The Thermal Conductivity Calculator is designed to compute the thermal conductivity of materials or determine the heat flux through objects based on Fourier’s law. This guide offers a clear explanation of thermal conductivity, demonstrates how to apply the heat flux formula accurately, and discusses the units of thermal conductivity in detail.
What Is Thermal Conductivity?
Thermal Conductivity is defined as how well a material can conduct heat, a characteristic intrinsic to the material itself, unaffected by external factors or the mass of the object. This property is directly related to the amount of heat energy conveyed and the distance over which this heat is transferred, while being inversely related to the difference in temperature throughout the material.
The most common example looked at within educational institutions is a wall with insulation. So consider a wall with insulation. If it only allows a minimal amount of heat to pass through, its thermal conductivity is considered to be low.
Fourier’s Law Definition
Fourier’s Law, states that the rate at which heat is transferred through a material is proportional to the negative gradient of the temperature and the area through which the heat is being transferred. In simpler terms, it means that heat moves from regions of higher temperature to regions of lower temperature, and the amount of heat transferred per unit of time is directly related to how quickly the temperature changes in space (temperature gradient) and the size of the area over which the heat transfer occurs.
Heat Flux Definiton
Heat flux refers to the amount of heat energy that moves through a specific area every second. It is used within Fourier’s Law and is usually combined as seen below.
Heat Flux and Fourier’s Law
According to Fourier’s law, heat flux is defined as:
Where:
- q – Heat Flux, measured in (W/m²)
- Δx – Thickness of the object (or the distance the heat has to travel) in (m)
- ΔT – The temperature difference across the object in (K)
- λ – The Thermal Conductivity of the material (W/mK)
The negative sign expresses the direction of heat transfer. Due to heat always flowing from a warm area to a cold area, the direction of heat transfer is always opposite to the temperature gradient.
Thermal Conductivity Calculator
Table To Show The Thermal Conductivity Constants of Materials and Substances
| Materials /Substances | Thermal Conductivity (W/mK) |
|---|---|
| Acetals | 0.23 |
| Acetone | 0.16 |
| Acetylene (gas) | 0.018 |
| Acrylic | 0.2 |
| Agate | 10.9 |
| Air, atmosphere (gas) | 0.0262 |
| Air, elevation 10000 m | 0.02 |
| Alcohol | 0.17 |
| Alumina | 36 |
| Aluminum | 236 |
| Aluminum Brass | 121 |
| Aluminum Oxide | 30 |
| Ammonia (gas) | 0.0249 |
| Antimony | 18.5 |
| Apple (85.6% moisture) | 0.39 |
| Argon (gas) | 0.016 |
| Asbestos mill board 1) | 0.14 |
| Asbestos, loosely packed 1) | 0.15 |
| Asbestos-cement 1) | 2.07 |
| Asbestos-cement board 1) | 0.744 |
| Asbestos-cement sheets 1) | 0.166 |
| Asphalt | 0.75 |
| Balsa wood | 0.048 |
| Beef, lean (78.9 % moisture) | 0.43 – 0.48 |
| Benzene | 0.16 |
| Beryllium | 201 |
| Bismuth | 8.1 |
| Bitumen | 0.17 |
| Bitumen | 0.17 |
| Bitumen/felt layers | 0.5 |
| Blast furnace gas (gas) | 0.02 |
| Boiler scale | 1.2 – 3.5 |
| Boron | 25 |
| Brass | 109 |
| Breeze block | 0.10 – 0.20 |
| Brick dense | 1.31 |
| Brick, fire | 0.47 |
| Brick, insulating | 0.15 |
