Selecting building automation systems–step by step

Selecting building automation systems–step by step

Piper, James


Building automation systems have become powerful and effective tools for facility executives. They help resolve problems quickly, reduce energy use, improve system performance, increase occupant comfort and safety, and help manage maintenance costs. Savings produced by the systems can pay for installation in as little as three to five years.

What’s more, developments in system architecture allow previously independent building systems – such as lighting, HVAC, fire safety, security and maintenance planning – to be seamlessly integrated into a single, comprehensive building system. In spite of the advantages and capabilities offered by BAS today, many systems never achieve their full potential. Installed capabilities go unused. Needed functions are never installed. Projected cost savings never fully materialize.

Although some of these problems can be traced back to poor installation on the part of the contractor, it is far more likely that the system selected was not matched to the needs of the facility.

In these cases, the owner, the facility executive and the system designer did not do their homework. They simply selected a particular system, then forced it onto the facility. It was quick and simple.

But quick and simple does not always work well when it comes to BAS installations. It is far better to invest several months in planning the installation than to spend several years trying to get it to work.

The time required to plan a BAS installation will vary with the complexity of the facility and the system being installed. Although the time required may vary, the selection process remains essentially the same.


The single most important step in the BAS planning process is identifying how the system is to be used. Too often, this step is skipped.

A wide range of functions is available with different BAS options. Failing to identify the facility’s BAS needs increases the chances that the system being installed will be unnecessarily expensive or will underperform.

The first step is to list the reasons why a BAS is being installed. Typical reasons include high energy costs, lack of coordination among building systems, poor system performance and inefficient maintenance operations.

Some factors will be more important than others to a particular facility. Identify those that are essential in the facility, and list them in order of importance.

If the new BAS is to be effective, it must be capable of performing all the functions that have been identified. And it must be particularly effective in performing those functions that have been identified as being the most important.

Identifying needs also will help in another way. BAS systems today are very powerful and offer a wide range of capabilities. Not all facilities need all of these capabilities.

One of the most common complaints from operators of new systems is that they are overwhelmed with information generated by the system – information that they do not need and cannot use. As a result, much of this information is simply discarded, and the money spent buying a system with those capabilities is wasted. It is far more costeffective to base the purchasing decision on the actual needs of the facility.


One of the problems common to underperforming systems lies not in the systems themselves, but rather in the expectations of system managers. Unfortunately, overzealous sales people sometimes create unrealistically high expectations on the part of prospective system owners. Once installed, no matter how well the system performs, it cannot live up to these high expectations. Owners then fault the system for not working properly.

The best way to avoid this problem is to become familiar with system capabilities and limitations. Study write-ups on product offerings from different manufacturers. Conduct site visits where various systems are installed. Talk to system operators and managers at those sites. What works and doesn’t work in systems? Has the system lived up to expectations? What features are most effective? If the process were repeated, what additional features would be included? Which omitted?

BAS system capabilities must also be examined in the context of the facility in which it is being installed. The types and complexity of building systems vary widely from facility to facility. The functions performed by the BAS that will benefit the facility will depend to a great extent on the types of systems installed in that facility.

Similarly, differences in how the facility is operated will affect the functions that can be used there. For example, a facility that is in use 24 hours per day, seven days per week will have little to gain from installing a system that focuses on reducing costs by turning off equipment when the facility is unoccupied, unless that control strategy can be exercised on a room-by-room basis.


Once facility executives have gained an understanding of how systems can benefit a facility, a financial analysis should be performed to determine the system’s cost-effectiveness. That analysis should be specific to the facility and the system being installed. It must take into consideration how the facility is being used and how the facility is charged for energy use.

A common mistake made when estimating the savings produced by a BAS is to project electricity cost savings based on a flat rate that is the average cost for electricity. If the facility is on a time-of-day rate schedule, the cost of electricity can vary by as much as a factor of 10 between peak and off-peak rates.

Similarly, the on-peak rate can vary by a factor of two or three between summer and winter rates.

If the estimated savings are to be accurate, the actual rate schedule in effect for the facility must be used in the analysis.

The financial analysis also should reflect how the facility is being operated. Savings generated by unoccupied-hour shutdown of HVAC and lighting systems can occur only if areas of the facility are unoccupied, and if equipment and functions found in those areas will not be adversely affected by the shutdown.

