Who’s in control of controls?

By Patrick Lynch, Associate Editor, Michael Ivanovich, Editor-in-Chief, July 1, 2009

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CSE: What real benefits are owners gaining from open standards such as BACnet and LONworks? Are we really better off than we were with proprietary controls?

Nicos Peonides : Yes we are. Owners have more options in procuring direct digital controls (DDC) and BAS for both new and existing buildings, resulting in more competitive pricing for these systems. Open standards enable more straightforward integration of systems with the BAS, a higher degree of automation, more functional and consequently more energy-efficient and sustainable buildings. One caveat is to avoid unnecessarily complicating systems and ongoing maintenance by designing systems with components from too many different vendors.

Bill Michell : Open-protocol control systems give the owner the flexibility to maximize a prior investment in a BAS in which the system backbone may still be viable and have useful life; integrate the existing programming into a new system; or converge multiple systems under a common access.

Karl Stum : The area I see open standards providing the most benefit is in giving the building engineer and other interested parties (controls contractor, energy engineers, and commissioning providers) access to view specific inputs of the equipment, such as motor speeds, compressor stages, refrigerant temperatures and pressures, etc. In addition, the protocols allow the central BAS to write to many more parameters allowing more customized and optimized routines for improved control, comfort, and energy efficiency.

CSE: What are the most significant challenges that design/consulting engineers face when taking on BAS projects for commercial buildings?

Michell : Understanding the project’s intent and owner’s expectations, as well as ensuring that adequate future capabilities are built into the BAS, to facilitate continuous commissioning and measurement activities. Selecting a BAS that is user-friendly for the operating staff, and that has future potential for expansion, are critical considerations.

Peonides :

  • BAS do not always meet requirements of owners/design/consulting engineers

  • We have not yet achieved full open standards interoperability between controls and other systems

  • Not all vendors support all open standards; even if they do, interfaces between systems are not straightforward

  • There is concern within the industry of how to delineate responsibilities within a multivendor/product environment

  • Ongoing support/maintenance of systems comprised of components from multiple vendors can be complex.

David Sellers : They actually need to design the control system versus abdicating the responsibility to the control contractor with little definition to level the playing field in a competitive bidding environment. That does not mean they need to be computer gurus; rather, it means that they need to clearly define how the mechanical systems they have designed need to perform for their design intent to be realized. This can be accomplished by:

  • Providing a points list to identify not only the points that are required for control, but also the points that are required to ensure that the operating staff has the tools they need to ensure the long-term persistence of the design intent

  • Providing a detailed narrative control sequence (ideally supplemented by logic diagrams) to specifically define what they expect the systems to do under all operating modes

  • Providing a system diagram that shows the individual elements of a system and the individual elements in the context of the system, which will help the field staff better understand how the individual components will fail to deliver the intended result if they are not integrated into one, cohesive system.

Stum : There are at least three primary areas that appear to challenge engineers who are committed to a quality product:

  • Incorporating state-of-the-art sequences of operation rather than the same ones used for the last 20 years

  • Writing detailed sequences of operation rather than general overviews full of holes

  • Taking advantage of the power of current systems. BAS capabilities are far ahead of engineers using their power.

CSE: How often are lighting, fire, and security systems integrated with HVAC systems, and in what applications is multisystem integration prevalent?

Peonides : In most cases, these systems are integrated where there is a business need (e.g., in larger and more complex projects such as airport terminals, transportation facilities, museums, libraries, smart residential/multiuse complexes, HQ buildings, etc.).

Typical applications for multisystem integration are:

  • Lighting integration: control/monitoring of lighting for energy management

  • Fire alarm system integration: secondary annunciation

  • Security system integration: alarm monitoring and smart building applications.

Stum : I have found that lighting systems are occasionally integrated with HVAC systems; fire systems are rarely integrated and then only the fire smoke dampers; and security systems almost never.

Michell : This depends on the municipality and if codes prevent certain types of system integration. For example, in New York City fire alarm systems must be separate from HVAC controls systems but can be integrated for fan control, purge functions, etc. With than in mind, HVAC and lighting are the most commonly integrated systems. Ultimately, the complexity of a building should determine if these systems should be integrated or kept independent.

CSE: Is multisystem integration (HVAC, fire, lighting, security) being done with one manufacturer or different providers using open protocol? What drives vendor selection for multisystem integration?

Stum : I have seen some of both, but using different providers with an open-protocol will likely continue to be popular; since the familiarity, features, and reputation of the manufacturer’s systems of each of these applications differ so much.

Michell : Multisystem integration can be achieved with different providers in an open-protocol application. Ultimately, compatibility is a large driver in this decision.

Peonides : It is more often done with different providers using open protocols, provided they are supported by the different systems. The selection depends on the types of different systems specific vendors offer as well as their overall functionality. Our recommended approach is to select “best-of-breed” systems that also offer best value to the owner and to define/specify the open-protocols/interfaces to be used for the integration between the various systems.

CSE: How is the most appropriate level of integration decided for a project, and what drives this decision?

Sellers : I think that you should not use the capability to integrate systems from various vendors as an excuse for competitively bidding multiple vendors to provide the same function. While standards like BACnet may mean that a solo operator might be able to see everything as if it was one system, in order to work on the system at a component level, there are several other requirements. The operator still must have, understand, and maintain all of the tools, software, and spare parts required by each vendor’s system.

