# Malleable iron threaded fittings, Class 150 (ASME B16.3): elbow, tee, coupling and union dimensions, NPS 1/8 to 6

> What are the center-to-end dimensions of a Class 150 malleable iron (black iron) 90° elbow, 45° elbow, tee, coupling and union?

- Category: Tri-clamp & pipe › Pipe, tube & threads
- Kind: Standard part
- Basis: Anvil International's published spec sheets (FIG. 3101 90° elbow, 3102 45° elbow, 3105 tee, 3121 coupling, 463 union) and Smith-Cooper's catalogs for tee and coupling outside diameters; inches, with mm as printed by Anvil or converted at 25.4
- Page: https://xemstudio.com/objects/malleable-iron-fittings-class-150/ · JSON: https://xemstudio.com/api/geometry?object=malleable-iron-fittings-class-150 · Plain text: https://xemstudio.com/objects/malleable-iron-fittings-class-150/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- Class 150 'standard' malleable iron fittings (ASTM A197, NPT threads per ASME B1.20.1) are made to ASME B16.3; unions are ASME B16.39. Anvil prints one dimension per figure: A, the centre to the end of the threaded opening for elbows and tees, and the end-to-end length for the coupling. Smith-Cooper's catalogs agree with Anvil for the 90° tee A and the coupling length for every size they share (for example NPS 1/2: 1.12 in tee, 1.34 in coupling).
- Smith-Cooper also prints the outside diameter of the tee (B) and the minimum outside diameter of the coupling (A): NPS 1/2 tee OD 1.20 in, NPS 1 1.77 in, NPS 2 2.96 in. They are the same series, so the coupling OD min equals the tee B for NPS 1/8 to 5. A 6 in coupling is printed 7.36 in against a 7.77 in tee band; that row is left out of the coupling column and flagged here. Nominal cast wall thickness is also printed (0.10 in at 1/2, 0.17 in at 2); it is the wall away from the threads and the thread-end walls are thicker, so it is not used to draw a bore.
- Not tabulated by Anvil's sheets read: elbow and tee outside diameters from Anvil (Smith-Cooper's OD above is used), 3-1/2 and 5 in elbows (Anvil omits them), and Class 300 (the 300 lb series is a separate B16.3 table). Anvil's sheets stop at NPS 6, Smith-Cooper at NPS 8 for tees. The union column is Anvil FIG. 463 (bronze-to-iron seat, Class 150, ASME B16.39), end-to-end in mm as printed with the inch fraction; B16.39 is its own standard, not B16.3.
- Files: Class 150 straight tees and couplings at NPS 1/4, 1/2, 3/4 and 1: Xem-drawn envelopes of the published values. The tee is cylinders of the maker's outside diameter B meeting at a sphere, out to A on run and branch; the coupling is a tube of the maker's minimum OD and the published end-to-end length. Threads are plain bores: the bore is the NPT tap-drill size from npt-bsp-thread-envelopes (Ø11.1 / 18.3 / 23.4 / 29.4 mm), thread and band are not drawn. Elbows have no file: the elbow outside diameter is not printed in the sheets read.
- Why sizes stop at 1 in for files: the tap-drill table this site already carries (npt-bsp-thread-envelopes) ends at 1 in; larger sizes would need NPT tap-drill sizes from a source read. Dimensions in the table cover every size the sheets print.
- Several Smith-Cooper coupling inside-diameter entries are plain misprints (a 4 in coupling is printed with an inside diameter of 0.54 / 0.58 in) and are not used.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| plain bore (NPT tap-drill size, thread not drawn) | Ø11.1 (1/4), Ø18.3 (1/2), Ø23.4 (3/4), Ø29.4 (1) mm | tap with an NPT tap to ANSI/ASME B1.20.1 for the male thread on npt-bsp-thread-envelopes (taper 1:16) | designed | mi150-* |
| end-to-end / centre-to-end | tee A 28.45 / 33.27 / 38.10 mm (1/2 / 3/4 / 1); coupling 34.04 / 38.61 / 42.42 | set-back of the next pipe or fitting | designed | mi150-* |

