Black Iron Fittings

205 products

Showing 1 - 96 of 205 products

Black malleable iron threaded fittings for gas, steam, compressed air and hydronic heating. Sizes 1/8" through 4", in FIP, MPT x FPT, three-way FPT and flanged configurations.

Black iron is used on gas because it carries no zinc. Zinc coating can shed inside a fuel gas line and the flakes foul controls and orifices downstream, which is why black is the trade default even though a galvanized fitting looks identical on the shelf. NFPA 54 does permit galvanized steel pipe for fuel gas, so the requirement on any given job comes from the local code and the gas utility rather than from a blanket ban.

Threads are NPT and taper — the seal comes from thread deformation, not from the sealant, so the correct engagement depth matters more than how much dope is applied. Use a sealant rated for the medium: standard pipe dope is not approved for gas, where a yellow gas-rated PTFE tape or a listed compound is required.

Tees, couplings, 90° elbows and street elbows, bushings, caps and plugs make up the range.

Predominantly Mueller Streamline.

Thread engagement figures, Class 150 pressure ratings and Schedule 40 pipe dimensions are collected in our black iron reference guide.

Black iron fittings by size: Mueller Streamline part numbers

The most-ordered Mueller Streamline black malleable iron fittings, by size and type. Each part number links to the product page. Reducing tees, reducing couplings, bushings, 45° street elbows and floor flanges are in the full collection below.

Size	90° Elbow	45° Elbow	90° Street Elbow	Tee	Coupling	Union	Cap	Plug
1/2"	520-003	520-203	520-303	520-603	521-203	521-703	521-403	521-803
3/4"	520-004	520-204	520-304	520-604	521-204	521-704	521-404	521-804
1"	520-005	520-205	520-305	520-605	521-205	521-705	521-405	521-805
1-1/4"	520-006	520-206	520-306	520-606	521-206	521-706	521-406	521-806
1-1/2"	520-007	520-207	520-307	520-607	521-207	521-707	521-407	521-807
2"	520-008	520-208	520-308	520-608	521-208	521-708	521-408	521-808

See also: black iron pipe and black iron nipples.

For 2" and larger steel pipe in fire protection and HVAC risers, Gruvlok grooved fittings and couplings join pipe without threading or welding.

Showing 1 - 96 of 205 products

Mueller Streamline Mueller Streamline 521-610 3" Black Iron Floor Flange

$29.01

Only 4 units left

Mueller Streamline Mueller Streamline 521-810 3" Black Iron Plug

$12.90

Sold out

Ward Ward 1D.BU 1-1/2" Black Iron Union

$46.58

In stock, 28 units

Mueller Streamline 4" x 2-1/2" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-919 4" x 2-1/2" Black Iron Bushing

$26.71

Only 1 unit left

Mueller Streamline 3" x 2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-308 3" x 2" Black Iron Coupling

$33.69

In stock, 12 units

Mueller Streamline 3" Black Iron Elbow - 90° (Street)

Mueller Streamline Mueller Streamline 520-310 3" Black Iron Elbow - 90° (Street)

$64.97

Only 5 units left

Mueller Streamline Mueller Streamline 520-510 3" Black Iron Elbow - 45° (Street)

$80.66

In stock, 6 units

Mueller Streamline 3" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-210 3" Black Iron Coupling

$39.86

In stock, 20 units

Mueller Streamline Mueller Streamline 521-410 3" Black Iron Cap

$25.20

In stock, 14 units

Mueller Streamline 3" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-010 3" Black Iron Elbow - 90°

$45.20

In stock, 8 units

Mueller Streamline 3" Black Iron Elbow - 45°

Mueller Streamline Mueller Streamline 520-210 3" Black Iron Elbow - 45°

$54.30

Only 5 units left

Mueller Streamline Mueller Streamline 2-1/2" x 2-1/2" x 2" Black Iron Tee

$53.73

Only 1 unit left

Mueller Streamline 2-1/2" x 2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-398 2-1/2" x 2" Black Iron Coupling

$26.05

In stock, 47 units

Mueller Streamline Mueller Streamline 2-1/2" x 2-1/2" x 1" Black Iron Tee

$53.73

In stock, 6 units

Mueller Streamline 2-1/2" Black Iron Union

Mueller Streamline Mueller Streamline 521-709 2-1/2" Black Iron Union

$72.99

Only 5 units left

Mueller Streamline Mueller Streamline 520-609 2-1/2" Black Iron Tee

$41.31

In stock, 15 units

Mueller Streamline 2-1/2" Black Iron Elbow - 90° (Street)

