COMFORT HEATING - Training Comfort Heating Sizing Guide
General Industrial Sizing Guide
Methods of Heat Transfer
To thoroughly understand which method of comfort heating best meets your application,
it is important to understand the basic methods of heat transfer. Heat transfer
is accomplished by CONDUCTION, CONVECTION, or RADIATION.
CONDUCTION is defined as transferring heat through a conducting
medium by way of direct contact.
CONVECTION transfers heat via a medium such as liquid or air. In
comfort heating a source of heat is used to warm the air and create a desired comfort
level around people. Heated air can be circulated by fans or blowers to disperse
the heat in a large enclosed area. Home heating with a forced-air furnace is an
example of CONVECTION heat.
RADIANT or INFRARED heat uses invisible, electromagnetic
waves from an energy source. An example of electromagnetic infrared energy is heat
from the sun. In an infrared system, these energy waves are created by a heat source
- quartz lamp, quartz tube, or tubular. These waves are directed by optically designed
reflectors toward or onto the object or person being heated. A fireplace is
a familiar form of radiant heat.
Sizing Comfort Heating Applications
To get an approximate sizing of the heating requirements for a room, the following
guide may be utilized. For a more detailed analysis it is recommended that the ASHRAE
guidelines be followed when performing an analysis for a complete building. Also
available is a computer-sizing tool that is designed to perform room-by-room heat
loss estimates. When sizing the job, the first step is to determine the construction
data and sizing requirements. You will need to collect the following information:
- Voltage and phase
- Length, width, and height of building
- R-factor for ceilings and walls
- Air changes or how much fresh air is brought in per hour
- Outside lowest temperature
- Desired inside temperature
- Size and number of windows and doors
- Floor Construction
Quick Estimations of Room Heat Loss
If a quick estimate is required, Graph 1 may be used to estimate heating requirements.
This is an excellent chart when doing up front budgeting and sizing, or if there
is simply a small room that needs some heat.
Graph 1: Quick Estimation Chart for Various Room Heat Loss Conditions
|
Curve A:
|
Rooms with little or no outside exposure. No roof or floor with outside exposure;
only
|
|
one wall exposed with not over 15% door and window area.
|
|
Curve B:
|
Rooms with average exposure. Roof and 2 or 3 exposed walls, up to 30% door and window
area, but with roof, walls, and floor insulated if exposed to outside temperatures.
|
|
Curve C:
|
Rooms with roof, walls, and floor uninsulated but with inside facing on walls
and ceiling.
|
|
Curve D:
|
Exposed guard houses, pump houses, cabins, and poorly constructed rooms with reasonably
tight joints but no insulation. Typical construction of corrugated metal or plywood
siding, single layer roofs.
|
General Industrial Sizing Guide
If more detail is required when doing the application sizing, a worksheet can be
found at the back of this manual that may be used when gathering information and
performing the calculations. A sample of the worksheet is shown below. The factors
for the Uvalues may be found in Table 1 on the next page. NOTE: U = 1 / R.
In addition, outside design temperatures may be found in Table 2 for various parts
of the country.
Table 1: U-Values for Common Building Materials
|
|
MATERIAL
|
DESCRIPTION
|
THICKNESS
|
R- FACTOR
|
|
Glass
|
Single Pane
|
-
|
.88
|
|
|
Double Pane
|
-
|
2.22
|
|
|
Triple Pane
|
-
|
3.56
|
|
|
Glass Block (avg.) 2”
|
-
|
2.50
|
|
|
Glass Block (avg.) 4”
|
-
|
3.22
|
|
|
Translucent Curtain Wall
|
-
|
2.50
|
|
|
|
|
|
|
Woods
|
Hardwoods (Maple, Oak)
|
1”
|
0.91
|
|
|
Softwoods (Fir, Pine)
|
1”
|
1.25
|
|
|
|
|
|
|
Insulating Materials/
|
|
|
|
|
Blanket and Batt:
|
Cotton Fiber
|
3” to 3-1/2”
|
11.00
|
|
|
Mineral Wool
|
5 1⁄4” to 6-1/2”
|
19.00
|
|
|
Wood Fiber
|
8-1/2”
|
30.00
|
|
|
|
|
|
|
Board and Slabs:
|
Cellular Glass
|
1”
|
2.50
|
|
|
Corkboard
|
1”
|
3.70
|
|
|
Glass Fiber (Avg.)
|
1”
|
4.00
|
|
|
Expanded Rubber (Rigid)
|
1”
|
4.55
|
|
|
Expanded Polystyrene (Styrofoam)
|
1”
|
4.35
|
|
|
Expanded Polyurethene
|
1”
|
6.25
|
|
|
Rapco Foam
|
1”
|
5.00
|
|
|
Mineral Wood with Resin Binder
|
1”
|
3.70
|
|
|
Mineral Fiberboard, wet felted (Acoustical tile)
|
1”
|
2.86
|
|
|
Mineral Fiberboard, molded (Acoustical tile)
|
1”
|
2.38
|
|
|
Homosote
|
1”
|
2.38
|
|
|
Roof Insulation (performed for above deck)
|
1”
|
2.78
|
|
|
|
|
|
|
Loose Fill:
|
Cellulose 1 “ 3.70
|
|
|
|
|
Mineral Wool (glass, slag or rock)
|
1”
|
3.70
|
|
|
Sawdust or Shavings
|
1”
|
2.22
|
|
|
Silica Aerogel
|
1”
|
6.25
|
|
|
Vermiculite (Expanded)
|
1”
|
2.13
|
|
|
Wood Fiber (Avg.)
|
1”
|
3.57
|
|
|
Perlite (Expanded)
|
1”
|
2.70
|
|
|
|
|
|
|
Masonry Materials:
|
Concretes:
|
|
|
|
|
Cement Mortar
|
1”
|
0.20
|
|
|
Gypsum-Fiber Concrete
|
1”
|
0.60
|
|
|
Stucco
|
1”
|
0.20
|
|
|
Dry Wall
|
1/2”
|
0.50
|
|
|
|
|
|
|
Masonry Units:
|
Brick, Common (Avg.)
|
1”
|
0.20
|
|
|
Brick Face (Avg.)
|
1”
|
0.11
|
|
|
Concrete Blocks (three oval core)
|
|
|
|
|
Sand & Gravel Aggregate
|
8”
|
1.11
|
|
|
Cinder Aggregate
|
8”
|
1.72
|
|
|
Lightweight Aggregate
|
8”
|
2.00
|
|
|
Stucco
|
1”
|
0.20
|
|
Siding Materials:
|
Asbestos-Cement Shingles
|
-
|
0.21
|
|
|
Wood (7-1⁄2” Exposure)
|
16”
|
0.87
|
|
|
Wood (12” Exposure)
|
10”
|
1.19
|
|
|
Asbestos-Cement 1⁄4”, lapped
|
-
|
0.21
|
|
|
Asphalt roll siding
|
-
|
0.15
|
|
|
Asphalt insulating siding 112’ bd.
|
-
|
1.46
|
|
|
Wood, plywood, %’ lapped
|
-
|
0.59
|
|
|
Wood, bevel, 1⁄2’ x 8” lapped
|
-
|
0.81
|
|
|
Sheet Metal, single sheet (avg.)
