Insulation datasheets are technically accurate and frequently misleading at the same time, because the selection of what to print is itself a sales decision. Here is how to read one critically, including ours.
Thermal conductivity: ask for the curve, not the number
A single conductivity value is almost always quoted at 25 C, and for a hot service application it is close to useless on its own. Conductivity rises with temperature, sometimes by a factor of three or more across a product range. Always ask for the full curve and use the value at your actual mean temperature. A supplier who will not provide the curve is telling you something.
Maximum service temperature: ask what fails first
Maximum service temperature is a judgement, not a physical constant. Ask what happens at that limit: does the material shrink, slump, lose hydrophobicity, or simply perform worse? Ask for shrinkage data after sustained exposure, because a blanket that shrinks three percent opens gaps at every joint and the installed system fails long before the material does.
Density: relevant, but not how you think
Density mostly tells you about handling, shipping weight and load on supports. It is a poor proxy for thermal performance. Do not let a density comparison stand in for a conductivity comparison.
Hydrophobicity: ask how it was measured, and how it ages
- Which test method, and at what temperature
- Is the material hydrophobic throughout its thickness or only at a facing
- Does hydrophobicity survive extended exposure at service temperature
- What happens after a wet-dry cycle, which is the real service condition
Fire performance: the words matter enormously
Non-combustible, fire resistant, fire rated and jet fire tested mean four different things. A material can be non-combustible and still provide no useful protection duration. Ask for the test standard, the report number and the tested build-up, and check that the build-up matches what you intend to install.
What is never on the datasheet but should be asked
- Batch to batch consistency and whether a certificate of analysis is provided
- Lead time and minimum order quantity for your actual sizes, not standard stock
- Whether an installation guide and contractor training are available
- What the supplier will put in writing versus what they will only say on a call
- Whether they will tell you when their product is the wrong choice
