Roof-Wrenches, You might look into getting a roofer's lift-bed truck. This isn't a panacea, but it's great on most resi applications where you can get close to the building. If you're a real slave driver, you can put a porta-john on the bed and make sure your roof-crew never gets off the roof until it's time to go home! For commercial scale rooftops, you're gonna need to buy or rent an extended-reach forklift (Gradeall, Lull, Gehl, whatever). Weight capacity & boom length dependent on project.
If a lift-bed truck isn't in the cards and it's not a low, single-story roof, I always use a crane. The professional kind. As in, you schedule them to meet you at the job, they show up, lift your gear, and leave. $100-300 depending on the size of the crane, time on job, and distance to job. Make friends with your local crane company(ies). Find out who the HVAC guys use to lift their equipment and go talk to them. That's the outfit you want. You will need to talk with them to find out their pricing and setup limitations... Slopes, clearances, boom lengths & angles vs. capacity, etc. (PV is way lighter than package HVAC units) You will need to make sure your site survey and price includes consideration for the crane. Not a big deal. The way I see it, the reduced fatigue is worth a whole lot of extra productivity later in the day. It also cuts down deployments per project since your total "truck to roof" time is cut to 20 minutes or less in most cases. Less chance of damage to modules. Reduces trips across roof which minimizes wear and tear on the roof. The most undervalued savings is in safety. Transporting modules and equipment to the roof is arguably one of the most dangerous parts of the job. Any time you can minimize risk and gain extra benefits, it's a no-brainer. Just do it! If you pre-panelize in the shop, then use glazer's lifting suction cups to fly 3 or 4-module panels one at a time. McMaster-Carr Part #53615A13. Catalog page 1458. http://www.mcmaster.com/#suction-cups/=35r4ht You need to buy 5 lifting cups for each crew. 4 to use for lifting each panel. The 5th is your backup. Fly each panel straight into place on your standoffs. Two guys on the roof bolt 'er down while the crane is swinging back to get the next one. The guy on the truck does the stick and go. Average about 2 to 2-1/2 minutes per cycle. If you're flying glass to the blind side of the roof, you will need a signal guy at the ridge to guide the operator. The truck/ground guy can climb up and do this job if need be. Once you've done it this way, you'll never go back to 1-module at a time. This method saves a bunch of broken tiles on tile jobs compared to walking all over carrying extra weight. (Note about the suction cups: Always buy the spare suction cup! The one time a cup failed we were glad to have the spare! Make sure your guys don't "pound" the piston with the side of their fist to pump the cup! There is a plastic rod inside that doesn't like being pounded on.) If you install the traditional way, 1 module at a time, you'll need to build some "ridge-tables" to land stacks of stuff on. If you're organized, two guys can have 4kW of racking and modules on the roof in 5 minutes. 3 lifts. Safely. Ridge-table is the name I gave to the platforms I built for this purpose. Basically, they are heavy-duty tables that span the ridge with adjustable, fold-out legs on either end. The legs have a cross-member that sits on the roof surface and spans at least two rafters/trusses/joists. You will need to strategically place the tables so they aren't in your way while you're installing. Same principle as "not painting yourself into a corner". I built my originals out of wood. They were heavy and bulky, but they were reliable and we installed thousands of modules using them. (Before moving to pre-panelization) If anybody wants a sketch, give me a holler off-list. (Note: May or may not be compatible with your metal roof. Must remove section of tile where cross-member sits on roof for tile jobs) Funny thing about using cranes... People don't think of them for PV. I come from the HVAC industry originally. Flying equipment with cranes, and sometimes choppers, was normal to me. Been doing it since I was a kid. Bob-O thinks I'm still a kid, but that's another topic. ;) When I stumbled into this solar gig, I worked for Dave Metcalf @ UPG. He thought I was crazy to want to use a crane. Couldn't imagine it being a money-saver. Had to see it for himself. I called up the crane company I'd used for 15 years. They showed up, lifted 5 pallets of glass in less than 10 minutes and left. Dave was pretty much sold from that point on. (For those of you who remember, this was the project with the Bell-box cover screw that pierced the wire nut and took so long to find. Use your Megger or megger-like device! "Megger is a registered trademark...") When we got to the point where we were switching to more conventional modules, we wanted to pre-panelize. We had the roofer's lift-truck by then, but knew from experience that the benefits of using a crane outweighed dragging 200# panels very far across a roof. If we could backup close to the array location, then we would hand-carry, of course. This is when the suction cups came in. I knew about them from working with a friend doing skylight work. I looked at it this way, What are we dealing with? Big pieces of glass. What do glass guys use? These suction cups. They worked like a charm. Gives your guys a safe way to handle and position panels as well as lifting attachment points. When I moved over to working "at" SMUD, instead of "for" SMUD, I had to train and manage installation contractors. When we did the training, I had my crane company of choice come out. The contractors were skeptical... Until they actually did it. Changed their lives. Flying glass. It's the only way to go! A couple years ago, one of my crews had only done pre-panelized jobs for 3 or 4 years. Then we had a job where it had to be stick-built... Lead-guy threatened to quit if he ever had to do another one like that. The whole crew moaned and groaned. I told them that's how most "solar installers" do it every day and that they should be grateful. They didn't see how anybody would ever do it that way on purpose when pre-panelization is so smooth. One thing they all mentioned was how difficult it is to police the wiring beneath the array very well. They were used to having everything all tidied up and ready to go when it lands on the roof. 4 bolts, 2 MC connectors, and 1 or 2 grounding jumper connections per 4-module panel. If you are using 3 or more installers on a job and you have some shop or secure yard space, you should look at doing pre-panelization when you can. I'd be happy to outline the design, logistics, and installation considerations for anybody that wants to take a look at this methodology. In general, it is best applied when you are using the same type of modules and racking over and over. Your own "kit" if you will. At least in the beginning. This gives your team (survey, design, installation) the chance to streamline the process. Once you've got the key pieces worked out, applying the process to a different module type isn't a big deal. Happy lifting! Matt Lafferty _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