|
-
|
0.83
|
|
|
Architectural Glass
|
-
|
0.10
|
|
|
|
|
|
|
Roofing:
|
Asbestos-Cement Shingles
|
-
|
0.21
|
|
|
Asphalt Shingles - 0.44
|
|
|
|
|
Slate 1⁄2 “ 0.05
|
|
|
|
|
Built-up Roofing 3/8 “ 0.33
|
|
|
|
|
|
|
|
|
Air Spaces:
|
Horizontal: Ordinary materials-vertical flow
|
3⁄4” to 4”
|
0.80
|
|
|
Vertical: Ordinary matericals-horizontal flow
|
3⁄4” to 4”
|
.96
|
|
|
|
|
|
|
Exposed Doors:
|
Metal-Single Sheet
|
-
|
0.83
|
|
|
Wood 1”
|
1.56
|
|
|
|
Wood 2”
|
2.33
|
|
NOTE: R = L/k, where L is the thickness in inches and k is BTU*in / (ft 2
*°F*hr)
Table 2: Typical Outside Design Temperatures for the United States
|
|
State
|
City
|
Mean Wind Speed: MPH3
|
Heating Degree Days1
|
Yearly Snowfall Mean4
|
Outside Design Temp
|
|
Alabama
|
Birmingham
|
7.4
|
2844.0
|
1.2
|
17.0
|
|
|
Huntsville
|
8.0
|
3302.0
|
2.5
|
11.0
|
|
|
Mobile
|
9.2
|
1684.0
|
0.5
|
25.0
|
|
|
Montgomery
|
6.8
|
2269.0
|
0.4
|
22.0
|
|
Alaska
|
Anchorage
|
6.7
|
10911.0
|
70.2
|
-23.0
|
|
|
Fairbanks
|
5.3
|
14344.0
|
68.8
|
-51.0
|
|
|
Juneau
|
8.5
|
9007.0
|
108.2
|
-4.0
|
|
|
Nome
|
10.8
|
14325.0
|
54.5
|
-31.0
|
|
Arizona
|
Flagstaff
|
7.4
|
7322.0
|
88.6
|
-2.0
|
|
|
Pheonix
|
6.2
|
1552.0
|
0.0
|
31.0
|
|
|
Tucson
|
8.2
|
1752.0
|
1.4
|
28.0
|
|
|
Winslow
|
8.8
|
4733.0
|
11.1
|
5.0
|
|
Arkansas
|
Ft. Smith
|
7.6
|
3336
|
5.7
|
12.0
|
|
|
Little Rock
|
8.1
|
3354
|
5.1
|
15.0
|
|
California
|
Bakersfield
|
6.4
|
2185
|
0.0
|
30.0
|
|
|
Bishop
|
N/A
|
4313
|
8.6
|
10.0
|
|
|
Fresno
|
6.3
|
2650
|
0.1
|
28.0
|
|
|
Los Angeles
|
7.4
|
1819
|
0.0
|
37.0
|
|
|
Sacramento
|
8.3
|
2843
|
0.1
|
30.0
|
|
|
San Diego
|
6.7
|
1507
|
0.0
|
42.0
|
|
|
San Francisco/Oakland
|
8.2
|
3080
|
0.1
|
35.0
|
|
Colorado
|
Colorado Springs
|
10.4
|
6473
|
39.3
|
-3.0
|
|
|
Denver
|
9.1
|
6016
|
59.0
|
-5.0
|
|
|
Grand Junction
|
8.1
|
5605
|
26.3
|
2.0
|
|
|
Pueblo
|
8.7
|
5394
|
30.9
|
-7.0
|
|
Connecticut
|
Hartford
|
8.9
|
6350
|
53.0
|
3.0
|
|
|
New Haven
|
N/A
|
6026
|
N/A
|
3.0
|
|
|
Bridgeport
|
12.0
|
5461
|
26.8
|
6.0
|
|
Delaware
|
Wilmington
|
9.1
|
4940
|
19.9
|
10.0
|
|
D.C.
|
Washington DC
|
9.3
|
4211
|
16.3
|
14.0
|
|
Florida
|
Daytona Beach
|
9.0
|
902
|
0.0
|
32.0
|
|
|
Jacksonville
|
8.5
|
1327
|
0.0
|
29.0
|
|
|
Miami
|
9.1
|
206
|
0.0
|
44.0
|
|
|
Orlando
|
8.7
|
733
|
0.0
|
44.0
|
|
|
Pensacola
|
8.3
|
1578
|
0.3
|
25.0
|
|
|
Tallahassee
|
6.9
|
1563
|
0.0
|
27.0
|
|
|
Tampa
|
8.8
|
718
|
0.0
|
36.0
|
|
Georgia
|
Atlanta
|
9.1
|
3095
|
1.5
|
17.0
|
|
|
Augusta
|
6.6
|
2547
|
0.9
|
20.0
|
|
|
Columbus/Lawson
|
6.9
|
2378
|
0.4
|
21.0
|
|
|
Macon
|
7.8
|
2240
|
1.0
|
21.0
|
|
|
Rome
|
N/A
|
3342
|
2.0
|
17.0
|
|
|
Savannah/Travis Fld.
|
8.1
|
1952
|
0.4
|
24.0
|
|
Idaho
|
Boise
|
9.0
|
5833
|
21.5
|
3.0
|
|
|
Lewiston
|
N/A
|
5464
|
17.9
|
-1.0
|
|
|
Pocatello
|
10.3
|
7063
|
40.0
|
-8.0
|
|
Illinois
|
Rockford
|
9.9
|
6845
|
34.1
|
-9.0
|
|
|
Moline
|
9.9
|
6395
|
30.3
|
-9.0
|
|
|
Peoria
|
10.3
|
6098
|
24.3
|
-8.0
|
|
|
Springfield
|
11.4
|
5558
|
23.1
|
-3.0
|
|
|
Chicago
|
10.3
|
6497
|
37.4
|
-8.0
|
|
|
|
|
|
|
|
|
Indiana
|
Evansville
|
8.2
|
4629
|
13.4
|
4
|
|
|
Fort Wayne
|
10.3
|
6209
|
31.5
|
-4
|
|
|
Indianapolis
|
9.7
|
5577
|
21.6
|
-2
|
|
|
South Bend
|
10.6
|
6462
|
68.5
|
-3
|
|
|
Terre Haute
|
N/A
|
5366
|
N/A
|
-2
|
|
|
|
|
|
|
|
|
Iowa
|
Burlington
|
10.3
|
6149
|
25.7
|
-7
|
|
|
Des Moines
|
11.1
|
6710
|
33.1
|
-10
|
|
|
Dubuque
|
N/A
|
7277
|
42.6
|
-12
|
|
|
Sioux City
|
10.9
|
6953
|
30.6
|
-11
|
|
|
Waterloo
|
10.7
|
7415
|
31.2
|
-15
|
|
|
|
|
|
|
|
|
Kansas
|
Dodge City
|
14.1
|
5046
|
18.2
|
0
|
|
|
Goodland
|
12.7
|
6119
|
33.6
|
-5
|
|
|
Topeka
|
10.4
|
5243
|
20.8
|
0
|
|
|
Wichita
|
12.5
|
4687
|
15.1
|
3
|
|
|
|
|
|
|
|
|
Kentucky
|
Lexington
|
9.7
|
4729
|
15.9
|
3
|
|
|
Louisville
|
8.4
|
4645
|
17.6
|
5
|
|
|
|
|
|
|
|
|
Louisiana
|
Baton Rouge
|
7.9
|
1670
|
0.0
|
25
|
|
|
Lake Charles
|
8.8
|
1498
|
0.0
|
27
|
|
|
New Orleans
|
8.3
|
1465
|
0.0
|
29
|
|
|
Shreveport
|
8.8
|
2167
|
0.0
|
20
|
|
|
|
|
|
|
|
|
Maine
|
Caribou
|
11.2
|
9632
|
112.9
|
-8
|
|
|
Portland
|
8.8
|
7498
|
74.5
|
-6
|
|
|
|
|
|
|
|
|
Maryland
|
Baltimore
|
9.4
|
4729
|
21.2
|
10
|
|
|
|
|
|
|
|
|
Massachusetts
|
Boston
|
12.6
|
5621
|
42.1
|
6
|
|
|
Worcester
|
10.4
|
6848
|
74.2
|
0
|
|
Michigan
|
Alpena
|
7.6
|
8518
|
84.9
|
-11
|
|
|
Detroit/Metro.
