Curved Segments vs. V-Grooved Block: Head-to-Head

When it comes to insulating large diameter pipes and vessels, there are a variety of insulating options available, including Johns Manville’s Thermo-1200™ calcium silicate curved segments and V-grooved/scored block. Given that these two insulation products are largely used for the same purpose, it can be challenging to know which one to select for your large-diameter application. We recently sat down with Jack Bittner, Johns Manville’s Industrial Product Manager, to discuss the differences in curved segments and V-grooved/scored block and where they are each most applicable.

Find out what Jack had to say about the differences between the two products in terms of installation, applications, and performance below.

  1. What are curved segments?
    Curved Segments are 6” wide by 36” long segments of water-resistant Thermo-1200TM calcium silicate. Curved segments are furnished with a curved radius on the top and bottom surfaces that corresponds to the diameter of the large diameter pipe or vessel.

  2. How do curved-segments differ from V-grooved/scored block?
    V-grooved/scored blocks are 12” wide by 36” long and are flat on both the top and bottom surfaces rather than curved. V-grooved/scored blocks come as 3 v-grooved, with three grooves cut into the insulation, or single v-grooved, with one groove cut into the insulation. V-grooved/scored blocks are used for the same types of large diameter pipes and vessels as curved segments; however they are installed slightly differently and don’t have an upper limit for diameter. V-grooved/scored blocks are installed by “breaking” the blocks at the grooves/scores during installation so that the final product is formed to the curvature of the pipe or vessel.

  3. Why did JM start manufacturing curved segments?
    We saw indications in the industry that engineers were looking for a product that could offer a more precise fit around large pipes and vessels than V-grooved/scored block could offer. The curved segments are made precisely for specific diameters, so they offer a more exacting fit than V-grooved/scored block once installed.

  4. What applications would be ideal for curved segments?
    Curved segments are made for pipes and vessels ranging between 30” to 126” in diameter, operating at temperatures at or below 1200°F.  

  5. What applications would be ideal for V-grooved/scored block?
    V-grooved/scored blocks are typically used on pipes and vessels that are 36” and larger in diameter. For applications between 36” and 126”, the V-grooved/scored block is offered with 3 Vs scored into the insulation. For applications larger than 126”, the materials is offered with a single V scored into the insulation. Since V-grooved/scored blocks are made from the same calcium silicate as the curved segments, they can be used on applications that operate at temperatures between 150°F and 1200°F as well. They have no upper diameter limit, however, and as such can cover a broader range of pipe and vessel sizes.  

  6. Are there any materials you can use on pipes or vessels that are larger than 126” in diameter?
    While you can use single-V score V-grooved/scored block on vessels that are larger than 126” in diameter, we also offer beveled lags.  A beveled lag is a 6” x 36” segment that is flat on the top and bottom that has a slight angle cut on both sides.  When you start insulating surfaces that are greater than 126” in diameter, cutting a radius in a small, 6” wide piece of insulation becomes impractical since the 6” wide piece essentially lays flat on the substrate anyway.  Instead, we cut the angle into the sides of the insulation to ensure a tight fit between the segments.

  7. How does the installation differ?
    The installation techniques for V-grooved/scored block and curved segments are almost the same. Tie a bungee cord around the pipe/vessel and slide the block or curved segments under the tie until the full circumference is covered. While installing the block, the installers should “break” the block along the grooves so that it sits flush against the curve of the pipe or vessel and the edges of the grooves are flush against each other. When installing the curved segments, this step is unnecessary as it is manufactured to sit flush against the curve of the pipe or vessel. Then install a stainless-steel band around the insulation and remove the bungee cord. Repeat this process until the pipe or vessel is fully insulated. Given the difference in the width of the two products, it’s usually faster to install the V-grooved/scored block because they are twice as wide as the curved segments.

  8. Do both products offer water-resistance?
    Yes, both products are water-resistant. See this video to learn more about Thermo-1200TM Caclium Silicate’s water-resistance.

  9. Do these products offer the XOX Corrosion Inhibitor®?
    Yes, these products are made with the same calcium silicate formulation, and they each come with the XOX Corrosion Inhibitor® as part of the material formulation.

If you are looking for more information about the types of materials that are available for large diameter pipes and vessels, please visit the Industrial page on the JM website. There are a variety of materials available for a myriad of applications. If you need any technical assistance with your specification or installation, please reach out to our technical support team at 1-800-866-3234.