Cellular glass thermal conductivity is a key factor for engineers evaluating insulation materials. This article explains its performance, standards, and comparisons to help you select insulation for demanding thermal applications.
Cellular glass thermal conductivity typically ranges from 0.033 to 0.045 W/m·K, making it a reliable insulation material for consistent thermal performance across various temperatures and environments. It is valued for its non-combustibility, moisture resistance, and long-term stability.
Cellular glass insulation k-value?
The cellular glass insulation k-value, also known as thermal conductivity, is a measure of how effectively the material resists heat flow. For cellular glass, the k-value typically falls between 0.033 and 0.045 W/m·K, depending on density and temperature. This low k-value means cellular glass provides strong thermal insulation, making it suitable for industrial, commercial, and building applications where energy efficiency and temperature control are critical.
Cellular glass insulation is produced by foaming glass powder to create a rigid, closed-cell structure. This unique composition ensures that the insulation is non-combustible, vapor-tight, and resistant to moisture, mold, and most chemicals. These properties help maintain the specified k-value over decades, even in harsh or fluctuating environments.
When specifying insulation, it is important to compare k-values under similar test conditions. Cellular glass’s k-value is measured according to recognized standards such as ASTM C518 or EN 12667. Always check whether published values refer to mean temperature or specific installation conditions.
Cellular glass insulation ASTM C552 data sheet?
Cellular glass insulation is standardized under ASTM C552, which outlines requirements for block and board forms used in thermal insulation. The data sheet for ASTM C552 provides key specifications, including density, compressive strength, maximum service temperature, and thermal conductivity at various temperatures.
Typical ASTM C552 values for cellular glass insulation include:
| Property | Typical Value | Test Method |
|---|---|---|
| Thermal Conductivity | 0.036 W/m·K (24°C) | ASTM C518 |
| Density | 120–160 kg/m³ | ASTM C303 |
| Compressive Strength | ≥ 690 kPa | ASTM C165 |
| Service Temperature | -260°C to +430°C | ASTM C411 |
| Water Vapor Permeance | < 0.02 perm | ASTM E96 |
| Non-combustibility | Yes | ASTM E136 |
These data points help engineers and specifiers verify that cellular glass insulation meets project requirements for safety, durability, and thermal performance. For procurement professionals, ASTM C552 compliance ensures quality consistency and ease of sourcing from reputable suppliers.
Cellular glass thermal conductivity at different temperatures?
Cellular glass thermal conductivity is stable across a wide temperature range, but some variation occurs with temperature changes. At a standard mean temperature of 24°C (75°F), k-values are typically around 0.036 W/m·K. As temperature increases, thermal conductivity may rise slightly, but cellular glass remains more stable than many polymer-based alternatives.
For example, at mean temperatures of:
- 0°C: ~0.033 W/m·K
- 24°C: ~0.036 W/m·K
- 100°C: ~0.040 W/m·K
- 200°C: ~0.045 W/m·K
This predictable thermal conductivity across varying temperatures is essential in applications where insulation experiences wide thermal swings, such as process piping, tanks, and building envelopes. The closed-cell structure prevents moisture ingress, which can otherwise degrade insulation performance over time.
When specifying insulation for high- or low-temperature applications, always request thermal conductivity data at the relevant mean temperature for your design.
Cellular glass vs polyurethane insulation?
Comparing cellular glass thermal conductivity to polyurethane insulation highlights important differences for material selection. Polyurethane foams (PUR/PIR) generally offer lower initial k-values, around 0.022–0.028 W/m·K, making them highly efficient insulators for certain applications. However, their performance can degrade over time due to blowing agent loss, moisture ingress, or fire exposure.
Cellular glass, while having a slightly higher k-value (0.033–0.045 W/m·K), maintains its thermal performance for decades because it is inorganic, non-combustible, and vapor-tight. The table below summarizes key differences:
| Property | Cellular Glass | Polyurethane Foam |
|---|---|---|
| Thermal Conductivity | 0.033–0.045 W/m·K | 0.022–0.028 W/m·K |
| Fire Resistance | Non-combustible | Flammable (unless faced) |
| Moisture Resistance | Impermeable | Can absorb moisture |
| Dimensional Stability | Excellent | May shrink or warp |
| Service Temperature Range | -260°C to +430°C | -180°C to +120°C |
| Long-Term Performance | Stable | May degrade |
| Typical Forms | Board, block, pipe, gravel | Board, spray, pipe |
Selection depends on project priorities: if lowest initial k-value is essential and fire risk is managed, polyurethane may be preferred. For long-term durability, non-combustibility, and performance in harsh environments, cellular glass is often the better choice.
What should B2B buyers know about cellular glass thermal conductivity ?
B2B buyers should understand that cellular glass thermal conductivity is a reliable indicator of long-term energy efficiency. Key considerations include:
- Specification accuracy: Confirm k-value data is tested to recognized standards and matches your application’s mean temperature.
- Quality consistency: Source from suppliers with proven production control to ensure uniform thermal properties across shipments.
- Certification: Look for ASTM C552 or equivalent compliance to streamline procurement and approval.
- Packaging and lead time: Cellular glass is typically supplied as boards, blocks, or pipe insulation, with standard and custom sizes available. Check packaging and shipping options to minimize damage and ensure timely delivery.
- Lifecycle cost: While initial cost may be higher than some alternatives, cellular glass’s durability, fire safety, and stable thermal conductivity often reduce total lifecycle costs.
Consult technical data sheets and, where possible, request project-specific test data or references to ensure the insulation will perform as required.
FAQ
Q1: What is the typical density of cellular glass insulation?
A1: Standard densities range from 120 to 160 kg/m³, depending on product form and manufacturer.
Q2: Is cellular glass insulation suitable for exterior wall applications?
A2: Yes, its moisture resistance and non-combustibility make it ideal for exterior walls, especially where fire safety and durability are priorities.
Q3: How does cellular glass perform in humid environments?
A3: Cellular glass is impermeable to water vapor and liquid moisture, so its thermal conductivity and structural integrity are unaffected by humidity.
Q4: Can cellular glass insulation be cut or shaped on site?
A4: Yes, boards and blocks can be cut with standard hand or power tools, allowing for custom fitting around penetrations or irregular surfaces.
Q5: Does cellular glass contain any CFCs or HCFCs?
A5: No, cellular glass is made from recycled glass and contains no ozone-depleting substances.
Conclusion
Cellular glass thermal conductivity provides reliable, long-term insulation performance for demanding applications. Its stability, fire resistance, and moisture-proof nature make it a preferred choice for engineers seeking durable insulation solutions.