Specifying for Mechanical Insulation Systems

Michael J. King

July 1, 2003

Mechanical insulation has long been underutilized and its importance in the overall mechanical system unappreciated. Many engineers who have devoted far too little time on insulation material selection and specifications don’t consider mechanical insulation an engineered system. For those who understand mechanical insulation’s importance, many don’t know where to begin the process of designing systems and creating specifications. This article will identify important steps in designing insulation systems and creating comprehensive specifications.

Although the main focus of this article is specifying mechanical insulation, system design concepts must be addressed to set the stage. Also, designing and specifying are overlapping tasks with the common ground being product selection.

System Design

Designing insulation systems involves listing and prioritizing criteria; then selecting materials and calculating insulation thickness that meet those criteria. This design process is required for each item to be insulated and for each environment in which each item exists. What follows is a brief overview of some points covered in the National Insulation Association’s National Insulation Training Program (NITP).

Why Insulate

The first task in designing insulation systems is to document the answer(s) to "why insulate?" There are many reasons to insulate, but most assume the main reason is to conserve energy. The following is a partial list of reasons to insulate in addition to energy conservation:

Protect equipment and personnel.
Increase process efficiency.
Prevent condensation.
Prevent excess heat in fire hazard areas.
Control noise.
Maintain temperature.
Reduce greenhouse gas emissions.
Maximize return on investment.
Improve process control and efficiency.

An unbelievable amount of energy is lost through uninsulated valves, bare pipes, and defective insulation. NIA’s Insulation Energy Appraisal program states that uninsulated surfaces have a heat loss 20 times higher than properly insulated surfaces. This program also points out that insulation is the most effective technology available today that allows energy users to conserve energy, save money, and preserve the environment; and that return on investment often is less than six months.

Insulation Selection Criteria

The following is a partial list of considerations in setting a prioritized criteria list:

What are you insulating? (pipe, tank, vessel?)
What is the nature of the process?
What is the primary reason for insulating?
What is the base material of the pipe or equipment?
What is the operating temperature of the system?
What are the ambient conditions?
What is the relative humidity; will there be condensation issues?
Is the system located indoors, outdoors, or both?
How much wind or air movement is there? (Ventilation rates required for indoors means there are wind speeds to consider.)
Will the system need to be heat traced?
Will you need to address leak detection and monitoring within the insulated system? How critical is the appearance of the finished system?
Do you need to meet specific code criteria, such as U.S. Department of Agriculture, Food and Drug Administration, fire ratings and building codes?
Will there be people working around the insulated surface?
Will the system or equipment be exposed to physical damage?
Are the contents inside the pipe or equipment flammable? Will there be areas of the system that need regular maintenance checks, such as valves and fittings, specialties, and access panels?
What is the expected life of the system?
Does acoustical treatment need to be addressed?
Installed cost and return on investment?

There are many other considerations in designing systems. Some criteria outweigh others in importance. At some point, economics will play a role; especially when you have several insulation materials that work equally well.

Material Selection

Determining the right insulation for each application requires consideration of the previously mentioned questions. No two jobs will have identical criteria; so don’t just dust off the previous project specifications for the next project. Before selecting insulation materials, gather data on the systems and equipment being insulated and environmental conditions in which they exist.

To begin, organize and prioritize the responses to the previous questions (selection criteria). Then list the primary reason for insulating, matched with the prioritized selection criteria. In most cases selection is a result of combining prioritized reasons and criteria. You may need to design and specify an insulation material and thickness that fulfills multiple criteria.

Specifying Systems

After designing each insulation system, create precise and concise prescriptions of required materials and workmanship. To do so, describe the quality of materials required for the project, the quality of workmanship required for the project, and how you will know that those quality requirements are fulfilled.

Drawings and specifications are part of the documents that form the contract between the contractor and the facility owner. These contract requirements don’t include the insulation selection criteria, thickness calculations, and other selection considerations (such as economic factors) that form the basis of the insulation system design. To fulfill their contract, installers only need to know what materials to use and where to install them.

Drawings for commercial construction do not identify insulation materials, thicknesses, and many installation requirements. Drawings rarely identify what items (pipe, equipment, and ducts and plenums) are required to be insulated. The specification sections that specify the items to be insulated (e.g., pipes, equipment, and ducts and plenums) also don’t include insulation requirements. So, insulation specification sections must be written to include the extent of insulation and the quality of materials and workmanship.

Insulation installers need to know what must be insulated, with what insulating and finishing materials, and in what thickness. Installers then use the project drawings and specifications to see the description, quantities, and locations of the items to be insulated. The combination of insulation specifications and drawings and specifications for insulated items sets the quantity and quality on which installers prepare bids and owners form contracts.

