Facility Maintenance Decisions

The Power to Detect and Prevent

By James Piper   IAQ

Despite all of the advances in building design and technology, most maintenance and operations departments operate in a reactive mode. Maintenance technicians react to problems called in by building occupants. Unfortunately, for every problem called in, many more go undetected. Even with many facilities implementing extensive preventive and predictive maintenance programs, many operating problems continue to go undetected.

Building automation systems (BAS) catch some, but not all, of these problems. BAS recognize only those conditions they are programmed to recognize. Many common operational problems — deteriorated equipment, improperly calibrated sensors, poor installations, and poor past maintenance practices — go undetected.

Compounding the problem is that technicians too often react to problems they do discover. They make changes to equipment, controls and systems without fully understanding the nature of the problem, the impact it has on operations, and the impact changes they make will have on energy use. Rather than correct the real problem, changes often mask it .

The primary reason so many problems go undetected and uncorrected for so long is that they do not overtly impact operations. Advances in system monitoring and diagnostics are helping engineering and maintenance technicians with the early detection and identification of problems that otherwise would go undetected. Improved communications between building components and system interoperability, combined with advanced diagnostic technology developed by system manufacturers, have given technicians powerful new maintenance tools.

These diagnostic systems collect and store data from building systems and components so managers can compare it to the historic norm for that item or to norms provided by the system manufacture. When variances from normal operation occur, the system identifies the variance, helps technicians isolate the cause, and suggests possible required corrective action.

Benefits of Diagnostics

One significant benefit from advances in monitoring and diagnostic technology is a reduction in whole-building energy use. Demonstration programs established in a range of commercial and institutional facilities have shown an average reduction in overall energy use of 15 percent. Assuming an annual energy cost of 30 cents per square foot, this translates into a savings of $150,000 per year for a typical 500,000-square-foot facility.

And that is just the average savings. Some facilities have reduced energy use as much as 40 percent. The typical energy payback for monitoring and diagnostic systems ranges from six months to two years.

Another benefit of the technology is the identification of previously undiscovered problems. Every facility has its own unknown or unrecognized operational problems resulting from errors in design, installation, equipment and maintenance. While technicians might not notice these problems, they impact operations every day through increased energy and operating costs and reduced equipment service life.

Monitoring and diagnostic technology can improve a facility’s overall operation by reducing response time. When a problem occurs, time passes before someone calls in a service request. With ongoing monitoring and diagnostic technology, technicians can detect and address a problem well before occupants notice it.

Implementation Options

Managers have three broad methods for using monitoring and diagnostic systems: portable tools geared to specific tasks; OEM-installed systems on specific building systems; and field-retrofitted equipment and software on existing building systems.

Of these three methods, portable monitoring and diagnostic tools require the smallest investment for implementation. They also require the smallest investment in training, and managers can apply them easily to specific pieces of equipment or components. Their biggest drawback is that, while they are good for individual tasks, they are so specific managers often cannot apply them facilitywide.

For example, manufacturers have developed a whole family of diagnostic equipment to sense infrared radiation. Technicians can use non-contact temperature sensors to make accurate measurements of surface temperatures in mechanical and electrical systems. They also can use infrared cameras to produce images of infrared radiation from mechanical and electrical components and from insulated components.

They also can use these temperature sensors and thermal imagers to identify heat-related problems, such as loose electrical connections, failed thermal insulation, wet roof insulation, and plugged heat-transfer tubes. Advances in system design have made these tools less expensive to buy, easier to use, and more reliable to operate.

Breakthroughs in technology also have created new generations of low-cost, easy-to-use diagnostic equipment, including monitors for air quality, temperature, air flow, and vibration. Some tools are available with special software packages to assist in diagnosing common problems in building systems.

Manufacturers have designed other portable tools for temporarily installation on specific building systems, such as an air handler. They fit the equipment to be monitored with a number of sensors that are wired back to the portable monitoring tool. The sensors collect data and stored it in the tool for review or downloading to a computer for analysis. Once sensors have collected and analyzed enough data, technicians remove the sensors and relocate the tool to another building system.

A number of BAS manufacturers are adding various levels of monitoring and diagnostics to their systems. For example, elevator manufacturers offer the option of on-site monitoring of elevator operations and performance. When problems occur, the diagnostic system notifies technicians of the problem.

In facilities without on-site maintenance capabilities, the elevator monitoring function can be forwarded to a local elevator maintenance company. The advanced diagnostic capabilities can identify and correct most common problems in elevator-system operation without having to dispatch maintenance personnel to the site, thus improving response time while reducing maintenance costs. Manufacturers are installing similar systems on a range of HVAC equipment.

The widespread use of BAS has created another opportunity for the application of monitoring and diagnostic systems. BAS traditionally have been used to control the operation of a range of building systems, trigger alarms for system operators when a predefined error occurs, and track and report energy use. Now, the development of diagnostic software has expanded this role to include identifying and diagnosing system faults that go beyond the traditional alarms.

New-generation systems use a BAS’s data-gathering capabilities of the to drive software packages that track operational data, identify developing problems and alert operators when problems develop. What made this new generation of diagnostic software possible is the development and increasing use of standard communication protocols among BAS.

What Lies Ahead

To improve systems’ capability and accuracy, manufacturers are moving to lab-quality sensors that offer greater reliability and better accuracy. To provide a better baseline for system operation, systems now sample data from sensors more often.

They also model the performance of different systems — particularly building HVAC systems — under a range of conditions, including faulty and no-fault conditions. They compare actual operating parameters to model conditions to determine if equipment is performing according to the specifications. When deviations from expected conditions occur, a comparison to the database of faulty operation can identify the most likely causes.

James Piper, P.E., is a national facilities maintenance and management consultant based in Bowie, Md., with more than 25 years of experience.

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  posted on 7/1/2007   Article Use Policy

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