contractor's estimate and providing a means to effectively specify interfaces.

So what do you think? Is this a concept worth exploring?

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