The particular requirements for insulation are contained in one or more specification sections. For commercial projects following MasterFormat?, (the "master list of numbers and titles for the construction industry") these sections are located in Division 15 – Mechanical. There can be as many as three sections (i.e., duct insulation, equipment insulation, and pipe insulation) or these subjects can be consolidated into a single section (i.e., mechanical insulation). Building and roof insulation specifications are included in Division 7, according to MasterFormat?. Whether mechanical insulation is written in one or three sections, the specifications must include a description of the required materials and the location where each material shall be installed. This sounds like a simple task. However, because most projects include numerous systems and equipment to be insulated and because each item can have multiple criteria and conditions, this task is very complex.

Each item that requires insulation can have several conditions for which to design. Domestic water piping, for example, includes both cold and hot water each having different insulating criteria. Domestic water piping passes through different environments, perhaps requiring freeze protection in some locations and personnel protection in other locations (i.e., hot-water supplies at handicapped lavatories). Because of different environments through which domestic water piping passes, some locations must consider condensation control and other locations must consider energy conservation. There are more considerations for domestic water piping, but these should begin to illustrate the point of how complex each system design can be. Now, consider that there are many other systems, each with a variety of insulating criteria.

Each system presents interesting design problems, but taken in combination, the design and the number of systems multiplies and the problem and specifications task is compounded. Once design solutions are developed, the problem now becomes one of how to specify the compound variations of insulation systems in a concise and easy to read specification that will result in competitive bids and enforceable contract requirements.

The following is a list of simple steps for comprehensive, concise, and accurate specification.

Specification Organization and Content

The Construction Specifications Institute (CSI) publishes a Manual of Practice, which prescribes the format and arrangement of subject matter for project specifications, individual specification sections, and page layout and arrangement. The Manual of Practice also prescribes proper writing style and methods of specifying. These organizational and writing principles have become the de facto standard of the commercial construction industry throughout North America. These principles aren’t discussed in this article; instead, this article focuses on the application of those principles as they apply to specifying mechanical insulation.

Specifying Material, Workmanship

The following expands on the steps listed previously. The location and arrangement of these subjects will be discussed later in this article.

Create a List of Systems and Equipment

Create a list of systems and equipment to be insulated from the information developed when designing the insulation systems. You will also need to identify what systems and equipment or portions of systems and equipment must not be insulated. Gather as much information as possible for each system and equipment. This information will be used to select appropriate materials and calculate thicknesses. See the discussion later on calculating thickness for a list of questions to consider about items to be insulated.

Select Appropriate Insulation Material

Select appropriate insulation material for each system and equipment listed. Because there are many systems and items of equipment to be insulated and many differing conditions and criteria, it’s likely that the project will include several different types of insulation materials, jackets, and finishes. The result of this step will be a list of insulation materials required for the project independent from the list of items to be insulated. This separate list of insulation materials will be used to create the "quality of materials" specifications discussed (page 11). Specifiers may wish to limit the installer’s choices to a single type of insulation or may wish to allow the installer to choose among several types to impose a competitive bidding environment. The two lists (items to be insulated and list of insulation materials) will be combined later and expanded to include thicknesses and will be included in the insulation schedules. Schedules are discussed later in this article.

Calculate and Specify Thickness

Calculate and specify thickness for each application. Calculations for insulation thickness can be made to fulfill different criteria. Criteria for calculating thickness include energy conservation, personnel protection, condensation control, and much more. The results of calculations for each criterion will be different. Calculations using the same criterion for different insulation materials will also yield different thicknesses. So, when including more than one type of insulation for a particular application to impose a competitive environment include, equivalent thicknesses (not necessarily the same thickness) so the competitive field is level. Thickness of each insulation application should be included in the schedule that identifies the type(s) of insulation for each system. Including thicknesses in the schedule adds another level of complexity to the specifying task because each application can have multiple materials and varying thicknesses. For example, for hydronic heating piping, the insulation thickness will vary according to the pipe size. So the thickness for NPS 3/4 (DN20) pipe will be different than for NPS 12 (DN 300) pipe; thicknesses for one type of insulation will be different than another type. Continuing this piping example, thicknesses will also vary depending on the ambient conditions for the pipe. Indoor pipe will have a different thickness (and perhaps different insulation materials) from the same pipe size installed outdoors.

