"It's where cool meets convenience. And urban living convenes with the outdoors. Green living meets gorgeous." These are the marketing taglines employed by The Arbors at Baltimore Crossroads, a 365-unit, luxury market-rate rental apartment community that opened in November 2011.
The Arbors is the residential component of Baltimore Crossroads @95, a mixed-use development with the capacity to support more than six million square feet of commercial office, flex, research and development, and warehouse space—including several hotels and retail villages. More than 10,000 employees are expected to work in the Crossroads project upon final completion.
The apartment home community, which is located in the White Marsh section of Baltimore County, just 10 miles north of Baltimore City, was designed with LEED Gold certification in mind. The project's developer, Somerset Construction Company, put sustainability at the top of its specification list.
"One of our main goals in the design of The Arbors at Baltimore Crossroads was to examine every aspect of its construction and determine innovative ways to i incorporate sustainability across the board, as technology allows," explains Somerset's Chief Operating Officer Neil Greenberg.
LEED elements integrated into the project include extensive solar energy generation, energy-efficient HVAC and hot water systems combined with low-flow plumbing fixtures and ENERGY STAR appliances designed to significantly reduce monthly water, gas and electric bills. In addition, air filtration systems and the use of low-VOC paints and carpeting will create healthier indoor environments. Approximately 98 percent of the project's lighting consists of light-emitting diodes (LED) and compact fluorescent lamps (CFL).
The Arbors at Baltimore Crossroads was designed in a "Texas Doughnut" configuration which consists of apartment homes built around a parking garage that allows residents to park and live on the same level of the building. Approximately 23 different apartment designs are available in single-, two- and three-bedroom formats at varying price points, including homes with dens, lofts and balconies.
HVAC and Plumbing - What 'Wood' Be Best?
When the M/E/P design team began working on The Arbors at Baltimore Crossroads, several challenges arose. Central to the challenges was the fact that the buildings were all wood framed.
According to Richard Grier, owner of Krick Plumbing, which served as the project's M/E/P contractor, Somerset Construction specified a hydronic heating and cooling system as opposed to a split, forced-air system. "But hydronic systems and wood buildings don't generally mix very well together because it's tough to route the pipe through the building," he explains.
"We're a commercial contractor, and we do very few wood-frame jobs. When you have fitters who aren't used to working with those materials, it can create a dangerous situation. For instance, when erecting the mains with big steel or copper, you have an open flame literally inches from the wood, and there exists a strong possibility for fires," Grier says.
Coincidentally, Grier had recently been introduced to Aquatherm's polypropylenerandom (PP-R) pipe systems by the German pipe company's manufacturer's rep, N.H. Yates Co. Inc. Yates' Peter FitzGerald had explained that Aquatherm is relatively new to North America, but it has been used in PHVAC applications in more than 70 countries for nearly four decades.
The product has proven to be corrosion-proof, chemically inert and durable—and most importantly for this project—connected via heat fusion. The heat fusion process, used to connect the pipe and fittings, involves no flame and is virtually leak-proof.
Grier began researching whether PP-R was a fit for the company and the Arbors project and, in spring 2010, he spent a day and a half touring a jobsite in Texas to see Aquatherm in action. "I was able to watch how the product was utilized on an active jobsite and see how the mechanical contractor was putting it together. Most importantly, I experienced how easy the installation process was, as well as its positive and negative points."
Insurance and Downsizing
He returned to Maryland confident the Aquatherm system would work well at the Arbors despite the large scope of the project. When he presented Somerset executives with Aquatherm, they weren't particularly fond of being "guinea pigs."
Grier explained to Somerset Construction officials that, due to the pipe's flow rates, the buildings' pipe systems could be resized and allow the pipe to be installed without altering the ceiling height and walls. "That was significant. By using Aquatherm, we were able to downsize pipe and reduce insulation with a smaller diameter footprint throughout the building. With steel and copper, you start out with, in typical installations, a 6-inch pipe. Once you insulate it, the result is a 9-inch pipe," Grier recalls. Somerset also liked the environmental benefits of Aquatherm and its lighter weight, and Aquatherm was specified for both the heat and chilled water mains and for the domestic water supply.
The Somerset Construction officials were impressed, and Yates and Aquatherm conducted an initial factory-training session at the Krick shop for approximately 30 installers followed by an onsite follow-up training for the remainder of the Arbors crew.
"The onsite training replicated a field experience. The installers were able to put pipe up and see it work. Some experienced trouble the first few times, but on average, they emerged knowing they could handle the situation. We had very little problem with the installation," Grier adds.
Krick made a sizeable investment in the Aquatherm fusionwelding equipment, purchasing several handheld welding irons and jigs (used for up to 4-inch) and butt fusion units (for up to 6-inch connections), and utilized at least a half-dozen crews running at all times.
Initially Hesitant Crews Won Over
The Krick crew was a bit apprehensive of fusing PP-R at first. "But once they went through the training and got out in the field, they'll tell you now they'd rather use that than anything else," says Grier. "This job was supposed to be an 18-month job but was completed in 12 months, so they really accelerated the job. A few old timers still gripe but, as a whole, the average guy embraced its use." Grier adds that the crews made superb time with the 2-inch and smaller fusion connections, although the larger sizes were a little slower, "As the guys learned how to make the jig work faster, the production picked up."
Making connections at the 10-12 foot ceiling meant that the installers did a portion of the prefabrication on the ground and at the shop. They also created a platform to place the welding jig and managed to create other efficiencies.
"With Aquatherm, the more you can complete on the ground, the more efficient the job becomes. We would place 50-60 foot lengths of various sizes of Aquatherm with four sets of mains (2-inch to 3-inch supply return and hot and chilled supply lines) using a high jack lift, which allowed us to lift it up and place it in the rack with the connections ready to roll. The result was dramatically increased production," Grier says.
He recounted that if they had tried doing that with steel, they would have had to use a forklift instead of standard high jack lifts. With 6-inch pipe sizes they did the same thing, but put the Aquatherm up in 20-foot sections.
Aquatherm Greenpipe was used for all the domestic water, with the hot water version featuring a faser-composite layer to reduce thermal expansion. Climatherm, which is designed specifically for HVAC applications, was used for the hot and chilled water lines. The optional faser layer allows the pipe to reduce thermal expansion by up to 75 percent compared to other plastics, and withstand constant temperatures up to 180 F at 100 psi.
While Aquatherm was used throughout most of the domestic and HVAC systems, including the mains, laterals and risers, the main mechanical room was done in steel per the owner's specifications, and CPVC was used for the .5-inch water supply in the apartments.
Grier said ownership liked the fact that if the PP-R were to catch fire, it would produce no toxins—just vapor—and that thieves were unlikely to steal PP-R pipe, as copper theft from jobsites is a common occurrence nationwide.
Additionally, the installation of Aquatherm realized labor time savings, Grier says. "With this being our first job, we did not see significant savings because of the learning curve. But, we do visualize labor savings in the future now that my workers are comfortable with the material and familiar with it."
In fact, Krick is now installing 12-inch Aquatherm on another large project, and Somerset is looking to use the product on a similar project.