Mueller Streamline Mueller Streamline 520-309 2-1/2" Black Iron Elbow - 90° (Street)

$42.59

In stock, 11 units

Mueller Streamline 2-1/2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-209 2-1/2" Black Iron Coupling

$29.49

In stock, 23 units

Mueller Streamline 2-1/2" Black Iron Cap

Mueller Streamline Mueller Streamline 521-409 2-1/2" Black Iron Cap

$16.95

In stock, 27 units

Mueller Streamline 2-1/2" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-009 2-1/2" Black Iron Elbow - 90°

$30.30

In stock, 24 units

Mueller Streamline 2" x 1-1/2" x 1-1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-877 2" x 1-1/2" x 1-1/2" Black Iron Tee

$24.70

In stock, 39 units

Mueller Streamline 2" x 2" x 1-1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-787 2" x 2" x 1-1/2" Black Iron Tee

$21.67

In stock, 66 units

Mueller Streamline 2" x 1-1/2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-387 2" x 1-1/2" Black Iron Coupling

$10.21

In stock, 101 units

Mueller Streamline 2" x 1-1/2" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-987 2" x 1-1/2" Black Iron Bushing

$6.52

In stock, 11 units

Mueller Streamline 2" x 1-1/2" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-187 2" x 1-1/2" Black Iron Elbow - 90°

$14.70

In stock, 25 units

Mueller Streamline 2" x 2" x 1-1/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-886 2" x 2" x 1-1/4" Black Iron Tee

$21.67

In stock, 59 units

Mueller Streamline 2" x 1-1/4" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-386 2" x 1-1/4" Black Iron Coupling

$11.69

In stock, 97 units

Mueller Streamline 2" x 1-1/4" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-986 2" x 1-1/4" Black Iron Bushing

$5.85

In stock, 15 units

Mueller Streamline 2" x 1-1/4" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-186 2" x 1-1/4" Black Iron Elbow - 90°

$16.74

In stock, 8 units

Mueller Streamline 2" x 2" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-785 2" x 2" x 1" Black Iron Tee

$20.50

In stock, 61 units

Mueller Streamline 2" x 1" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-385 2" x 1" Black Iron Coupling

$11.05

In stock, 67 units

Mueller Streamline 2" x 1" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-985 2" x 1" Black Iron Bushing

$5.85

In stock, 18 units

Mueller Streamline 2" x 1" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-185 2" x 1" Black Iron Elbow - 90°

$16.74

In stock, 36 units

Mueller Streamline 2" x 2" x 3/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-884 2" x 2" x 3/4" Black Iron Tee

$20.50

In stock, 86 units

Mueller Streamline 2" x 3/4" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-384 2" x 3/4" Black Iron Coupling

$11.69

In stock, 41 units

Mueller Streamline 2" x 3/4" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-984 2" x 3/4" Black Iron Bushing

$6.24

Only 4 units left

Mueller Streamline 2" x 2" x 1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-783 2" x 2" x 1/2" Black Iron Tee

$20.50

In stock, 78 units

Mueller Streamline 2" x 1/2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-383 2" x 1/2" Black Iron Coupling

$13.27

In stock, 20 units

Mueller Streamline Mueller Streamline 521-708 2" Black Iron Union

$30.29

In stock, 46 units

Mueller Streamline Mueller Streamline 520-608 2" Black Iron Tee

$20.09

In stock, 110 units

Mueller Streamline 2" Black Iron Elbow - 90° (Street)

Mueller Streamline Mueller Streamline 520-308 2" Black Iron Elbow - 90° (Street)

$17.25

In stock, 18 units

Mueller Streamline Mueller Streamline 521-808 2" Black Iron Plug

$5.16

In stock, 104 units

Mueller Streamline 2" Black Iron Floor Flange

Mueller Streamline Mueller Streamline 521-608 2" Black Iron Floor Flange

$13.88

Only 2 units left

Mueller Streamline 2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-208 2" Black Iron Coupling

$10.83

In stock, 231 units

Mueller Streamline Mueller Streamline 521-408 2" Black Iron Cap

$6.82

In stock, 126 units

Mueller Streamline 2" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-008 2" Black Iron Elbow - 90°