A financial analysis also should factor in operating and maintenance costs. A BAS does not run itself Operators must set up and modify system operating parameters. Maintenance personnel must troubleshoot problems and keep the system in good operating condition. Service contracts are required on major portions of the system. Software upgrades must be purchased.

Failing to take into consideration the financial side of operating a BAS will result in overly optimistic projections of savings. And rosy estimates of savings will endanger system expansions and upgrades.

Once the needs of the facility have been identified, the building systems that are to be connected to the new BAS system must be surveyed.

There are two purposes for this survey. First, the survey identifies at the component level exactly what will be connected to the system. This includes all HVAC system monitoring and control points, building energy meters, lighting system control points, monitoring points for smoke detector in the fire alarm system, and building security monitoring points. Develop a list by system, location and function of everything that is to be connected to the new system.

The second purpose of the facility survey is to evaluate the operating condition of all systems that will be connected to the new BAS. One of the biggest mistakes that facility executives can make is to assume that whatever problems existed in the building’s systems will be corrected by the installation of a BAS. In spite of its powerful capabilities, a BAS cannot compensate for poorly performing systems, nor can it correct for design errors, improperly set up systems or poorly maintained ones.

Thoroughly review the operation of each system that is to be connected to the new BAS. How effectively is the system operating? Is it functioning as intended, or have extensive modifications and patches been required just to make it work? Has the system been well maintained, or has maintenance been deferred? Could the operation of the system be made more effective if it could share information with other building systems?


The facility survey also should identify where existing automated systems are currently operating. These systems might include an older generation energy management system, a computer-based fire- and life-safety system, or a maintenance management system.

The operation and performance of these automated systems should be evaluated to determine their condition, and what, if any, components can be retained for use in the new system. The assessment also should include data collected and stored by the system, such as energy-use or financial information. If this data is available in the right format, it might be possible to import it into the new system.

Don’t limit the survey to the facility’s HVAC and lighting systems. It is also important to examine the operation of the facility’s fire safety, security and maintenance management operations. Deficiencies in the systems must also be corrected before they can be integrated into the new BAS.

Facility executives also should identify what network infrastructures exist in the facility. A number of BAS systems can be connected through different network protocols. If a compatible system already exists in the facility, the installation cost for the new BAS can be cut significantly.

Once the survey has been completed, identify systems and components that are in need of upgrade, overhaul or outright replacement if the BAS is to perform effectively. Ignoring existing problems can reduce a multimillion-dollar BAS to a glorified timeclock.


After the facility has been surveyed, the needs identified, and information compiled on what a BAS can and cannot do, facility executives will have a pretty good idea of which systems are suitable for use in the facility. Before narrowing the choice down to one system, however, several other factors should be taken into consideration.

One is the selection of a consulting engineering firm. A problem that owners run into is that many firms tend to work with only one or two system manufacturers. As a result, those firms will install one of those systems in any facility, even if a better-suited system is available from another manufacturer. The owner should narrow system choices to a couple, then select a consulting engineering firm that has experience with those systems.

Another factor to consider is how long a system has been on the market. A typical BAS has an expected sales life of five to 10 years. After that, advances in technology, changes in building systems and changes in how facilities are operated will make the BAS obsolete from a marketing standpoint. New systems are introduced, and the old ones fade away.

The key is timing. Facility executives do not want to be the first facility to purchase a particular system, nor the last. Too early in the system life, and the facility becomes a test site. Too late, and the facility executive runs the risk of ending up with an orphaned system.

It is also important to check out the reputation of the manufacturer. How well the manufacturer performs will greatly determine how well the completed system will perform. How long has the manufacturer been in business? How many systems has the manufacturer installed? How satisfied are the managers and operators of those systems? How well has the manufacturer supported systems once the installation has been completed? Investigating the manufacturer will require contacting as many facility executives as possible who are using the system, followed up with a number of site visits.

Building automation systems are a major investment for facility executives. They can be effective tools in helping to better manage facility operations while improving performance and operating efficiency. But to make the most of that investment, and to achieve the greatest improvement in operations, they require careful planning before installation. The end result will be a system that lives up to the expectations of system owners and managers while meeting the needs of facility occupants.

James Piper, PE, PhD., is a consultant and writer with more than 25 years of experience in the facilities field.

E-mail comments to

Copyright Trade Press Publishing Company Sep 2002

Provided by ProQuest Information and Learning Company. All rights Reserved