## Sizes

| NPS | 90° elbow A, in (mm) | 45° elbow A, in (mm) | tee A, in (mm) | tee OD B, in (mm) | nominal cast wall, in | coupling end-to-end, in (mm) | coupling OD min, in (mm) | union end-to-end (Fig. 463) |
|---|---|---|---|---|---|---|---|---|
| 1/8 | 0.69 (17.5) | 0.63 (16.0) | 0.69 (17.5) | 0.69 (17.5) | 0.09 | 0.96 (24.4) | 0.69 (17.5) | 33 mm (1 5/16 in) |
| 1/4 | 0.81 (20.6) | 0.73 (18.5) | 0.81 (20.6) | 0.84 (21.3) | 0.09 | 1.06 (26.9) | 0.84 (21.3) | 47 mm (1 13/16 in) |
| 3/8 | 0.95 (24.1) | 0.80 (20.3) | 0.95 (24.1) | 1.01 (25.7) | 0.10 | 1.16 (29.5) | 1.01 (25.7) | 47 mm (1 13/16 in) |
| 1/2 | 1.12 (28.4) | 0.88 (22.4) | 1.12 (28.4) | 1.20 (30.5) | 0.10 | 1.34 (34.0) | 1.20 (30.5) | 49 mm (1 15/16 in) |
| 3/4 | 1.31 (33.3) | 0.98 (24.9) | 1.31 (33.3) | 1.46 (37.1) | 0.12 | 1.52 (38.6) | 1.46 (37.1) | 52 mm (2 1/16 in) |
| 1 | 1.50 (38.1) | 1.12 (28.4) | 1.50 (38.1) | 1.77 (45.0) | 0.13 | 1.67 (42.4) | 1.77 (45.0) | 62 mm (2 7/16 in) |
| 1-1/4 | 1.75 (44.4) | 1.29 (32.8) | 1.75 (44.4) | 2.15 (54.6) | 0.14 | 1.93 (49.0) | 2.15 (54.6) | 67 mm (2 5/8 in) |
| 1-1/2 | 1.94 (49.3) | 1.43 (36.3) | 1.94 (49.3) | 2.43 (61.7) | 0.15 | 2.15 (54.6) | 2.43 (61.7) | 70 mm (2 3/4 in) |
| 2 | 2.25 (57.1) | 1.68 (42.7) | 2.25 (57.1) | 2.96 (75.2) | 0.17 | 2.53 (64.3) | 2.96 (75.2) | 75 mm (2 15/16 in) |
| 2-1/2 | 2.70 (68.6) | 1.95 (49.5) | 2.70 (68.6) | 3.59 (91.2) | 0.21 | 2.88 (73.2) | 3.59 (91.2) | 92 mm (3 5/8 in) |
| 3 | 3.08 (78.2) | 2.17 (55.1) | 3.08 (78.2) | 4.28 (108.7) | 0.23 | 3.18 (80.8) | 4.28 (108.7) | 95 mm (3 3/4 in) |
| 3-1/2 | — | — | 3.42 (86.9) | 4.84 (122.9) | 0.25 | 3.50 (88.9) | 4.84 (122.9) | — |
| 4 | 3.79 (96.3) | 2.61 (66.3) | 3.79 (96.3) | 5.40 (137.2) | 0.26 | 3.69 (93.7) | 5.40 (137.2) | — |
| 5 | — | — | 4.50 (114.3) | 6.58 (167.1) | 0.30 | — | — | — |
| 6 | 5.13 (130.3) | 3.46 (87.9) | 5.13 (130.3) | 7.77 (197.4) | 0.34 | — | — | — |
| 8 | — | — | 6.50 (165.1) | 9.76 (247.9) | 0.39 | — | — | — |

