The demands of mixed-use facilities: electrical/lighting/power and fire/life safety
Mixed-use facilities require engineers to handle several complex components. Here, engineers with experience on such facilities offer advice on bringing successful execution into the mix with electrical/lighting/power and fire/life safety.
Timothy Chatterton, PE, Project Manager, RMF Engineering, Selbyville, Del.
Kari Engen, PE, CxA, LEED AP, Senior Mechanical Engineer, WD Partners, Dublin, Ohio
Taner Tekin, PE, LEED AP, Project Manager, exp, Maitland, Fla.
John Torre, PE, LEED AP, Principal in Charge of Electrical Engineering Services, OLA Consulting Engineers, Hawthorne, N.Y.
Scott Vollmoeller, PE, LEED AP BD+C, Associate DBIA, Managing Principal, Glumac, Seattle
CSE: Describe a recent electrical/power system challenge you encountered when working on a mixed-use building, especially one with very different types of tenants.
Tekin: On a large mixed-use project we recently designed, we had to spend a considerable amount of time with the local power utility company to locate, size, and layout the power utility vaults. Due to the size of the project, we needed three different vaults serving three different city blocks. Stringent requirements of the utility company especially made it a challenge to complete this task.
Engen: Often, the electric demands within one space are very different than another. In small food service applications, most necessary voltage needs are 120/208 V, but large mixed-use buildings often furnish 480 V power and require transformers. Locating dedicated space for transformers and maintaining working clearances can be challenging.
Torre: We recently worked on a mixed-use development facility that had more than 700 residential tenants, more than 500,000 sq ft of retail/restaurant tenants, and a parking garage. From an equipment and cost perspective, a 208 Y/120 V service for the residential portion of the building and a 480/277 V service for the retail/restaurants and garage made the most sense. After reviewing the project and loads with the utility company, we were able to recommission the existing 208 Y/120 V underground vault. However, the vault did not have the capacity needed for the entire building. The existing vault was used for the residential portion of the building, and the utility company provided a 480/277 V service from their underutilized vault for the adjacent property. By the utility company re-purposing their existing infrastructure, the owner ended up with the most economical electrical distribution design without having to build new vaults or pay the utility company extra distributional charges.
CSE: How do you work with the architect, owner, and other project team members to make the electrical/power system both flexible and sustainable at the same time?
Engen: Often, decisions must be made for economic and sustainability reasons, which can conflict with each other. Early collaboration helps minimize such conflicts and allows for mutual decision making.
CSE: Is LED lighting in high demand from mixed-use facilities? If so, describe a recent lighting design project.
Engen: LED is in very high demand for retail applications. Retail clients demand substantial lighting levels to meet customer-experience goals. LED allows for high lighting output with lower power input per lumen, making it more common.
Tekin: We are currently designing several projects throughout the world that are using full LED design solutions. For example, on one of the confidential projects that we are working on, the facade is lit with LED floodlights; the interiors are lit with a combination of LED downlights, linears, and LED decorative lamps; and the pool deck has LED accents, step lights, and wall sconces.
Torre: We recently designed a 1-million-sq-ft mixed-use facility that uses primarily all LED fixtures. The high lumen output and low wattage of the LED light fixtures are a good fit in areas that require some level of 24/7 illumination for security purposes. LED fixtures in the remaining portions of the building also help meet the stringent lighting-power density of the state and local energy codes.
CSE: What one-of-a-kind detection, notification, or suppression systems have you specified for a mixed-use facility? What drove the design?
Tekin: As the demand for protection of special hazard areas becomes more prominent, the same challenges are always present with each project I see. These reoccurring challenges always include one or more of the following: lack of room integrity, cleanup and downtime concerns, sustainable green design, and the use or availability of water. Whether I'm specifying for a data room, a server space, or a machine space, only one product in the market addresses all of these challenges in one package, Victaulic's vortex fire suppression system. The vortex system is a hybrid technology that combines the best capabilities of both water mist and inert gas systems. The system discharges a homogeneous mixture of water droplets less than 10 microns in size and nitrogen gas with nearly zero wetting and with enough energy to overcome the drag effect that has limited the effectiveness of traditional water-mist systems. In addition, unlike other systems, maintaining room integrity is not essential. The fires can be extinguished in open, naturally ventilated areas while providing a 100% green design.
CSE: Describe any challenging sprinkler systems you recently specified.
Tekin: I was recently challenged with providing protection of a switchgear room in a remote area with room-integrity issues and limited water availability; the owner was also requesting the use of a nontoxic chemical. Since vortex emitters discharge only a fraction of a gallon per minute, the system is available with a self-contained water supply. I was able to provide a system that met the owner's request for a green system while overcoming the challenges of water supply and room integrity issues.
CSE: Describe unique security and access-control systems you have specified in mixed-use projects.
Tekin: The challenge associated with designing mixed-use security and access-control systems is successfully navigating the differing goals of each occupant type while providing a unified system. For example, the goal of security for residential space is to control access while in commercial areas—access needs to be free-flowing and open. When mixing public, commercial, and residential spaces, the challenge revolves around how to maintain an inviting and open space while not presenting an overbearing level of security when transitioning to residential spaces. The same challenge applies to surveillance and other security systems, where creating a safe environment needs to be balanced against negatively affecting the inviting atmosphere through the overt use of security devices.