R-value is a measure of thermal resistance and is commonly used in the building industry to evaluate the thermal performance of insulating materials (like the insulation between the walls of your home). In laboratory testing, R-value (R) is determined by measuring a material’s intrinsic thermal conductivity (k) alongside its physical thickness (d), expressed as R = d/k. While thermal conductivity (k) represents an inherent property of a material regardless of size, the R-value accounts for the actual thickness used in practice. As a result, increasing a material’s physical thickness directly increases its R-value.
Dynalene provides laboratory testing for manufacturers, engineers, and researchers evaluating insulation materials, building products, and thermal management materials. Our experience with thermal property testing allows us to evaluate thermal performance in the context of material composition, temperature, geometry, and intended application.
Dynalene utilizes a FOX 314 Heat Flow Meter for steady-state thermal transmission testing in accordance with ASTM C518 and ISO 8301. The instrument measures heat flow under controlled temperature conditions to determine thermal transmission properties, including thermal conductivity and thermal resistance of insulation materials.
The FOX 314 provides precise thermal conductivity measurements through a controlled steady-state heat flow method. The instrument uses calibrated heat flux transducers and precision temperature measurement to determine heat transfer through a sample.
| Parameter | Capability |
|---|---|
| Test Standard | ASTM C518, ISO 8301 |
| Maximum Sample Thickness | 102 mm (4 in.) |
| Sample Size | 305 mm × 305 mm |
| Temperature Range | -5°C to 60°C |
| Thermal Conductivity Range | 0.005 to 0.35 W/m·K |
| Accuracy | ±1% |
| Reproducibility | ±0.5% |
Dynalene has experience evaluating a wide range of insulation and thermal materials, including:
Testing can support material development, product qualification, quality control, comparative material evaluations, and thermal performance studies.
Dynalene provides thermal property testing services for manufacturers, researchers, and engineers developing insulation systems and heat management materials. Our laboratory evaluates materials ranging from traditional building insulation products to advanced composites, polymers, foams, and engineered thermal materials.
Testing is performed using established thermal measurement techniques including ASTM C518 heat flow meter analysis, ASTM E1461 laser flash thermal diffusivity testing, and ASTM D5334 transient hot wire measurements. The appropriate test method is selected based on sample composition, geometry, thermal conductivity range, and intended application.
Laser flash analysis measures thermal diffusivity by applying a short energy pulse to one side of a sample and monitoring the temperature response on the opposite surface. This technique is ideal for thin, high-thermal-conductivity specimens—such as metals, ceramics, alloys, and graphite—where traditional steady-state methods are impractical. When combined with accurate specific heat capacity and density values, the measured thermal diffusivity allows for the direct calculation of thermal conductivity.
Transient hot wire testing determines thermal conductivity by introducing a controlled heat pulse through a probe and measuring the resulting temperature response. This technique is particularly useful for liquids, gels, powders, and semi-solid materials that are suitable for probe-based measurement.
The appropriate method depends on sample thickness, thermal conductivity, physical structure, and application requirements. The client specifies the desired testing conditions, while Dynalene reviews the sample and testing requirements to determine the most suitable analytical method. Rigid insulation boards are typically suited to heat flow meter testing, while thin, high-conductivity materials may be better evaluated using laser flash analysis. Liquids and gels generally require a probe-based technique such as transient hot wire testing.
| Material Type | Commonly Used Method | Why |
|---|---|---|
| Rigid insulation boards | ASTM C518 | Measures steady-state thermal transmission properties |
| Foam insulation | ASTM C518 | Suitable for many rigid and semi-rigid insulation specimens |
| Thin materials | Laser Flash | Well suited to thin specimens where steady-state testing may be impractical |
| High-conductivity solids | Laser Flash | Suitable for materials with relatively high thermal conductivity |
| Liquids and gels | Transient Hot Wire | Designed for probe-based thermal conductivity measurements |
| Cementitious materials | ASTM C518 or other applicable methods | Method selection depends on specimen properties |
ASTM C518 determines steady-state thermal transmission properties using a heat flow meter. Thermal resistance and thermal conductivity can be calculated from the measured heat flow and specimen conditions, with R-value related to the specimen’s thermal resistance and thickness.
Thermal conductivity describes how easily heat passes through a material, while R-value represents resistance to heat flow (insulation capabilities) and incorporates the material’s thickness.
Yes. Dynalene evaluates solids, foams, powders, gels, liquids, and engineered thermal materials using multiple thermal measurement techniques.
Yes. R-value measures a material’s total thermal resistance and scales linearly with thickness. Doubling the thickness of a uniform material doubles its R-value and halves the rate of conductive heat transfer through it.
The FOX 314 typically accommodates samples approximately 305 mm × 305 mm with thicknesses up to 102 mm.
Yes. R-value is not a fixed constant across all temperatures; thermal conductivity can change as mean temperature shifts. Standard laboratory tests report R-value at a specific mean testing temperature—typically 75°F for building insulation.
Certain foam insulations experience aging due to gas diffusion, where blowing agents trapped inside the cells gradually exchange with atmospheric air.