## Where the files are

- Anvil International (maker): [Class 150 malleable iron FIG. 3101 90 deg elbow: dimension A](https://econtent.adhq.com/dam/Original/608/Anvil_0810002618_Specification_Sheet.pdf) — web — Maker spec sheet; numbers only
- Anvil International (maker): [Class 150 malleable iron FIG. 3102 45 deg elbow: dimension A](https://res.cloudinary.com/dzhpkjoqj/TradeService/ASCEngineeredSolutions-AnvilSPF_00003_1_SPEC.pdf) — web — Maker spec sheet; numbers only
- Anvil International (maker): [Class 150 malleable iron FIG. 3105 straight tee: dimension A](https://res.cloudinary.com/dzhpkjoqj/TradeService/ASCEngineeredSolutions-AnvilSPF_00008_1_SPEC.pdf) — web — Maker spec sheet; numbers only
- Anvil International (maker): [Class 150 malleable iron FIG. 3121 coupling: dimension A (end to end)](https://res.cloudinary.com/dzhpkjoqj/TradeService/ASCEngineeredSolutions-Anvil_00189_1_SPEC.pdf) — web — Maker spec sheet; numbers only
- Smith-Cooper (maker), via buyfittingsonline.com: [Malleable iron Class 150 straight tee (ASME B16.3): centre to end A, outside diameter B, nominal metal thickness, NPS 1/8 to 8](https://www.buyfittingsonline.com/content/Malleable-Iron-150-SM-Straight-Tees.pdf) — web — Maker catalog; numbers only
- Smith-Cooper (maker), via buyfittingsonline.com: [Malleable iron Class 150 banded full coupling (ASME B16.3): outside diameter min A, inside diameter B, end to end C, internal thread length D, NPS 1/8 to 6](https://www.buyfittingsonline.com/content/Malleable-Iron-150-SM-Banded-Full-Couplings.pdf) — web — Maker catalog; numbers only (several of its inside-diameter entries are misprints and are not used)
- Anvil International (maker), via hvacdiscounters.com: [Malleable iron unions FIG. 463 (Class 150) and 554 (Class 250), ASME B16.39: end-to-end length by NPS](https://www.hvacdiscounters.com/customer/docs/skudocs/mal-union.pdf) — web — Maker datasheet PF-11.13; numbers only
- Anvil / ASC Engineered Solutions (maker): [BIM/CAD library: Class 150 malleable iron threaded fittings (per-figure 3D CAD)](https://bimcadshare.asc-es.com/category/mi-threaded-fittings-class-150) — CAD, BIM — Maker's site terms: check before use (verify at link)
- ANSI Webstore (standard body storefront): [ASME B16.3-2016 Malleable Iron Threaded Fittings, Classes 150 and 300 (paywalled; listing only)](https://webstore.ansi.org/Standards/ASME/ASMEB162016) — web — Storefront page

## Free STEP/STL (8 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/index.json

- mi150-tee-nps0p25: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps0p25.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps0p25.stl) — NPS 1/4 Class 150 malleable iron straight tee envelope: centre-to-end 20.57 on run and branch, body OD Ø21.34, plain bore Ø11.1 (NPT tap-drill size; thread not drawn)
- mi150-tee-nps0p5: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps0p5.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps0p5.stl) — NPS 1/2 Class 150 malleable iron straight tee envelope: centre-to-end 28.45 on run and branch, body OD Ø30.48, plain bore Ø18.3 (NPT tap-drill size; thread not drawn)
- mi150-tee-nps0p75: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps0p75.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps0p75.stl) — NPS 3/4 Class 150 malleable iron straight tee envelope: centre-to-end 33.27 on run and branch, body OD Ø37.08, plain bore Ø23.4 (NPT tap-drill size; thread not drawn)
- mi150-tee-nps1: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps1.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-tee-nps1.stl) — NPS 1 Class 150 malleable iron straight tee envelope: centre-to-end 38.10 on run and branch, body OD Ø44.96, plain bore Ø29.4 (NPT tap-drill size; thread not drawn)
- mi150-coupling-nps0p25: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps0p25.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps0p25.stl) — NPS 1/4 Class 150 malleable iron coupling envelope: end-to-end 26.92, OD (min) Ø21.34, plain bore Ø11.1 (NPT tap-drill size; thread not drawn)
- mi150-coupling-nps0p5: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps0p5.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps0p5.stl) — NPS 1/2 Class 150 malleable iron coupling envelope: end-to-end 34.04, OD (min) Ø30.48, plain bore Ø18.3 (NPT tap-drill size; thread not drawn)
- mi150-coupling-nps0p75: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps0p75.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps0p75.stl) — NPS 3/4 Class 150 malleable iron coupling envelope: end-to-end 38.61, OD (min) Ø37.08, plain bore Ø23.4 (NPT tap-drill size; thread not drawn)
- mi150-coupling-nps1: [STEP](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps1.step) · [STL](https://xemstudio.com/files/hardware/malleable-iron-fittings-class-150/mi150-coupling-nps1.stl) — NPS 1 Class 150 malleable iron coupling envelope: end-to-end 42.42, OD (min) Ø44.96, plain bore Ø29.4 (NPT tap-drill size; thread not drawn)

## Questions

**What is the centre-to-end of a 1/2 inch black iron 90° elbow?**

1.12 in (28.45 mm); a 3/4 in elbow is 1.31 in (33.27 mm) and a 1 in elbow 1.50 in (38.10 mm) (Anvil FIG. 3101).

**How long is a 1/2 inch malleable iron coupling?**

1.34 in (34.04 mm) end to end (Anvil FIG. 3121); outside diameter 1.20 in (Smith-Cooper).

**What is a ground joint union's length in 1/2 inch?**

49 mm (1 15/16 in) end to end for the Class 150 Anvil Fig. 463 union.

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