Planning multifamily dwellings

Engineers know these multifamily structures are more than just simply boxes to keep human beings in. They’re as complex and varied as the people inside.

By Consulting-Specifying Engineer May 22, 2019


Kris Cotharn, PE, LEED AP 

Client Executive 

IMEG Corp. 

Madison, Wisconsin 


Wayne Griswold, PE, CFPS 

Principal Fire Protection Engineer 




Randall V. Moss, P.E., LEED AP 


RTM Engineering Consultants 

Irvine, California 


Joseph Russo, PE, LEED AP BD+C 

Senior Engineer 

Kohler Ronan 

Danbury, Connecticut 


Rafi W. Wartan, PE, LEED AP BD+C, CQM-C 

Regional Director/Principal 

TLC Engineering Solutions 

Jacksonville, Florida 

CSE: What’s the biggest trend in multifamily dwelling projects? 

Kris CotharnWe see a high demand for multiple support spaces or activities within a complex. Providing a complete environment for the residents is important. I’d say this trend applies to both higher education and independent/senior living settings. Residents want convenience and variety to enhance their experience. This provides an interesting challenge on the engineering side to provide system infrastructure to support the needs of not just the dwelling unit but the whole environment for the community within the complex. 

Wayne Griswold: In recent years, the use of Type I construction as the foundation/podium with Type V construction above. This construction methodology gives designers and contractors flexibility when determining allowable area, height and use restrictions. The  use of Type V construction above the podium gives builders flexibility as inherently wood construction is easier to work with. It also reduces the need for longer lead construction items such as steel, which has become both more expensive and more difficult to obtain in the market.  

Randall V. MossThe biggest trend we’ve seen in multifamily dwelling projects is the introduction of smart home technology into the living units. This technology allows residents to control climate, access and lighting remotely via smartphone applications. The residents can also bring in their own digital assistants, like Google Home and Amazon Echo. It also helps the building managers to control devices across the apartment community, saving time and costs. 

Joseph Russo: We’re seeing a couple of things: 

  • Incorporating spaces similar to communal living spaces, meeting rooms, cafes, theaters and natatoriums, almost mirroring a resort style living is the biggest trend we are seeing in multifamily dwelling projects.  
  • Flexibility of mechanical, electrical and plumbing systems and resident room unit types that allow for seamless integration of independent living, assisted living and skilled nursing seems to be where the industry is going. Senior care facilities on recent projects have included all three space types listed above. On these projects, incorporating smaller, shared community and household living and dining areas in lieu of centralized gathering dining areas required the MEP systems design to be more localized.

Rafi W. WartanI’m not sure if I would call it a trend, but in 2017 Hurricane Irma caused loss of power in a nursing home in south Florida that led to the death of 8 residents. After this incident, the Florida governor issued a Rule (58A-5.036) requiring all nursing homes and assisted living centers to provide emergency power to serve the heating, ventilation and air conditioning equipment to maintain the maximum of 81 F. The ruling has forced a change in the way HVAC and electrical systems are being designed in new facilities. It also has forced existing facilities to modify their existing systems to comply with the rule. 

CSE: What trends do you think are on the horizon for multifamily dwellings? 

MossI see continued incorporation and expansion of smart home technology to improve residents’ and building managers’ control of lighting, HVAC and power systems, as well as access control, saving them time and money. 

RussoOn the horizon, we see modular construction and prefabricated MEP systems being used to save construction cost and time. The use of modular and prefabricated systems allows the construction and infrastructure to be built in a controlled environment and reduces the amount of labor required in the field. 

Griswold: With green construction on the rise, the use of integrated energy storage systems is a trend I see growing for multifamily buildings. This trend is twofold as green energy helps reduce overall project carbon footprint and the cost associated with solar and lithium-ion batteries has dropped.  

CSE: Each type of project presents unique challenges  what types of challenges do you encounter for multifamily dwelling projects that you might not face on other types of structures? 

Griswold: Whenever various construction types are used (i.e., Type I vs Type V), we generally see confusion regarding firestopping and fireproofing and which assemblies apply to which locations. In many cases, the assemblies are installed with a carte blanche approach, not realizing that fire-rated assemblies are often specific to the construction type in which they are installed. In these instances, we become involved either as a third-party special inspector per IBC Chapter 17 or conduct an engineering judgment to determine the applicability of the installed assembly.  

