Space and Flexibility
Commercial and industrial clients are constantly transforming their roles and paradigms. Flexible companies need flexible facilities and—as the electrical engineers in this month's M/E Roundtable can attest—these facilities need power systems that can adapt and grow with them.CSE: What type of client typically changes the most over the life of a facility? Are there certain f...
Commercial and industrial clients are constantly transforming their roles and paradigms. Flexible companies need flexible facilities and—as the electrical engineers in this month's M/E Roundtable can attest—these facilities need power systems that can adapt and grow with them.
CSE: What type of client typically changes the most over the life of a facility? Are there certain facilities that, by their nature, are very dynamic?
KING: Industrial manufacturing clients typically grow and change over their lifetime. In particular, the automotive industry changes a product model every four to five years. This typically involves updating the process equipment.
DINGER: I have seen more of our clients fitting into this category in recent years. Today's business culture is forcing owners to continually update and change processes to keep up with new applications and growth in their customer base. The cycle of change is much shorter than it has been historically.
Three major industries that come to mind are high-tech manufacturing , communications facilities and health-care providers . High-tech manufacturing facilities have product life expectancies that can be very short. Communications facilities face a lot of competition, and growth in this industry in recent years has been difficult to predict. And health-care providers are facing costs that have been increasing faster than most other goods and services in recent years, which leaves both consumers and insurance companies struggling to keep up. This has created the need for change among providers to maintain cost effective services.
PASTORE: I have found that almost all types of clients grow and change a great deal over the life of a facility. Similarly, some of the more volatile ones I have dealt with are health-care facilities, R&D clients and those involved in manufacturing advanced technologies. Laboratories, whether for private industry or academia, also seem to be more dynamic. The impact of technology drives the electrical system design to be very flexible, adaptable and expandable.
CSE: What is the economic impact of planning for future growth at a facility? What are the costs of poor planning?
DINGER: There are different levels of planning for facility growth, ranging from moderate to substantial cost impact. I have seen facilities install controls, wire and conduit for future equipment, with the assumption that future equipment will be the same or very close to existing equipment. Though initially expensive, this will drastically reduce impacts to operations when future growth is experienced.
PASTORE: Obviously, it is much more economical, from both a construction standpoint and a client's efficiency, to plan for future growth at the outset of a project. Initially, electrical systems can be designed with spare capacity, or provisions to add capacity. This is much easier and less costly than waiting until after the facility is built. The incremental cost difference to do this is a very small portion of the overall construction budget.
DINGER: Allowing physical space for growth up front is a relatively inexpensive option. When space for growth is adequately planned, the costs of future growth are reduced. There is a great impact on operations when the electrical contractor shuts down a portion of a facility to install new electrical equipment. Attempting to increase the capacity of a master control center (MCC) room in the middle of a plant has a large impact on the cost of future growth.
PASTORE: The costs of poor planning are numerous, including loss of worker productivity, downtime and possibly expensive renovation because of unmet future needs.
CSE: What are some of the most important electrical design considerations when creating a facility slated to expand?
KING: Future space and redundancy in equipment. These are important because they will allow for the integration of new equipment with minimum impact to existing operations.
DINGER: I agree. Physical space in the proper location is the most critical thing. To plan appropriately, both the owner and engineer must be open-minded and able to focus on the big picture because small details are nearly impossible to predict.
PASTORE: I think that the three most important overall considerations are flexibility, adaptability and expandability. Taken into the electrical design realm, this translates into capacity, distribution and power quality.
Depending on the rate of expansion, adequate capacity with the appropriate primary and secondary selective schemes should be designed into the facility initially, or accommodations should be made for this down the road. This should also involve the local utilities, especially if large expansions are planned so that their service can meet future needs.
The distribution system should be easy to modify, expand and reconfigure with minimal interruption of service and inconvenience to users. This includes planning for and preserving adequate physical space in the building to handle increased distribution needs. I have successfully designed distribution schemes that use dedicated utility splines adjacent to, but physically separate from, user areas to house equipment and run services. This provides a very flexible space that can be modified with minimal interruption and quickly meet changing needs.
Power quality is another very important design consideration. It is usually not difficult to provide good initial power quality throughout the electrical system. However, when a facility expands, if adequate consideration is not given to how power quality will be sustained, then initial concepts such as load segregation, harmonic distortion mitigation and clean ground systems may be compromised.
CSE: How does a multiple-facility campus setting affect design?
PASTORE: The same considerations apply, except that the issue of capacity and distribution from main power sources to the various buildings and between buildings is more critical. On one hand, multiple facilities allow an engineer to take advantage of load diversity. On the other hand, they present a greater variety of needs and services that must be accommodated.
DINGER: With multiple facilities, planning to add future kVA with spare feeder conduits and floor space located near electrical loads is critical. Allowing space for routing branch circuit conduits to future loads is also necessary. Other disciplines should be included in the space planning process.
CSE: What are the typical mistakes made when facilities expand or alter their electrical systems? Does this affect power quality?
