Prefab boosts efficiency, accuracy, ergonomics
It took nearly nine months of planning (sometimes penciled out on barroom napkins), another year of setup and testing, a substantial real estate investment and countless hours of consultations with skilled tradesmen, superintendents and BIM experts. But project managers at Denver-Elek say their company’s decision to branch into prefabrication this year is already generating benefits.
Opportunities to engage in prefabrication, off-site assembly and modular construction have intrigued and daunted construction industry leaders in recent years. While prefabrication can increase efficiency, ease construction-site challenges and even create new business opportunities, it also requires contractors to develop and execute new processes for completing their core work. So we asked two BC&E members, who have launched prefabrication operations in recent months, about the requirements, challenges, benefits and surprises of branching into prefab.
“Everything looks a lot simpler on a bar napkin,” said Steven Elek, a Denver-Elek Project Manager.
Elek and fellow Project Manager Scott Dougherty began hashing out plans to create a ‘fab shop’ at Denver-Elek, a full-service mechanical contractor, after learning about prefabrication processes through industry conferences, online research and site visits to other companies. That research convinced Elek and Dougherty that prefabrication of piping and support systems for plumbing and HVAC installations and even entire bathroom assemblies could help the company better cope with accelerated project schedules and tight site conditions.
“A general contractor could be building a bathroom floor while we are building carrier assemblies and prefabbing the total system in our shop so that we can set it in place the day he is ready for it,”
Dougherty said.“It also minimizes our impact on the job site because we wouldn’t need as much laydown space and we don’t need to send as many guys there.”
Creating a prefab shop required a significant physical expansion: 4,000 square feet of interior space to store raw material, fabricate product, perform quality control checks, and prepare parts for shipping; and another 4,000 square feet of exterior space for a laydown yard and shipping/ transportation area.
“We started off almost like a science lab,” Elek said. An open floor plan and mobile equipment enabled Denver-Elek staff to alter the prefab shop’s configuration to meet individual project needs and improve efficiencies.
To determine how to tailor prefab services to individual projects, the company conducts extensive preconstruction talks among project managers and the tradespeople who“handle every nut and bolt,” Dougherty said. The perspective of field staff is essential to understanding site conditions, challenges to delivering equipment, and ensuring“the prefabricated assemblies will not be a bear to move on site.”
A similar desire to speed installation and minimize construction- site problems prompted Bunting Door and Hardware to establish a preassembly shop and service this year.
“Even though doors and hardware are a very small part of most projects, they are the source of many problems,” said Frank Gunther, Chief Marketing Officer. “Our work happens at the end of the job which gets rushed. Also, one door assembly might have parts from seven different manufacturers.”
That means drywall or millwork contractors, who complete door installations on most projects, “have to go through all the boxes and pull out the proper hinges, the proper locks and other hardware,” said Doug McGinnis, Bunting’s CEO. “That takes time, and on a job site, it’s common for people to drop things, lose things, mix things up.”
Then there are the projects, like new warehouse construction, where there isn’t a drywall/millwork contractor to complete those installations. Bunting’s work on a few warehouse projects prompted its installers to start experimenting with preassembling door hardware in the shop.
“We had a crew of six people install 28 doors in one day because they were preassembled,” Gunther said.“So that process became the norm for those projects, and we have done 11 of them now.”
Based on those trials plus encounters with door companies across the country that have preassembly shops, Bunting added a mezzanine to its warehouse and began offering preassembly services.
In addition to increasing speed and reducing errors in door installations, the service is providing another benefit to general contractors, namely a sharp reduction in construction site trash. All the cardboard, plastic wrapping, boxes and padding that surround doors and hardware land in Bunting’s recycling bins rather than piling up on job sites.
Prefabrication is also generating in-house benefits.
The preassembly process has increased efficiency in Bunting’s warehouse by enabling workers to spend small amounts of free time assembling doors.
Both Bunting and Denver-Elek have discovered that prefab also creates better conditions for workers.
“To install a kick plate on a door on site, you have to be down on your knees predrilling 16 holes and adding 16 screws. That would kill me,” Gunther said. “Place that door horizontal on sawhorses in the shop and that process is much easier on everyone’s knees.”
“Safety and ergonomics is huge in our fab shop,” Elek said.“We have hydraulic tables that we can raise and lower, so we’re doing everything right at belly button level.”
Both companies are working on scattered challenges as they seek to improve and expand their prefab operations.
Shipping preassembled product has posed the biggest challenges to Bunting Door. Staff have been refining packaging to prevent any damage during transportation and adjusting to new transportation needs.
“Instead of having a truck with 20 doors on a pallet, you’re sending out a truck with seven preassembled, packaged doors on a pallet,”Gunther said.
At Denver-Elek, the solutions are often boiling down to “you need a bigger boat.”
“If you’re packing things up that are 22 feet long and your truck is only 18 feet long, that can pose a problem,” Dougherty said.
Operating on schedule when other parts of a project run behind can also create an equipment shortfall. One large, delayed project has tied up many of Denver-Elek’s carts and prompted discussions about acquiring more equipment.