Why the site survey is the key to project success
This post was written by Josh Weiner, Solar Expert Witness & Solar Engineering Expert and discusses the crucial task of performing a solar site survey. Weiner has been at the forefront of the solar industry for over 20 years and is an industry leader on solar-plus-storage engineering & design. Josh’s expertise spans both in-front of and behind-the-meter initiatives including residential, commercial, utility, grid-scale, and ev charging solar and storage applications.
Ever heard someone say one man’s trash is another man’s treasure? They might be talking about a site survey for a distributed energy project.
We know. Some contractors don’t value site surveys.
Here, let’s take a poll. Results are anonymous. Tell us what you truly think.
If you marked any of the first three answers, chances are you view site surveys as a necessary evil. Maybe an unnecessary one.
So why is it that sophisticated, experienced developers and construction firms build in-house staff to handle site surveys? If we were in your shoes, we’d have site survey expertise in house too.
Site surveys are hands down the most important part of the discovery process.
In addition, we’d augment internal resources by contracting with a specialized project engineering and design firm. Bringing engineers, construction managers, project managers and project owners together for a couple hours, you get the best insight on your project all at once. With a trusted engineering and design team that can be on site in your place, as needed, you can also turn to outsourced service when your own bandwidth is constrained.
The site survey is an intimate and high-touch activity that is supremely important for overall project success. All the information, requirements, and other pieces of the installation process fall out of the original site survey. Site surveys make or break sales verification, discovery, data acquisition and analysis, and the entire project plan.
The problem with doing a site survey alone
You make decisions efficiently when the project host, the contractor, and an independent engineer are on site together. Instead of passing questions and answers back and forth remotely, with expected delays and potential for miscommunication every step of the way, we can all walk it through and talk it through at one time, in one place, and make decisions accordingly.
It’s not easy to select conduit paths and construction means and methods within project engineering constraints. But when you weigh the options on site, you flush out the best ideas to draft and the details to check and verify in a feasibility assessment.
Site survey is a collaborative process. You get a limited analysis when one party performs a site survey alone.
Project planning is complex. The site survey can address many of the challenges that emerge through development and construction, including
- Operational constraints of the host during and after construction
- Labor constraints from workplace safety authorities, such as Cal/OSHA
- Facility
- Site
- Roof penetrations
- Unnecessary liabilities
The goal of a recent site survey that SepiSolar performed at the office of an industrial services company in Northern California goes well beyond obtaining engineering requirements. We captured details for a structural engineer to determine whether the structure can handle the additional load of a rooftop solar project. We compiled photos and information for potential paths of conduit and appropriate electrical switchgear and infrastructure. And we delivered findings to the contractor, along with a property report showing highly accurate building dimensions.
Expected outcomes from a good site survey
Thorough project planning consists of far more than engineering feasibility. It includes sales verification, discovery, and data acquisition and analysis.
Sales verification
The site survey is the first line of defense for testing and verifying expectations set in the sales process. Why wait when you can get a technical expert involved to resolve problems before they cost money?
Whoever does the site survey should be familiar with the entire construction process. This will help prevent the ‘snowball effect’ that happens in poorly managed construction projects.
Think about real estate. Often, salespeople and developers overestimate the space available for a project. Why? They’re not looking at fire setbacks, property setbacks, shading obstructions from parapet walls or HVAC units, and other nuanced bits of technical detail.
Another commonly missed detail is the run of conduit, giving rise to a host of questions that only an experienced project engineer would ask.
- Should conduit go inside the wall or outside?
- How does conduit affect aesthetics? And wall fire ratings and sealing?
- If conduit goes underground, should there be trenching or boring?
- Are there cheaper or better ways to run the conduit with fewer penetrations into / out of the building?
We’ve seen deals where 20-30 percent of the entire job is in the conduit run.
Think about a solar project on a six-story roof. You can’t run conduit outside the building because of aesthetics and bay windows that run ceiling to floor. So conduit must find its way down six floors and a basement or a parking garage.
This is no small conduit, either. We’re talking 2- to 2.5-inch tubes. Each requires fireproofing and sealing when penetrating fire-rated walls. Some go through crawl spaces or cavities in the ceilings and floors. There are lots of holes to drill and interior surfaces to open and close back up.
What is the best time and place to evaluate and discuss options? The site survey.
Discovery
Site surveys are inherently part of the discovery process.
Everyone has had that horrific experience when someone misses one detail, just one, causing immeasurable problems downstream. Often by surprise.
An independent engineering and design firm has to think about permitting requirements, site constraints, equipment specs, design strategies, construction means and methods, and more. All these facets work their way into the process anyway. Professional assistance can help you address them during the site survey.
We know a contractor that always conducts site surveys on its own to save cost. On one project at an agriculture facility, the contractor read “208 delta” on the nameplate of the panelboard and noted it in the site survey.
After construction, the inverters wouldn’t fire up. Input voltage was too high. To make matters worse, PG&E had to upgrade the transformer to accommodate the energy expected to backfeed to the grid. The utility crew installed the new transformer to the specification on the panelboard.
The entire site lost power. The site owner brought in backup generators to keep the business running. PG&E had to replace the transformer again, at the customer’s expense. The contractor also swapped out inverters. And we essentially redesigned the project post-construction. It was very expensive. Liabilities and losses continue to emerge. All because the site survey said “208” instead of “240.”
Measuring on-site voltage at the main service panel, a 5- to 10-minute process, would have solved the problems before they began.
Data acquisition and analysis
Yes, data acquisition is important. But it’s not just about grabbing data points. It’s about grabbing the right data points. And all the data points. It’s good to be accurate, precise, and comprehensive.
Engineers need to think comprehensively because plans are inherently meant to communicate the entire project’s construction to permitting officials, utility officials, and construction teams.
When we see a building’s architectural plans during discovery, we ask for the as-builts. We all know what gets built isn’t always the same as the design.
Hunting for as-built plans is a process itself. We try the owner first. Then the construction company that finished the work. If neither has them, we dig them up from city records (sometimes in microfiche, in the basement), scan them (sometimes with a large-format scanner), and work to decipher them for assistance in the design phase.
One overlooked detail is data exchange. All the tools we now have to exchange data—email, Box.com, Dropbox, FTP, SepiSolar portal, SMS—are great. But they can lead to failures.
Communication transmits and receives information. Many times we receive information through three or more communication channels, all for the same project. Letters and packages get lost in the mail. We’ve all tried to view information online and found access is denied. All these little exchanges are failure points, opportunities for good, hard-earned data to get lost or misplaced.
Sidestep these risks by having an engineer on-site to directly grab details.
Walk away with a sound project plan
The best outcome of a site survey is to walk away with a plan. After the site survey, there will be details to verify and research. But the overall plan should be sound. A sound plan needs consensus from the design, construction, and ownership teams.
It is very efficient to have all stakeholders together at the job site, developing a plan to execute most advantageously.
Download SepiSolar’s site survey checklists for C&I projects, energy storage projects, and residential projects. Or contact our technical sales team to find out how SepiSolar engineers can add value to your next site survey.
