Dimensions Square Edge Flow Metering Orifice Plates for ASME B16.36 RF Orifice Flanges

NPS	DIA D3	L	N	P	T
1/2	13	0.24	1.5	30	1.5
3/4	19	0.34	1.5	30	1.5
1	25	0.42	1.5	30	1.5
1.1/2	40	0.64	1.5	30	1.5
2	51	1	2	30	2
3	76	1.5	3	40	3
4	102	1.5	3	40	3
6	152	1.5	4	40	4
8	202	3.5	6	40	4
10	253	3.5	6	45	4
12	302	3.5	8	45	5
14	341	6	10	45	6
16	392	6	10	50	6
18	443	8	12	50	8
20	494	8	12	50	8
24	595	10	16	60	12

NPS	ASME B16.36 Flange Class
	300	600	900	1500	2500
	S
1/2	120	120	130	130
3/4	125	125	135	135
1	125	125	135	135
1.1/2	120	120	145	145
2	115	115	125	125	130
3	120	120	125	135	140
4	125	125	130	140	150
6	120	130	135	145	170
8	125	135	145	155	170
10	130	145	145	165	185
12	135	140	145	165	195
14	140	145	145	175
16	145	150	155	180
18	145	155	160	195
20	150	155	165	205
24	160	165	190	220

NPS	ASME B16.36 Flange Class
	300	600	900	1500	2500
	DIA D4
1/2	72.4	72.4	78.6	78.6
3/4	72.4	72.4	78.6	78.6
1	72.4	72.4	78.6	78.6
1.1/2	94.3	94.3	97.5	97.5
2	110.6	110.6	143.8	143.8	146.4
3	148.1	148.1	169.7	175	197.6
4	180	194.6	206.9	209.5	235.7
6	251.8	267.1	289.6	283.9	317.1
8	308.3	320.6	359.7	353	386.9
10	361.8	400	435.5	435	476.2
12	422.2	456.8	498.3	520.4	549.2
14	485	492.3	520.9	577.6
16	539.5	564.7	574.3	640.7
18	596.3	612.2	637.4	703.8
20	653.1	682	696.8	754.9
24	774	789	837	901

TOLERANCES

D1 & D2 = ± 1%

D3 = ± 1 mm

D4 = 0/-0.4 mm

L = ± 0.1 mm

N = see note 6

P = ± 0.1 mm

S = ± 0.1 mm

T = see note 2

Notes..

Marking
The Upstream side of the orifice tab shall be stamped at the indicated locations with..
- the word UPSTREAM
- the Tag Number
- the ASME flange class, followed by RF
- the nominal pipe size (NPS)
- the measured orifice D1 (in mm)
- the material of the orifice plate
- the type of orifice plate (Square, Restriction etc.)
Letter height approx. 4 mm
Welding of tab
Tab may be integral with orifice plate up to and including 7 mm plate thickness. In other cases full penetration joint to be applied.
Finish of plate
The upstream and downstream faces of the orifice plate to a diameter equal to D3 shall have a surface roughness Ra ≤ 0.8 µm ASME B46.1. The remaining annular part (between D4 & D3) of upstream and downstream faces shall have a surface roughness Ra between 3.2 and 3.6 µm ASME B46.1. This finish shall be obtained by machining with a round nosed cutting tool having a 0.8 mm radius at a feed rate between 0.35 and 0.45 mm per revolution.
Concentricity
The centre of the orifice shall not differ from the centre of the plate by more than 0.1 mm for ≤ NPS 8 and 0.2 mm for > NPS 8.
Finish of throat
The throat and outlet cone shall have a surface roughness Ra ≤ 0.4 µm ASME B46.1. All edges shall be sharp and free from burrs, so that when viewed with the naked eye no light is reflected by the corners.
Plate thickness
The difference between any two measurements of plate thickness, for annular part D1-D3, shall not differ by more than 0.001 DN in mm. The plate shall not depart from flatness along any diameter by more than 0.01 D3. Tolerance for N shall be.. N ≤ 6 mm +0.1/-0.25 mm N > 6 mm +0/-1.5 mm Thickness for annular part D3-D4, may be slightly less, max 0.05 mm, due to surface finishing difference between D1-D3 & D3-D4. (see note 3)