Are you in the Insulated Concrete Block business? Then FTC Rule 460 applies to you…

Words: Richard Porter, Bob Sullivan

If you supply, sell, or use any of these…

  • Pre-insulated concrete block...

  • Loose-Fill Insulation...

  • Injectable Foam-in-Place Insulation...

  • Foam Plastic Inserts...
Then you must abide by FTC Rule 460, 16 CFR 460, which governs R-value testing and claims for insulation products and insulated wall systems.

  • R-values for insulated block must be properly tested and calculated.

  • Overstating R-values by more than 10% is not allowed.

  • The fines can be hefty, up to $53,080, every time you break any of the rules.
The IECC Building Code requires that R-values for Concrete Block Mass Walls be determined by ASHRAE/ANSI/IES Standard 90.1 Normative Appendix A, which offers three options:

  1. Tables of Pre-Calculated R-values for “generic” insulated concrete block.

  2. Testing of insulated block wall panels.

  3. Calculating whole-wall R-values. Calculations must be done via the “Isothermal Planes” method. None of the following methods is acceptable:
  • Parallel Path Method
  • Effective or Equivalent R-Value
  • “Delayed Conductance”
  • Polynomial Equations
  • “Added” R-Value
Is FTC Rule 460 required by the building code? YES. Compliance is required by the IECC for both commercial and residential buildings per IECC sections C303.1.4 and R303.1.4.

What does Rule 460 prescribe? How to test the R-value (resistance to heat flow) of the insulation and/or insulated concrete block. Testing must be done using test methods listed in Section 460.5 of the Rule:

  1. Current versions of ASTM standards: a. ASTM C177-2013 or newer b. ASTM C518-2017 or newer c. ASTM C1363-2011 or newer. Note 1: R-value claims based upon results of outdated versions of listed test methods do not comply with either the Rule or the IECC.

  2. Testing must be done at a 75°F mean temperature (not lower temperatures that make foam deceptively appear to have a higher R-value).

  3. R-value claims must reflect steady-state conditions (not delayed conductance).

  4. Advertised R-values must deviate no more than 10% from the results of tested R-values.

  5. R-value testing should be performed on insulated block wall panels, not just on the insulation by itself.
Breaking any of these rules is an “unfair or deceptive act or practice or an unfair method of competition”...in other words, it’s cheating.

Can’t I just rely on the insulation manufacturer’s R-values for insulated concrete block walls? NO. If you suspect or know that those claims are overstated or improperly substantiated or calculated, then the liability for violating FTC Rule 460 shifts to you.

Are proprietary pre-insulated concrete masonry wall systems covered by FTC Rule 460? YES. Section 460.22 of the Rule reads: “If you make an R-value claim for a product, other than a fenestration-related product, that is not home insulation and is marketed in whole or in part to reduce residential energy use by slowing heat flow, you must test the product pursuant to §460.5 [sic] using a test or tests in that section appropriate to the product. Any advertised R value claims must fairly reflect the results of those tests.”

How can I know if the manufacturer’s R-value claims are legitimate or not?

  1. Ask for an up-to-date, current R-value test report of a wall panel constructed with their insulated concrete block.

  2. Ask for an independent evaluation report e.g., ICC-ESL report.

  3. Here are some good guidelines…
A.) R-values of insulated exterior block walls are rather limited because heat flows in/out of the building through the webs of the concrete block.

B.) Fewer Webs Matter: Two-web block walls generally have higher R-values than three-web block walls.

C.) Web Cross-Section Matters: Thin, short webs allow less heat to flow through the block.

D.) Block Density Matters: LWT block walls have higher R-values than NWT block walls.

E.) Based on these factors, the R-values of insulated block walls can range widely…R-3 to R-12 for 8-inch. R-4 to R-16 for 12-inch.

Claims of higher R-values than these should be very closely scrutinized. Ask for a copy of the R-value test report. In other words, “trust but verify.”

For many years, the masonry industry has been losing market share to competing wall systems. Given the newborn synergy within the block industry to promote the many advantages of block masonry – resilience, reliability, performance, strength & style – coupled with promoting innovative energy efficient block masonry walls, it would be counterproductive to promote block masonry in a manner that could be construed as deceptive or unfair to consumers.


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