|
10.4
|
6419
|
39.9
|
3
|
|
|
Flint
|
10.4
|
7041
|
45.3
|
-4
|
|
|
Grand Rapids
|
10.0
|
6801
|
76.6
|
1
|
|
|
Lansing
|
10.3
|
6904
|
48.7
|
-3
|
|
|
Marquette
|
8.3
|
8351
|
107.3
|
-12
|
|
|
Muskegon
|
10.9
|
6890
|
95.9
|
2
|
|
|
Sault Ste. Marie
|
9.6
|
9193
|
110.8
|
-12
|
|
Minnesota
|
Duluth
|
11.4
|
9756
|
77.8
|
-21
|
|
|
International Falls
|
9.1
|
10547
|
60.1
|
-29
|
|
|
Mpls./St. Paul
|
10.5
|
8159
|
46.1
|
-19
|
|
|
Rochester
|
12.7
|
8227
|
44.4
|
-17
|
|
|
St. Cloud
|
8
|
8868
|
43.1
|
-15
|
|
Mississippi
|
Jackson
|
7.6
|
2300
|
0.0
|
21
|
|
|
Meridian
|
6
|
2388
|
0.0
|
19
|
|
Missouri
|
Columbia
|
9.9
|
5083
|
22.0
|
-1
|
|
|
Kansas City
|
10.3
|
5357
|
20.0
|
2
|
|
|
St. Joseph
|
10
|
5440
|
19.2
|
-3
|
|
|
St. Louis
|
9.5
|
4750
|
18.5
|
2
|
|
|
Springfield
|
11.1
|
4570
|
15.5
|
3
|
|
Nebraska
|
Grand Island
|
12.0
|
6425
|
29.0
|
-8
|
|
|
Lincoln
|
10.6
|
6218
|
28.4
|
-5
|
|
|
Norfolk
|
12.6
|
6981
|
28.8
|
-8
|
|
|
North Platte
|
10.3
|
6747
|
29.9
|
-8
|
|
|
Omaha
|
10.8
|
6049
|
32.0
|
-8
|
|
|
Scottsbluff
|
10.7
|
6774
|
38.0
|
-8
|
|
Nevada
|
Elko
|
6.0
|
7483
|
38.9
|
-8
|
|
|
Ely
|
10.5
|
7814
|
47.6
|
-10
|
|
|
Las Vegas
|
9.0
|
2601
|
1.4
|
25
|
|
|
Reno
|
6.4
|
6022
|
26.5
|
5
|
|
New Hampshire
|
Concord
|
6.7
|
7360
|
64.8
|
-8
|
|
New Jersey
|
Atlantic City
|
10.6
|
4940
|
15.8
|
10
|
|
|
Newark
|
10.1
|
5034
|
27.3
|
10
|
|
|
Trenton
|
9.0
|
4952
|
22.7
|
11
|
|
New Mexico
|
Albuquerque
|
9.0
|
4292
|
10.5
|
12
|
|
New York
|
Albany
|
8.9
|
6962
|
65.7
|
-6
|
|
|
Binghamton
|
10.3
|
7285
|
86.9
|
-2
|
|
|
Buffalo
|
12.3
|
6927
|
92.9
|
2
|
|
|
New York/LaGuardia
|
12.2
|
4909
|
26.2
|
11
|
|
|
Rochester
|
9.7
|
6719
|
86.9
|
1
|
|
|
Syracuse
|
9.9
|
6678
|
110.7
|
-3
|
|
North Carolina
|
Asheville
|
7.8
|
4237
|
17.4
|
10
|
|
|
Charlotte
|
7.6
|
3218
|
5.3
|
18
|
|
|
Greensboro/Winston-Salem
|
7.7
|
3825
|
8.7
|
15
|
|
|
Raleigh/Durham
|
7.9
|
3514
|
6.8
|
16
|
|
|
Wilmington
|
9.0
|
2433
|
1.9
|
23
|
|
North Dakota
|
Bismarck
|
10.5
|
9044
|
38.7
|
-23
|
|
|
Fargo
|
12.7
|
9271
|
35.5
|
-22
|
|
|
Grand Forks
|
N/A
|
9871
|
N/A
|
-26
|
|
Ohio
|
Akron/Canton
|
9.9
|
6224
|
47.8
|
1
|
|
|
Cincinnati
|
9.1
|
5070
|
23.9
|
1
|
|
|
Cleveland
|
10.8
|
6154
|
52.2
|
1
|
|
|
Columbus
|
8.7
|
5702
|
27.7
|
0
|
|
|
Dayton
|
10.2
|
5641
|
27.8
|
-1
|
|
|
Mansfield
|
11.1
|
5818
|
41.2
|
0
|
|
|
Toledo
|
9.5
|
6381
|
38.9
|
-3
|
|
|
Youngstown
|
10.1
|
6426
|
57.6
|
-1
|
|
Oklahoma
|
Oklahoma City
|
12.8
|
3695
|
8.8
|
9
|
|
|
Tulsa
|
10.6
|
3680
|
9.1
|
8
|
|
Oregon
|
Baker
|
N/A
|
7087
|
N/A
|
-1
|
|
|
Eugene
|
7.6
|
4739
|
7.6
|
17
|
|
|
Medford
|
4.8
|
4930
|
8.7
|
19
|
|
|
Pendleton
|
9.2
|
5240
|
17.7
|
-2
|
|
|
Portland
|
7.8
|
4632
|
7.4
|
17
|
|
Pennsylvania
|
Allentown
|
9.4
|
5827
|
31.5
|
4
|
|
|
Erie
|
11.4
|
6851
|
83.3
|
4
|
|
|
Harrisburg
|
7.7
|
5224
|
34.5
|
7
|
|
|
Philadelphia
|
9.6
|
4865
|
20.2
|
10
|
|
|
Pittsburgh
|
9.4
|
5930
|
45.3
|
1
|
|
|
Williamsport
|
7.9
|
5982
|
43.8
|
2
|
|
Rhode Island
|
Providence
|
10.7
|
5972
|
38.0
|
5
|
|
South Carolina
|
Charleston
|
8.8
|
2146
|
0.0
|
24
|
|
|
Columbia
|
6.9
|
2598
|
1.7
|
20
|
|
|
Greenville
|
6.8
|
3163
|
5.7
|
18
|
|
South Dakota
|
Aberdeen
|
11.2
|
8616
|
36.4
|
-19
|
|
|
Huron
|
11.9
|
8054
|
39.5
|
-18
|
|
|
Pierre
|
N/A
|
7283
|
N/A
|
-15
|
|
|
Rapid City
|
11.3
|
7324
|
39.3
|
-11
|
|
|
Sioux Falls
|
11.2
|
7838
|
39.1
|
-15
|
|
Tennessee
|
Bristol
|
5.6
|
4306
|
15.6
|
9
|
|
|
Chattanooga
|
6.3
|
3505
|
4.0
|
13
|
|
|
Knoxville
|
7.3
|
3478
|
12.2
|
13
|
|
|
Memphis
|
9.1
|
3227
|
5.5
|
13
|
|
|
Nashville
|
8.0
|
3696
|
10.9
|
9
|
|
Texas
|
Abilene
|
12.2
|
2610
|
4.5
|
15
|
|
|
Amarillo
|
13.7
|
4183
|
14.3
|
6
|
|
|
Austin
|
9.3
|
1737
|
1.0
|
24
|
|
|
Brownsville
|
11.8
|
650
|
0.0
|
35
|
|
|
Dallas/Ft. Worth
|
10.9
|
2382
|
2.9
|
17
|
|
|
El Paso
|
9.5
|
2678
|
4.7
|
20
|
|
|
Galveston
|
11.0
|
1224
|
0.3
|
31
|
|
|
Houston
|
7.6
|
1434
|
0.4
|
27
|
|
|
San Antonio
|
9.4
|
1570
|
0.5
|
18
|
|
Utah
|
Milford N/A
|
6412
|
43.8
|
5
|
|
|
|
Salt Lake City
|
8.7
|
5983
|
58.3
|
3
|
|
Vermont
|
Burlington
|
8.8
|
7876
|
79.3
|
-12
|
|
Virginia
|
Lynchburg
|
7.9
|
4233
|
18.1
|
12
|
|
|
Norfolk
|
10.6
|
3488
|
7.0
|
20
|
|
|
Richmond
|
7.5
|
3939
|
13.9
|
14
|
|
|
Roanoke
|
8.4
|
4307
|
24.1
|
12
|
|
Washington
|
Olympia
|
6.7
|
5530
|
19.2
|
16
|
|
|
Seattle
|
9.2
|
5185
|
14.6
|
21
|
|
|
Spokane
|
8.7
|
6835
|
53.3
|
-6
|
|
|
Walla Walla
|
5.3
|
4835
|
20.0
|
0
|
|
|
Yakima
|
7.2
|
6009
|
24.5
|
-2
|
|
West Virginia
|
Beckley
|
9.5
|
5613
|
55.8
|
-2
|
|
|
Charleston
|
6.5
|
4590
|
29.6
|
7
|
|
|
Huntingdon
|
6.4
|
4624
|
24.1
|
5
|
|
Wisconsin
|
Green Bay
|
10.2
|
8098
|
44.6
|
-13
|
|
|
LaCrosse
|
8.8
|
7417
|
42.9
|
-13
|
|
|
Madison
|
9.9
|
7730
|
40.2
|
-11
|
|
|
Milwaukee
|
11.8
|
7444
|
45.9
|
-8
|
|
Wyoming
|
Casper
|
13.1
|
7555
|
73.9
|
-11
|
|
|
Cheyenne
|
13.3
|
7255
|
51.2
|
-9
|
1 Heating Degree Days – A unit based upon temperature difference
and time, used in estimating fuel consumption and specifying nominal heating load
of a building in winter. For any one-day, when the mean temperature is less than
65˚F, there exist as many degree-days as there are Fahrenheit degrees difference
in temperature between the mean temperature for the day and 65˚F. These heating
degree-days (as listed in above chart) were compiled during the 1941-1970 period
as published by the National Climate Center.