$13.96

In stock, 292 units

Mueller Streamline 2" Black Iron Elbow - 45°

Mueller Streamline Mueller Streamline 520-208 2" Black Iron Elbow - 45°

$14.82

In stock, 43 units

Mueller Streamline 1-1/2" x 1-1/4" x 1-1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-767 1-1/2" x 1-1/4" x 1-1/2" Black Iron Tee

$21.81

Only 1 unit left

Mueller Streamline 1-1/2" x 1-1/4" x 1-1/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-769 1-1/2" x 1-1/4" x 1-1/4" Black Iron Tee

$21.81

In stock, 68 units

Mueller Streamline 1-1/2" x 1-1/4" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-768 1-1/2" x 1-1/4" x 1" Black Iron Tee

$13.85

In stock, 62 units

Mueller Streamline 1-1/2" x 1-1/4" x 3/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-764 1-1/2" x 1-1/4" x 3/4" Black Iron Tee

$16.14

In stock, 14 units

Mueller Streamline 1-1/2" x 1-1/2" x 1-1/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-776 1-1/2" x 1-1/2" x 1-1/4" Black Iron Tee

$16.14

In stock, 77 units

Mueller Streamline 1-1/2" x 1-1/4" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-376 1-1/2" x 1-1/4" Black Iron Coupling

$7.04

In stock, 182 units

Mueller Streamline 1-1/2" x 1-1/4" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-976 1-1/2" x 1-1/4" Black Iron Bushing

$4.91

In stock, 72 units

Mueller Streamline 1-1/2" x 1-1/4" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-176 1-1/2" x 1-1/4" Black Iron Elbow - 90°

$11.61

In stock, 95 units

Mueller Streamline 1-1/2" x 1" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-755 1-1/2" x 1" x 1" Black Iron Tee

$16.14

In stock, 76 units

Mueller Streamline 1-1/2" x 1-1/2" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-766 1-1/2" x 1-1/2" x 1" Black Iron Tee

$13.10

In stock, 118 units

Mueller Streamline 1-1/2" x 1" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-375 1-1/2" x 1" Black Iron Coupling

$8.14

In stock, 185 units

Mueller Streamline 1-1/2" x 1" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-975 1-1/2" x 1" Black Iron Bushing

$4.29

In stock, 81 units

Mueller Streamline 1-1/2" x 1" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-157 1-1/2" x 1" Black Iron Elbow - 90°

$11.61

In stock, 90 units

Mueller Streamline 1-1/2" x 3/4" x 1-1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-747 1-1/2" x 3/4" x 1-1/2" Black Iron Tee

$16.14

In stock, 9 units

Mueller Streamline 1-1/2" x 1-1/2" x 3/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-774 1-1/2" x 1-1/2" x 3/4" Black Iron Tee

$13.10

In stock, 147 units

Mueller Streamline 1-1/2" x 3/4" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-374 1-1/2" x 3/4" Black Iron Coupling

$9.18

In stock, 109 units

Mueller Streamline 1-1/2" x 3/4" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-974 1-1/2" x 3/4" Black Iron Bushing

$4.89

Only 4 units left

Mueller Streamline 1-1/2" x 3/4" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-174 1-1/2" x 3/4" Black Iron Elbow - 90°

$11.61

In stock, 183 units

Mueller Streamline 1-1/2" x 1-1/2" x 1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-773 1-1/2" x 1-1/2" x 1/2" Black Iron Tee

$13.85

In stock, 114 units

Mueller Streamline 1-1/2" x 1/2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-373 1-1/2" x 1/2" Black Iron Coupling

$8.14

In stock, 42 units

Mueller Streamline 1-1/2" x 1/2" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-973 1-1/2" x 1/2" Black Iron Bushing

$4.89

In stock, 30 units

Mueller Streamline Mueller Streamline 1-1/2" x 1/2" Black Iron Elbow - 90°

$11.87

In stock, 10 units

Mueller Streamline 1-1/2" Black Iron Union

Mueller Streamline Mueller Streamline 521-707 1-1/2" Black Iron Union

$20.04

In stock, 136 units

Mueller Streamline 1-1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-607 1-1/2" Black Iron Tee

$11.82

In stock, 214 units

Mueller Streamline 1-1/2" Black Iron Elbow - 90° (Street)

Mueller Streamline Mueller Streamline 520-307 1-1/2" Black Iron Elbow - 90° (Street)

