ASME B16.9 Reducers Dimension - Huitong Pipeline Equipment

Reducers are one of the key fittings in the ASME B16.9 standard. They are used to connect two pipes with different nominal diameters, enabling the fluid to transition in diameter within the pipe while maintaining the stability of the fluid flow and reducing pressure loss or turbulence caused by sudden changes in flow velocity. They are widely used in industrial piping systems such as petrochemical, natural gas, power, and water treatment.

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Classification of Reducer Types

Concentric Reducers: The axes of the pipes at both ends coincide, and the cross-section is symmetrical and circular. They are suitable for scenarios where high consistency of pipe axes is required and there is no need for gas-liquid separation (such as liquid transport pipelines).

Eccentric Reducers: The axes of the pipes at both ends are parallel but do not coincide, with an eccentricity. They are suitable for transporting gas-liquid mixed fluids (such as steam pipelines) or scenarios where liquid accumulation at the bottom of the pipe needs to be avoided. They can be adapted to different working conditions through "top-flat" or "bottom-flat" installation methods.

ASME B16.9 Dimensional Tolerances for Reducers

Outer Diameter Tolerance

The permissible deviation for the outer diameter of both the large and small ends is ±1%, with a maximum deviation not exceeding ±1.6mm.

Wall Thickness Tolerance

The minimum wall thickness shall not be less than 90% of the standard specified value, and there is no upper limit to the maximum wall thickness (but the inner diameter must meet the fluid flow requirements).

Length Tolerance

The permissible deviation for standard length is ±6.4mm (for nominal diameter ≤ DN200) and ±12.7mm (for nominal diameter > DN200). Special lengths must have tolerances indicated on the drawings, and the deviation shall not exceed ±3%.

Eccentricity Tolerance

The permissible deviation of eccentricity is ±0.8mm (for nominal diameter ≤ DN100) and ±1.6mm (for nominal diameter > DN100). Exceeding this limit will cause the pipeline axis to shift after installation, affecting sealing performance.

dimension of reducers

DIMENSIONS OF REDUCERS

Nominal Pipe Size (NPS)	DN	Outside Diameter at Bevel		End-to-End, H	Nominal Pipe Size (NPS)	DN	Outside Diameter at Bevel		End-to-End, H
Nominal Pipe Size (NPS)	DN	Large End	Small End	End-to-End, H	Nominal Pipe Size (NPS)	DN	Large End	Small End	End-to-End, H
3/4 x 1/2	20 ×15	26.7	21.3	38	5 × 4	125 ×100	141.3	114.3	127
3/4 x 3/8	20 ×10	26.7	17.3	38	5 × 3 1/2	125 ×90	141.3	101.6	127
1 × 3/4	25 ×20	33.4	26.7	51	5 × 3	125 ×80	141.3	88.9	127
1 × 1/2	25 ×15	33.4	21.3	51	5 × 2 1/2	125 ×65	141.3	73.0	127
1 1/4 × 1	32 ×25	42.2	33.4	51	5 × 2	125 × 50	141.3	60.3	127
1 1/4 ×3/4	32 ×20	42.2	26.7	51	6 × 5	150 ×125	168.3	141.3	140
1 1/4 x 1/2	32 ×15	42.2	21.3	51	6 × 4	150 ×100	168.3	114.3	140
1 1/2 x 1 1/4	40 ×32	48.3	42.2	64	6 × 3 1/2	150 ×90	168.3	101.6	140
1 1/2 × 1	40 ×25	48.3	33.4	64	6 × 3	150 ×80	168.3	88.9	140
1 1/2 x 3/4	40 ×20	48.3	26.7	64	6 × 2 1/2	150 ×65	168.3	73.0	140
1 1/2 x 1/2	40 ×15	48.3	21.3	64	8 × 6	200 ×150	219.1	168.3	152
2 ×1 1/2	50 ×40	60.3	48.3	76	8 × 5	200 ×125	219.1	141.3	152
2 ×1 1/4	50 ×32	60.3	42.2	76	8 × 4	200 ×100	219.1	114.3	152
2 × 1	50 ×25	60.3	33.4	76	8 × 3 1/2	200 ×90	219.1	101.6	152
2 ×3/4	50 ×20	60.3	26.7	76	10 × 8	250 ×200	273.0	219.1	178
2 1/2 x 2	65 ×50	73.0	60.3	89	10 × 6	250 ×150	273.0	168.3	178
2 1/2 x 1 1/2	65 ×40	73.0	48.3	89	10 × 5	250 x 125	273.0	141.3	178
2 1/2 x 1 1/4	65 ×32	73.0	42.2	89	10 × 4	250 ×100	273.0	114.3	178
2 1/2 × 1	65 ×25	73.0	33.4	89	12 × 10	300 ×250	323.8	273.0	203
3 ×2 1/2	80 ×65	88.9	73.0	89	12 × 8	300 ×200	323.8	219.1	203
3 × 2	80 ×50	88.9	60.3	89	12 × 6	300 ×150	323.8	168.3	203
3 × 1 1/2	80 ×40	88.9	48.3	89	12 × 5	300 ×125	323.8	141.3	203
3 × 1 1/4	80 ×32	88.9	42.2	89	14 × 12	350 ×300	355.6	323.8	330
3 1/2 × 3	90 ×80	101.6	88.9	102	14 × 10	350 ×250	355.6	273.0	330
3 1/2 x 2 1/2	90 ×65	101.6	73.0	102	14 × 8	350 ×200	355.6	219.1	330
3 1/2 × 2	90 ×50	101.6	60.3	102	14 × 6	350 ×150	355.6	168.3	330
3 1/2 × 1 1/2	90 ×40	101.6	48.3	102	16 × 14	400 ×350	406.4	355.6	356
3 1/2 x 2 1/4	90 ×32	101.6	42.2	102	16 × 12	400 ×300	406.4	323.8	356
4 × 3 1/2	100 ×90	114.3	101.6	102	16 × 10	400 ×250	406.4	273.0	356
4 × 3	100 ×80	114.3	88.9	102	16 × 8	400 ×200	406.4	219.1	356
4 × 2 1/2	100 ×65	114.3	73.0	102	18 × 16	450 ×400	457	406.4	381
4 × 2	100 ×50	114.3	60.3	102	18 × 14	450 ×350	457	355.6	381
4 ×1 1/2	100 ×40	114.3	48.3	102	18 × 12 18 × 10	450 ×300 450 ×250	457 457	323.8 273.0	381 381