PASTORE: One of the most common mistakes is assuming that there will be no future expansion beyond the one at hand. The issue is naively reduced to meeting only the needs of the current expansion or alteration without regard to how further changes will occur. In this scenario, what eventually happens is a patchwork that is unreliable, difficult to maintain and hinders—rather than supports—the facility's mission.
DINGER: The two most common mistakes I have seen are installing switchboard/distribution board ampacity for future growth without the proper physical space for electrical system growth and not modularizing the electrical distribution by system process or area. Giving in to the least expensive solution today without thinking about tomorrow's growth often causes this.
PASTORE: Another common mistake is not evaluating the current electrical system's protective device coordination and its ability to handle increased short-circuit current. When facilities expand or alter the makeup of their electrical loads, it is not uncommon for the available short-circuit current to increase as well. The existing equipment may not have been designed to withstand the higher levels. This may also be the case even if a facility does not expand but is located in an area with increasing growth. The available fault current from the utility may increase even though a facility's internal loads are relatively constant. Likewise, as loads change, the level of the initial protective device coordination may be compromised. Not re-evaluating the electrical system's level of coordination, especially with respect to ground-fault currents, can lead to widespread loss of power in a facility because the over-current protective devices are not coordinated and the devices nearest the fault do not operate as intended.
KING: Another mistake is the failure to conduct detailed studies of fault current, load flow and the harmonic impact of new equipment to existing equipment. Harmonics can severely affect power quality, and with today's equipment, harmonics can be introduced to the existing systems.
DINGER: If expansion is not adequately planned, trying to squeeze every last drop out of the existing electrical system could impact power quality. If the cost of expansion becomes too great it could look attractive to shortcut quality construction practices.
CSE: For commercial clients with a high churn rate, does an underfloor setup for electrical distribution make sense?
PASTORE: An underfloor system—whether an in-floor raceway system such as cellular metal deck or a raised-floor system—is a very practical and effective horizontal distribution choice for high churn rate clients.
Both systems, but especially raised-floor systems, provide a great deal of flexibility and adaptability. When combined with a modular wiring system, a raised-floor system provides the greatest degree of flexibility, is quickly modified because of the plug-in type arrangement and can be easily adapted to changing office layouts. It is equally flexible for power systems and telecommunication systems. The latter should be combined with an underfloor wire-management system to preserve order and integrity to the various telecommunication systems.
DINGER: Raised-floor systems are expensive, but the cost can be justified if maximum flexibility—and minimized impact to operations—is necessary for future growth. The computer room or data center offer good examples of where the added cost could be justified. I typically advise against it when it would require special or custom applications, which would often be due to floor-load requirements or harsh corrosive environments.
KING: In office environments equipped with modern equipment, I believe that overhead distribution is more flexible and not as constrained by designated distribution.
PASTORE: Raised floor is often recommended when clients truly have a high churn rate. However, it is very important to thoroughly understand the client's churn rate and perform a cost-benefit analysis so that the client's interests are best served. Almost all clients believe they have a high churn rate, but often upon analysis, their rate is not sufficient to justify the cost of a raised-floor system. In such cases, more economical solutions such as in-floor raceway systems can be proposed.
CSE: What specific challenges have you recently faced when either creating a facility that is planned to grow or retrofitting a facility that has changed their electrical needs?
KING: For a new facility, convincing the client to spend a little extra up front is the key; for existing buildings it's enough space.
DINGER: One recent facility expansion we were involved in had a floor-to-floor height that was very low—9 inches of ceiling space! The coordination effort between the owner, personnel, architectural, structural, mechanical and electrical disciplines was critical.
One example of space-saving design was sleeving concrete beams for conduit and data cables. Also, branch circuits were encased within the floor slabs. This allowed the mechanical contractor more freedom to route ducts and piping. The design team explored the options with the owner and explained the pros and cons. In the end, some fairly expensive space-saving solutions were implemented. Since the entire project team understood the problem, we all worked together to solve it.
PASTORE: A current project for a major university involves design of four buildings: a research lab, conference center and parking deck that are being concurrently designed, as well as a classroom building that will follow the lab design. Future plans entail a 50% to 100% expansion of the research lab.
Some of the biggest challenges were: understanding the diverse load profiles of the buildings; developing a primary power infrastructure, accommodating future internal growth that could expand for the future lab; and coordinating with ongoing medium-voltage upgrades in the central power plant. Because the upcoming lab expansion had such a wide range of possible expansion, the appropriate primary and secondary power infrastructure design was critical. By providing a dual-loop, primary selective scheme, establishing pathways for future expansion, and using multiple double-ended substations, we were able to address the university's concern for not only significant growth, but also flexibility, security and adaptability.
M/E Roundtable Participants
Dominic Pastore , P.E., director of electrical engineering, SmithGroup, Detroit, Mich.
Randy Dinger , P.E., project engineer, Power Engineering, Hailey, Idaho
Mike King , P.E., project engineer, Black & Veatch, Ann Arbor, Mich.
Jeromie Winsor , moderator