A software program called 3E Plus^® from the North American Insulation Manufacturers Association (NAIMA) calculates thicknesses and accommodates many fuel types and five different surface applications. Thermal conductivity values are built in to the program for several different American Society of Testing Materials (ASTM) referenced insulation materials, and the user can input conductivity values for any other material. The large number of possible combinations and options is what gives this program its tremendous flexibility. 3E Plus calculates the following:

heat gain and loss (also translated to dollars)
surface temperatures
thickness to control condensation
thickness required for personnel protection
heat loss efficiencies for particular insulation designs versus bar surface
payback period or return on investment
emissions reduction

Within the 3E Plus program there’s a questionnaire for gathering information about items to be insulated. The following are the first 10 questions, which are required to run the program out of a total of 22:

Specifying thickness for each item and each condition is the next step. The following is an excerpt for one application from MASTERSPEC Section 15080 – Mechanical Insulation:

N. Heating-Hot-Water Supply and Return, above 200 Degrees Fahrenheit (F) (93 degrees Celsius [C]):

1. [NPS 3/4 (DN 20)] <Insert pipe size> and Smaller: Insulation shall be[ any of] the following:

2. [NPS 1 (DN 25)] <Insert pipe size> and Larger: Insulation shall be[ any of] the following:

In the excerpt, the boldface text in square brackets and angle brackets are choices the specifier must make when she or he edits the master to create a project specification. The example identifies the changes in pipe sizes where insulation thickness changes are likely to occur, and leaves the option for the specifier to insert a different pipe size for this break point. There may be additional pipe size break points as pipe sizes increase. Insulation thickness choices presented in the illustration are the most common and the smallest thickness that complies with the energy standard enforced by most authorities of building and mechanical codes. The specifier can insert a different thickness based on project criteria and his or her calculations and judgment.

Describing Quality of Material

Describing the quality of material is the next step. After listing all required materials, including acceptable alternatives where applicable, describe the quality requirements for each required material. Include requirements for insulation performance such as thermal performance, permeance where applicable, rigidity, density, and other attributes that are important to the design solution.

Writing insulation material specifications is done by first identifying the product by a generic title (e.g., calcium silicate or mineral fiber insulation). Sometimes the form must also be included in this generic title because the same material may be required in different forms (e.g., mineral fiber blanket insulation and mineral fiber board insulation). Choose these terms carefully so not to include proprietary or trade names, thereby setting an unfair advantage for one particular manufacturer (unless setting the advantage is your objective). This term(s) becomes an article or a paragraph title, which is followed by a description of that product. The description must include all of the important attributes about the material to distinguish it from other materials. Writing descriptions for insulation materials is made easy by citing a national standard such as published by ASTM International, The following is a discussion from the Evaluations document MASTERSPEC^® Section 15080 – Mechanical Insulation:

"Preformed-pipe-type, mineral-fiber thermal-insulation properties are specified in ASTM C 547. When specifying mineral-fiber insulation by referencing ASTM C 547, specifiers are assured of product qualifications for density and dimension, linear shrinkage, apparent thermal conductivity, surface-burning characteristics, hot surface performance, sag resistance, water-vapor sorption, and non-fibrous contents. This standard specifies four types of mineral-fiber insulation with different properties. Type I is suitable for operating temperatures up to 850 degrees F (454 degrees [C]); Types II and III up to 1,200 degrees F (650 degrees [C]) and Type IV up to 1,000 degrees F (538 degrees [C]). The apparent thermal conductivity for all types at 100 degrees F (38 degrees [C]) is 0.25 Btu-in/hr. sq. ft. F (0.036 W/m°K). Types I, II, and IV are molded and Type III is V-groove. Grade A doesn’t require a heat up schedule and Grade B does require a heat up schedule. Grade B products aren’t commonly used in the HVAC industry. The most common section lengths are 3 feet (900 mm). Available nominal thicknesses range from 0.5 inch (13 mm) up to 6 inches (150 mm) in 0.5 inch (13 mm) increments. Common facings available include: aluminum foil, reinforced fiberglass scrim with kraft paper back (FSK), white kraft paper, reinforced fiberglass scrim with aluminum foil back, generally known as All Service Jacket (ASJ), and aluminum foil, reinforced fiberglass scrim with polyethylene back (FSP)."

From the excerpt you can see that there’s much to describe about this product, which can be omitted from the project specification by simply referencing the ASTM standard. There are some pitfalls, however. First, as seen in the excerpt, there are choices of types and grades for which the specifier must be aware and must identify in the specification. It’s not sufficient to reference ASTM C 547 without further identifying types and grades. If they aren’t identified, the installer doesn’t know if one or another type or grade is important, and the correct type may not be provided. Second, the project criteria might indicate that the values in the standard must be exceeded. In this case, these additional requirements must be specified in addition to the citation of the standard. National standards are updated frequently, so specifiers must keep up with revisions in standards. National standards are developed using a consensus process that involves all that have a vested interest. So, consensus-based national standards are those for which all participants (mainly manufacturers) can comply. Therefore, the resulting standard sets minimum requirements that may not be sufficient to fulfill project requirements and design criteria.