2 Outside Design Temperature – This figure represents the temperature
which will include 99% of all the winterhour Fahrenheit temperatures. A base of
2160 hours (total hours in Dec., Jan., and Feb.) was used. Therefore, using this
figure, as a design temperature will, on an average, cover all but 22 hours of expected
winter temperatures. ASRAE 1976 SYSTEMS HANDBOOK.
3 Mean Wind Speed: MPH – This figure was arrived at through existing
and comparable exposures. This information was obtained from the Local Climatological
Data, 1977. (This figure is for reference only – not required in computation)
4 Yearly Snowfall: Mean – This mean value is for the period beginning
1944 through 1977. This information was obtained from the Local Climatological Data,
1977.
Electric Infrared Comfort Heating
HEATS PEOPLE WITHOUT HEATING AIR Infrared travels through space
and is absorbed by people and objects in its path. The air does not absorb infrared
energy. With convection heating the air itself is warmed and circulated, however,
warm air always rises to the highest point of a building. With Infrared heating,
the warmth is directed and concentrated at the floor and people level where
it is really needed.
ZONE CONTROL FLEXIBILITY Infrared heating is not dependent upon
air movement like convection heat. Infrared energy is absorbed solely at the area
it is directed. Therefore, it is possible to divide any area into separate smaller
zones while maintaining a different comfort level in each zone. For example, Zone
A, with a high concentration of people, could be maintained at a 70 degree comfort
level while at the same time Zone B, a storage area, could be kept at 55 degrees
or even turned off completely.
REDUCED OPERATING COSTS The previous statements are advantages
in themselves; but combined, they account for an energy/fuel savings of up to 50
percent. Actual savings will vary from building to building depending on factors
such as insulation, ceiling height and type of construction.
INSTANT HEAT Electric infrared produces virtually instant heat
There is no need to wait for heat buildup. Turn the heaters on just prior to heating
requirements.
STAGING Another unique control feature of electric infrared that
increases comfort conditions and saves energy consumption is staging. Where most
systems are either “fully ON” or “fully OFF” the staging
feature allows only a portion of the equipment's total capacity to be used.
For example, a two-stage control would work as follows: During the first stage,
one heat source in every fixture would be energized. During the second stage, two
heat sources in every fixture would be energized. For further control sophistication,
a large area can be both zoned and staged. These systems, then, allow a more consistent
and uniform means of maintaining a specific comfort level and avoid the “peak
& valley” syndrome.
LOW MAINTENANCE Electric infrared is strictly a resistance type
heat. There are no moving parts or motors to wear out; no air filters or lubrication
required. Periodic cleaning of the reflectors and heat source replacement
is all that will be required.
CLEAN Electric infrared, like other forms of electric heating,
is the cleanest method of heating. There are no by-products of combustion as with
fossil fuel burning units. Electric infrared adds nothing to the air nor takes anything
from it.
SAFE · No open flame · No moving parts to malfunction
· No fuel lines to leak · No toxic by-products of combustion ·
UL available on some models
EFFICIENT Electric Heaters convert energy to heat at 100% efficiency.
Indoor Spot Heating
An indoor spot heating design will maintain an isolated comfort level within a larger
and cooler area. The ambient temperature of the surrounding areas must be considered
to help determine proper input to the work area. The ambient temperature in the
area will not increase by the spot heating approach. Many times a series of spot
heat areas can be incorporated within the total area to avoid maintaining a higher
ambient temperature throughout the building.
Comfort levels will depend on the intensity of the wattage delivered. Wattage should
be sufficient to balance normal body heat losses, and will depend on ambient conditions,
dress, and activity of the individual in the work area.
Since actual ambient temperatures are not maintained, several factors involved with
indoor spot heating must be considered:
Figure 2: Typical Infrared Heating Pattern
- Beam patterns should always cross approximately 5’ above floor
level to provide even heat at the work area.
- Avoid installing only one fixture directly over a person’s
head at a workstation.
- All spot heat applications, regardless of area size, should heat
the person or object from two sides.
- Fixtures should be mounted so that the long dimension of the heat
pattern is parallel to the long dimensions of the area to be heated.
- Spot heating systems can be controlled manually, or preferably, with
a thermostat located away from the direct pattern of the heaters. Percentage timers
may be used, but are not as effective.
- Avoid mounting fixtures at heights less than 8’.
The estimator must also have the following specific information available before
calculating the heating load and fixture layout:
- Design voltage and phase to be employed.
- Minimum practical mounting height for the heating equipment.
- Specific dimensions of the area to be heated.
- Specific statement of the heating task including the design temperature
required.
The following procedures facilitate the calculation of the required infrared capacity
and system layout of infrared heater fixtures.
Supplemental Spot Heating - Indoor
Consider these guidelines for spot heating (areas with length or width less than
50 feet).
- Determine the coldest inside temperature the system must overcome.
If freeze protection is provided by another heating system, this temperature will
be around 40˚Fahrenheit.
- Determine the operational temperature desired. (That temperature
which the customer would want if convection heating were installed. 70˚Fahrenheit
is a nominal average.)
- Subtract 1 from 2 to determine the increase in operational temperature
(Δt 0 ) expected from the infrared system. If drafts are present
in the occupied area (air movement over 44 feet per minute velocity), wind shielding
for the area occupants should be provided.
- Determine the area to be heated. This is termed the “design
area” (A d ).
- Multiply 4 above by the watt density found in Table 3 for total KW
required.
Table 3A: Required Watt Density By Application and Temperature
Rise Requirement
|
|
WATT DENSITY FOR TYPICAL APPLICATIONS Vs. TEMPERATURE RISE
|
|
APPLICATION
|
CONDITION
|
DENSITY WATTS / SQUARE FOOT
|
|
DESIRED COMFORT TEMPERATURE RISE ° F
|
|
5°F
|
10°F
|
15°F
|
20°F
|
25°F
|
|
Indoor Supplementry Heat
|
|
15 TO 30 WATTS / SQUARE FOOT
|
|
Indoor Personnel Comfort
|
No Drafts No Cold Walls
|
5 to 6
|
11 to 13
|
17 to 20
|
22 to 26
|
28 to 33
|
|
Indoor Personnel Comfort Indoor Personnel Comfort
|
Average Conditions Drafty Area Cold Walls
|
7 to 9 10 to 12
|
15 to 18 20 to 24
|
23 to 28 30 to 36
|
30 to 36 40 to 48
|
39 to 47 50 to 60
|
|
Indoor Personnel Comfort
|
Large Mall Type Buildings
|
40 TO 60 WATTS / SQUARE FOOT
|
|
Indoor Moisture
|
Removal and Control
|
15 TO 30 WATTS / SQUARE FOOT
|
|
Outdoor Loading Dock
|
Protected Area With Wind Shield
|
80 TO 120 WATTS / SQUARE FOOT
|
|
Outdoor Marquee Heating
|
Snow & Ice Melting 20 ft. Mounting Hgt.
|
Use Table 3B
|
|
Outdoor Personnel Comfort
|
Not Open To Sky Protected Area No Wind
|
10 to 12
|
20 to 24
|
30 to 36
|
40 to 48
|
50 to 60
|
|
Radiant Fixtures for spot heating of individuals should be mounted 10 to 12 feet
from the floor with coverage from at least two (2) sides and directed at the individuals
waist and never directly overhead. If fixture must be mounted over 12' from the
floor, add 25% to the indicated watt density up to a maximum of 15'.
|
Table 3B: Snow Control Design Guidline
|
|
Outside Design Temperature ˚F
|
Annual Snowfall Inches
|
Exposed* w/ sq.ft.
