Fabricated For Peak Performance

Laurence B. McNabb

August 1, 2003

Thermal insulation has been used for hundreds of years and has taken many forms. For most of that time, the insulation was for heat conservation; that is, the insulation was used on piping and ducting systems that carried above ambient liquid or vapor. During the last half of the 20th Century, advances in technology demanded that insulation be designed to accommodate a new range of temperatures.

The advent of commercial air conditioning, refrigeration and cryogenic systems, to name a few, changed the range of temperatures and conditions that needed to be considered. These new systems all involved below ambient temperatures, some as low as minus 300 degrees Fahrenheit (F), and the insulation for those systems needed to be able to function effectively within those temperature ranges.

The insulation systems commonly used for high temperature applications were not suited for below ambient conditions. Most of the insulations were not closed cell and did not have the properties required for the lower temperatures that these new systems would face.

Technology Moves Forward

Fortunately, insulation technology was also moving forward. Cellular glass was first introduced as an industrial insulation shortly after World War II. Cellular glass has a wide temperature range, from minus 300 degrees F to 900 degrees F. Polystyrene (temperature limit minus 297 degrees F to 165 degrees F) and polyisocyanurate (temperature limit minus 297 degrees F to 300 degrees F) followed, and by 1970 all of these items had taken their place in the insulation material family.

The development of these materials altered the way they came to the marketplace. Insulations for heat conservation were generally manufactured by companies and sold to distributors. The distributors then sold the materials, along with accessories, to insulation contractors and end users.

Cellular glass, polystyrene and polyisocyanurate are all manufactured in block or bun form and require additional fabrication to turn them into pipe insulation, fitting covers and curved segments, in the various sizes and thickness required by contractors and end users. In the beginning, some manufacturers attempted to provide this service themselves, but over time it was recognized that a separate entity could more efficiently provide this service. This new entity was the INSULATION FABRICATOR.

There are currently many of these fabricators doing business across the United States and they have become an important part of the insulation industry. By the very nature of the materials they deal with, fabricators are involved in some of the industry’s most critical projects, and their knowledge of products and specifications are important in the successful completion of these jobs.

The Fabricator’s Role

The insulation fabricator is not a manufacturer, he is in reality a converter; turning raw materials manufactured by others into finished products. The insulation products that the traditional fabricator converts will insulate systems that range in temperature from minus 300 degrees F to 1,200 degrees F. The conditions that these products face require that all parties in the insulation chain, from the specifying engineer to the installer of the insulation to the final end user, be aware of and accept their responsibilities so that the finished insulation system can function efficiently. The insulation fabricator is one of the most important parts of the insulation chain.

Many of these products will be used in systems, which will fail if the insulation system does not function correctly. A rooftop refrigeration system operating at minus 20 degrees F has to be designed, installed and maintained correctly for that system to operate efficiently over its expected life cycle. The same can be said for the underground steam distribution system, the low temperature gas plant or the cryogenic system.

If the insulation on a commercial hot water heating system is not designed correctly or installed properly, there will be consequences. Energy will be wasted as heat losses will cause excess fuel to be used. Personnel may be at risk by coming in contact with uninsulated hot piping. The solutions to those problems, however, would be relatively easy to fix.

Hypothetical Projects

Consider some other hypothetical projects; (1) On an insulated underground steam line, the weather barrier has failed, and moisture has been introduced and has penetrated the insulation; years have gone by and the pipe has been severely corroded, necessitating removal and replacement of the insulation and possibly the pipe; (2) A refrigeration system has been installed without proper vapor retarder or weather barrier. Moisture, either in liquid or vapor form, has penetrated the insulation system and has turned to ice as it reaches the freezing point. The moisture expands as it freezes, further degrading the system. This situation continues until the system is one large ice ball, having minimal insulation value.

Both of the above examples will be very expensive to repair, both in terms of the cash outlay and the down time the system will incur. The insulation in the hypothetical cases above would most likely have been designed by an engineer, produced by a fabricator, installed by an insulation contractor and maintained by the end user.

In the commercial heating system example, the deficiencies in the insulation may go undetected for a long time. As a matter of fact, they may never be found. Energy, however slight, is being wasted but the piping system is functioning properly.

Compare that with the next two examples. In the case of the underground piping, ground water continues to enter the insulation envelope. Some of this water could turn to steam and expand, further damaging the insulation. The owner of the facility will see a significant increase in the amount of fuel needed to achieve the steam pressures required at the terminus of the line. The location of the underground steam line will be known to all; in the summer grass will not grow above it, in the winter snow will melt above it. At some point, remedial action will be required, which will entail shutting down the system, digging up the steam line and replacing the insulation and possibly the pipe.

In the refrigeration example, the owner will find that his energy costs have increased significantly. It may be that the capacity of his refrigeration equipment is not sufficient to provide the necessary cooling required to run his plant. As in the underground case, the system will have to be shut down and the insulation replaced.

The difference between the commercial heating piping system example and those of the underground steam line or the refrigeration system, for the purposes of this discussion, is that an insulation fabricator would most likely be involved in the latter two cases.

Providing Guidance

The insulation fabricator has no direct responsibility for the design of an insulation system itself nor is he responsible for the installation or the maintenance of the finished product. I do believe, however, he is uniquely positioned to offer informed guidance to help insure the completion of a successful project.

The fabricator is most likely approved by the manufacturer of the products that he fabricates. He has available to him the engineering resources of those organizations and he should possess knowledge of correct specifications as they relate to those products.

If a fabricator gets an order for cellular glass to be used in a direct burial system and he is not asked to quote on a jacketing material, he needs to ask about this. If it is determined that an inadequate jacket is going to be used, I believe it is his responsibility to inform his customer of his concerns.

Let’s look at a hypothetical situation. If a large order for insulation for a refrigeration system comes from a contractor who the fabricator knows is inexperienced, that order should ring bells of caution in the mind of the fabricator. The same type of workmanship and attention to detail that is used in the barely adequate results of insulation in the commercial heating piping job will almost certainly result in failure if applied to a refrigeration project. The fabricator can pass on the information he possesses about the recommended installation procedures of the manufacturer of the materials he is providing to the contractor. (Editor’s note: the views expressed in this paragraph are based on the opinions and beliefs of the author. Others may have different opinions and interpretations regarding the hypothetical situation described in the paragraph.)

Industry Knowledge Important

A successful fabricator must possess a great deal of knowledge about the insulation industry. He must be familiar with and fabricate materials to ASTM standards. The fabricator must not only know that 2½ inch IPS x 2½ inch thick cellular glass or polyisocyanurate pipe insulation will have a 8.63 inch OD, and an actual wall thickness of 2.875 inches, but he should make this fact known to his customer. (If he does not, he is likely to get a few calls each year from customers who will complain that their insulation has been fabricated incorrectly.) He must know what fabrication adhesive to use on each cellular glass order, and that this is determined by the operating temperature of the surface to be insulated. The successful fabricator should have working knowledge of the NAIMA 3E Plus® program, and be able to use this program when asked by his customers. He should be familiar with typical specifications and use that knowledge to assist his customers and, hopefully, prevent some problems from happening.

The insulation fabricator who can successfully do all these things provides a unique and very important service to the entire insulation industry.