When you think of prefabrication, do you think it can only be done for MC cable and Romex assemblies? Think again! We received two separate requests from foreman to pre-fab pipe assemblies. The first request came from our Hagle Hall job. The second was from our foreman in charge of the Logansport Intermediate School project.
For Hagle Hall, our Pre-Construction Services Engineer, Eric, took every device room by room and created a build sheet for it based on our pre-fab SOP (standard operating procedure). He gave each assembly a device type, raceway type, a circuit number, quantity, and to the request of the foreman for the job, Adam Robbins, marked whether it had an offset.
Adam came to prefab asking for an offset on the pipe assemblies to gain access to the device in the wall from above the ceiling. A simple 3-1/2” offset near the top end of the assembly was all that was needed. This building also had window pockets around the entire exterior of the building. Instead of an offset there, we gave Adam a 90-degree bend above the window pocket and out 3’ to be able to access the device. Both assembly types were made with wire already in the conduit sticking out 16” to 24” so the field install only consisted of mounting the device box at the correct height, securing the conduit inside the wall, mounting a junction box to the other end of the conduit, and connecting the wires from the power source.
We could have easily put a 10’ stick of conduit and been done with it but we wanted to expand the potential of what we can do in pre-fab shop As you may recall from the last Pre-Fab Blog, BIM coordination was completed on this job so we took the pre-fab one step further. We flew through the coordinated 3D model of the building and looked above the ceiling of every single device. If there was an HVAC duct, fire main, plumbing lines, etc. up against the wall above a device, we measured from the top of the device box to the item in the way and marked the build sheet with enough conduit to get either above or below the obstruction based on how close to the ceiling it was. This greatly helped in the area above the “World’s Largest Drum Display” where the ceilings were 20’+ with massive windows and very little space to access the required power devices down low.
As for Logansport Intermediate School, the foreman, Avery Zink, requested pipe assemblies with 4-11/16 boxes with extension rings above the ceiling to gain access to those devices. We had several different device types for this job which included the typical power assembly, power/data Assembly, data only, wireless access points, and projector locations.
New to the pre-fab shop were the wireless access points and the projector locations. The wireless access points (WAP) are a simple T-bar ceiling grid hanger bracket with a 4SQ electrical box. The most challenging component was the projector assembly which required a more complex assembly. The specification for the assembly was a 4SQ box for the power with two duplex receptacles on the same bracket as a 5SQ box for the data portion. If you do some research for a bracket that holds both, you will find there is not a lot of options. In Pre-Fab we are fond of the typical adjustable spanner bracket but being as the two different boxes are separate depths this would not work. So, we found a three hole bracket that fit both boxes, we put the power on one side, the data on the other side using a 5SQ and a two gang mud ring with 2, 1-1/4” conduit stubs out of the top of the box. All the electrician in the field must do is mount the bracket to the studs at the correct height and run the data cables. A very simple and clean install.
Copyright Huston 2015