|
Semi-Protected* w/ sq.ft.
|
Protected*w/ sq.ft.
|
|
-20 to -60
|
80 to 115
|
200
|
185
|
160
|
|
-20 to -60
|
50 to 79
|
175
|
160
|
145
|
|
-20 to -60
|
20 to 49
|
125
|
110
|
100
|
|
-20 to -60
|
10 to 19
|
110
|
100
|
90
|
|
-20 to -60
|
0 to 9
|
100
|
90
|
85
|
|
-10 to -19
|
80 to 115
|
175
|
160
|
145
|
|
-10 to -19
|
50 to 79
|
125
|
110
|
100
|
|
-10 to -19
|
20 to 49
|
110
|
100
|
90
|
|
-10 to -19
|
10 to 19
|
100
|
90
|
85
|
|
-10 to -19
|
0 to 9
|
100
|
80
|
75
|
|
0 to -9
|
80 to 115
|
125
|
110
|
100
|
|
0 to -9
|
50 to 79
|
110
|
100
|
90
|
|
0 to -9
|
20 to 49
|
100
|
90
|
85
|
|
0 to -9
|
10 to 19
|
100
|
80
|
75
|
|
0 to -9
|
0 to 9
|
100
|
70
|
65
|
|
19 to 1
|
80 to 115
|
110
|
100
|
90
|
|
19 to 1
|
50 to 79
|
100
|
90
|
85
|
|
19 to 1
|
20 to 49
|
100
|
80
|
75
|
|
19 to 1
|
10 to 19
|
100
|
70
|
65
|
|
19 to 1
|
0 to 9
|
100
|
70
|
60
|
|
40 to 18
|
80 to 115
|
100
|
70
|
60
|
|
40 to 18
|
50 to 79
|
100
|
70
|
60
|
|
40 to 18
|
20 to 49
|
100
|
70
|
60
|
|
40 to 18
|
10 to 19
|
100
|
70
|
60
|
|
40 to 18
|
0 to 9
|
100
|
70
|
60
|
- *Exposed = Totally open area
- *Semi-Protected = One side closed plus roof or overhang
- *Protected = Three sides plus roof or overhang
|
|
Heater Selection Guidelines
- Always use clear quartz lamps as the correct element selection
- Use CRDS or CRTS stainless steel enclosures for outdoor locations
- For best results use 30˚ symmetric units. 60˚ symmetric
or assymetric enclosures are generally satisfactory in semi-protected or shielded
areas. Never use 90˚ reflectors.
|
6. Determine fixture mounting locations:
a. In areas where the width dimension is 25’ or less, warm personnel from
at least 2 directions, tilting in the heaters so more area of the person is covered.
Tilt should be such that the upper limit of the beam is about six feet above the
center of the work station. Refer to Figure 5.
Figure 4: Typical Infrared Heating Pattern
b. When locating fixtures, be sure to allow adequate clearances for large moving
equipment such as cranes and lift trucks.
c. Don’t direct infrared onto outside walls. This practice usually results
in waste of energy.
Figure 5: Radiated Pattern Area
7 . Tentatlively estimate the readiated pattern area. Add length of fixture to the
fixture pattern (W) to establish pattern Length (L). Pattern area = L x W. See Figure
6. The formulas for the width and length of the pattern area are shown in figure
8.
Figure 6: Cross Coverage of the RadiationPattern by Angling the Heater in a Supplemental
HEat Application
Radiation Pattern Areas (pattern area = W X L)
Figure 7: Radiation Pattern Areas for Vertical and Tilt Mount.
NOTE: For vertical mounting of RBC type fixtures, refer to Graphs 2-6.
|
Heater Type
|
KR, SKR, RBC-1
|
RBC-3, STAR-6
|
STAR-14
|
|
Fixture Width (FW)
|
0 feet
|
1.0 feet
|
2.0 feet
|
|
Table 4: Suggested Fixture Widths (FW) for Various Chromalox Heaters
|
8. Divide the design area (Step 4) into the pattern area (Step 7).
Q = Pattern Area÷Design Area
If the Pattern Area exactly equals the Design Area, the above quotient will be “1”,
and the radiation per square foot per degree operational temperature difference
will be equal to requirements in Step 5. (For maximum efficiency, try to maintain
a “Q” equal to 1).
Chart 1: 90° Symmetrical Reflectors for Single Element RBC-1 Infrared
Heaters
|
|
|
METAL SHEATH ELEMENT
|
|
RADIANT EFFICIENCY 60%
|
Mounting
Height
Ft.
|
Area (WxL)
Ft.
|
Square
Ft
|
1 KW w/sq. ft.
|
1.5 KW w/sq. ft.
|
2 KW w/sq. ft.
|
2.5 KW w/sq. ft.
|
|
8
|
16 X 16
|
256
|
2.3
|
3.5
|
4.7
|
5.9
|
|
9
|
18 X 18
|
324
|
1.9
|
2.8
|
3.7
|
4.6
|
|
10
|
20 X 20
|
400
|
1.5
|
2.3
|
3.0
|
3.8
|
|
11
|
22 X 22
|
484
|
1.2
|
1.9
|
2.5
|
3.1
|
|
12
|
24 X 24
|
576
|
1.0
|
1.6
|
2.1
|
2.6
|
|
13
|
26 X 26
|
676
|
0.9
|
1.3
|
1.8
|
2.2
|
|
14
|
28 X 28
|
784
|
0.8
|
1.1
|
1.5
|
1.9
|
|
15
|
30 X 30
|
900
|
0.7
|
1.0
|
1.3
|
1.7
|
Chart 2: 60° Symmetrical Deflectors for 1 & 3 Element STAR
Infrared Heaters
|
|
|
|
|
|
|
METAL SHEATH ELEMENT RADIANT EFFICIENCY 60%
|
|
Mounting Height Ft.
|
Area (WxL) Ft.
|
Square Ft.
|
1.5 KW w/sq.ft.
|
2 KW w/sq.ft.
|
4.5 KW w/sq.ft.
|
6 KW w/sq.ft.
|
13.5 KWw/sq.ft.
|
|
8
|
9.2 X 9.2
|
85
|
10.6
|
14.2
|
31.9
|
42.5
|
95.7
|
|
9
|
10.35 X 10.35
|
107
|
8.4
|
11.2
|
25.2
|
33.6
|
75.6
|
|
10
|
11.5 X 11.7
|
132
|
6.1
|
9.3
|
20.6
|
27.4
|
61.4
|
|
11
|
12.65 X 12.65
|
160
|
5.6
|
7.5
|
16.9
|
22.5
|
50.6
|
|
12
|
13.8 X 13.8
|
190
|
4.7
|
6.3
|
14.2
|
18.9
|
42.5
|
|
13
|
14.95 X 14.95
|
224
|
4
|
5.4
|
12.1
|
16.1
|
36.2
|
|
14
|
16.1 X 16.1
|
259
|
3.5
|
4.6
|
10.4
|
13.9
|
31.2
|
|
15
|
17.25 X 17.25
|
298
|
3
|
4
|
9.1
|
12.1
|
27.2
|
|
16
|
18.4 X 18.4
|
339
|
2.7
|
3.5
|
8
|
10.6
|
23.9
|
|
17
|
19.55 X 19.55
|
382
|
2.4
|
3.1
|
7.1
|
9.4
|
21.2
|
|
18
|
20.7 X 20.7
|
428
|
2.1
|
2.8
|
6.3
|
8.4
|
18.9
|
|
19
|
21.85 X 21.85
|
477
|
1.9
|
2.5
|
5.7
|
7.5
|
17
|
|
20
|
23 X 23
|
529
|
1.7
|
2.3
|
5.1
|
6.8
|
15.3
|
|
21
|
24.15 X 24.15
|
583
|
1.5
|
2.1
|
4.6
|
6.2
|
13.9
|
|
22
|
25.3 X 25.3
|
640
|
1.4
|
1.9
|
4.2
|
5.6
|
12.7
|
|
23
|
26.45 X 26.45
|
700
|
1.3
|
1.7
|
3.9
|
5.1
|
11.6
|
|
24
|
27.6 X 27.6
|
762
|
1.2
|
1.6
|
3.5
|
4.7
|
10.6
|
Chart 3: 90˚ Symmetrical Reflectors for 2 & 3 Element
High-Intensity Infrared Heaters
|
|
|
METAL SHEATH ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
1.6 KW w/sq.ft.
|
3 Element
2.5 KW w/sq.ft.
|
2 Element
3 KW w/sq.ft.
|
3 Element
4.5 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6 KW w/sq.ft.
