Question: What are the key elements I should include in my facility maintenance plan to ensure a “clean power” supply?
Answer: When it comes to power supplies for clean manufacturing facilities, and their support areas, there’s truth in the adage that “an ounce of prevention is worth a pound of cure.”
Failure to develop and adequately resource installation guidelines and a Planned Maintenance Schedule aimed at your power systems can result in:
- Disrupted production time, including lines down;
- Damaged or destroyed product;
- Poor yield;
- Product quality issues;
- Sudden increases in corrupted data or hard drive failures;
- Unstable electrical supplies to sensitive equipment, which can damage or reduce the useful life of even multi-million dollar tools;
- Failures of motors and variable frequency drives;
- Lights either dimming or suddenly getting brighter; and
- Failures of sensitive electronic equipment including computers, PLCs, sensors, and circuit boards, among other issues.
The underlying poor power quality associated with these symptoms includes, but isn’t limited to, low voltage, voltage sags (short term voltage reductions), voltage surges, high voltage, voltage spikes, harmonics, momentary utility outages, localized utility outages, and blackouts.
While we could expand these lists, I’d like to focus instead on the steps you can take to ensure these issues don’t keep you awake at night. First, some background: “clean power” is industry slang referring to a problem-free electric power system which is stable and can be counted upon to run smoothly and efficiently. What a power system maintenance plan can avoid is a “dirty” power system that is plagued with (and defined by) nagging problems such as surges, spikes, brownouts, isolated blackouts, and fluctuating power levels—readily apparent to the casual observer as the nuisance of inconsistent light levels. To the operators and managers of your cleanroom, the results are much more ominous. Often times these power quality issues occur so quickly that they can only be detected with sensitive power quality measuring equipment. Though very short in duration, their cumulative effect can have catastrophic results. The potential impacts on customers and the company’s bottom line aren’t trivial matters.
Inconsistent power from utilities at manufacturing plants offshore has been an issue historically; however, we have come to expect a consistent and high quality power supply domestically. External sources of poor power quality include acts of nature—such as lightning strikes or other severe weather conditions, or issues such as utility switching surges and re-closer operations, neighboring power users, utility controlled “brownouts” and “rolling blackouts,” and complete loss of power due to equipment failure somewhere along the power supply chain.
Some studies have determined that approximately 90% of the power quality problems in buildings occur because of electrical system issues within the structure or on the site—not due to inadequacies in the utility provided power. Typical internal triggers in a poorly scoped and maintained facility include large motor starts, overloaded circuits, harmonic generating loads, poor connections, and poorly maintained distribution equipment. Typical root causes include breakers that have not been maintained, loose electrical connections, grounding and bonding problems, improper conductor sizes, overloaded conductors, overfilled conduits, and poorly coordinated breakers.
To avoid the most common problems, be sure to follow these simple guidelines:
- Electrical systems should be designed, coordinated, and installed by qualified personnel. The more sophisticated your facility, tools, and processes, the more critical it is to secure the services of an engineer with experience in your facility and tool types.
- Beware of “power system creep”—as your company and the demands on the power system grow, be sure that system expansions are thoughtfully added in a coordinated manner.
- Exercise circuit breakers as recommended by the manufacturer.
- Check all major connections on a regular schedule to ensure proper tightness and review for signs of damage, corrosion, or normal wear and tear. Infrared imagery is a very effective tool to find overloaded circuits, power imbalances, and improperly installed wiring connections.
- Check panels for signs of overheating.
- Check the resistance of the grounding system annually.
- Follow manufacturer instructions when installing sensitive electronic and electrical equipment.
- Pay attention to any water leaks, moisture, or condensation issues throughout your plant and support areas. Address these issues immediately.
- Develop clear corporate guidelines regarding the installation of equipment or other electronics by employees throughout the facility: a permissionbased program controls not only loads but more importantly proper installation and connections, eliminating potential impacts on the operation of other equipment and reducing the possibility of fire.
- Don’t forget power components located on your site. Maintain all lines and conduit, and ensure that any underground utilities are clearly marked with appropriate signage. Your facilities personnel should have clearly delineated plans readily available, and they must be kept current. Maintain any substations, and the area surrounding this infrastructure—including keeping the area clear from emerging vegetation, and installing adequate fencing and animal deterrents. Make sure your systems are sealed, both externally and any potential pathways that could be used by animals internally. I stood next to the remains of a dead squirrel and a woodchuck who met their demise after finding their way into the switchgear, before short-circuiting the equipment. While their deaths may have been untimely, production lines were brought down by the resulting power failure. The destroyed product, the cost to the company, and the impact on its customers didn’t paint a pretty picture.
- The move toward renewable power sources such as solar or wind, even as a partial supply for support areas, presents its own maintenance challenges. Don’t forget to routinely ensure tight connections between the wind turbine and the tower, and to check the connections and supply lines on any alternate energy sources. Solar and wind power equipment can’t be installed and forgotten.
The goal is to avoid any power systems problems. When you do have a problem, fixes may include surge suppression equipment, line conditioning equipment (including various types/technologies such as battery UPS, flywheel UPS, voltage regulators, power conditioners, reactors, and filters), redundant utility feeders or onsite power generating equipment or, in more severe cases, new or upgraded utility feeders. Sensitive equipment may require the consideration and application of one of the above technologies to ensure clean power supply.
The availability of trouble free, clean power in your facility offers dramatic savings in power use, greater longevity for capital equipment, and a safer workplace. The key is to have a roadmap that keeps you one step ahead of any potential problems.
Richard Bilodeau, PE, is director of engineering at SMRT, architects and engineers (www.smrtinc.com). His 30 year career includes plant engineering positions in clean manufacturing. Richard has designed, operated, and supervised the construction of advanced technology facilities, numerous industrial projects, healthcare facilities, and corporate offices. He’s engineered clean manufacturing facilities for lithium-ion batteries, medical devices, electronics, and pharmaceutical clients. Richard can be reached at: [email protected].
