Wall Emissivity is defined as the fraction of energy being emitted relative to that emitted by a thermally black surface (a black body). Most objects have an emissivity between 0 and 1. The surface of a perfect black body has an emissivity of 1, objects with lower emissivities emit radiation at correspondingly lower rates. cove.tool is referring ASHRAE Handbook – Fundamentals version 2009 for wall emissivity value. A list of sample wall emissivity values can be found below.
Surface Material | Emissivity Coefficient ( ε ) |
Alloy 24ST Polished | 0.09 |
Alumina, Flame sprayed | 0.8 |
Aluminum Commercial sheet | 0.09 |
Aluminum Foil | 0.04 |
Aluminum Commercial Sheet | 0.09 |
Aluminum Heavily Oxidized | 0.2 - 0.31 |
Aluminum Highly Polished | 0.039 - 0.057 |
Aluminum Anodized | 0.77 |
Aluminum Rough | 0.07 |
Aluminum paint | 0.27 - 0.67 |
Antimony, polished | 0.28 - 0.31 |
Asbestos board | 0.96 |
Asbestos paper | 0.93 - 0.945 |
Asphalt | 0.93 |
Basalt | 0.72 |
Black Body Matt | 1.00 |
Black lacquer on iron | 0.875 |
Black Parson Optical | 0.95 |
Black Silicone Paint | 0.93 |
Black Epoxy Paint | 0.89 |
Black Enamel Paint | 0.80 |
Brass Dull Plate | 0.22 |
Brass Rolled Plate Natural Surface | 0.06 |
Brass Polished | 0.03 |
Brass Oxidized 600oC | 0.6 |
Brick, red rough | 0.93 |
Brick, fireclay | 0.75 |
Carbon, not oxidized | 0.81 |
Carbon filament | 0.77 |
Carbon pressed filled surface | 0.98 |
Cast Iron, newly turned | 0.44 |
Cast Iron, turned and heated | 0.60 - 0.70 |
Cement | 0.54 |
Chromium polished | 0.058 |
Clay | 0.91 |
Coal | 0.80 |
Concrete | 0.85 |
Concrete, rough | 0.94 |
Concrete tiles | 0.63 |
Cotton cloth | 0.77 |
Copper electroplated | 0.03 |
Copper heated and covered with thick oxide layer | 0.78 |
Copper Polished | 0.023 - 0.052 |
Copper Nickel Alloy, polished | 0.059 |
Glass smooth | 0.92 - 0.94 |
Glass, pyrex | 0.85 - 0.95 |
Granite, natural surface | 0.96 |
Gravel | 0.28 |
Gypsum | 0.85 |
Inconel X Oxidized | 0.71 |
Iron polished | 0.14 - 0.38 |
Iron, plate rusted red | 0.61 |
Iron, dark gray surface | 0.31 |
Iron, rough ingot | 0.87 - 0.95 |
Lampblack paint | 0.96 |
Lead pure unoxidized | 0.057 - 0.075 |
Lead Oxidized | 0.43 |
Limestone | 0.90 - 0.93 |
Lime wash | 0.91 |
Magnesium Oxide | 0.20 - 0.55 |
Magnesium Polished | 0.07 - 0.13 |
Marble White | 0.95 |
Masonry Plastered | 0.93 |
Mild Steel | 0.20 - 0.32 |
Molybdenum polished | 0.05 - 0.18 |
Mortar | 0.87 |
Nickel, elctroplated | 0.03 |
Nickel, polished | 0.072 |
Nickel, oxidized | 0.59 - 0.86 |
Nichrome wire, bright | 0.65 - 0.79 |
Oak, planed | 0.89 |
Oil paints, all colors | 0.92 - 0.96 |
Paper offset | 0.55 |
Plaster | 0.98 |
Platinum, polished plate | 0.054 - 0.104 |
Pine | 0.84 |
Plaster board | 0.91 |
Porcelain, glazed | 0.92 |
Paint | 0.96 |
Paper | 0.93 |
Plaster, rough | 0.91 |
Plastics | 0.90 - 0.97 |
Polypropylene | 0.97 |
Polytetrafluoroethylene (PTFE) | 0.92 |
Porcelain glazed | 0.93 |
Pyrex | 0.92 |
PVC | 0.91 - 0.93 |
Quartz glass | 0.93 |
Roofing paper | 0.91 |
Rubber, foam | 0.90 |
Rubber, hard glossy plate | 0.94 |
Rubber, natural hard | 0.91 |
Rubber, natural oft | 0.86 |
Salt | 0.34 |
Sand | 0.9 |
Sandstone | 0.59 |
Sapphire | 0.48 |
Sawdust | 0.75 |
Silica | 0.79 |
Silicon Carbide | 0.83 - 0.96 |
Silver Polished | 0.02 - 0.03 |
Soil | 0.90 - 0.95 |
Steel Oxidized | 0.79 |
Steel Polished | 0.07 |
Stainless Steel, weathered | 0.85 |
Stainless Steel, polished | 0.075 |
Stainless Steel, type 301 | 0.54 - 0.63 |
Steel Galvanized Old | 0.88 |
Steel Galvanized New | 0.23 |
Thoria | 0.28 |
Tile | 0.97 |
Tin unoxidized | 0.04 |
Titanium polished | 0.19 |
Tungsten aged filament | 0.032 - 0.35 |
Wood Beech, planned | 0.935 |
Wood Oak, planned | 0.885 |
Wood, Pine | 0.95 |
Wrought Iron | 0.94 |
Zinc Tarnished | 0.25 |
Zinc polished | 0.045 |