As essential but often concealed systems in healthcare facilities, mechanical pipes support a range of processes throughout the enclosure. Domestic hot water pipes, chilled water pipes and steam supply piping serve as core mechanical infrastructure in hospitals as they carry water and steam used in healthcare functions ranging from sterilization and humidification to HVAC and laundry operations.
Ensuring that mechanical pipes are adequately insulated is a longstanding best practice for conserving energy and supporting safety in health care facilities. Process pipes are “always-on” workhorses in hospitals operating 24 hours a day, 365 days a year. Some pipes in the healthcare setting present a bigger opportunity to mitigate thermal loss than other pipes. Insulating steam pipes generally delivers more economic return on investment than insulating chilled water or plumbing pipes. Although chilled water systems may not have the biggest energy economic return, certainly insulation is critical for the prevention of problems caused by condensation on chilled water systems. The savings can be explained by the difference in temperature between steam inside the pipe and the temperature of the outside air surrounding the pipe. Steam usually runs at about 350○F. As steam drive causes warm air from the pipe to move toward cooler outside surfaces, the steam continually seeks to exit toward the cooler pipe surface, reducing thermal performance and potentially leading to higher energy bills.
Insulation – a tool for mitigating energy loss
According to the U.S. Department of Energy (DOE), uninsulated steam distribution and condensate return lines are a constant source of wasted energy.1 However, a properly sized and installed insulating system can help defend against thermal loss and support energy efficiency on steam pipes. The DOE goes on to say that as insulation can typically reduce energy losses by 90% and help ensure proper steam pressure for plant equipment, any surface over 120◦ F should be insulated, including boiler surfaces, steam and condensate return piping, and fittings.1 As noted above insulating can also support safety. Insulating pipes presents exposure to hot pipe surfaces and the practice is to insulate hot surfaces to be below 140○F.
In general, hospitals appear to have gotten the message when it comes to the importance of insulating mechanical process pipes. A study conducted in 2021 by the National Insulation Association (NIA) looked at insulation in nine hospitals representative of the range of climates in the U.S. and found that quantities of steam piping in hospitals ranged from about 800 linear feet to roughly 11,000 linear feet – slightly more than two miles of steam piping. Piping sizes ran from ½ inch to 18 inches. On average, the study found that hospitals had about 0.015 linear feet of steam piping per square foot of floor area.2
The return on investment is important on every healthcare project. The average energy savings for the nine hospitals was 149 kBtu/sq. ft./yr. These savings, expressed as a percentage of having insulation on the building’s total projected energy usage, range from 4% to 101%.2
Defending against damage
Installing the correct thickness of insulation and ensuring that the insulating system is properly maintained are both important. Without sufficient thickness, insulation will not deliver its full thermal performance. Steam pipe surface temperatures above 140○may also be exposed. Insulation that is damaged or sections of equipment where insulation is missing will compromise energy efficiency. In busy mechanical spaces, insulation can become damaged by equipment, foot traffic (unfortunately, personnel are often fond of standing on pipes to access other areas), or activities in the area. Similarly, insulation may be removed to perform maintenance and not be replaced when the repair or maintenance is completed.
Beyond damage, the presence of moisture can reduce the thermal performance of mechanical insulation. Wet insulation should be replaced immediately to avoid reducing the insulation’s thermal value. Common causes of wet insulation may include leaking valves, external pipe leaks, tube leaks or moisture leaking from other equipment in the area.1 While small breaches, wet areas on insulation or a missing piece of insulation on a pipe section may not seem substantial, they can have a big impact on energy efficiency and costs as we’ll see below.
Calculating the opportunity to conserve
A free tool developed by the North American Insulation Manufacturers Association (NAIMA) makes it easy to see how even a small area of missing/damaged insulation can diminish energy efficiency. The 3E Plus® software can calculate heat loss for different thicknesses of insulation. The tool also shows the costs resulting from damaged or missing insulation (keep in mind that the type of fuel used will affect rates).
