By / Larry Rice, Retired Technical Products Manager, North America Ideal Products
An integral part of any insulation system is the protective jacket. While there are many types of jackets for insulation systems, aluminum and stainless-steel jackets tend to be the most used in exterior industrial applications.
The American Society of Testing and Materials (ASTM), with the input of several manufacturers from the insulation industry, has developed material specifications, guides, and practices that address these jackets. Material specifications define the products for the purpose of creating minimum quality standards. Guides offer advice on how to choose the best components for your project. Practices define the recommended use and installation of these jacket products.
ASTM B209 defines the chemical components and physical properties for each grade of aluminum allowing rolling mills and distributors to certify the grades and temper they supply. The grades used in aluminum jacket are predominantly 3003 and 3105 half-hard temper (H14-H24) for straight and fabricated jacketing, 1100-O temper for formed products such as elbow covers, and Alclad, which has inner and outer laminates of aluminum 7072 over an aluminum 3004 core. While 3003 and 1100-O are high purity grades, 3105 has a greater recycled content and is often preferred for LEED projects. Alclad is used where increased chemical resistance is preferred and mainly available in sheet products. Alloy 5052 can be used for marine applications.
ASTM A240 and ASTM A480 define the chemical components and physical properties for grades of stainless steel. The insulation industry uses T304 and T316 as standard for jacketing material, banding, and fasteners.
ASTM A666 Standard Specification for Annealed or Cold Worked Austenitic Stainless-Steel Sheet, Strip, Plate and Flat Bar define stainless-steels when greater workability, such as 180-degree free bend, is desired.
ASTM C1729 is the Standard Specification for Aluminum Jacketing for Insulation. This standard defines the aluminum through a classification system of Type, Grade, and Class. Type describes the exterior surface, which can be bare, pigmented with paint or clear coat, or have a PVDF coating for improved chemical resistance. Grade references the aluminum grade and temper. Class describes the moisture and galvanic corrosion barrier, such as painted, polykraft paper, and polyfilm. Also defined are the various jacket products, such as pipe jacket, fitting covers, and sheet profiles to standardize these products for the industry. Lastly, the standard sets quality limits and test methods with tolerances for thickness and inner and outer surface properties.
ASTM C1767 is the Standard Specification for Stainless Steel for Insulation. This standard uses a classification system of Type, Grade, and Class like the one used in C1729. In the same light, C1767 follows the template in C1729 to define the various standard products, quality limits, and test methods.
There are a number of test methods that influence the insulation industry materials and products. Among those are ASTM E84 (Can/ULC-S102) Flame and Smoke Spread, ASTM F1249 Water Vapor Transmission Rate of the Moisture Retarder, and ASTM C1371 Standard Test Method for Determination of Emittance of Materials Near Room Temperature Using Portable Emissometers.
Both C1729 and C1767 require E84 (Can/ULC-S102) test results of 25/50 flame and smoke spread. E84 only requires one test to be done but CAN/ULC-S102 requires taking the average of three tests.
The acceptable F1249 test limit of the water vapor transmission rate depends on the moisture barrier being tested. For polyfilm, that limit is less than or equal to 0.1 grams per 100 square inches per day and for polykraft the limit increases to 1.1 grams per 100 square inches per day to satisfy the C1729 and C1767 requirements.
The emittance levels required for the outer surface of the metal jacket depends on the surface texture and coatings of the jacket. Aluminum jacket can have an emittance as low as 0.1 for bare aluminum (0.3 for stainless-steel), 0.5 for a clear coat paint, 0.8 for a pigmented paint, and 0.85 for a PVDF coating system.
Both ASTM C450 and C585 are standard practices that influence the fit of metal jackets and should be considered when fabricating elbows.
C1879 Standard Practice for Installation of Aluminum and Stainless Steel Jacketing over Thermal Insulation on Pipe and Rigid Tubing addresses the issue of proper overlap of the jacketing and considers metal thickness, circumferential, and longitudinal overlaps, out of roundness of the insulation and jacket finish patterns such as embossing or cross crimp. The increase in stretch-out length of the jacket can vary from 1/8” for .010” thickness to as much as 1/2” for .040 thicknesses. Cross crimp will add another ¼” to those increases.
Should you have any further questions or require more information, please contact your supplier.
I recommend that you consider having at least one person from your organization become members of ASTM C16 Insulation. Membership grants you access to all the C16 insulation specifications at a cost of $115 USD per member. Those who are engineers or have extensive industry knowledge in design and installation provide valuable information improving these standards. Should you wish to attend the meetings as a member, the 2026 meetings will take place as follows:
March 22-25, 2026, at the Hyatt Regency Dallas | Dallas, TX
October 4-7, 2026, at the Hyatt Regency Jacksonville Riverfront | Jacksonville, FL ▪
