Designing efficient office buildings with visual appeal
Office buildings can be highly complex, with complicated features and advanced technology. Experienced engineers share advice on how to handle these structures and identify trends impacting such structures now and in the future.
- Jason Gerke, Mechanical & Plumbing Group Manager, GRAEF, Milwaukee
- James Hansen, PE, BEMP, LEED AP, Principal and Senior Mechanical Engineer, GHT Ltd., Arlington, Va.
- Tyler Jensen, PE, LEED AP, Senior Associate, Environmental Systems Design, Inc. Chicago
- John Yoon, PE, LEED AP, Lead Electrical Engineer, McGuire Engineers Inc., Chicago.
CSE: What’s the biggest engineering trend you see today in office buildings?
Jason Gerke: Many of the projects we are currently designing include no or very open ceiling systems. This deviation from a more traditional lay-in ceiling system has caused us to rethink the layout of ductwork, locations of variable air volume (VAV) boxes, and potential HVAC breakout noise. While this is not an engineering-specific trend, it does require all of the building engineers to be more thoughtful in the design of their respective systems. Without ceilings, the layout of ductwork, piping, conduit, cable trays, and the building steel and concrete must have an aesthetically pleasing aspect to it, besides being functionally sufficient for the building. This is a trend that some engineers have an issue with because they do not feel it is their responsibility to create a design layout that works with the architect’s plan for the building’s visual appeal.
James Hansen: Providing tenants with a customizable building experience is becoming increasingly important, from an architectural and engineering standpoint. In the Washington, D.C., metropolitan-area office market, tenants are now taking ownership of their utility consumption, thoughtfully managing their waste streams, and demanding controllability in their building’s operations. Property owners and developers have responded to tenant demands by requesting that, we as engineers, design HVAC, lighting, and plumbing systems that can respond to unique tenant requirements. As one of the leading consulting engineers in Washington D.C.’s very active commercial real estate market, we are also responding to these demands by specifying systems that have monitoring, ongoing accountability, and increased controllability, as opposed to maximizing capacity and providing over-redundancy.
Tyler Jensen: The biggest trend I see is that clients are looking to use their office buildings to differentiate themselves and create a competitive advantage. Office buildings are no longer just a place to house employees, but a means to attract and retain top talent and increase employee productivity. Owners want office buildings that provide access to daylight and views, proper ventilation and thermal comfort, and a healthful environment for their employees. I also have seen more intelligent building systems employed that create a positive, interactive experience for employees, guests, and operators of office buildings. End users want to be able to use their smartphones for access-control credentials, to reserve amenity space, to modify light levels and temperature of their space, and to interface with their office building.
John Yoon: Not an "engineering" trend per se, but there are significant trends in corporate office design that can have a dramatic impact on the supporting mechanical, electrical, plumbing (MEP) systems that we specify. A major driving force in office design is a need to use space more efficiently. There is a real cost associated with that space and the resources needed to support the employees using it.
The elimination of a standard workstation in favor of bench-style seating allows significantly greater density and is commonplace in "tech" companies. "Hoteling," where employees aren’t permanently assigned desks or offices but rather move around on a day-to-day basis, also isn’t a new concept. It is regularly employed where a significant percentage of the workforce works remotely. Hoteling helps "rightsize" the quantity of workspaces to more closely match the actual need. Technology is enabling the hoteling concept to go to the next level. It is still standard practice to assign offices/workstations/benches to permanent employees who generally don’t work outside the office on a one-to-one basis.
However, in very large corporate environments, it is understood that there is always a certain percentage of the permanent workforce that isn’t in the office for whatever reason (sickness, vacation, etc.). Also, many employers recognize a need for flexible seating to accommodate grouping employees together on a temporary basis for certain projects. But there is always a level of uncertainty regarding how many workstations/offices are actually needed. To address these issues, we’re seeing the deployment of computerized "seat-management systems" that use statistical analysis of employee-attendance patterns and project staffing requirements to dynamically assign seating on a day-to-day basis and put more people in a smaller quantity of work areas.
