TABLES
ANDCHARTS
PRESSURE CLASSIFICATION FOR DUCTWORK
STATITC PRESSURE
DUCT SEALING REQUIREMENTS
DUCT GUAGE AND ENFORCEMENT FOR 1” ESS AND DRIVE (+/-) HEAVY GA METAL
DUCT GUAGE AND ENFORCEMENT FOR 1”W.G.AND DRIVE (+/-) TDF
NOTES
1.
TDC DUCT CONSTRUCTED PER SMACNA STANDARDS - FIRST EDITION 1995
2.
DUCT FABRICATED USING PITTSBURG SEAMS
3.
ALL DUCT STIFFENED BY MACHINE FORMED BEADS SPACEDAT 12”O.C.
4.
DUCTWORK TO BE SEALED PER SMACNA HVAC TABLE 1-2
5.
TDC CNT-JNT-CONDU-LOCAT
TDC CONNECTOR CENTER OF DUCTANDAT TDC CONNECTOR
STATIC PRESSURE CLASS
-INCHES(Pa)W.G.-
+1/2" -1/2" +1" -1" +2" -2" +3" -3" +4" -4" +6" -6" +10" -10"
RECTANGULAR STYLE
A
A
STD STD STV A A A A A A A
A
A
ROUND STYLE
STV
A A
A
A
FLAT OVAL STYLE
STD
STV
A
A
A
FLEXIBLE STYLE
A
A
STD STD STV
A
A
A
A
DUCT PRESSURE CLASS
OPERATING PRESSURE
INCH
Pa
1/2" W.G.
125
UP TO 1/2" W.G.
1" W.G.
250
OVER 1/2" W.G. UP TO 1" W.G.
2" W.G.
500
OVER 1" W.G. UP TO 2" W.G.
3" W.G.
750
OVER 2" W.G. UP TO 3" W.G.
4" W.G.
1000
OVER 3" W.G. UP TO 4" W.G.
6" W.G.
1500
OVER 4" W.G. UP TO 6" W.G.
10" W.G.
2500
OVER 6" W.G. UP TO 10" W.G.
SEAL CLASS
SEALING REQUIRED
STATIC PRESSURE
CONSTRUCTION CLASS
A
ALL TRANSVERSE JOINTS,
LONGITUDE SEAMS AND
DUCT WALL PENITRATIONS
4" W.G.AND UP
B
ALL TRANSVERSE JOINTS
AND LONGITUDE SEAMS
3”W.G.
C
TRANSVERSE JOINTS
2" W.G.
GAUGE OF METAL
DUCT
DIMENSIONS
5’
JOINT
4’
JOINT
2.5’
JOINT
2’
JOINT
JOINT CONSTRUCTION
REINFORCING
0-12”
26
26
26
26
FLAT ESSES AND DRIVE
NONE
13-30”
24
24
24
24
1”ST ESSES AND DRIVE
NONE
31-54”
22
22
22
22
1”ST ESSES AND DRIVE
NONE
55-60”
20
20
20
20
1”ST ESSES AND DRIVE
NONE
61-72”
20
20
20 NO
CNT. REF
20 NO
CNT. REF
TDF
NONE
73-84”
20
20
20 NO
CNT. REF
20 NO
CNT. REF
TDF
NONE
85”AND UP
18
18
20 NO
CNT. REF
20 NO
CNT. REF
TDF CNT - JNT 48”MAX SPACING
1 ½WIDE X 1 ½ HEIGH
18GA V-TYPE STIFFENER
GAUGE OF METAL
DUCT
DIMENSIONS
5’
JOINT
4’
JOINT
2.5’
JOINT
2’
JOINT
JOINT CONSTRUCTION
REINFORCING
0-12”
26
26
26
26
HEMMED “S”AND DRIVE
NONE
12-36”
24
24
24
24
TDF
NONE
37-48”
24
24
24
26
TDF
NONE
49-60”
22
22
24
24
TDF
NONE
61-72”
22
22
22 NO
CNT. REF
22 NO
CNT. REF
TDF CNT - JNT
NONE
73-96”
22
22
22 NO
CNT. REF
22 NO
CNT. REF
TDF CNT - JNT
NONE
97”AND UP
18
18
20 NO
CNT. REF
20 NO
CNT. REF
TDF CNT - JNT 48”MAX SPACING
1 ½WIDE X 1 ½ HEIGH
18GA V-TYPE STIFFENER