I am an advocate for standardizing one vendor for a given building function and then using other mechanisms to ensure fair pricing. I think the available integration capability is a powerful way to maximize the capability of our systems. This capability allows your manufacturer of choice to interface with more depth to devices that are not in its product line. For instance, I might be able to control a chiller by making a few interfaces between inputs and outputs on a control system and proprietary control panel. However, if I make a network-level interface and integrate the systems via BACnet, I can perform the control functions I need to perform. Meanwhile, I also can make all of the other operating and diagnostic information available to the system and the various operator workstations.

Michell : Ultimately, the design intent of the project should be the filter to determine levels of integration. If the project design requires a single operator station for all building systems functions, a higher level of integration is recommended. If the project allows for a multidiscipline monitoring approach (i.e., HVAC, security, etc.), then the level of integration can be reduced. Cost is usually the driving force in this decision, as a higher level of integration has numerous positive and few negative attributes.

Peonides : It is decided based on the owner’s business requirements, which are collected and translated into functional and technical requirements. A cost estimate is established for the required integration/interoperability and it is reviewed with the owner. In many cases, an analysis of the cost-benefit and an estimate of payback period for the integration investment are carried out. The owner typically makes a commercial decision based upon whether the integration is a good investment.

CSE: To what degree have controls networks become the decision-making domain of information technology (IT) managers? How often are the DDC systems running on a dedicated building controls local area network (LAN) and how often using the existing LAN infrastructure?

Michell : With the advent of virtual LAN (VLAN) technology and security, a dedicated LAN for a BAS has become a costly proposition, especially in a retrofit application. In new construction, I would encourage a dedicated LAN for the core BAS backbone, but not in a retrofit, as long as the existing IT infrastructure has adequate expansion capacity well beyond the requirements of the BAS.

Peonides : It is rare that control networks are defined by IT managers. Building controls are generally supported by dedicated LANs. This is mainly due to concerns that functional controls are required to provide an appropriate environment for LAN equipment so building LANs are not generally available when building controls are commissioned. The controls LAN can be interfaced with the common-shared LAN to facilitate interoperability and integration.

Sellers : Before there were IT networks, there were building control systems, which came into being as a natural consequence of our desire to control the built environment. As technology evolved, we discovered that the IT infrastructure could provide a desirable platform for integrating building control systems into more responsive systems. I think we should be telling the IT folks what we need the IT system to do to allow us to deliver optimized, efficient building control solutions, instead of the IT folks telling us what we need to do to be allowed to use their network. If the business function served by the building is crippled by their requirements, then the need for the business function will cease to exist.

CSE: Recently, it was discovered that utility grids have been hacked. To what degree are integrated building controls a security threat? Who might hack into buildings and why?

Peonides : There are potential hackers both within buildings/organizations and outside. There are a variety of reasons for hacking (disgruntled employees, desire to harm the organizations, adolescent fun, etc.). Integrated building controls do pose a certain security threat, but no greater threat than other applications. To address this, an overall information security program should be implemented that deals with all systems that are supported by or interface with the common-converged LAN in a holistic manner.

Michell : Integrated building controls are a security threat unless some basic steps are implemented to protect system integrity, such as password and user identifications; systems ability to monitor and record user access and activity; and security of VLAN (if used). Candidates to hack systems could be terrorists, other building operators, and product competitors.

CSE: What measures can engineers and owners take to increase the odds that investments for sophisticated building controls will perform over the life of a building?

Michell : Partnering with a well-versed PE in the area of building controls and systems is critical. The PE needs to understand current and future requirements of the project to be able to advise effectively. Systems that will help facilitate operator ease-of-use and continuous commissioning activities are also critically important to the long-term viability. Lastly, the ability to expand or enhance a system is vital to ensure the investment meets or exceeds its anticipated useful life.

Stum : First, the controls must be designed in complexity commensurate with the operations staff’s ability, interest, and available time to maintain them. Second, the control system must be fully commissioned, including support in the first year to debug and fine tune. Third, the BAS documentation must include complete, accurate, and detailed control drawings and sequences of operation. Fourth, the operations staff must be fully trained. Fifth, system documentation must be thoroughly updated after any changes.

Peonides :

  • Designs should be based upon proven commercial-off-the-shelf systems/ technology

  • System managers/operators should better understand building controls and be involved during design and commissioning of systems

  • Implement training programs for operators/maintainers/users on effective use/long-term benefits of controls

  • Monitor and measure benefits of using sophisticated controls

  • Maintenance and support agreements should incorporate vendor independence provisions, such as staff taking over responsibility for maintenance (to gain better service at lower cost).

Sellers: In my experience, one thing that they can do is to recognize that, at this point, the improvements tend to happen in the controllers rather than in the field hardware. In most instances, the input/ouput (I/O) system, which may represent 40% to 60% of the investment in a control system, is pretty well defined at this point. Doing things like adopting I/O standards based on industry standard protocols; applying specialty terminal strips for interfacing the field wiring to the controllers it serves, and providing the points you need to control but also the points you need to operate, sets owners up for making an investment persist long-term.


Bill Michell , RPA, FMA, CEOE

Director of Engineering, New York Marriot Marquis New York City

Nicos Peonides

Associate Principal, Arup, New York City

David Sellers , PE

Senior Engineer, Facility Dynamics Engineering Inc., Portland, Ore.

Karl Stum , PE

Principal, Summit Building Engineering, Vancouver, Wash.