The traditional diversities that are often factored into our MEP system designs for office buildings are quickly eroding. The combination of benching and automated hoteling concepts creates office spaces with unusually high population densities and little to no diversity. As such, the engineered factor of safety in our MEP systems has to be reconsidered for these types of office environments. This can be a challenge when renovating older office buildings in which the original engineers never anticipated this type of usage.
CSE: What trends and technology do you think are on the horizon for office building projects?
Yoon: Building owners are always looking for a way to gain a competitive edge and distinguish their property from the competition. For Class A, multitenant office buildings, the market for tenants remains unusually competitive and finding that special something to set a building apart is something of a holy grail. Unfortunately, this usually devolves into a "me too" attitude, where every building has to offer more or less the same feature set to attract new tenants. Often, there is minimal consideration as to the actual value of what’s being installed. For example, you would be amazed at how many fireplaces we’ve designed for new shared-tenant lounges just because another building had that particular feature. The office building market is cyclical, with major trends developing at intervals of roughly 5 to 10 years. Not surprisingly, this interval mirrors the lease terms for most tenant spaces.
In the dot.com era of the late 1990s to early 2000s, having extremely robust base-building MEP infrastructure with high levels of power and cooling capacity was that holy grail. Then, when the U.S. Green Council’s LEED v2009 was introduced, we saw a frenzy of LEED CS- and EB-certification activity to make buildings stand out from the pack. But eventually, after several years, the markets that we worked in reached saturation; it became more or less an expectation that Class A properties would already have LEED certification.
In the last year or two, the "next big thing" was to offer increased building amenities to prospective tenants. These shared amenities took the form of Wi-Fi lounges, party decks, fitness centers, restaurants, etc. However, it is expected that this too will quickly reach saturation—and may not be sustainable in the long term. The capital expense associated with constructing the supporting MEP infrastructure and the ongoing operational expenses (that may or may not be recoverable based on how the tenant leases are structured) are not insignificant. With the new norm being ever-increasing density in commercial office buildings, the primary question is when will we reach that critical threshold where it becomes detrimental to employee productivity? The expectation is that the next major trend will be a renewed emphasis on the health and well-being of building occupants to help offset this eventuality.
While the International WELL Building Institute (IWBI)’s WELL Building Standard is still in its infancy, it appears to foreshadow these next major MEP design trends. Expect to see increased requirements for indoor-air quality well beyond ASHRAE 62.1: Ventilation for Acceptable Indoor Air Quality, an emphasis on the quality of illumination, and numerous other criteria that are incorporated into the WELL Building Standard.
Hansen: We’re seeing the Washington D.C. market grow increasingly saturated with Class A office buildings. Energy efficiency is very important in our area. Ultimately, the office buildings that get (and stay leased) are the properties with highly efficient, customizable HVAC systems. Typically, the systems also have negligible aesthetic impact and low first costs for installation. We’re seeing variable refrigerant flow (VRF) systems satisfying these requirements for a variety of owner and project types.
Jensen: Forward-thinking owners will look beyond minimum energy code requirements and consider highly sustainable and even net zero energy office buildings. Net zero office buildings can create a powerful story around strong corporate values for employees and the public.
Gerke: There are so many networked communication systems in buildings today that it is surprising that companies have not developed a breakout technology that combines cabling systems. While some companies do offer project-development services to consolidate communication systems (ranging from HVAC controls to lighting controls and security/surveillance to servers), there is no one disruptive technology solution that has combined all these systems on a single cabling backbone linked to a single networked control system. Today’s solutions still include multiple controllers to individually handle most systems.
CSE: Tell us about a recent project you’ve worked on that’s innovative, large-scale, or otherwise noteworthy.
Hansen: GHT Ltd. is finishing an MEP design for the modernization of an existing 1 million-sq-ft office building in the Arlington, Va., area: Stafford Place. The scope includes a substantial retail addition to one corner of the building with an all-glass façade and upgrades to the existing retail storefronts. Our team of mechanical engineers and energy modelers has been collaborating closely with Arlington County code officials and the design team to specify a design that ensures the addition complies with ASHRAE 90.1-2010: Energy Standard for Buildings Except Low-Rise Residential Buildings.
