In the world of high performance building design and construction there is a generally accepted two-step documentation process of pre-planning. The first is the creation of the Owner’s Project Requirements (OPR); the second is the creation of a Basis of Design (BOD). This two-step process is meant to facilitate early team communication and integration. However, it is our experience this process may actually hinder cost efficiency, integration and innovation.
The ASHRAE Guideline definition of the OPR and BOD is as follows:
Owner’s Project Requirements (OPR): A written document that details the requirements of a project and the expectations of how it will be used and operated. This includes project goals, measurable performance criteria, cost considerations, benchmarks, success criteria, and supporting information.
Basis of Design (BOD): A document that records the concepts, calculations, decisions, and product selections used to meet the Owner’s Project Requirements (OPR) and to satisfy applicable regulatory requirements, standards, and guidelines. The document includes both narrative descriptions and lists of individual items that support the design process.
At Passiv Science, our goal is to deliver successful projects. As of April 2014, my personal definition of a successful project is one that is:
1. Completed on time
2. Completed on budget
3. Performs on an energetic level a minimum of 50% better than the current building standard
4. Maintains a consistently high level of interior air quality
5. Maintains a consistently high level of thermal comfort
6. Completed at a local market rate cost
It is the last item that is the sticking point for many teams. Our experience with IPD has shown that the approach in the pre-planning phase is often the key to successfully achieving market rate cost. The issue comes in the differentiation and separation of the OPR and the BOD. The OPR document assumes a process where silos exist; each discipline is contracted to perform in their area of expertise. The outcome of the project is not a jointly held responsibility, but rather an orchestrated process in which some entity, commonly the architect, construction manager or owner’s representative, takes on the role of “chief cat herder”. This entity attempts to facilitate and coordinate each discipline’s additive portion of the design to achieve a well performing and hopefully cost effective high performance solution. While this outcome is sometimes achieved, very often the outcome is less than optimal creating either: (i) expensive solutions, or (ii) cost effective projects that leave energy savings, thermal comfort and air quality “on the table”.
The process Passiv Science advocates, when employed effectively, has demonstrated the capacity to consistently deliver on all the points listed above. There are many reasons for this, but in this post I will only cover the pre-planning document.
We do not use the OPR and BOD process. Instead we create a Statement of Project Objectives (SPO). This is a single document that is performance based. It starts with the business case or cost proforma of the project. Added to this are the functional, aesthetic and performance metrics. There is no BOD document.
Let’s examine why we do this. When we are orchestrating IPD and/or utilizing a relational contract, we want to employ the lean technique of “pull” production or the last planner approach. We do this not only in the construction of the project but also in the design of the project. We want all possible solutions on the table for all aspects of the project until the correct moment where we can decide as an informed group which set of options produces the optimized solution that delivers the SPO.
Let me give a quick example:
On a recent dormitory project the SPO had two items of particular interest to this discussion. The first is that the cost of the dorm had to be equal or less than a benchmark dorm built two years prior; the second was that individual dorm room occupants had to have thermostatic control of their rooms (as the recent benchmark dorm had through the wall PTAC units.) These were a small part of a long list of objectives. If you are reading this and you are familiar with OPR documents you may ask’ “how is that any different from the standard process?” In fact the OPR and the SPO are very similar, but the process is different. The SPO is created as a group
whereas typically the OPR is created for the owner by a single entity potentially missing creative opportunity in setting objectives. The real issue lies not with the OPR, but with the BOD. With project, if we had employed the standard pre-planning method we would have next created a BOD. I can tell you that the team initially thought before any design or analysis had been completed that a multi head mini split system was a logical choice and if the budget allowed a variable refrigerant flow system would be nice. Had we entered that assumption in a BOD we may have unintentionally “locked” in this thought.
As it turned out as we were developing the design, energy and load analysis and cost figures it became clear that the significant performance we could achieve very inexpensively with minor envelope changes, peak loading on the individual rooms was dropping to the point where the smallest mini split heads available were 2.5 times larger than the peak load! Now if we had a BOD document we could have said, “That’s OK, the units will scroll down to 30% load” and have been done thinking about the HVAC system. But, because the SPO document did not pre-dictate the system types only calling for the performance and control parameters, a more detailed search was undertaken to optimize the HVAC solution. Many solutions were presented, but after research a small fan coil unit that was rated for potable water was found that was correctly sized for the load and because it was rated for potable water, it became just another fixture in the plumbing string in the room, making it very inexpensive to install. The dormitory already had a recirculating hot water line, so a simple buffer tank and return was added to the cold water supply and an optimized, low cost, correctly sized system was installed.
So my point is not that one must employ this system, if your project is using standard delivery, pre-supposing through the OPR/BOD process may be fine, my point is that if one uses the standard method, you may be leaving additional performance or cost optimization on the table.