| Brickwork, common (Building Brick) | 0.6 -1.0 |
| Brickwork, dense | 1.6 |
| Bromine (gas) | 0.004 |
| Bronze | 70 |
| Brown iron ore | 0.58 |
| Butter (15% moisture content) | 0.2 |
| Cadmium | 96.6 |
| Calcium silicate | 0.05 |
| Carbon | 1.7 |
| Carbon dioxide (gas) | 0.0146 |
| Carbon monoxide | 0.0232 |
| Carbon Steel | 45 |
| Cast iron | 53 |
| Cellulose acetate, molded, sheet | 0.17 – 0.33 |
| Cellulose nitrate, celluloid | 0.12 – 0.21 |
| Cellulose, cotton, wood pulp and regenerated | 0.23 |
| Cement, mortar | 1.73 |
| Cement, Portland | 0.29 |
| Ceramic materials | 26-30 |
| Chalk | 0.09 |
| Charcoal | 0.084 |
| Chlorinated poly-ether | 0.13 |
| Chlorine (gas) | 0.0081 |
| Chrom-oxide | 0.42 |
| Chrome Nickel Steel | 16.3 |
| Chromium | 94 |
| Clay, dry to moist | 0.15 – 1.8 |
| Clay, saturated | 0.6 – 2.5 |
| Coal | 0.2 |
| Cobalt | 69.21 |
| Cod (83% moisture content) | 0.54 |
| Coke | 0.184 |
| Concrete, dense | 1.0 – 1.8 |
| Concrete, lightweight | 0.1 – 0.3 |
| Concrete, medium | 0.4 – 0.7 |
| Concrete, stone | 1.7 |
| Constantan | 23.3 |
| Copper | 398 |
| Corian (ceramic filled) | 1.06 |
| Cork | 0.07 |
| Cork board | 0.043 |
| Cork, re-granulated | 0.044 |
| Cotton | 0.04 |
| Cotton wool | 0.029 |
| Cotton Wool insulation | 0.029 |
| Cupronickel 30% | 30 |
| Diamond | 1000 |
| Diatomaceous earth (Sil-o-cel) | 0.06 |
| Diatomite | 0.12 |
| Dichlorodifluoromethane R-12 (liquid) | 0.09 |
| Dichlorodifluoromethane R-12 (gas) | 0.007 |
| Duralium | 140 |
| Earth, dry | 1.5 |
| Ebonite | 0.17 |
| Emery | 11.6 |
| Engine Oil | 0.15 |
| Epoxy | 0.35 |
| Ethane (gas) | 0.018 |
| Ether | 0.14 |
| Ethylene (gas) | 0.017 |
| Ethylene glycol | 0.25 |
| Feathers | 0.034 |
| Felt insulation | 0.04 |
| Fiber hardboard | 0.2 |
| Fiber insulating board | 0.048 |
| Fiberglass | 0.04 |
| Fire-clay brick 500 o C | 1.4 |
| Fluorine (gas) | 0.0254 |
| Foam glass | 0.045 |
| Gasoline | 0.15 |
| Glass | 1.05 |
| Glass, Pearls, dry | 0.18 |
| Glass, Pearls, saturated | 0.76 |
| Glass, window | 0.96 |
| Glass, wool Insulation | 0.04 |
| Glycerol | 0.28 |
| Gold | 318 |
| Granite | 1.7 – 4.0 |
| Graphite | 168 |
| Gravel | 0.7 |
| Ground or soil, dry area | 0.5 |
| Ground or soil, moist area | 1 |
| Ground or soil, very dry area | 0.33 |
| Ground or soil, very moist area | 1.4 |
| Gypsum board | 0.17 |
| Hairfelt | 0.05 |
| Hardboard high density | 0.15 |
| Hardwoods (oak, maple..) | 0.16 |
| Hastelloy C | 12 |
| Helium (gas) | 0.142 |
| Honey (12.6% moisture content) | 0.5 |
| Hydrochloric acid (gas) | 0.013 |
| Hydrogen (gas) | 0.168 |
| Hydrogen sulfide (gas) | 0.013 |
| Ice (0 o C, 32 o F) | 2.18 |
| Inconel | 15 |
| Ingot iron | 47 – 58 |
| Insulation materials | 0.035 – 0.16 |
| Iodine | 0.44 |
| Iridium | 147 |
| Iron | 73 |
| Iron-oxide | 0.58 |
| Kapok insulation | 0.034 |
| Kerosene | 0.15 |
| Krypton (gas) | 0.0088 |
| Lead | 34 |
| Leather, dry | 0.14 |
| Limestone | 1.26 – 1.33 |
| Lithium | 85 |
| Magnesia insulation (85%) | 0.07 |
| Magnesite | 4.15 |
| Magnesium | 156 |
| Magnesium alloy | 70 – 145 |
| Marble | 2.08 – 2.94 |
| Mercury, liquid | 28.9 |
| Methane (gas) | 0.03 |
| Methanol | 0.21 |
| Mica | 0.71 |
| Milk | 0.53 |
| Mineral wool insulation materials, wool blankets .. | 0.04 |
| Molybdenum | 142 |
| Monel | 22 |
| Neon (gas) | 0.046 |
| Neoprene | 0.05 |
| Nickel | 92 |
| Nitric oxide (gas) | 0.0238 |