CotharnConstructing for a home environment within a commercial setting is a challenge. This means not just one of something, such as laundry, kitchen, etc., but hundreds of such spaces. The infrastructure required to support these spaces grows well beyond residential-level support when you start adding this number of units or residents. The complexity of these environments also is seen in the economics of vertical stacking and high-rise support of systems like plumbing, fire protection and vertical transportation. We often find ourselves working closely with local authorities to discuss how to approach these challenges and address occupant safety related to building operations and functions.

RussoMultifamily dwellings typically require independent utilities and metering. This requires additional program space for MEP equipment and distribution. In buildings that incorporate residential living areas, retail, fitness centers and natatoriums, the challenge is that the buildings require both residential and commercial-style MEP systems. 

MossThe electrical distribution from the main electrical service to the dwelling units, as well as to the house electrical loads, is the main challenge for multifamily dwellings. The buildings are large and spread out, so the problem is to get the power where it is needed, using the least amount of building floor space and yet accommodating code required voltage drop limitations. It is a process to coordinate with the architects and space planners for remote meter rooms closer to the loads, ensuring compliance with utility requirements and complying with the electrical code. 

CSE: What are engineers doing to ensure multifamily dwellings meet challenges associated with emerging technologies? 

RussoThe biggest challenge with emerging technologies in multifamily dwellings is to anticipate the future system requirements and to provide the infrastructure to allow the flexibility to adapt to the new technologies. When it comes to technology, in most residential environments, we typically provide the infrastructure for the chosen internet service provider’s equipment and the cables from that location to the TV, computers and phone. One way we can solve the challenge associated with emerging technology is to offer the use of fiber to residential units instead of copper to support the future bandwidth requirements of such systems and the need to provide additional horizontal copper outlets to support pervasive Wi-Fi. 

MossAs far as emerging low-voltage technologies are concerned (highspeed data and communications cabling), we are designing “shadow” conduit distribution systems alongside of the normal low-voltage pathways to provide for future extensions of new content sources. Additionally, each apartment is being provided with an apartment distribution frame box, to enable the addition of new technologies within the dwelling units. 

Griswold: The best thing an engineer can do is to get involved early in the process. While this is reliant on the owner of the dwelling, early intervention is beneficial to all parties, as it provides the engineer the time to address any emerging technologies as they come on board the project. Conversely, it gives the project owner feedback if the technology may impact other portions of the facility that may not have been originally intended.  

CSE: Tell us about a recent project you’ve worked on that’s innovative, large-scale or otherwise noteworthy.  

Russo: Located in Williamstown, Massachusetts, the Williams College Residence Hall for the Center for Development Economics was designed to meet the Net-Zero Energy Petal of the Living Building Challenge. The 17,000square-foot building is served by allelectric MEP systems to eliminate the reliance on fossil fuels as well as being independent of the central campus heating plant. The annual photovoltaic system generation was optimized to offset the total annual site energy consumption of the building, including heating and cooling equipment, lighting, elevators and domestic hot water heating. The MEP systems were coordinated with the energy analysis completed by the sustainability consultant early in the concept phase of design through the completion of construction documents. The building massing orientation and envelope were optimized through coordination with the architect and sustainability consultant. The MEP systems include ground source heat pumps, four-pipe valance units, a centralized dedicated outside air unit, LED lighting and electric water heaters. 

Cotharn: We are currently working on the Maine Veterans’ Homes project under construction in Augusta, Maine, a 138-resident senior living facility designed in the small house environment model. This means building a facility to house 138 residents, staff and visitors in a one- or two-occupancy setting while maintaining a home environment. This home environment includes a restaurant, bistro, movie theater, salon and medical support for the residents. Providing an MEP system that was integrated with the facility and the aesthetics while providing the robust support for the complexity of spaces was a challenge. Several systems were evaluated and a heat pump system was selected due to the energy efficiency, maintainability and local zoning capacity to fit within the framework of the building. 

CSE: How are engineers designing such projects to keep costs down while offering appealing features, complying with relevant codes and meeting client needs? 

CotharnBeing involved early is key to having an impact on minimizing firstcost. We can help identify infrastructure needs and how best to locate these systems (in behind-the-scene spaces) to minimize first cost in distribution. Evaluating system options early in the process is also vital to the success of a project. Helping an owner understand the long-term cost of operating a system as well as the expected longevity is all part of the cost evaluation. 

MossMultifamily buildings are being designed with higher seasonal energy-efficiency ratio rated HVAC systems, energyefficient LED lighting and integrated lighting controls to be more efficient. Photovoltaic systems also are being employed to reduce the utility demands of these projects. 