Here’s a practical example of how the NAIMA tool can help calculate the cost of damaged or missing insulation. Using the tool, a user will input data relevant to fuel type, energy costs, etc. Assume that a steam line includes a section of 3” pipe operating at 350◦F. Let’s further assume that the relatively high ambient temperature is about 100◦F. Applying the NAIMA 3E Plus® software, Table 1 shows that a one-foot section of damaged or missing insulation will lead to an expense of $56.89 annually to recapture the lost heat (actual data will depend upon the type of fuel and energy costs.)
This continual energy cost can be reduced by simply installing 2” of fiberglass insulation on the 3” pipe section. The NAIMA tool available here shows that the replaced insulation will reduce energy costs to $4.33 – an annual savings of $52.56 achieved every year. Considering the 2021 NIA study that reported between 800 and 11,000 linear feet of piping in hospital environments, replacing damaged insulation with the appropriate thickness could generate a sizeable reduction in energy consumption depending on the amount of insulation that needs to be repaired/replaced.
In addition to calculating energy costs, the NAIMA 3E Plus® software can also generate data on CO2 emissions when typical energy usage is entered. Returning to the example above, the damaged or missing one-foot section of insulation on a steam line will result in 1046.43 pounds of CO2 being produced. Replacing the damaged/missing insulation with two inches of insulation on a steam line will reduce the CO2 emissions to 79.61 pounds of CO2 annually (Table 2). As always, fuel source and energy costs will influence actual savings.
Beyond thermal – moisture and exposed piping concerns
Facility and maintenance personnel may not realize that the energy codes governing thermal performance do not address concerns related to moisture. Any signs of moisture – such as dripping pipes or condensation forming on jacketing – should demand further investigation. The presence of moisture can lead to mold growth. Mold can grow anywhere there is a mold spore, food, water and proper temperature. Jacket material should also be considered. Some jackets have a polymer surface that can be cleaned. Paper surfaces on jacketing can stain and be harder to clean. Choosing insulation with a jacket that can be wiped down can help support a hygienic environment, although it remains important to identify the source of any condensation or water on piping.
Energy codes also do not cover freeze events, posing a concern for exposed pipes outside of the enclosure. Exterior piping requires sufficient insulation to guard against dangers posed by cold weather. The ice storm that brought parts of Texas to a standstill in 2021 demonstrated the stress that nature can impose on exposed pipes, and the necessity of adequate insulation. Regardless of the amount of insulation, it is important to note that standing water in pipes without heat tracing will eventually freeze inf they are placed in a location with temperatures below freezing.
When specifying insulating materials for process pipes used in hospitals, the choice of material matters. Selecting an insulation that can be wiped down and that resists stains contributes to a clean, hygienic environment. Safety, ease of handling and aesthetics on the job site should also be considered. For example, Owens Corning® SSL II® with ASJ Max FiberglasTM Pipe Insulation was designed to be easily compressed and fitted over copper and iron pipe applications. The “hand-fitted” insulation makes it easy to get a smooth, non-wrinkled install that contributes to an aesthetically pleasing environment. Because the insulation does not need to be fileted with a knife, it also supports safety on the jobsite. The double adhesion closure system removes the need for staples or mastic during installation on the jobsite simplifying the installer’s job, reducing the perforations that can make the vapor barrier fail, and supporting jobsite safety.
Operating around the clock and around the calendar, hospitals will always require high-performing building components that support energy efficient operations. Insulating process pipes with adequate levels of mechanical insulation can support both energy efficiency and emission savings. While the size, fuel type and climate zone of hospitals varies widely, tools like the NAIMA 3E Plus® software can help hone in on the actual benefit a hospital may expect when installing or replacing insulation on mechanical pipes.
1 Insulate steam distribution and condensate return lines. (2006, January). U.S. Department of Energy: Energy Efficiency and Renewable Energy. Retrieved August 15, 2023 from https://www.nrel.gov/docs/fy06osti/39306.pdf
Bill Tolliver is Product Technical Manager-Pipe & Mechanical Insulation for Owens Corning.