Washington Steam Plant Wraps Up Savings With Insulation Blankets
“Insulation systems appear to be simple, but doing them correctly can be complex,” says John Puskar, president of Prescient Technical Services and an expert on codes and standards related to piping, furnaces, and boilers. “Everything on a piping system should be insulated, including fittings. The most popular method is to use flexible, reusable covers custom fit for an application.
While piping is commonly insulated, facilities managers do not often cover valves, flanges, and the like. Puskar adds, “High temperature and pressure applications can cause an insulation blanket’s fasteners to fail, unless designed by a supplier that accounts for the added heat.”
Greg Westphal is well acquainted with the benefits of insulating steam systems. As steam distribution manager for the U.S. General Services Administration’s Heating Operation & Transmission Division in Washington, Westphal overseas a steam plant that during peak loads supplies up to 800,000 lbs/hr to federal and district buildings including the Department of Agriculture, the Smithsonian Institution, the State Department, and the White House. He estimates his group has purchased hundreds of custom-fit, reusable insulation blankets for his system since 2002.
“We have 75 manholes across the system, and the working conditions in and around the pipes and mechanicals are very difficult. The manholes had no, or very little, insulation on the pipes,” recalls Westphal. “In winter, you’d see steam coming from the manholes; it was all heat loss, wasted money.”
Westphal’s system includes steam piping and fittings that are 30 ft below street level, in confined spaces with no venting or ventilation. The environment is extremely hot, moist, and wet, and can be acidic from either road salt or steam vapor released on carbon steel, which produces carbonic acid. All of these were challenges for traditional insulation materials.
Through an energy savings performance contract, a financing vehicle approved by Congress for energy conservation in federal buildings, GSA contracted with a third party to perform an energy audit. The energy loss calculations from the audit estimated Westphal would save millions of Btuh by using reusable insulation blankets to cover bare pipe, joints, and valves.
“We had insulation on some of our pipes,” adds Westphal, “so taking that into account, we calculated installing reusable insulation blankets in manholes as well as other elements of the system would save us around 1.3 million Btuh, with a payback in approximately eight months.”
Westphal hired a company that custom fit each blanket for his equipment and expansion joints.
“Straight pipe is easy to insulate,” remarks Westphal, “but when you have an elbow, and you’re trying to get an exact fit, that’s not easy.”
To address the challenges in the manholes, the insulation company used a PTFE laminated NoMex® fiber as a base fabric and had it coated to make a highly resistant material. The custom-fit, pre-engineered insulation system included heavy duty polypropylene side-release buckles that provide access to remove and replace the blankets in less than one minute. And even if the manhole was submerged in water, the blanket would hold up.
“They measured every single piece of equipment in every manhole and designed and installed reusable blankets that fit perfectly,” adds Westphal. “They tagged each blanket, so if we remove or replace the insulation, we can identify what the blanket is insulating. Most of our blankets have lasted 15 years or more.”
In spite of the benefits Westphal has seen, experts say part of the challenge to insulating industrial applications lies in a lack of standards and uniform specifications.
“We actually teach the value of reusable insulation in the Certified Industrial Energy Practitioner (CIEP) course that we offer,” notes Tim Janos, director of special projects for the Association of Energy Engineers. “We recommend putting reusable insulation blankets on from the outset, but maintenance folks aren’t energy folks. When they repair a leaking valve, the as-built insulation comes off, sometimes damaged, and it’s not always replaced.”
To help plant and district managers like Westphal tackle the job of insulating their systems, several organizations provide resources. The North American Insulation Manufacturers Association developed software called 3E Plus® to help engineers and plant managers calculate the appropriate thickness of insulation for a variety of applications. Shannon Enterprises of WNY Inc., a maker of thermal and acoustic blanket insulation, offers free energy surveys to develop an Energy Conservation Measure for thermal blanket insulation.
If there’s any downside it’s CUI, or corrosion under insulation.
“In this kind of corrosion, which occurs where systems are frequently exposed to changing temperatures and high humidity, insulation can get wet and accelerate corrosion,” adds Puskar. “This can remain hidden for years.”
Puskar notes that preventing CUI requires an audit, the correct insulating materials, and adherence to certain tolerances, fibers and design specifications. With this in mind, industry professionals say it’s possible to insulate any problem area, componentry, and geometry.