Gerke: Our mechanical team recently completed the design and construction phases of a major building expansion at Milwaukee Electric Tool Co. in Brookfield, Wis. The design phase of this project was extremely aggressive and included the early onboarding of some of the subcontractors, specifically MEP trades. Our team also included the involvement of GRAEF low-voltage design staff for all telecommunication systems, fire alarms, and security/surveillance. This project presented a unique aesthetic goal for a new building to look industrial/under construction. The client, in this case, was a manufacturer of construction-related tools and wanted to showcase an environment of construction.
CSE: Have you designed any such projects using the integrated project delivery (IPD) method?
Jensen: I have used the IPD method for a Fortune 500 client designing net zero office buildings at a few different sites across the U.S. It has been valuable for the client, architect/engineer design team, and contractor to work together from the onset of the project. This collaborative approach allowed the project team to effectively balance the programming and aesthetic needs with the sustainability goals for the project. We were also able to take an iterative design approach and get timely budgetary feedback on various options. Since we were engaged early, we were able to run energy models to optimize the building massing and orientation and to advise passive-energy-reduction strategies. The IPD method is critical for designing high-performance and net zero office buildings.
Gerke: While our team has not been involved in a project specifically using an IPD contract, we have been involved in many projects that include the subcontractors early on. These projects include input from the general contractor or, typically, subcontractor early in the design phase, once we move into design development plans. Early involvement must start before plans and specifications move past the 15% or 20% phase in order to maximize the impact the early involvement will allow. Design teams need to be receptive to the involvement of contractors earlier in the design due to the fast pace of most projects and to minimize construction-phase questions and issues. Reducing construction issues will result in lower costs for the design team and will minimize the risk of having any claims during construction.
Hansen: GHT Ltd is close to completion of the 2112 Pennsylvania Ave. project in Washington, D.C. This project used several IPD methods including working with a design-build mechanical contractor in the earliest stages of design under a "design-assist" application with the owner, Skanska USA, who also happened to be the general contractor. Working within the owner’s budget, our team collaborated with the mechanical contractor to rightsize and right-specify HVAC systems that met the owner’s and occupants’ requirements, while also creating a set of construction documents that Skanska and the mechanical contractor could build. The project was delivered under budget, and the team continued to collaborate during construction to address field-installation concerns.
CSE: Each type of project presents unique challenges-what types of challenges do you encounter on office building projects that you might not face on other types of structures?
Gerke: Depending on the level of completion, sound reduction from HVAC equipment is one of the primary concerns for our projects. The lack of ceilings and requirements for aesthetically pleasing ductwork layouts does not always allow for the best measures for sound control. Smaller mechanical rooms result in equipment spaces that are squeezed to the limit. Therefore, electrical transformers that might otherwise be located in closets are out in the office areas, producing noise. Other building infrastructure may be spread throughout the building instead of consolidated in a single location.
Hansen: Competition in the Washington D.C. commercial office buildings market is the biggest challenge owners and designers currently face, due to oversaturation of Class A office buildings. To attract and retain the best tenants, MEP systems must be modular, controllable, and efficient—all while maximizing ceiling heights, reducing noise, and keeping first costs low. For any two planned office buildings entering the market, the one that can support a 2-ft taller ceiling or twice as many control zones is likely the property that wins our area’s competitive leasing battle. Our challenge and ultimate responsibility as MEP engineers is to assist clients in designing and constructing the building that is marketable, attracts high-quality tenants, and ensures a profitable return on investment (ROI).
Yoon: With a few notable exceptions (i.e., the proposed Amazon HQ2 project, which is projected to include 8 million sq ft of new office space), large businesses don’t materialize out of thin air. Most commercial office building projects are driven by the incremental expansions, consolidations, and relocations of existing businesses. For every new office building or commercial-office interior build-out, there’s usually a corresponding, existing office building or tenant suite of similar size that has suddenly become vacant. That vacant space has to somehow be reabsorbed into the local commercial real estate market. If the building is thought of as a financial asset to the owner, how do you maintain the value of that asset once it is empty and not generating revenue? Given the evolution of commercial-office design over the last 20+ years, that often means substantial base-building MEP infrastructure upgrades to maintain its competitiveness with other commercial real estate offerings in that market. However, those upgrades still represent a capital expense that must be recovered somehow through those new-tenant leases or property-sale proceeds.
