Controlling Condensation Provides Priceless Savings

Roger Schmidt

Roger Schmidt has worked in the rubber/plastics industry for 40 years, holding positions in Research and Development and marketing. He retired in 2009 but continues to consult for his last employer, K-FLEX USA. He has a BS in Chemistry and an MBA from Indiana University. He is a member of ASTM. Mr. Schmidt has contributed articles to Insulation Outlook on several occasions. He can be reached at rogerschmidt@triad.rr.com.

July 1, 2005

Generally, the principles of condensation control are very straightforward, but let’s consider the consequences of an

insulation system failure in a condensation control application. Insulation, including accessory products such as adhesives,

mastics, caulks, pipe-hanger supports, jackets and coatings, should all be considered as a system. Consideration of the

consequences of a failure should drive the initial design and installation of the system.

The principles of preventing condensation are very simple: Maintain the surface temperature of the insulation above the dew

point, and prevent any intrusion of moisture or moist air into the insulation system (particularly between the insulation and

the pipe being insulated).

These principles are accomplished through proper insulation design (the correct selection of type and thickness),

installation and maintenance. As a matter of fact, maintenance of an insulation system can be greatly reduced if the design

accounts for the environmental conditions that the insulation will encounter. Proper completion of the above steps will

ensure a successful project.

Pipe size, ambient temperature, pipe temperature, wind speed, emissivity of insulation or jacket, location of application,

and most importantly, the relative humidity, must also be considered for a proper design.

Most project specifications will state that the insulation should be installed according to the manufacturer’s

recommendations. Some basic installation guidelines are often given as well. However, if the design engineer fails to

consider the level of difficulty for properly installing an insulation system, particularly under the labor, site and climate

conditions in which the insulation system will be installed—this can play a major role in the failure of the insulation

system. Labor experience, severe weather conditions, logistics and project timetables all must be considered in the

installation step. Failures during installation always result in finger-pointing, but can often be avoided if potential

installation problems are considered in the initial plan.

Periodic maintenance of the insulation system is critical for preventing premature failure of the system and for reaching the

life expectancy of the system. When you consider the lifespan of the insulation system, it is often less expensive to build

more reliability into the insulation system in the beginning than it is to rely on excessive maintenance afterward. This is

especially true for installations in which the required maintenance may not get done, resulting in a premature and costly

system failure.

If the insulation system is designed and installed properly, the worst failure scenario would be condensation formation on

the outside of the insulation in those extreme cases when the actual dew point exceeds the dew point limit of the design. If

the insulation is properly designed and prevents water intrusion, moisture on the insulation surface generally will not

result in a catastrophic failure of the system: It either will be a short-term problem or will be correctable by adding

insulation thickness.

Unfortunately, however, most condensation control application failures do result in catastrophic or complete insulation

system failures. Unlike insulation on hot systems where a failure may only result in excessive loss of energy, failures in

below-ambient systems can have major consequences and are usually easily detected. Even in concealed spaces, the consequences

of condensation control failures usually show evidence quickly, resulting in costly repairs.

Failures are often caused by the inadequate performance of special areas that are difficult to insulate, such as pipe hangers

and valves. Another potential cause of failure is when work needs to be done by another tradesman (i.e., an electrician) and

in the process of doing his work he damages the insulation. The insulation then needs to be replaced.

In some instances, design flaws can result in failures, such as not leaving adequate clearance for insulation to be

installed, or failing to specify the adequate insulation for items such as valve stems/handles. Condensation control

applications require all areas be insulated and sealed properly. The insulation system is only as good as its weakest link.

The typical consequence of condensation control failures is saturated insulation—particularly if the insulation is not

closed-cell or if the jacket protecting an open-cell product has failed. Moisture will contribute to the following

conditions:

  1. Loss of insulation value: One percent weight gain due to moisture results in 7.5 percent loss in thermal efficiency.

    Reduction in insulation value can contribute to further insulation failure, quickly resulting in a total failure of the

    system.

  2. Increased insulation weight: This can cause it to deform and possibly fall from the pipe.
  3. Potential corrosion of pipes.
  4. Mold and mildew on the insulated surface itself as well as surrounding areas: ceiling tiles, carpets, throughout the

    insulation and under jacketing—especially in open-cell insulation. Mold and mildew could potentially affect the entire

    building if they get in the air stream.

  5. Loss of energy and higher operating cost.
  6. Unsafe conditions: Water dripping and accumulating in ceiling tiles or on floors, possibly even forming ice, can

    create slip hazards to the personnel below. Condensation falling onto electrical equipment can cause shock hazards and can

    damage sensitive equipment.

  7. Condensate dripping can also contaminate the product being produced below the piping system.
  8. Unpleasing aesthetics, such as water-stained ceiling tiles, walls and carpets, as well as deformed and discolored

    insulation.