| Nitrogen (gas) | 0.024 |
| Nitrous oxide (gas) | 0.0151 |
| Nylon 6, Nylon 6/6 | 0.25 |
| Oil, machine lubricating SAE 50 | 0.15 |
| Olive oil | 0.17 |
| Oxygen (gas) | 0.024 |
| Palladium | 70.9 |
| Paper | 0.05 |
| Paraffin Wax | 0.25 |
| Peat | 0.08 |
| Perlite, atmospheric pressure | 0.031 |
| Perlite, vacuum | 0.00137 |
| Phenol-formaldehyde moulding compounds | 0.13 – 0.25 |
| Phenolic cast resins | 0.15 |
| Phosphorbronze | 110 |
| Pinchbeck | 159 |
| Pit coal | 0.24 |
| Pitch | 0.13 |
| Plaster light | 0.2 |
| Plaster, metal lath | 0.47 |
| Plaster, sand | 0.71 |
| Plaster, wood lath | 0.28 |
| Plasticine | 0.65 – 0.8 |
| Plastics, foamed (insulation materials) | 0.03 |
| Platinum | 71.6 |
| Plutonium | 6 |
| Plywood | 0.13 |
| Polycarbonate | 0.19 |
| Polyester | 0.05 |
| Polyethylene high density, PEH | 0.42 – 0.51 |
| Polyethylene low density, PEL | 0.33 |
| Polyisoprene hard rubber | 0.16 |
| Polyisoprene natural rubber | 0.13 |
| Polymethylmethacrylate | 0.17 – 0.25 |
| Polypropylene, PP | 0.1 – 0.22 |
| Polystyrene, expanded | 0.03 |
| Polystyrol | 0.043 |
| Polytetrafluoroethylene (PTFE) | 0.25 |
| Polyurethane foam | 0.03 |
| Polyvinylchloride, PVC | 0.19 |
| Porcelain | 1.5 |
| Potassium | 1 |
| Potato, raw flesh | 0.55 |
| Propane (gas) | 0.015 |
| Pyrex glass | 1.005 |
| Quartz mineral | 3 |
| Radon (gas) | 0.0033 |
| Red metal | |
| Rhenium | 39.6 |
| Rhodium | 151 |
| Rock Wool insulation | 0.045 |
| Rock, porous volcanic (Tuff) | 0.5 – 2.5 |
| Rock, solid | 2 – 7 |
| Rosin | 0.32 |
| Rubber, cellular | 0.045 |
| Rubber, natural | 0.13 |
| Rubidium | 58 |
| Salmon (73% moisture content) | 0.5 |
| Sand, dry | 0.15 – 0.25 |
| Sand, moist | 0.25 – 2 |
| Sand, saturated | 2 – 4 |
| Sandstone | 1.7 |
| Sawdust | 0.08 |
| Selenium | 0.52 |
| Sheep wool | 0.039 |
| Silica aerogel | 0.02 |
| Silicon carbide | 120 |
| Silicon cast resin | 0.15 – 0.32 |
| Silicon oil | 0.1 |
| Silver | 429 |
| Slag wool | 0.042 |
| Slate | 2.01 |
| Snow (temp < 0 o C) | 0.05 – 0.25 |
| Sodium | 140 |
| Softwoods (fir, pine ..) | 0.12 |
| Soil, clay | 1.1 |
| Soil, saturated | 0.6 – 4 |
| Soil, with organic matter | 0.15 – 2 |
| Solder 50-50 | 50 |
| Soot | 0.07 |
| Steam, low pressure | 0.0188 |
| Steam, saturated | 0.0184 |
| Steatite | 2 |
| Steel, Carbon | 10-18 |
| Steel, Stainless | 10-18 |
| Straw slab insulation, compressed | 0.09 |
| Styrofoam | 0.033 |
| Sugars | 0.087 – 0.22 |
| Sulfur dioxide (gas) | 0.0086 |
| Sulfur, crystal | 0.2 |
| Tantalum | 57 |
| Tar | 0.19 |
| Tellurium | 4.9 |
| Thorium | 54 |
| Timber, alder | 0.17 |
| Timber, ash | 0.16 |
| Timber, birch | 0.14 |
| Timber, larch | 0.12 |
| Timber, maple | 0.16 |
| Timber, oak | 0.17 |
| Timber, pitchpine | 0.14 |
| Timber, pockwood | 0.19 |
| Timber, red beech | 0.14 |
| Timber, red pine | 0.15 |
| Timber, walnut | 0.15 |
| Timber, white pine | 0.15 |
| Tin | 67 |
| Titanium | 22 |
| Tungsten | 170 |
| Uranium | 27 |
| Urethane foam | 0.021 |
| Vacuum | 0 |
| Vermiculite granules | 0.065 |
| Vinyl ester | 0.25 |
| Water | 0.606 |
| Water, vapor (steam) | 28 |
| Wheat flour | 0.45 |
| White metal | 35 – 70 |
| Wood across the grain, balsa | 0.055 |
| Wood across the grain, white pine | 0.12 |
| Wood across the grain, yellow pine, timber | 0.147 |
| Wood wool, slab | 0.1 – 0.15 |
| Wood, oak | 0.17 |
| Wool, felt | 0.07 |
| Xenon (gas) | 0.0051 |
| Zinc | 120 |