|
5
6
7
8
9
10
|
10 X 10
12 X 12
14 X 14
16 X 16
18 X 18
20 X 20
|
100
144
196
256
324
400
|
9.6
6.7
4.9
3.8
3.0
2.4
|
15.0
10.4
7.7
5.9
4.6
3.8
|
18.0
12.5
9.2
7.0
5.6
4.5
|
27.0
18.8
13.8
10.5
8.3
6.8
|
24.0
16.7
12.2
9.4
7.4
6.0
|
36.0
25.0
18.4
14.1
11.1
9.0
|
11
12
13
14
15
|
22 X 22
24 X 24
26 X 26
28 X 28
30 X 30
|
484
576
676
784
900
|
2.0
1.7
1.4
1.2
1.1
|
3.1
2.6
2.2
1.9
1.7
|
3.7
3.1
2.7
2.3
2.0
|
5.6
4.7
4.0
3.4
3.0
|
5.0
4.2
3.6
3.1
2.7
|
7.4
6.3
5.3
4.6
4.0
|
16
17
18
19
20
|
32 X 32
34 X 34
36 X 36
38 X 38
40 X 40
|
1024
1156
1296
1444
1600
|
|
1.5
1.3
1.2
1.0
|
1.8
1.6
1.4
1.2
1.1
|
2.6
2.3
2.1
1.9
1.7
|
2.3
2.1
1.9
1.7
1.5
|
3.5
3.1
2.8
2.5
2.3
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
2 KW w/sq.ft.
|
3 Element
3 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6KW w/sq.ft.
|
2 Element
6 KW w/sq.ft.
|
3 Element
9 KW w/sq.ft.
|
5
6
7
8
9
10
|
10 X 10
12 X 12
14 X 14
16 X 16
18 X 18
20 X 20
|
100
144
196
256
324
400
|
16.0
11.1
8.2
6.3
4.9
4.0
|
24.0
16.7
7.7
12.2
9.4
6.0
|
32.0
22.2
16.3
12.5
9.9
8.0
|
48.0
33.3
24.5
18.8
14.8
12.0
|
48.0
33.3
24.5
18.8
14.8
12.0
|
72.0
50.0
36.7
28.1
22.2
18.0
|
11
12
13
14
15
|
22 X 22
24 X 24
26 X 26
28 X 28
30 X 30
|
484
576
676
784
900
|
3.3
2.8
2.4
2.0
1.8
|
5.0
4.2
3.6
3.1
2.7
|
6.6
5.6
4.7
4.1
3.6
|
9.9
8.3
7.1
6.1
5.3
|
9.9
8.3
7.1
6.1
5.3
|
14.9
12.5
10.7
9.2
8.0
|
16
17
18
19
20
|
32 X 32
34 X 34
36 X 36
38 X 38
40 X 40
|
1024
1156
1296
1444
1600
|
1.6
1.4
1.2
1.1
1.0
|
2.3
2.1
1.9
1.7
1.5
|
3.1
2.8
2.5
2.2
2.0
|
4.7
4.2
3.7
3.3
3.0
|
4.7
4.2
3.7
3.3
3.0
|
7.0
6.2
5.6
5.0
4.5
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
3.2 KW w/sq.ft.
|
3 Element
4.9 KW w/sq.ft.
|
2 Element
5 KW w/sq.ft.
|
3 Element
7.5 KW w/sq.ft.
|
2 Element
7.3 KW w/sq.ft.
|
3 Element
10.95 KW w/sq.ft.
|
5
6
7
8
9
10
|
10 X 10
12 X 12
14 X 14
16 X 16
18 X 18
20 X 20
|
100
144
196
256
324
400
|
25.6
17.8
13.1
10.0
7.9
6.4
|
38.4
26.7
19.6
15.0
11.9
9.6
|
40.0
27.8
20.4
15.6
12.3
10.0
|
60.0
41.7
30.6
23.4
18.5
15.0
|
58.4
40.6
29.8
22.8
18.0
14.6
|
87.6
60.8
44.7
34.2
27.0
21.9
|
11
12
13
14
15
|
22 X 22
24 X 24
26 X 26
28 X 28
30 X 30
|
484
576
676
784
900
|
5.3
4.4
3.8
3.3
2.8
|
7.9
6.7
5.7
4.9
4.3
|
8.3
6.9
5.9
5.1
4.4
|
12.4
10.4
8.9
7.7
6.7
|
12.1
10.1
8.6
7.4
6.5
|
18.1
15.2
13.0
11.2
9.7
|
16
17
18
19
20
|
32 X 32
34 X 34
36 X 36
38 X 38
40 X 40
|
1024
1156
1296
1444
1600
|
2.5
2.2
2.0
1.8
1.6
|
3.8
3.3
3.0
2.7
2.4
|
3.9
3.5
3.1
2.8
2.5
|
5.9
5.2
4.6
4.2
3.8
|
5.7
5.1
4.5
4.0
3.7
|
8.6
7.6
6.8
6.1
5.5
|
Chart 4: 60° Symmetrical Reflectors for 2 & 3 Element High-Intensity
Infrared Heaters
|
|
|
METAL SHEATH ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
1.6 KW w/sq.ft.
|
3 Element
2.5 KW w/sq.ft.
|
2 Element
3 KW w/sq.ft.
|
3 Element
4.5 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6 KW w/sq.ft.
|
5
6
7
8
9
10
|
5.8 X 10
6.9 X 12
8.1 X 14
9.2 X 16
10.4 X 18
11.5 X 20
|
57.5
82.8
112.7
147.2
186.3
230.0
|
16.7
11.6
8.5
6.5
5.2
4.2
|
26.1
18.1
13.3
10.2
8.1
6.5
|
31.3
21.7
16.0
12.2
9.7
7.8
|
47.0
32.6
24.0
18.3
14.5
11.7
|
41.7
29.0
21.3
16.3
12.9
10.4
|
62.6
43.5
31.9
24.5
19.3
15.7
|
11
12
13
14
15
|
12.7 X 22
13.8 X 24
15.0 X 26
16.1 X 28
17.3 X 30
|
278.3
331.2
388.7
450.8
517.5
|
3.4
2.9
2.5
2.1
1.9
|
5.4
4.5
3.9
3.3
2.9
|
6.5
5.4
4.6
4.0
3.5
|
9.7
8.2
6.9
6.0
5.2
|
8.6
7.2
6.2
5.3
4.6
|
12.9
10.9
9.3
8.0
7.0
|
16
17
18
19
20
|
18.4 X 32
19.6 X 34
20.7 X 36
21.9 X 38
23.0 X 40
|
588.8
664.7
745.2
830.3
920.0
|
1.6
1.4
1.3
1.2
1.0
|
2.5
2.3
2.0
1.8
1.6
|
3.1
2.7
2.4
2.2
2.0
|
4.6
4.1
3.6
3.3
2.9
|
4.1
3.6
3.2
2.9
2.6
|
6.1
5.4
4.8
4.3
3.9
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
2 KW w/sq.ft.
|
3 Element
3 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6KW w/sq.ft.