DIMENSIONS OF REDUCERS (CONT'D)

Nominal Pipe Size (NPS)	DN	Outside Diameter at Bevel		End-to-End, H	Nominal Pipe Size (NPS)	DN	Outside Diameter at Bevel		End-to-End, H
Nominal Pipe Size (NPS)	DN	Large End	Small End	End-to-End, H	Nominal Pipe Size (NPS)	DN	Large End	Small End	End-to-End, H
20 × 18	500 × 450	508	457	508	36 × 34	900 × 850	914	864	610
20 × 16	500 × 400	508	406.4	508	36 × 32	900 × 800	914	813	610
20 × 14	500 × 350	508	355.6	508	36 × 30	900 × 750	914	762	610
20 × 12	500 × 300	508	323.8	508	36 × 28 36 × 26	900 × 700 900 × 650	914 914	660 610	610 610
22 × 20	550 × 500	559	508	508
22 × 18	550 × 450	559	457	508	38 × 36	950 × 900	965	914	610
22 × 16	550 × 400	559	406.4	508	38 × 34	950 × 850	965	864	610
22 × 14	550 × 350	559	355.4	508	38 × 32	950 × 800	965	813	610
24 × 22	600 × 550	610	559	508	38 × 30	950 × 750	965	762	610
24 × 20	600 × 500	610	508	508	38 × 28	950 × 700	965	711	610
24 × 18	600 × 450	610	457	508	38 × 26	950 × 650	965	660	610
24 × 16	600 × 400	610	406.4	508	40 × 38	1000 × 950	1016	965	610
26 × 24	650 × 600	660	610	610	40 × 34	1000 × 850	1016	864	610
26 × 22	650 × 550	660	559	610	40 × 32	1000 × 800	1016	813	610
26 × 20	650 × 500	660	508	610	40 × 30	1000 × 750	1016	762	610
26 × 18	650 × 450	660	457	610	40 × 36	1000 × 900	1016	914	610
28 × 26	700 × 650	711	660	610	42 × 40 42 × 38	1050 × 1000 1050 × 950	1067 1067	1016 965	610 610
28 × 24	700 × 600	711	610	610	42 × 36	1050 × 900	1067	914	610
28 × 22	700 × 550	711	508	610	42 × 34	1050 × 850	1067	864	610
28 × 20	700 × 500	711	457	610	42 × 32	1050 × 800	1067	813	610
30 × 28	750 × 700	762	711	610	42 × 30	1050 × 750	1067	762	610
30 × 26	750 × 650	762	660	610	44 × 42	1100 × 1050	1118	1067	610
30 × 24	750 × 600	762	610	610	44 × 40	1100 × 1000	1118	1016	610
30 × 22	750 × 550	762	508	610	44 × 38	1100 × 950	1118	965	610
32 × 30	800 × 750	813	762	610	44 × 36	1100 × 900	1118	914	610
32 × 28	800 × 700	813	711	610	46 × 44	1150 × 1100	1168	1118	711
32 × 26	800 × 650	813	660	610	46 × 42	1150 × 1050	1168	1067	711
32 × 24	800 × 600	813	610	610	46 × 40	1150 × 1000	1168	1016	711
34 × 32	850 × 800	864	813	610	46 × 38	1150 × 950	1168	965	711
34 × 30	850 × 750	864	762	610	48 × 46	1200 × 1150	1219	1168	711
34 × 28	850 × 700	864	660	610	48 × 44	1200 × 1100	1219	1118	711
34 × 26	850 × 650	864	610	610	48 × 42 48 × 40	1200 × 1050 1200 × 1000	1219 1219	1067 1016	711 711

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