Essential criteria for designing and implementing control systems that every building operator should consider and demand
The five principles for building automation systems were created by David Sellers, senior engineer with Facility Dynamics Engineering. Sellers writes about commissioning, control systems and mechanical engineering on his blog, A Field Perspective on Engineering.
Control systems are the essential element for ongoing optimization of a facility’s energy consumption. Through effective design and implementation of a building automation system, operators can get an inside peek into their buildings and improve comfort while reducing energy use. In practice, however, not all control systems are designed, implemented or maintained to be effective in optimizing a facility’s systems. Defining a set of principles for control systems improves communication and understanding between all stakeholders – from contractors to administration.
Grande Prairie School Division is located in Grande Prairie, Alberta, 450 kilometres northeast of Edmonton.
Scott Campbell is the mechanical lead hand for the facilities department at Grande Prairie Public School District (GPPSD), an Alberta school district that has over 8,000 students in 18 schools. A challenge Campbell has witnessed in his district and beyond is a lack of understanding of the potential for control systems.
“They think it is all smoke and mirrors when you talk to some guys about controls. They think it is voodoo,” says Campbell, a plumber and gasfitter by trade who has worked at GPPSD for six years.
The lack of understanding can stem from a multiple of reasons, explains Campbell. Building operators may not have the resources or information about their building’s controls to know how to make effective changes. They may not have a sequence of operations or may be using general resources that are not specific to their facilities. Or there may have been a bad experience with controls contractors (whom may themselves not have enough information to make proper decisions).
Overall, a lack of information makes it difficult to run systems – never mind optimize them.
An Oregon-based engineer has outlined five principles that every building owner or operator should consider when designing or implementing control systems. David Sellers, who writes about building commissioning and control system design in his blog, created the following principles.
Principle 1
Control system must first and foremost provide effective and reliable control, commensurate with the systems it is controlling
Obviously, the types, complexities and the criticalities of the systems being controlled will dictate the quality/power of the control system that should be applied to them. The ultimate quality of the control system is primarily dictated by the components that sense, execute logic for, actuate, and document the systems they are controlling.
Principle 2
The manufacturer and installer must be highly qualified with extensive experience and must be committed and bound to thorough Commissioning (Cx)
While the control system power/quality is very important, equally or more important is the expertise and commitment of the installing contractor and their collaboration with the overall commissioning team. Qualifications should insure that a quality contractor with an extensive proven track record is specified; and that effective, thorough commissioning of the control systems by that contractor – whether or not a formal commissioning process is employed – is essential. Given this, there lies a challenge to the designer to fairly restrict installers to those that can deliver effectively within the context of both the construction and the service/support arenas.
Principle 3
Control installation must be fully documented as consistently as practical with nothing required to fully operate and maintain the system withheld
Point naming conventions, programming logic, network configuration requirements, security information, etc. must be strictly adhered to and totally documented. No element for the continued operation and maintenance of the control system may be withheld in any way. No part of the installation may be considered confidential or proprietary information. This specification requires applicable documentation throughout. These requirements are not optional; however, certain documents are only applicable for certain approaches.
Principle 4
Specify sequence of operations logic
The designer must specify the logic of equipment sequences of operations. Often sequences of operations are specified only in general, and often ambiguous, terms, with much of the sequence left to the contractor’s programmer. The programmers should not be put in the position of having to complete the engineer’s sequence, and often resort to sequences which are not optimal for the particular building. Therefore, logic diagrams must be included in design documents. If the project is being done using a design-build methodology, then the design-builder must submit logic diagrams as a design submittal in advance of programming.
Principle 5
Require sufficient instrumentation
The designer must require instrumentation to support both the sequence of operations, and the data acquisition capability to support equipment performance monitoring and building diagnostics analysis. A listing generally establishing minimum instrumentation requirements is included with the specifications. This identifies minimum instrumentation for common types of system. The designer is responsible for requiring additional instrumentation as necessary to support the sequence of operations, or to supplement data acquisition capabilities when the nature of the equipment or systems to be installed makes this sensible. Additional higher end devices shall be specified for control of critical systems or areas in the facility.
Sellers’ principles create a framework for engineers, contractors, maintenance staff and administration to understand what is expected for controls systems.
For major projects, the principles can also be used to formally outline expectations for the design and implementation of controls. Campbell intends to have the five principles included in an upcoming tender for a new facility.
The principles contribute to improving the understanding and appreciation for proper automation systems from staff beyond the maintenance department.
“School divisions maybe aren’t investing the amount of time or don’t have the right management who understands it,” says Campbell.
Campbell intends to continue to reduce barriers between tradesmen, control operators and administrative staff to reduce energy consumption and save money in his facilities. A major part of this is educating their electricians, plumbers and maintenance workers in operating and analyzing control systems. GPPSD doesn’t segregate control operations to a distinct role or department, but the district directly involves the workers who work on the devices every day.
A comprehensive understanding of the systems and data is a powerful tool.
“The hands-on guys like the plumbers and the electricians should be more involved in the controls and on the computer,” he says.
“Trend logs don’t lie.”