by Ben Gries, PE, LEED AP
Why hire an engineer? Are they necessary? The answer is, not so simple at times. Law stipulates that a professional must design certain projects — healthcare facilities, high-hazard buildings and buildings that have an occupancy of more than 100 people, to name a few. Aside from specific project types, an engineer is not required by law to design a project.
So that begs the question, why use an engineer if it isn’t required? When a client has specific needs and goals for a project, an engineer can put together a design to meet those needs. The client can use the design to obtain competitive bids and to hold the contractor accountable to scope of work. Engineers help ensure the owner’s requirements are met during construction.
Spending the time and money to hire an engineer to create a design typically saves time and money overall for the project. This is accomplished by creating a design that has been thought through, coordinated, budgeted and reviewed with the owner. Competitive bids ensure the owner gets the best price. A well-documented design includes a complete scope of work that the contractor can build on schedule, minimizing the occurrence of surprises. And the project is completed to meet the owner’s documented expectations.
At the start of the project, the scope is often not well defined. It is more of a client vision or mission. The engineer spends time discussing the project needs and goals with the owner, identifying project requirements and helping the owner define the project scope. The scope typically includes use of the space, budget, energy requirements and control of the space. Documenting these discussions and expectations helps ensure a successful project delivery.
Once the project requirements are determined, the engineer starts the design. They typically discuss a design basis with the owner that helps further define the project scope. Once the owner and engineer agree on the proper direction for the project, the engineers dive into the design details.
Code research is completed to ensure the design is compliant. Specialty space uses are researched to determine if any unique aspects will need to be addressed and if they affect the engineering design. Local climate is reviewed to determine average and peak temperatures, humidity levels, rainfall, sun light, sky clarity, cloud cover and anything else that may affect design.
Calculations are completed —numerous calculations. Load, density, performance simulations, photometrics, friction loss, head loss, temperature differences, composite assembly heat transfer, velocity, noise, weight, stress, comfort and dew point/condensation. All of these are performed repeatedly to check different operating conditions at various states. The goal is to predict how the selected systems will perform and to determine if they will meet the owner’s project requirements.
Once systems are sized and selected, the design begins. Space is allocated and coordinated. Mains are routed and sized. Terminals and fixtures are circuited and connected. System layouts are completed. And more calculations! Everything is built on paper and verified to ensure it will work. A good design proves that the systems will work and meet the owner’s project requirements.
Designs are often reviewed and costs estimated as they are completed, allowing adjustments to be made to the design to keep the project within budget. All of these calculations, designs and reviews are completed before a single item is purchased and before anything is installed.
When a design is complete, it is used to seek bids from contractors. Competitive bids ensure the owner gets the best pricing for his/her project.
The design is also used to write construction contracts. The design documents are the work scope agreed to be completed by the contractor and to be paid for by the owner. It helps protect the owner and contractor. The owner pays for the project he wants completed and the contractor installs the project according to the design. Expectations on both sides are better understood with a good design.
Engineers are not always required for a project, but they are an invaluable resource. They ensure the owner’s project goals are met through their design efforts. They make sure everything is proven to work on paper before the first shovel hits the dirt. Engineers represent and protect the owner’s interests throughout construction, ensuring the project delivered meets the owner’s expectations and requirements.