Optimizing for Speed in Commercial Rooftop Applications: Page 3 of 3
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To help the construction crew get in a flow and move fast, use simple repetitive patterns in the array layout and string wiring. While you may be able to better utilize a roof area with oddly shaped arrays or reduce wire costs with unique string-wiring practices, it will come at the cost of additional field labor.
It is also important to consider roof access, work coordination, staging and layout. On the one hand, a mounting system with a 5° tilt may allow you to pack more kW on a roof; on the other, it could slow the project down if the installers cannot even walk between the rows. Fall protection is another consideration. The fire codes allow 4-foot setbacks on small commercial flat roofs that are less than 250 feet in length in either direction. If the roof does not have a parapet, however, OSHA guidelines require a warning line located 6 feet from the roof edge and fall protection (harnesses, ropes and anchors) for anyone working beyond this perimeter. The extra labor costs required to meet these OSHA requirements may not justify placing modules and electrical equipment beyond the perimeter of the warning line.
Foster Open Communications
Clear and transparent communications are the most effective way to foster an atmosphere of shared goals. It is especially important to be clear, open and honest with project team members when things are not going as expected. Strong relationships built on trust help you not only get the information you need to save money on projects, but also get it fast. This is true whether you are trying to obtain cost estimates from a subcontractor to evaluate value engineering options or spending approval from management to gather valuable site investigation data.
By building trust, clarifying priorities, and providing the right guidelines and resources to the project team, you can accelerate project schedules without increasing costs or risk. Reducing design and construction timelines while putting less pressure on the project team to reduce costs or increase yields after contract signing also better aligns the activities of the project team with the goals of the company and the client.
K. Randy Batchelor, PE / Sol Rebel Power Systems / Alameda, CA / solrebel.com