CSE: Is your team using BIM in conjunction with the architects, trades, and owners to design a project? Describe an instance in which you’ve turned over the BIM model to the owner for long-term operations and maintenance (O&M) or measurement and verification (M&V).
Yoon: No, although we do use BIM, the level of detail (LOD) that we typically develop our models to (LOD300-350) doesn’t include the amount of information necessary to adequately perform these types of functions. The expectation is that, to perform these types of O&M functions, the model has to accurately reflect the as-built attributes of the installed equipment. Therefore, the make, model, serial number, installation dates, warranties, etc. must be included. BIM definitely has potential as a converged building lifecycle tool, but the primary limitation is the additional incremental cost associated with that last as-built documentation step. Building owners typically don’t want to pay for that extra documentation without a clear understanding of the potential ROI. I haven’t seen any white papers that provide a convincing/compelling ROI business case.
Hansen: Our firm has been using Revit MEP for nearly a decade, and many of our local contractors use 3-D BIM programs to create as-builts and bill-of-materials based on our coordinated Revit models. To date, we haven’t seen extensive use of the BIM models for long-term O&M or M&V—indeed, we have seen quite the opposite, where M&V efforts have required the sustained involvement of the architect and engineer, essentially prohibiting the exclusive use of BIM by the owner. These trends may shift in the future, but for now, successful M&V is achieved as a team effort.
Gerke: Our entire firm designs all building-related projects in Revit as a BIM product. We use BIM files to coordinate amongst our internal disciplines as well as other subconsultants on the project team. Using 3-D modeling is a must, due to today’s tight project deadlines, to reduce clashes amongst systems in the field.
CSE: It seems owners constantly want more features, but with a tighter budget. How are engineers designing office buildings to keep initial costs down while also offering appealing features, complying with relevant codes, and meeting client needs?
Hansen: Flexibility is key, and over-engineering is not a luxury. Gone are the days where an owner could afford to build an office building, with HVAC systems designed to support a conservative 7 W/sq ft, and let it sit unoccupied as they marketed to potential tenants. Flexible HVAC systems, like VRF, are becoming increasingly common as they allow rightsizing for tenant needs, individual metering and control, and the ability to offset initial core-and-shell construction costs until tenant fit-out occurs.
Gerke: One important advancement has been using wireless controls for some building systems. Using wireless systems allows for appropriate temperature control to meet zoning requirements or for lighting-level controls required by energy codes that must function as designed for energy efficiency in buildings. Using wireless sensors reduces the amount of wiring, thus may reduce the cost of installation. Another benefit of wireless-control options for lighting and HVAC is how simple it is to modify the systems at a later date, due to the avoidance of wiring that requires rerouting for new wall layouts and other floor plan changes.
Yoon: Oftentimes, this is more a question of where the money to construct and operate a building comes from. The CapEx/OpEx budget priorities for an owner-occupied building are going to be different from that of a tenant-occupied building, especially if the developer for a new tenant building intends to sell/flip it once it’s fully occupied. For tenant-occupied buildings, it may be possible to pass through a significant percentage of day-to-day operating expenses to the tenant(s), which increases pressure to decrease the initial capital expenses by simplifying the base-building MEP infrastructure and accept the potential reductions in functionality/efficiency. However, for owner-occupied buildings, there’s a greater emphasis on the building as an investment asset and less tolerance for higher ongoing operational expenses.
CSE: Technology is driving many engineering trends-wireless offices, high-bandwidth video and audio requirements, and "smart" office spaces that meet the HVAC, lighting, etc. needs of occupants. What are engineers doing to help meet these needs?
Hansen: In general, the biggest opponents to the newer communication and control protocols of office spaces are proprietary control systems. Open-source building automation systems are now widespread, and specifying them is the best way to future-proof for emerging engineering trends.