$10.63

In stock, 32 units

Mueller Streamline 1-1/2" Black Iron Plug

Mueller Streamline Mueller Streamline 521-807 1-1/2" Black Iron Plug

$3.62

In stock, 217 units

Mueller Streamline 1-1/2" Black Iron Floor Flange

Mueller Streamline Mueller Streamline 521-607 1-1/2" Black Iron Floor Flange

$10.63

In stock, 20 units

Mueller Streamline 1-1/2" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-207 1-1/2" Black Iron Coupling

$7.44

In stock, 324 units

Mueller Streamline 1-1/2" Black Iron Cap

Mueller Streamline Mueller Streamline 521-407 1-1/2" Black Iron Cap

$5.22

In stock, 225 units

Mueller Streamline 1-1/2" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-007 1-1/2" Black Iron Elbow - 90°

$8.14

In stock, 304 units

Mueller Streamline 1-1/2" Black Iron Elbow - 45°

Mueller Streamline Mueller Streamline 520-207 1-1/2" Black Iron Elbow - 45°

$9.84

In stock, 179 units

Mueller Streamline 1-1/4" x 1" x 1-1/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-656 1-1/4" x 1" x 1-1/4" Black Iron Tee

$13.77

In stock, 106 units

Mueller Streamline 1-1/4" x 1" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-655 1-1/4" x 1" x 1" Black Iron Tee

$11.88

In stock, 316 units

Mueller Streamline 1-1/4" x 1" x 3/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-654 1-1/4" x 1" x 3/4" Black Iron Tee

$11.88

In stock, 144 units

Mueller Streamline 1-1/4" x 1" x 1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-653 1-1/4" x 1" x 1/2" Black Iron Tee

$12.57

In stock, 54 units

Mueller Streamline 1-1/4" x 1-1/4" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-765 1-1/4" x 1-1/4" x 1" Black Iron Tee

$10.37

In stock, 168 units

Mueller Streamline 1-1/4" x 1" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-365 1-1/4" x 1" Black Iron Coupling

$5.56

In stock, 261 units

Mueller Streamline 1-1/4" x 1" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-965 1-1/4" x 1" Black Iron Bushing

$3.85

In stock, 94 units

Mueller Streamline 1-1/4" x 1" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-165 1-1/4" x 1" Black Iron Elbow - 90°

$7.08

In stock, 304 units

Mueller Streamline 1-1/4" x 3/4" x 1-1/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-646 1-1/4" x 3/4" x 1-1/4" Black Iron Tee

$12.29

In stock, 115 units

Mueller Streamline 1-1/4" x 3/4" x 1" Black Iron Tee

Mueller Streamline Mueller Streamline 520-645 1-1/4" x 3/4" x 1" Black Iron Tee

$12.60

Only 2 units left

Mueller Streamline 1-1/4" x 3/4" x 3/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-644 1-1/4" x 3/4" x 3/4" Black Iron Tee

$13.52

In stock, 102 units

Mueller Streamline 1-1/4" x 1-1/4" x 3/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-664 1-1/4" x 1-1/4" x 3/4" Black Iron Tee

$10.37

In stock, 148 units

Mueller Streamline 1-1/4" x 3/4" Black Iron Coupling

Mueller Streamline Mueller Streamline 521-364 1-1/4" x 3/4" Black Iron Coupling

$5.56

In stock, 236 units

Mueller Streamline 1-1/4" x 3/4" Black Iron Bushing

Mueller Streamline Mueller Streamline 521-964 1-1/4" x 3/4" Black Iron Bushing

$3.85

Only 4 units left

Mueller Streamline 1-1/4" x 3/4" Black Iron Elbow - 90°

Mueller Streamline Mueller Streamline 520-164 1-1/4" x 3/4" Black Iron Elbow - 90°

$8.04

In stock, 81 units

Mueller Streamline 1-1/4" x 1/2" x 1-1/4" Black Iron Tee

Mueller Streamline Mueller Streamline 520-636 1-1/4" x 1/2" x 1-1/4" Black Iron Tee

$13.52

In stock, 99 units

Mueller Streamline Mueller Streamline 520-635 1-1/4" x 1/2" x 1" Black Iron Tee

$13.17

In stock, 10 units

Mueller Streamline 1-1/4" x 1-1/4" x 1/2" Black Iron Tee

Mueller Streamline Mueller Streamline 520-663 1-1/4" x 1-1/4" x 1/2" Black Iron Tee

$11.82

In stock, 204 units

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Black Iron Fittings

Black iron fittings by size: Mueller Streamline part numbers

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