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

Beryllium

0.18

Beryllium, Anodized

0.9

Bismuth, bright

0.34

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

Cadmium

0.02

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

Gold not polished

0.47

Gold polished

0.025

Granite, natural surface

0.96

Gravel

0.28

Gypsum

0.85

Ice smooth

0.966

Ice rough

0.985

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

Magnesia

0.72

Magnesite

0.38

Magnesium Oxide

0.20 - 0.55

Magnesium Polished

0.07 - 0.13

Marble White

0.95

Masonry Plastered

0.93

Mercury liquid

0.1

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

Snow

0.96 - 0.98

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 polished

0.04

Tungsten aged filament

0.032 - 0.35

Water (0 - 100oC)

0.95 - 0.963

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

Related Links

  1. Wall

  2. Guide to your first cove.tool project

  3. Below Grade

  4. Envelope Heat Capacity

  5. Emissivity

Did this answer your question?