|
2 Element
6 KW w/sq.ft.
|
3 Element
9 KW w/sq.ft.
|
5
6
7
8
9
10
|
5.8 X 10
6.9 X 12
8.1 X 14
9.2 X 16
10.4 X 18
11.5 X 20
|
57.5
82.8
112.7
147.2
186.3
230.0
|
27.8
19.3
14.2
10.9
8.6
7.0
|
41.7
29.0
21.3
16.3
12.9
10.4
|
55.7
38.6
28.4
21.7
17.2
13.9
|
83.5
58.0
42.6
32.6
25.8
20.9
|
83.5
58.0
42.6
32.6
25.8
20.9
|
125.2
87.0
63.9
48.9
38.6
31.3
|
11
12
13
14
15
|
12.7 X 22
13.8 X 24
15.0 X 26
16.1 X 28
17.3 X 30
|
278.3
331.2
388.7
450.8
517.5
|
5.7
4.8
4.1
3.5
3.1
|
8.6
7.2
6.2
5.3
4.6
|
11.5
9.7
8.2
7.1
6.2
|
17.2
14.5
12.3
10.6
9.3
|
17.2
14.5
12.3
10.6
9.3
|
25.9
21.7
18.5
16.0
13.9
|
16
17
18
19
20
|
18.4 X 32
19.6 X 34
20.7 X 36
21.9 X 38
23.0 X 40
|
588.8
664.7
745.2
830.3
920.0
|
2.7
2.4
2.1
1.9
1.7
|
4.1
3.6
3.2
2.9
2.6
|
5.4
4.8
4.3
3.9
3.5
|
8.2
7.2
6.4
5.8
5.2
|
8.2
7.2
6.4
5.8
5.2
|
12.2
10.8
9.7
8.7
7.8
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
3.2 KW w/sq.ft.
|
3 Element
4.9 KW w/sq.ft.
|
2 Element
5 KW w/sq.ft.
|
3 Element
7.5 KW w/sq.ft.
|
2 Element
7.3 KW w/sq.ft.
|
3 Element
10.95 KW w/sq.ft.
|
5
6
7
8
9
10
|
5.8 X 10
6.9 X 12
8.1 X 14
9.2 X 16
10.4 X 18
11.5 X 20
|
57.5
82.8
112.7
147.2
186.3
230.0
|
44.5
30.9
22.7
17.4
13.7
11.1
|
66.8
46.4
34.1
26.1
20.6
16.7
|
69.6
48.3
35.5
27.2
21.5
17.4
|
104.3
72.5
53.2
40.8
32.2
26.1
|
101.6
70.5
51.8
39.7
31.3
25.4
|
152.3
105.8
77.7
59.5
47.0
38.1
|
11
12
13
14
15
|
12.7 X 22
13.8 X 24
15.0 X 26
16.1 X 28
17.3 X 30
|
278.3
331.2
388.7
450.8
517.5
|
9.2
7.7
6.6
5.7
4.9
|
13.8
11.6
9.9
8.5
7.4
|
14.4
12.1
10.3
8.9
7.7
|
21.6
18.1
15.4
13.3
11.6
|
21.0
17.6
15.0
13.0
11.3
|
31.5
26.4
22.5
19.4
16.9
|
16
17
18
19
20
|
18.4 X 32
19.6 X 34
20.7 X 36
21.9 X 38
23.0 X 40
|
588.8
664.7
745.2
830.3
920.0
|
4.3
3.9
3.4
3.1
2.8
|
6.5
5.8
5.2
4.6
4.2
|
6.8
6.0
5.4
4.8
4.3
|
10.2
9.0
8.1
7.2
6.5
|
9.9
8.8
7.8
7.0
6.3
|
14.9
13.2
11.8
10.6
9.5
|
Chart 5: 30° Symmetrical Reflectors for 2 & 3 Element High-Intensity
Infrared Heaters
|
|
|
METAL SHEATH ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
1.6 KW w/sq.ft.
|
3 Element
2.5 KW w/sq.ft.
|
2 Element
3 KW w/sq.ft.
|
3 Element
4.5 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6 KW w/sq.ft.
|
5
6
7
8
9
10
|
2.7 X 10
3.2 X 12
3.8 X 14
4.3 X 16
4.9 X 18
5.4 X 20
|
27.0
38.9
52.9
69.1
87.5
108.0
|
35.6
24.7
18.1
13.9
11.0
8.9
|
55.6
38.6
28.3
21.7
17.1
13.9
|
66.7
46.3
34.0
26.0
20.6
16.7
|
100.0
69.4
51.0
39.1
30.9
25.0
|
88.9
61.7
45.4
34.7
27.4
22.2
|
133.3
92.6
68.0
52.1
41.2
33.3
|
11
12
13
14
15
|
5.9 X 22
6.5 X 24
7.0 X 26
7.6 X 28
8.1 X 30
|
130.7
155.5
182.5
211.7
243.0
|
7.3
6.2
5.3
4.5
4.0
|
11.5
9.6
8.2
7.1
6.2
|
13.8
11.6
9.9
8.5
7.4
|
20.7
17.4
14.8
12.8
11.1
|
18.4
15.4
13.1
11.3
9.9
|
27.5
23.1
19.7
17.0
14.8
|
16
17
18
19
20
|
8.6 X 32
9.2 X 34
9.7 X 36
10.3 X 38
10.8 X 40
|
276.5
312.1
349.9
389.9
432.0
|
3.5
3.1
2.7
2.5
2.2
|
5.4
4.8
4.3
3.8
3.5
|
6.5
5.8
5.1
4.6
4.2
|
9.8
8.7
7.7
6.9
6.3
|
8.7
7.7
6.9
6.2
5.6
|
13.0
11.5
10.3
9.2
8.3
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
2 KW w/sq.ft.
|
3 Element
3 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6KW w/sq.ft.
|
2 Element
6 KW w/sq.ft.
|
3 Element
9 KW w/sq.ft.
|
5
6
7
8
9
10
|
2.7 X 10
3.2 X 12
3.8 X 14
4.3 X 16
4.9 X 18
5.4 X 20
|
27.0
38.9
52.9
69.1
87.5
108.0
|
59.3
41.2
30.2
23.1
18.3
14.8
|
88.9
61.7
45.4
34.7
27.4
22.2
|
118.5
82.3
60.5
46.3
36.6
29.6
|
177.8
123.5
90.7
69.4
54.9
44.4
|
177.8
123.5
90.7
69.4
54.9
44.4
|
266.7
185.2
136.1
104.2
82.3
66.7
|
11
12
13
14
15
|
5.9 X 22
6.5 X 24
7.0 X 26
7.6 X 28
8.1 X 30
|
130.7
155.5
182.5
211.7
243.0
|
12.2
10.3
8.8
7.6
6.6
|
18.4
15.4
13.1
11.3
9.9
|
24.5
20.6
17.5
15.1
13.2
|
36.7
30.9
26.3
22.7
19.8
|
36.7
30.9
26.3
22.7
19.8
|
55.1
46.3
39.4
34.0
29.6
|
16
17
18
19
20
|
8.6 X 32
9.2 X 34
9.7 X 36
10.3 X 38
10.8 X 40
|
276.5
312.1
349.9
389.9
432.0
|
5.8
5.1
4.6
4.1
3.7
|
8.7
7.7
6.9
6.2
5.6
|
11.6
10.3
9.1
8.2
7.4
|
17.4
15.4
13.7
12.3
11.1
|
17.4
15.4
13.7
12.3
11.1
|
26.0
23.1
20.6
18.5
16.7
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
3.2 KW w/sq.ft.
|
3 Element
4.9 KW w/sq.ft.
|
2 Element
5 KW w/sq.ft.
|
3 Element
7.5 KW w/sq.ft.
|
2 Element
7.3 KW w/sq.ft.
|
3 Element
10.95 KW w/sq.ft.
|
5
6
7
8
9
10
|
2.7 X 10
3.2 X 12
3.8 X 14
4.3 X 16
4.9 X 18
5.4 X 20
|
27.0
38.9
52.9
69.1
87.5
108.0
|
94.8
65.8
48.4
37.0
29.3
23.7
|
142.2
98.8
72.6
55.6
43.9
35.6
|
148.1
102.9
75.6
57.9
45.7
37.0
|
222.2
154.3
113.4
86.8
68.6
55.6
|
216.3
150.2
110.4
84.5
66.8
54.1
|
324.4
225.3
165.5
126.7
100.1
81.1
|
11
12
13
14
15
|
5.9 X 22
6.5 X 24
7.0 X 26
7.6 X 28
8.1 X 30
|
130.7
155.5
182.5
211.7
243.0
|
19.6
16.5
14.0
12.1
10.5
|
29.4
24.7
21.0
18.1
15.8
|
30.6
25.7
21.9
18.9
16.5
|
45.9
38.6
32.9
28.3
24.7
|
44.7
37.6
32.0
27.6
24.0
|
67.0
56.3
48.0
41.4
36.0
|
16
17
18
19
20
|
8.6 X 32
9.2 X 34
9.7 X 36
10.3 X 38
10.8 X 40
|
276.5
312.1
349.9
389.9
432.0
|
9.3
8.2
7.3
6.6
5.9
|
13.9
12.3
11.0
9.8
8.9
|
14.5
12.8
11.4
10.3
9.3
|
21.7
19.2
17.1
15.4
13.9
|
21.1
18.7
16.7
15.0
13.5
|
31.7
28.1
25.0
22.5
20.3
|
Chart 6: 60° Asymmetrical Reflectors for 2 & 3 Element High-Intensity
Infrared Heaters
|
|
|
METAL SHEATH ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Ft.Area (W X L)
|
Square Ft.
