RADIATION TABLES
The output of a radiator is measured in square feet of radiation. To determine the number of
square feet of radiation in a radiator:
1. Measure the height of the radiator.
2. Count the number of columns in a section.
3. Count the number of sections.
Multiply the total number of sections by the number of square feet per section as
shown in the following tables:
Column Type Radiators
SQ. FT. RADIATION PER SECTION
Height One Two Three Four
Inches Column Column Column Column Window
13 — — — — 3
16 — — — — 3
3
⁄4
18 — — 2
1
⁄4 34
1
⁄4
20 1
1
⁄2 2— —5
22 — — 3 4 —
23 1
2
⁄3 2
1
⁄3 ———
26 2 2
2
⁄3 3
3
⁄4 5—
32 2
1
⁄2 3
1
⁄3 4
1
⁄2 6
1
⁄2 —
38 3 4 5 8 —
45 — 5 6 10 —
SQ. FT. RADIATION PER SECTION
Height Three Four Five Six Window
Inches Tube Tube Tube Tube Seven Tube
14 — — — — 2
1
⁄2
17 — — — — 3
20 1
3
⁄4 2
1
⁄4 2
2
⁄3 33
2
⁄3
23 2 2
1
⁄2 33
1
⁄2 —
26 2
1
⁄3 2
3
⁄4 3
1
⁄2 44
3
⁄4
32 3 3
1
⁄2 4
1
⁄3 5—
38 3
1
⁄2 4
1
⁄4 56—
SQ. FT. RADIATION PER WALL RADIATOR SECTION
Type of Height Length or Thickness Heating Sq. Ft.
Section Inches Width, In. Inches Radiation
5-A 13
5
⁄16 16
5
⁄8 2
7
⁄8 5
7-A 13
5
⁄16 21
7
⁄8 2
7
⁄8 7
7-B 21
7
⁄8 13
3
⁄16 3
1
⁄16 7
9-A 18
5
⁄16 29
1
⁄16 2
7
⁄8 9
9-B 29
1
⁄16 18
5
⁄16 3
11
⁄16 9
Tube Type Radiators
Wall Type Radiators
Wall radiators are measured by their height, length and thickness. The following shows the
number of square feet of heating surface per section:
SIZE SHOWN 35 SQ. FT. RADIATION
38”
7 SECTIONS5 TUBE
SIZE SHOWN 5 SQ. FT. RADIATION
16
7
⁄8
13
11
⁄16
SIZE SHOWN 28 SQ. FT. RADIATION
36”
7 SECTIONS2 COL
NOTE: BOTH 2” SUPPLY
TAPPINGS MUST BE USED. ALL
NEAR BOILER SUPPLY HEADER
PIPING MUST BE A MINIMUM
OF 2”. DO NOT REDUCE.
RETURN
HEADER
Recommended Sizing
PEG 112–150 : 2”
PEG 187–225 : 2.5”
PEG 262–300 : 3”
STEAM MAIN RISER
(SUPPLY)
EQUALIZER
2” RECOMMENDED.
IF RETURN PIPE IS LARGER,
INCREASE SIZE TO EQUAL
RETURN PIPE SIZE
CLOSE NIPPLE
CLEANOUT TEES
SKIMMING TEE
2”
FROM BOTTOM OF BOILER
WATER LINE
28”
24” MIN.
2”
RECOMMENDED
12” MIN.
EQUALIZER
2” RECOMMENDED. IF RETURN PIPING
IS LARGER, INCORPORATE SIZE TO
EQUAL THE RETURN PIPE SIZE
CLOSE NIPPLE
HARTFORD LOOP
CONNECTION
RETURN MAIN
CLEANOUT TEES
FROM BOTTOM OF BOILER
SUPPLY
CONNECTION
SKIP TAPPING
ON BACK
OF BOILER
WATER
LINE
PIPE RELIEF VALVE WITHIN 12” OF FLOOR
OR IN ACCORDANCE WITH LOCAL CODES
2”
22.1/2”
28”
24” MIN.
HEADER
RECOMMENDED SIZING
3 SECTION: 2”
4 SECTION: 2.1/2”
5 SECTION: 3”
STEAM MAIN
RISER(S)
PIPE RELIEF VALVE
WITHIN 12” OF FLOOR
OR IN ACCORDANCE
WITH LOCAL CODES
Ed: 12/00
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