RussoStandardization of equipment (reducing the amount of attic stock required), minimizing MEP distribution and selecting systems with localized controls allows us to keep the project within budget while providing systems that meet the current codes and the client’s needs. Multifamily dwellings typically require a combination of commercial and residential equipment; therefore, carefully designing systems and selecting equipment that is costeffective and allows ease of system use for the client is advantageous to the project. 

GriswoldDesigners and engineers are more cognizant than ever with building “feel” and the use of biophilia throughout the built environment. Buildings designs are moving toward more efficient use of energy, including U.S. Green Building Council LEED elements and methodologies. Combined with the use of wood construction, these features may not necessarily save money upfront, but have the benefit of reducing overall carbon dioxide emissions while also saving energy costs over the building life span. 

CSE: How has your team incorporated integrated project delivery or virtual design and construction into a project? Define the owner’s project requirements and how the entire team fulfilled them using these methods. 

RussoMost multifamily dwelling projects have incorporated IPD into the design, allowing the design team, construction team and owner to work as one team to make informed design decisions throughout the project and to provide a cohesive project and well-coordinated building. We see that a design process incorporating IPD results in projects that come in on budget during the bidding phase and experience less constructability issues during construction. 

CotharnHaving a team attitude from the beginning of a project helps to make the final delivery a success. Each member needs to explain – and help the other team members understand  the decisions that were made and the approach to the design; this is paramount for an IPD approach.  

From an owner’s perspective, VDC is a great tool to guide the decision process in design. Presenting material that more closely represents the end product helps the communication. We’ve used VDC to walk an owner through a space to communicate aesthetics as well as functionality of a space. Using VDC to set the standards of a space  such as a dwelling unit that will be repeated throughout a facility  improves the efficiency of not just the design team but the construction side as well. We’ve found it just as powerful as a mock-up but requiring less time and at lower cost to the owner. 

CSE: How are multifamily buildings being designed to be more energy-efficient 

Russo: Multifamily buildings are being designed to be more energy-efficient by incorporating LED lighting, point of use and instantaneous water heaters, passive systems (envelope), electric heat pump systems and less reliance on fossil fuels. 

CSE: What is the biggest challenge you come across when designing multifamily projects? 

RussoMultifamily projects often include various program spaces, requiring multiple and differing system types. These systems can include commercial kitchen design, dedicated HVAC units serving natatoriums, residential-style HVAC systems and large domestic hot water demands all under a single project. Effective and frequent communication within the team is vital to the success of such projects. Regarding multifamily projects consisting of standard apartments, resident rooms or dorm rooms, small design changes, including architectural and structural changes, have a huge impact on the design and coordination of the MEP systems due to the repetitive nature of typical unit types within these types of projects. 

MossThe biggest challenge we have is getting architects and owners to provide remote meter rooms sized and located in such a way as to bring the meters closer to the apartments they serve. When a sufficient number and size of remote meter rooms are provided, then we can design the most costeffective electrical distribution system for the project. 

CSE: With the increased need for assisted living facilities  or similar facilities that serve an aging population — what mechanical, electrical, plumbing, fire protection, lighting or other engineering trends are you seeing?  

CotharnWe see a wide variety of trends based on the level of care provided, which varies greatly. The first step is to identify the resident needs that a facility is willing to support. One of the biggest trends and impacts we see for these facilities is with the lighting. Supporting the aging eye with light levels is important for the comfort and functionality of residents within these facilities. The use of tunable white technology, which allows the color temperature of lighting to be adjusted throughout the day, helps improve the health of residents within assisted living facilities as well as staff who are present 24/7 within these environments. Technology  such as the integration of controls and communication for residents and staff  also is an increasing demand. This includes everything from ordering dinner on a touchpad to sending notifications for emergency care. 

RussoFlexibility of MEP systems and resident room unit types that allow for seamless integration of independent living, assisted living and skilled nursing seem to be where the industry is going. Senior care facilities on recent projects have included all three space types listed. On these projects, incorporating smaller, shared community and household living and dining areas in lieu of centralized gathering dining areas required the MEP systems design to be more localized. This included MEP design for amenities such as residential kitchens with noncommercial kitchen exhaust hoods complying with NFPA 101: Life Safety Code and the electrical and technology infrastructure to support the health care requirements of the building in addition to the residents’ personal requirements.