The costs associated with remediation of the above consequences can be very expensive and generally far exceed the cost of

the insulation system. Repairs to the system, especially if the pipes are in concealed spaces of occupied areas, are several

times the cost of the insulation system. If a production facility has to be shut down for any length of time to make repairs,

the cost of lost production can mount up. Product quality may suffer if manufacturing processes are not kept at the correct

temperature, and overall plant efficiency may suffer as well. If the problem exists in a plenum or duct area, indoor air

quality will suffer, causing worker discontent and possible lost time on the job. In many cases, the above costs are brought

out in lawsuits, which can significantly increase the costs associated with the problem.

Moisture intrusion between the insulation and pipes caused by seam failure or saturated insulation can result in the need to

replace the piping. This will result in shutting down the facility to make the repairs. The cost to shut down a facility

multiplies the cost factor.

Some installation techniques that can be used to reduce the chances of a failure or lessen the costs associated with a

failure are:

  1. Prefabricate as much of the insulation as possible under ideal conditions prior to taking it to the job site, either

    at the manufacturer’s site or in the contractor’s shop.

  2. Adhere the insulation to the pipe every 20 feet, creating a water dam—this contains moisture from a failed area and

    prevents its travel to other areas of the system.

  3. Use systems with additional margins of safety, such as closed-cell insulation under a waterproof jacket or mastic.
  4. Use robust jacketing systems outdoors because they are designed for years of service and low maintenance.
  5. Use jacketing systems that adhere to the insulation in order to prevent moisture travel between the insulation and the

    jacket.

  6. Use adequate insulation thickness based on the design dew point. It is better to err toward “too thick” as the added cost

    of the insulation will be a small part of the total cost of the installed system, and will cost much less than if the system

    fails.

  7. Insulate all areas of the system: Remember that the system is only as good as its weakest link. Using accessories

    such as pre-insulated pipe hangers is a good idea—they save time and ensure proper insulation thickness.

Mold and mildew are the new key buzzwords in regards to liability. Insulation systems that limit moisture absorption or have

secondary layers of defense against moisture intrusion will greatly reduce liability for mold and mildew problems. Designers

of schools, hospitals, hotels and public buildings are looking for solutions to the mold/mildew issue. Preventing moisture in

the system will eliminate the issue. Selecting the proper materials, maintaining the material’s integrity at the job site and

correct installation are all key to prevention.

Generally, catastrophic failures can be traced back to seam failures (caused by improper installation) or failure of the

jacketing that protects open-cell insulation, both of which can be minimized in the design stage of the project. Insulation

systems that are easier to install should be a clear choice. Jacketing systems that have safety factors built in should also

be a clear choice. The initial cost of ensuring proper installation can be easily justified when one considers the future job

site labor savings and the increased reliability of the system.

Installing a system that you know will require a great deal of maintenance is a failure in the making. You must consider the

conditions in which the insulation will function when designing a system. For indoor applications, jacketing on the

insulation may or may not be needed, depending on the insulation selected and the expected use. For example, applications

that will experience mechanical abuse or wash-downs should be jacketed. Outdoor applications (e.g., rooftop applications)

will always need to be protected, not only from UV rays but also from other environmental factors. Outdoor applications with

extreme conditions (e.g., coastal or offshore applications) will require more robust jacketing. In many cases, adhesives,

mechanical fasteners and silicone sealants will be required to keep the insulation system moisture-proof. It should be

expected that people will walk on, lean ladders against and generally abuse the insulation system. A sign directing personnel

not to walk on the insulation is not adequate. Jacketing should be selected to be robust and, in the case of damage, easy to

repair.

The reliability of the insulation system should be of key concern in the design phase. As stated above, the primary reason

insulation systems fail is because they are improperly installed. Many design engineers have never seen insulation installed

and underestimate how difficult it is to provide a correct installation. It is the responsibility of the insulation

manufacturer, distributor and contractor to advise the design engineer of systems that are easier to install and are more

reliable in the field, even if the initial costs are higher. Standing behind the old adage, “I gave him what he asked for,”

will not benefit our insulation industry, nor will it build the positive relationship that is needed between the design

engineer and the insulation industry. We should not aim to be considered a manufacturer, distributor or a contractor, but to

be a highly specialized consultant to the design engineer.

The cost of a good insulation system can be easily calculated. The cost of the payback in terms of energy savings can also be

easily calculated. The cost of an insulation system failure can be priceless. Effective condensation control is not a matter

of chance, compromise or cost minimization: From the beginning of a project, it requires communication among all parties

involved—the engineer, the insulation contractor, the manufacturer of the insulation and accessory materials, and the

facility owner.

  
Click Photo to Enlarge

Figure 1

Figure 1

The consequences of condensation failures include mold and mildew, which can potentially

affect the entire building if they get in the air stream.

Figure 2

Figure 2

Figure 3

Figure 3

Figure 4

Figure 4

Condensation control is particularly important in below-ambient applications such as chilled water piping.

Figure 5

Figure 5

In below-ambient applications, condensation failure can cause unsafe conditions such as the ice on these

pipes.