Consulting Engineers Have Much to Offer

06/01/2006


There was a time when I thought that the terms re-commissioning and retro-commissioning could be used interchangeably, but I have since learned that this is not the case. Re-commissioning involves applying the commissioning process to buildings that have been commissioned previously; retro-commissioning involves commissioning facilities that have never been commissioned before. Both of these activities are great avenues to explore when looking for ways to develop and grow a commissioning business.

With energy costs on the rise, selling these services should be easy. A 2004 study of 224 new and existing buildings by researchers at the Lawrence Berkeley National Laboratory indicated a higher cost-effectiveness for commissioning existing buildings vs. new ones. The suggestion was that commissioning for existing buildings focuses more on energy-saving objectives. Commissioning for new buildings focuses instead on the broader goals of thermal comfort, indoor air quality and overall building performance.

Specifically, median commissioning costs for existing buildings were found to be $0.27 per sq. ft., with 15% energy savings and a payback of 0.7 years; these costs for new construction were $1.00 per sq. ft. with a payback of 4.8 years. Building owners seem to be wired to bite on projects with paybacks of 18 months and less, making retro-commissioning an attractive proposition.

If you are a commissioning agent in a consulting engineering firm, your stiffest competition might be third-party providers that have their roots in the testing, adjusting and balancing (TAB) profession. These companies tend to own this niche market, as it is their natural domain. Other types of providers, with backgrounds in consulting, may need to subcontract the air and water balance required for measuring, verifying and adjusting flows, as well as temperature control work associated with reviewing and modifying code and calibrating field devices.

The TAB guys will most likely have a jump on you if they did the original balance work on a particular facility and especially if they have been called back over the years to handle subsequent additions and renovations. Over time, complex mechanical systems wear down and are neglected, resulting in less than stellar performance. The original TAB contractor will probably be the first called on the scene if HVAC systems start performing poorly. They will not have to work hard to convince a building owner to go from a significant rebalancing effort to a full-blown retro-commissioning project.

But commissioning agents who work from a consulting engineer's office need not lose heart, because they have some definite advantages in the commissioning marketplace. For instance, their firms may have designed the mechanical and electrical systems for a facility, or they may be called in to do a building evaluation or study that could springboard into a retro-commissioning project. Engineers should also be more comfortable with and adept at the analysis and calculations required to come up with good commissioning objectives. They should also be able to provide better supporting information and convincing arguments to seal the deal with the building owner. Consulting engineers may also have the ability to appear more impartial. They don't have to make a hard sell to create a commissioning project where one doesn't exist. After all, their primary business is design, and they don't rely on commissioning to pay the bills.

At any rate, once a re-commissioning or retro-commissioning project is sold, the agent needs to get busy.

Making preparations

In addition to a thorough building survey, both re-commissioning and retro-commissioning efforts should start with interviews of key maintenance personnel and a review of utility bills from the past several years. Many of these early tasks may closely resemble those associated with energy management efforts such as identifying energy conservation measures. A major distinction, however, is that commissioning work stops short of implementing major capital improvement projects. The focus instead is to institute processes that improve and optimize the operation and maintenance aspects of a facility. The capital-intensive projects are for energy services companies.

Certain types of facilities are better candidates than others for these specialized services. It helps if the facility is a large energy user, and if its mechanical and electrical systems support critical functions. Hospitals, laboratories, data centers and pharmaceutical facilities all come to mind. Recently there has been much fertile ground developed in the area of laboratories with regard to energy conservation, with the U.S. Environmental Protection Agency and the Dept. of Energy having established an organization called Labs21 with the goal of improving the energy efficiency and environmental performance of labs. The American Society for Healthcare Engineering (ASHE) recently conducted a project, which culminated in the Healthcare Energy Guidebook . This document provides benchmarking data that might be useful in comparing the relative energy efficiency of health-care facilities. The American Society of Heating, Ventilating and Air Conditioning Engineers (ASHRAE) has not been idle in these areas either, having directed technical committees to focus on topics such as benchmarking the energy usage of medical equipment as well as questioning the long-held assumptions behind some of the rules of thumb for laboratory air change rates.

But much work still needs to be done in standardizing this data. Much of the information is not yet normalized on a square-footage basis, for specific use groups or by geographic regions that take into account varying climate conditions. But by staying abreast of ongoing research, development of new ideas and future trends, one can capitalize on this growing body of knowledge. Armed with information, you can create energy-saving scenarios that capture your clients' imaginations, and thereby sell them on the benefits of both re-commissioning and retro-commissioning.

Selling on commission

Many laboratories move from 12 to 15 air changes per hour (ACH) with vivariums sometimes doing 18 to 20 ACH. Operating this way 24 hours per day all year long, these facilities consume large amounts of energy. These air change rates might be overkill in many circumstances, creating the opportunity to suggest to a client that you perform a survey with the intent of scaling back air change rates in underutilized labs.

Future changes in lab use could also trigger the owner to call you back at that time to suggest and implement the appropriate adjustments. The survey might also uncover that the lab airflows are not set back at night. Changes to the building automation code plus some air balance work would set the owner up for major cost savings. Hospitals also have laboratory components, but the real savings here are in operating rooms and diagnostic areas where airflows are high and temperatures are often set very low. Airflows can be reduced after hours as long as pressure relationships can be maintained and temperatures can be set higher overnight.