Describing the insulation materials may also include the identification of manufacturers and products for which the specifier is aware of that meet the descriptions. Other proprietary information can be included, and this proprietary information can be used to limit the installer’s selection of materials or to set the quality requirements by which other manufacturer’s products will be evaluated for acceptance. The absence of proprietary information allows the installer to purchase any material that meets the description or cited standard. The excerpt at top right is an example of a description of mineral fiber pipe insulation taken from MASTERSPEC Section 15080 – Mechanical Insulation.

In the excerpt, the titles of the paragraphs are used later in the insulation schedule to specify where this material is required to be installed. The boldface texts in square brackets are choices the specifier must make when he or she is editing the section for a project specification. These are choices within the cited standard that are available from the manufacturers listed.

Describe Other Insulating Materials

Describing other insulating materials means considering all the other components of the insulation system. These include attachment and securement hardware, adhesives, mastics, insulating cements, jackets (factory and field applied), and other finishing materials. Each of these components applies in various situations and in many combinations. These components complete the insulation system and can’t be overlooked. Some components will have their own schedule and some will be included in the insulation material schedule(s). Still others may only appear in general installation articles.

Describing Quality of Workmanship Requirements

Each type of material and each application will have unique installation requirements. The Midwest Insulation Contractors Association (MICA), National Commercial & Industrial Insulation Standards include standard details for many insulation applications. These details can be put on drawings or referenced in the specifications to illustrate relationships and locations of various components of insulation systems. Contractors use the plates from this standard as submittal data to confirm requirements before proceeding with installation.

Specifying Administrative Requirements and Quality Assurance/Control Requirements

There are specific administrative and procedural requirements unique to insulation that must be included in the specifications. These include the types submittals and their specific contents and purpose, extra materials requirements, coordination requirements, installer qualifications, and more. Field quality control requirements must be included to let the installer know how you intend to verify compliance with the specifications.

For insulation installations, field quality control tests and inspections are destructive, so designers should budget the cost for removal and replacement of a quantity of insulation samples in the initial construction cost estimate. Engineers often will specify that a random sample of insulation will be removed to verify proper materials and installation methods are used. Normally, these inspection requirements include statements that all installations will be considered in noncompliance if samples don’t comply. The specifications should identify the quantity of sampling so the installer can include replacement costs in their original bids for those removed portions.

Drawings

The following is an excerpt from the Drawing Coordination Checklist of MASTERSPEC Section 15080 – Mechanical Insulation:

Drawings should indicate the following information:

details of expansion and contraction compensation.
details of joint staggering for multi-layer insulation applications.
thicknesses of insulation at coordination details (space required for insulation).
details of insulation at mechanical penetrations of the building (walls, floors, roofs, etc.).
details of insulation at hangers and other mechanical supports, and details of anchorages where a particular treatment is desired.
details of special requirements at valves, strainers, piping specialties, ductwork accessories, and equipment.
special protection for exterior systems and at other locations for protection against damage, but only to the extent not specified.
details of vapor retarder and sealing, but only to the extent not specified.
details of removable insulation covers for ductwork, equipment, valves and strainers including fasteners, frames, etc.
Details of special requirements for removable portions of insulation at manholes, handholes and access doors for access.
extent of piping with heat tracing installed under the insulation.
application details for each type of field insulated equipment. Include insulation and jacket fastening method and spacing. Show arrangements of special shapes and edge treatment.
details of jacket applications including attaching and sealing, but only to the extent not specified.

Specification Section Outline

The following is an outline of a three-part section for mechanical insulation that includes duct, equipment, and pipe insulation. The outline includes only the part and article titles with a brief explanation (in italics) of what should be presented in each. This outline is based on MASTERSPEC Section 15080 – Mechanical Insulation.

PART 1 – GENERAL

Articles in Part 1 specify the unique administrative and procedural requirements for mechanical insulation, which supplement to general requirements written in Division 1 of the Specifications. The following Articles should be included.

Summary
Like an executive summary of a report, this article summarizes the section’s contents for the benefit of the reader.
Definitions
Include terms used outside of their normal definitions or special use terms.
Submittals
Include types of submittals required and the purpose of the submittal (e.g., what must the submittal illustrate).
Quality Assurance
Include here, overall quality requirements for mechanical insulation. Specific requirements are included where they apply in other parts of the section.
Delivery, Storage, And Handling
Include unique requirements not already specified in Division 1 – General Requirements.
Coordination
Include unique requirements not already specified in Division 1 – General Requirements.
Scheduling
Include unique requirements not already specified in Division 1 – General Requirements.

