Several years ago, we had the unique experience to be members of an ASHRAE committee that was charged with developing a guideline for specifying DDC systems. Committee work is often frustrating, involving volunteers with different perspectives and levels of involvement, and this project was no exception. We met twice a year for over ten years, struggling to define the purpose, then to create a guide spec, and finally, to write a guideline that explained how to use the document. While this was often frustrating, it was also fascinating to be involved in the conversation that went on between committee members who represented owners, consultants, contractors, and suppliers. We had productive, spirited discussions about what went into a specification, how they where interpreted, and what was necessary to ensure a successful project. In the end, we completed what is now ASHRAE Guideline 13.
Spending this much time and effort focused on this topic resulted in several key lessons learned which are still very relevant today. We learned a lot about not only the end result but also the process that goes into the development of a good controls design. So what where the key lessons?
The controls design is much more than just the specificationOften, we think of the design of the controls system as being reflected in the controls specification. This is rarely the case. In fact, a good controls system design will have four key elements, which include:
- Detailed sequences of operations;
- Listing of all required hardware and software points/objects;
- System diagrams/cartoons;
- The written specification which provides details on methods, products, and performance.