|
2 Element
1.6 KW w/sq.ft.
|
3 Element
2.5 KW w/sq.ft.
|
2 Element
3 KW w/sq.ft.
|
3 Element
4.5 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6 KW w/sq.ft.
|
5
6
7
8
9
10
|
6 X 10
8 X 12
9 X 14
10 X 16
11 X 18
13 X 20
|
63
90
123
160
203
250
|
15.4
10.7
7.8
6.0
4.7
3.8
|
24.0
16.7
12.2
9.4
7.4
6.0
|
28.8
20.0
14.7
11.3
8.9
7.2
|
43.2
30.0
22.0
16.9
13.3
10.8
|
38.4
26.7
19.6
15.0
11.9
9.6
|
57.6
40.0
29.4
22.5
17.8
14.4
|
11
12
13
14
15
|
14 X 22
15 X 24
16 X 26
18 X 28
19 X 30
|
303
360
423
490
563
|
3.2
2.7
2.3
2.0
1.7
|
5.0
4.2
3.6
3.1
2.7
|
6.0
5.0
4.3
3.7
3.2
|
8.9
7.5
6.4
5.5
4.8
|
7.9
6.7
5.7
4.9
4.3
|
11.9
10.0
8.5
7.3
6.4
|
16
17
18
19
20
|
20 X 32
21 X 34
23 X 36
24 X 38
25 X 40
|
640
723
810
903
1000
|
1.5
1.3
1.2
1.1
1.0
|
2.3
2.1
1.9
1.7
1.5
|
2.8
2.5
2.2
2.0
1.8
|
4.2
3.7
3.3
3.0
2.7
|
3.8
3.3
3.0
2.7
2.4
|
5.6
5.0
4.4
4.0
3.6
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
2 KW w/sq.ft.
|
3 Element
3 KW w/sq.ft.
|
2 Element
4 KW w/sq.ft.
|
3 Element
6KW w/sq.ft.
|
2 Element
6 KW w/sq.ft.
|
3 Element
9 KW w/sq.ft.
|
5
6
7
8
9
10
|
6 X 10
8 X 12
9 X 14
10 X 16
11 X 18
13 X 20
|
63
90
123
160
203
250
|
25.6
17.8
13.1
10.0
7.9
6.4
|
38.4
26.7
19.6
15.0
11.9
9.6
|
51.2
35.6
26.1
20.0
15.8
12.8
|
76.8
53.3
39.2
30.0
23.7
19.2
|
76.8
53.3
39.2
30.0
23.7
19.2
|
115.2
80.0
58.8
45.0
35.6
28.8
|
11
12
13
14
15
|
14 X 22
15 X 24
16 X 26
18 X 28
19 X 30
|
303
360
423
490
563
|
5.3
4.4
3.8
3.3
2.8
|
7.9
6.7
5.7
4.9
4.3
|
10.6
8.9
7.6
6.5
5.7
|
15.9
13.3
11.4
9.8
8.5
|
15.9
13.3
11.4
9.8
8.5
|
23.8
20.0
17.0
14.7
12.8
|
16
17
18
19
20
|
20 X 32
21 X 34
23 X 36
24 X 38
25 X 40
|
640
723
810
903
1000
|
2.5
2.2
2.0
1.8
1.6
|
3.8
3.3
3.0
2.7
2.4
|
5.0
4.4
4.0
3.5
3.2
|
7.5
6.6
5.9
5.3
4.8
|
7.5
6.6
5.9
5.3
4.8
|
11.3
10.0
8.9
8.0
7.2
|
|
|
QUARTZ TUBE ELEMENT RADIANT EFFICIENCY 60%
|
|
24” Enclosure
|
33” Enclosure
|
46” Enclosure
|
|
Mounting Height Ft.
|
Area (W X L) Ft.
|
Square Ft.
|
2 Element
3.2 KW w/sq.ft.
|
3 Element
4.9 KW w/sq.ft.
|
2 Element
5 KW w/sq.ft.
|
3 Element
7.5 KW w/sq.ft.
|
2 Element
7.3 KW w/sq.ft.
|
3 Element
10.95 KW w/sq.ft.
|
5
6
7
8
9
10
|
6 X 10
8 X 12
9 X 14
10 X 16
11 X 18
13 X 20
|
63
90
123
160
203
250
|
41.0
28.4
20.9
16.0
12.6
10.2
|
61.4
42.7
31.3
24.0
19.0
15.4
|
64.0
44.4
32.7
25.0
19.8
16.0
|
96.0
66.7
49.0
37.5
29.6
24.0
|
93.4
64.9
47.7
36.5
28.8
23.4
|
140.2
97.3
71.5
54.8
43.3
35.0
|
11
12
13
14
15
|
14 X 22
15 X 24
16 X 26
18 X 28
19 X 30
|
303
360
423
490
563
|
8.5
7.1
6.1
5.2
4.6
|
12.7
10.7
9.1
7.8
6.8
|
13.2
11.1
9.5
8.2
7.1
|
19.8
16.7
14.2
12.2
10.7
|
19.3
16.2
13.8
11.9
10.4
|
29.0
24.3
20.7
17.9
15.6
|
16
17
18
9
20
|
20 X 32
21 X 34
23 X 36
24 X 38
25 X 40
|
640
723
810
903
1000
|
4.0
3.5
3.2
2.8
2.6
|
6.0
5.3
4.7
4.3
3.8
|
6.3
5.5
4.9
4.4
4.0
|
9.4
8.3
7.4
6.6
6.0
|
9.1
8.1
7.2
6.5
5.8
|
13.7
12.1
10.8
9.7
8.8
|
|
9 . If the design area exceeds the pattern area of individual fixtures, locate multiple
fixtures with patterns overlapping as necessary. Select fixtures based on 1⁄4
of the watts per square foot requirement (see Figure 9) at a given mounting height
and element. For example, if 25 watts per square foot are required, choose a fixture
with an input watt density of 6.3 at the required mounting height. For primary area
heating do not install less than 12 watts per square foot. Double the watt density
along areas adjacent to the outside walls of the building. Do not radiate outside
walls.
|
Figure 8: Typical Area Heating Layout
|
10. Choose specific fixtures that meet the heating requirements noting that half
the wattage should be on each side of the workstation in the design area. Space
the heaters to provide a 50% overlap using the formula provided in Figure 8. See
Figure 7 for typical layout.
11. To provide better control of comfort it is usually desirable to divide the total
heat required into two or three circuits so that each fixture or heating element
circuit can be switched on in sequence, as the ambient conditions require. It may,
therefore, require three fixtures on each side to provide maximum comfort in a spot
heating application.
Figure 9: Recommended spacing for 50% overlap
Primary Area Heating with Radiant
Primary area heating refers to all heating being done using radiant heat. Room temperature
is not maintained by convection. Radiant is the sole source of warmth. These guidelines
apply to any enclosed space of any size or design area with length and width each
having a dimension greater than 50 feet.
- Calculate Heat Loss. Calculate the room heat loss
as if the room air would be heated by a conventional heating system using the General
Industrial Sizing Guide.
- Determine Watts per Square Foot. Divide the heat
loss in watts by the design area to be heated to arrive at watt density per square
foot.
- Adjust Wattage for Radiant Application. Multiply
the watts per square foot in Step 2 by 0.85 to obtain the amount of actual watt
density radiation required. This multiplier compensates for the lower air temperature
possible in comfort infrared applications. This is due to the fact that the ambient
air does not get heated up in infrared heating.
Download the Comfort Heating Sizing Guide (PDF)
- may be used for sizing radiant applications in an enclosed space where radiant
is the primary heat source.
Important Note:
The facts and the recommendations made in this publication are based on our own
research and the research of others and are believed to be accurate. We cannot anticipate
all conditions under which this information and our products or the products of
other manufacturers in combination with our products may be used. We accept no responsibility
for results obtained by the application of this information or the safety and suitability
of our products either alone or in combination with other products. Users are advised
to make their own tests to determine the safety and suitability of each such product
or product combination for their own purposes.
Download the Comfort Heating Sizing Guide