Another common finding in retro-commissioning work is the occurrence of excessive simultaneous heating and cooling. This phenomenon goes hand-in-hand with the over-ventilation examples described above, because ventilation air invariably needs to be reheated to maintain the space temperature set point. During unoccupied times lighting is either at reduced levels or turned off, and heat-generating equipment is typically shut down, both of which force additional reheat energy to be expended.

Instances of simultaneous heating and cooling are often found in modern laboratories that are designed in a repetitive, modular configuration for flexibility. (For more about modern laboratory design, see "A New Lab Formula," CSE 03/06, p. 24.) The addition or removal of walls can quickly create larger or smaller lab spaces by splitting and combining modules. Each lab module will have its own thermostat, and when several modules are combined into one space, these thermostats can "fight" each other. However, by giving all three thermostats the same set point, or by temporarily giving control of all three HVAC zones to one thermostat, a significant amount of energy can be saved. This overlap of heating and cooling is equivalent to driving a car while pressing both the gas pedal and brake simultaneously. In other types of facilities, energy consumption that results from "thermostat fighting" isn't as great, because they may have recirculating air systems. But in the laboratory setting, we are often dealing with 100% outside-air systems. Lab ventilation systems also operate around the clock unlike those in schools and office buildings that would have night, weekend and holiday setbacks or shutdowns. Operating and maintenance costs are also much higher due to the intense energy usage and the sheer number and complexity of subsystems involved. Simple adjustments can yield large savings.

Time-of-day scheduling is yet another area where retro-commissioning can yield dividends. Not only scheduling of large systems, such as central station air-handling units, but many smaller items such as general exhaust fans. My firm was recently involved with wrapping up a cancer center project when it was noticed that indoor humidity levels were high. It was determined that exhaust fans were not being indexed off during the unoccupied hours, allowing them to draw in warm, moist air that did not have benefit of being conditioned with the air handlers indexed off at this time. Programming the exhaust fans to start and stop with their respective air handlers alleviated this humidity problem and also set the owner up to save operating dollars for years to come.

Overpumping of heating hot water and chilled water systems can also be a common occurrence in any facility with the telltale symptom of low temperature differential. If pump discharge pressures are high, perhaps the distribution pumps were oversized and are now overpowering the control valves and not allowing them to throttle closed.

It is possible that you might run into an amazing situation such as one that I encountered recently. A pharmaceutical facility had been experiencing 4° to 8° temperature differentials between the heating hot water supply and return mains for years. This is a low differential range and should have been on the order of 20° to 25°, but an unrestricted 8-in. bypass was allowing large quantities of hot water to pass by heating equipment and mix back into the cooler return stream. Not surprisingly, this system also suffered from a miniscule pressure difference between the supply and return mains. In dealing with aberrant hydronic systems, it is tempting to dial down the variable frequency drive if the system has one. A better idea is to have the pump impeller trimmed to deliver the design flow while the drive is operating the pump at full speed. This lets the drive modulate to match system requirements at reduced loads resulting in an optimized system.

Forming alliances

Examples such as these point to a potential need to form alliances with temperature controls contractors and TAB professionals. With this in mind, be careful when defining the scope of work on retro- and re-commissioning projects to include the costs of this type of specialty work.

Re-commissioning and retro-commissioning offer the potential of substantially cutting operational costs in energy-intensive facilities such as hospitals,laboratories and pharmaceutical plants. These efforts can also uncover latent defects and help to build peace of mind for owners, who can rest assured that their facilities function as intended and also meet the latest industry guidelines. Although commissioning agents with engineering backgrounds can make great contributions to this field, they face fierce competition from the TAB and temperature control folks. But you may also find that you can work with these more trade-oriented types.



Commissioning Tools: Plumbing for Health Care

Charles Brown, owner of Mobile Robotics, has been in the pipe inspection business for over 15 years. When a major Boston hospital called Brown to trace its sanitary sewer line system in preparation for its addition project, he had planned to use a traditional plumbing line locator, which does not always give the most accurate information. Also, the fact that the hospital did not have plans of its plumbing system added to the challenge of this particular project.

"With traditional locating equipment, there are false nulls and peaks. You could be far away from the target, and yet it tells you you're right on target," said Brown. "You can't make a confident decision with that piece of equipment."

According to Brown, it took him most of the day to trace the lines, which consisted of a couple hundred feet of piping. In that time frame, Brown used his conventional line locator and walked around the hospital trying to trace the plumbing system and to locate where it ended. The locator indicated the signal to Brown and then seconds later, the signal disappeared. Brown retraced his steps until the signal reappeared. The process was time-consuming and caused Brown to question the value and correctness of the information.

Ultimately, Brown could not positively determine where the lines were located and therefore, the point of excavation. Realizing how inconsistent conventional locators can be, Brown was not sure if the problem could be the magnetic field from the hospital's MRI room interfering with the locator's sonde. A sonde is an active beacon that transmits a magnetic signal to the locator. MRIs give a similar magnetic field, making it difficult to locate sondes. Nonetheless, Brown did not feel confident enough to determine where the contractor should excavate.

Then, Brown discovered a new tool designed to solve the most demanding camera and remote transmitter (sonde) locates. Regardless of how he held the unit, it guided him to the target quickly and easily by maximizing the signal strength. He also liked its ability to eliminate the nulls and false peaks that make locating with conventional locators difficult. It has four distinct sonde frequencies to locate almost any camera or remote transmitter. It also can be used to trace three-line trace frequencies as well as passive AC. The user is able to read the frequencies via the digital readout, which has a micro-mapping display.

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