PART 2 – PRODUCTS

This part describes all the products required for the project. Exclude products not required for the project.

2.1 MANUFACTURERS

Describe contractor’s options in selection among materials specified.

2.2 INSULATION MATERIALS

Include paragraphs that describe each insulation material required for project. These paragraphs shouldn’t describe where materials are applied, rather just the description of the important attributes of each type of insulation.

2.3 FIRE-RATED INSULATION SYSTEMS

Describe specific systems for fire-rated applications. Where these systems apply is listed in Part 3.

2.4 INSULATING CEMENTS

Include paragraphs that describe each insulating cement material required for project.

2.5 ADHESIVES

Describe adhesives applicable to the insulation materials specified in the Section.

2.6 MASTICS

Describe mastics applicable to the insulation materials specified in the Section.

2.7 LAGGING ADHESIVES

Describe lagging adhesives applicable to the insulation materials specified in the Section.

2.8 SEALANTS

Describe sealants applicable to the insulation materials specified in the Section.

2.9 FACTORY-APPLIED JACKETS

Include paragraphs that describe each jacket material required for project that are applicable to the insulation materials specified in the Section. These paragraphs should not describe where jackets are applied, rather just the description of the important attributes of each jacket.

2.10 FIELD-APPLIED FABRIC-REINFORCING MESH

Include paragraphs that describe each reinforcing mesh required for project that are applicable to the insulation materials specified in the Section.

2.11 FIELD-APPLIED CLOTHS

Include paragraphs that describe each cloth material required for project that are applicable to the insulation materials specified in the Section. These paragraphs should not describe where cloths are applied, rather just the description of the important attributes of each cloth.

2.12 FIELD-APPLIED JACKETS

2.13 TAPES

Include paragraphs that describe each type of tape required for project that are applicable to the insulation materials specified in the Section. These paragraphs should not describe where tapes are applied, rather just the description of the important attributes of each jacket.

2.14 SECUREMENTS

Describe securements applicable to the insulation materials specified in the Section.

2.15 CORNER ANGLES

Describe corner angles applicable to the project to protect corners of insulation exposed to damage.

PART 3 – EXECUTION

This part specifies the actions required for preparation, installation, field quality control, and where various insulation materials apply relating to systems and equipment.

3.1 EXAMINATION

Describe requirements to examine surfaces to be insulated

3.2 PREPARATION

Include requirements for surface preparation.

3.3 COMMON INSTALLATION REQUIREMENTS

Specify installation requirements that are common to most insulation materials and applications. Do not specify where to install, just how. Locations are specified in schedule articles.

3.4 PENETRATIONS

Specify requirements for installation where insulated items penetrate walls, floors, and roofs.

3.5 DUCT AND PLENUM INSULATION INSTALLATION

Specify installation requirements unique to ducts and plenums. Do not specify where to install, just how. Locations are specified in schedule articles.

3.6 EQUIPMENT, TANK, AND VESSEL INSULATION INSTALLATION

Specify installation requirements unique to equipment, tanks, and vessels. Do not specify where to install, just how. Locations are specified in schedule articles.

3.7 GENERAL PIPE INSULATION INSTALLATION

Specify installation requirements unique to piping and that is common to most piping systems. Do not specify where to install, just how. Locations are specified in schedule articles.

3.8 – INSULATION INSTALLATION

Include articles for each type of insulation material specified in Part 2 of the Section and specify installation requirements that are unique to that material. Do not specify where to install, just how. Locations are specified in schedule articles.

3.16 VAPOR-BARRIER INSTALLATION

Specify installation requirements that are unique to vapor barriers. Do not specify where to install, just how. Locations are specified in schedule articles.

3.17 FIELD-APPLIED JACKET INSTALLATION

Include articles for each type of field-applied jacket material specified in Part 2 of the Section and specify installation requirements that are unique to that material. Do not specify where to install, just how. Locations are specified in schedule articles.

3.18 FIRE-RATED INSULATION SYSTEM INSTALLATION

Specify installation requirements that are unique to fire-rated insulation systems.

3.19 FINISHES

Include articles for each type of finish material specified in Part 2 of the Section and specify installation requirements that are unique to that material.

3.20 FIELD QUALITY CONTROL

Specify field tests and inspections. Include a description of each type of test and inspection and a description of the extent of testing