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Technical
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Dixon Fire 2016
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Technical
Thread Chart
National
Standard
NH*
Straight
Iron Pipe
NPSH
New York
Corporation
NYCT
Pacific Coast
PCT
New York
Fire Dept.
NYFT
Chemical
Hose
CHT *
NH
Underwriter's
Play Pipe
PPS
Garden
Hose
GHT *
Chicago Fire
Dept.
(NEW) *
Chicago
Hose
Size ODM TPI
ODM TPI
ODM TPI
ODM TPI
ODM TPI
ODM TPI
ODM TPI
ODM TPI
ODM TPI
ODM TPI
¾"
1"
1¼"
1½"
2"
2½"
3"
3½"
4"
4½"
5"
6"
1.375
1.375
1.6718
1.990
2.5156
3.0686
3.6239
4.2439
5.0109
5.7609
6.260
7.025
8
8
9
9
8
7½
6
6
4
4
4
4
1.0353 *
1.2951 *
1.6399 *
1.8788 *
2.3528 *
2.841 *
3.470
3.970
4.470
4.970
5.530
6.590
14
11½
11½
11½
11½
8
8
8
8
8
8
8
--
--
--
2.093
2.547
3.000
--
--
--
--
--
--
--
--
--
11
11
8
--
--
--
--
--
--
1.0625
1.3125
1.860
2.100
2.550
3.035
--
--
5.000
--
--
--
11
11½
11
11
10
7½
--
--
4
--
--
--
--
1.660
--
2.100
--
3.030
3.630
4.070
4.610
5.800
--
--
--
8
--
8
--
8
8
8
8
4
--
--
1.375
1.370
--
--
--
--
--
--
--
--
--
--
8
8
--
--
--
--
--
--
--
--
--
--
--
--
--
2.1875
--
--
--
--
--
--
--
--
--
--
--
12
--
--
--
--
--
--
--
--
1.0625
1.0625
--
--
--
--
--
--
--
--
--
--
11½
11½
--
--
--
--
--
--
--
--
--
--
--
--
--
1.933
--
2.990
--
--
--
--
--
--
--
--
--
11½
--
7½
--
--
--
--
--
--
1.081
1.2951
1.705
1.946
2.522
3.043
--
--
--
--
--
--
11½
11½
11½
11½
8
7
--
--
--
--
--
--
* National Form Thread. Abbreviation for tapered iron pipe thread is TIPT or NPT (National Pipe Tapered).
ODM = Outside Diameter of Male
* B Threads are designed to connect with both BCT and AMA fittings.
Listed are the more popular thread types, other threads types are available, please contact Dixon™ for more information
Thread Legend
Initials
Common Name
Dixon Suffix
Region Normally Used
2-1/2" ODM
1
2-1/2" TPI
2
AMA & BCT Alberta Mutual Aid/ British Columbia Thread
B*
British Columbia & Alberta
3.00
8
CSA
Canadian Standard Association
C
Ontario
3.125
5
NS1
Nova Scotia 1
NS
Nova Scotia
3.23
5
QST & QMT
Quebec Standard Thread
Q
Quebec
3.031
7
WCT
Western Canada Thread
W
Saskatchewan & Manitoba
3.25
6
GHT
Garden Hose Thread
G
North America
1
outside diameter of male
2
threads per inch
NPS
National Pipe Straight
S
NPT
National Pipe Tapered
T
NST (NH)
National Standard Thread
F
Most of USA
NYC
New York Corporation
NYC
Newark, NJ
NYFD
New York Fire Department
NYFD
New York Fire Department
Fire Threads
Within North America there are many regional fire threads, the most popular being the "NST" (or "NH") thread, which is the
predominant USA fire thread. The NST thread is sometimes used in Canada especially in sizes 3" and larger.
Within Canada the most common threads used for fire applications are:
•
1", 1½" & 2" sizes use NPS (National Pipe Straight) thread
•
2½" each region uses different threads, please see the table below
•
3" and larger - NST threads are often used.
Before ordering, please confirm the type of thread required. Thread requirements change by region.