Tips to design multifamily and mixed-use buildings: Controls and automation
Multifamily dwellings and mixed-use buildings are becoming more prevalent. Some best practices and tips are offered for engineering building automation systems and controls in these residential buildings.
- Brian Berg, PE, LEED AP, CEM, Associate Principal, Glumac, Irvine, Calif.
- David Crutchfield, PE, Principal, RMF Engineering, Charleston, S.C.
- Kieran Healy, PE, Mechanical Engineer, CCJM, Chicago
- Lui Tai, PE, Technical Services Director, JENSEN HUGHES, Toronto
- Robert J. Voth, Executive Vice President, Bala Consulting Engineers, King of Prussia, Pa.
CSE: How have you worked with the building owner or facility manager to implement the Internet of Things (IoT) into their facility management? Have you helped catalog every device in multifamily dwellings and mixed-use buildings, such as lights, fire alarms, electrical outlets, room thermostats, and other products?
Tai: Staying to what we specialize in, virtually all fire alarm systems that we specify or design are intelligent systems, in that programming can be uploaded or downloaded through the internet, protected by passwords. This also helps to catalog every device on the system, allowing the characteristics of each device (i.e., sensitivity, type) to be changed by authorized personnel remotely, if required.
CSE: What are some of the challenges incorporating the IoT into facility design for existing buildings?
Healy: The IoT is, in theory, a great concept. Personally, I’ve adopted all sorts of gizmos and gadgets that adjust themselves based on whether I’m home or not, or that send me text messages when my laundry is done. In owned properties, the owner has complete control over security and who has access to settings and data. A challenge in incorporating the IoT into multitenant facility design is implementing it in such a way that privacy and security isn’t compromised for the tenants. Maintaining firewalls for network security infrastructure and personal privacy within multitenant facilities will be a major roadblock in implementing these technologies on a larger scale.
Tai: For existing facilities, having a fully addressable system would sometimes mean complete replacement of field wiring, as the type and condition of existing wiring is not compatible for addressable circuits. Because the previously embedded conduit and wire cannot be reused, running new wiring throughout the building can be costly and may create unsightly conduits in open spaces.
CSE: When working on monitoring and control systems in multifamily dwellings and mixed-use buildings, what factors do you consider?
Voth: Primarily, central system reliability and performance; we typically do not reach into the occupant level of control. We are seeing a trend to submeter domestic water usage through the control systems. On higher-end work using four pipe fan coil systems, we are using the central control and monitoring system to submeter energy usage for chilled and hot water.
Crutchfield: We always try to keep in mind that the staff charged with the maintenance and control of a facility could be any age and could operate at a variety of skill levels. There could be staff members who are fresh from a trade school where they were trained with an iPad and, therefore, have no desire for paper sets of drawings or operations and maintenance (O&M) manuals. Or, there could be more seasoned staff members who have worked on buildings for their entire careers and have no desire to use any device other than their own personal cell phone and a stack of manuals. Knowing that our systems must be easy to maintain by either type of person, using vastly different methods of troubleshooting, diagnosis, and repair is imperative to having a building that functions properly.
Berg: There’s a lot of submetering involved to charge tenants for the energy they use. On the HVAC side, these larger projects typically all involve some sort of central utility plant, and there’s a need for British thermal unit meters for condenser, chilled, or hot water to charge the tenants appropriately. We’ve worked with special submetering companies to set up a system of monitoring and billing the tenants for the energy they use. We’ve also set up all of the submetering through the building’s direct digital control system that the building owner uses to generate the tenant billing themselves. It all comes down to how the operator would like to handle their billing. So, we’ll make sure we have that conversation with the operator early in the project to identify the desire and design appropriately.
Tai: For retirement and care homes, we must take flexibility into consideration when designing fire alarm systems. For example, smoke-detector sensitivity and fire alarm audibility must be field-adjustable to allow changes to be made based on each tenant’s living habits. As an example, for a tenant who is always baking, the smoke detector installed near the kitchen must be adjusted so that it does not always go into nuisance alarm every time the oven is opened.
CSE: What types of system integration and/or interoperability issues have you overcome in such facilities, and how did you do so?
Tai: Because fire alarm systems are one of the most important systems in a building, they must be capable of interfacing with other systems (i.e., smoke control, security, access control, etc.) in the building. The various systems often have different communications protocols. To overcome this difficulty, addressable control relays and, sometimes, standardized serial communications (i.e., RS-485) are used between the different systems. Commissioning of the complete systems at the end of a project will ensure everything works as intended.
Berg: Everything is getting more automated. Building owners are developing their own apps for residents to pay rent, reserve amenity spaces, call the elevator, let the valet know to bring their car out front—everything you can think of! All that is being integrated with HVAC controls, lighting controls, and low-voltage design. Clear communications and understanding need to occur between the owners and design team on desires, as well as all of the design-team consultants and suppliers to ensure the owner is getting what he wants and all system components work together as they need to.
CSE: What unique tools are the owners of multifamily dwellings and mixed-use buildings including in their automation and controls systems?
Tai: We have seen a trend toward combining all systems into a common monitoring platform, which can effectively monitor all systems on one display, sometimes with graphic representation of the facility. This also can be done after the various building systems have been installed. This after-market common platform takes all outputs and communications from the many systems into one centralized processor. It displays and controls (with some limitation) the various systems via a common display and control unit.
Healy: The common thread through many of the current automation and controls technology trends is occupancy monitoring. The passive technology in virtually every new renovation, currently mandated by energy codes, is dual-technology occupancy sensors that let lighting controls and even ventilation systems know if a room is occupied. That in itself can lead to tremendous energy savings for the building common areas as well as individual units. What’s next, and is tied into the IoT question above, will be enabling the infrastructure to allow individual tenants to customize their units to match their technological sophistication. The key is to respect privacy concerns such that the sanctity of privacy remains within each tenant unit.
CSE: How has the convergence of automation and controls affected the design of multifamily dwellings and mixed-use buildings?
Berg: Submetering HVAC and plumbing utilities is standard practice in all residential and retail spaces nowadays. It’s an expectation from both the landlord and tenant side to ensure fair billing.
Tai: Because of the aforementioned trend in combining all systems into one platform, we have begun to see a trend in manufacturers diversifying their product, such that they can be the product of choice, to provide fire alarm, access control, closed-circuit TV (CCTV), smoke control, and building automation systems all under one roof.