Spectacle Blind Flange

A spectacle blind flange is a type of flange used in piping systems to block the flow of fluid in a pipeline. It’s essentially a dual-purpose component consisting of two separate pieces:

Blind Flange: A solid, flat flange that completely covers the end of a pipe to block flow.
Spacers (Spectacles): These are typically semi-circular or plate-like pieces that can be bolted in place to either seal the pipe (acting as a blind flange) or to allow flow through the pipe when the blind flange is removed.

The name “spectacle” comes from the shape of the flange assembly, which can resemble a pair of spectacles or glasses. This design allows for quick switching between a blocked and an open state without needing to remove and replace individual flanges.

Applications and Benefits:

Isolation: They are used to isolate a section of a pipeline for maintenance or repair without having to disassemble the entire system.
Safety: By providing a reliable method to close off a pipeline, they help in preventing accidental fluid leakage or release during maintenance activities.
Convenience: The dual design allows for quick changes in pipeline status, saving time and effort.

In summary, spectacle blind flanges are practical components in industrial piping systems, offering both flexibility and safety.

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 150 Raised Face Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	16	45	60	3.0	38
3⁄4	21	54	70	3.0	38
1	27	64	80	3.0	38
11⁄4	42	73	90	6.4	38
11⁄2	48	83	100	6.4	38
2	61	102	120	6.4	51
21⁄2	73	107	140	6.4	51
3	89	133	150	6.4	64
31⁄2	102	159	175	9.7	64
4	114	172	190	9.7	64
5	141	194	215	9.7	76
6	168	219	240	12.7	76
8	219	276	300	12.7	76
10	273	337	360	15.7	102
12	324	406	430	19.1	102
14	356	448	475	19.1	108
16	406	511	460	22.4	108
18	457	546	580	25.4	114
20	508	603	635	28.4	121
24	610	714	750	31.8	140

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 300 Raised Face Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	16	51	65	6.4	38
3⁄4	21	64	80	6.4	38
1	27	70	90	6.4	38
11⁄4	42	79	100	6.4	38
11⁄2	48	92	115	6.4	38
2	61	108	125	9.7	51
21⁄2	73	127	150	9.7	51
3	89	146	170	9.7	64
31⁄2	102	162	185	12.7	64
4	114	178	200	12.7	64
5	141	213	235	15.7	76
6	168	248	270	15.7	76
8	219	305	330	22.4	76
10	273	359	385	25.4	102
12	324	419	450	28.4	102
14	356	483	515	31.8	108
16	406	536	570	38.1	108
18	457	594	630	41.1	114
20	508	651	685	44.5	121
24	610	772	810	50.8	140

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 600 Raised Face Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	16	51	65	6.4	38
3⁄4	21	64	80	6.4	38
1	27	70	90	6.4	57
11⁄4	37	79	100	9.7	57
11⁄2	43	92	115	9.7	67
2	55	108	125	9.7	57
21⁄2	67	127	150	12.7	67
3	83	146	170	12.7	67
31⁄2	96	159	185	15.7	76
4	108	191	215	15.7	76
5	135	238	265	19.1	86
6	162	264	290	22.4	86
8	212	318	350	28.4	95
10	265	397	430	35.1	105
12	315	454	490	41.1	105
14	346	489	525	44.5	114
16	397	562	605	50.8	124
18	448	610	655	53.8	133
20	497	679	725	63.5	133
24	597	787	840	73.2	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 900 Raised Face Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	16	60	80	6.4	38
3⁄4	21	67	90	6.4	41
1	27	76	100	6.4	57
11⁄4	37	86	110	9.7	57
11⁄2	43	95	125	9.7	67
2	55	140	165	12.7	57
21⁄2	67	162	190	12.7	67
3	83	165	190	15.7	67
4	108	203	235	19.1	76
5	135	244	280	22.4	86
6	162	286	320	25.4	86
8	212	356	395	35.1	95
10	265	432	470	41.1	105
12	315	495	535	47.8	105
14	346	518	560	53.8	114
16	397	572	615	60.5	124
18	448	635	685	66.5	133
20	497	696	750	73.2	133
24	597	835	900	88.9	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 1500 Raised Face Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	16	61	80	6.4	38
3⁄4	21	67	90	9.7	41
1	27	76	100	9.7	64
11⁄4	35	86	110	9.7	64
11⁄2	41	95	125	12.7	70
2	53	140	165	12.7	70
21⁄2	63	162	190	15.7	76
3	78	172	205	19.1	76
4	102	206	240	22.4	89
5	128	251	290	28.4	89
6	154	279	320	35.1	89
8	203	349	395	41.1	102
10	255	432	480	50.8	114
12	303	518	570	60.5	114
14	333	575	635	66.5	127
16	381	638	705	76.2	133
18	429	702	775	85.9	146
20	478	752	830	95.3	152
24	575	899	990	111.3	178

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 2500 Raised Face Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	16	67	90	9.7	38
3⁄4	21	73	95	9.7	41
1	27	83	110	9.7	64
11⁄4	35	102	130	12.7	64
11⁄2	41	114	145	15.7	70
2	53	143	170	15.7	70
21⁄2	63	165	195	19.1	76
3	78	194	230	22.4	76
4	102	232	275	28.4	89
5	128	276	325	35.1	89
6	154	314	370	41.1	89
8	198	384	440	53.8	102
10	248	473	540	66.5	114
12	289	546	620	79.2	114

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 150 Male Oval Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

T_h = T + t where T is the ring gasket height specified in ASME B16.20.

NPS	Inside Diameter – B	Centerline Dimension – A	Thickness – t	Webwidth – W
1	34	80	6.4	51
11⁄4	42	90	6.4	51
11⁄2	48	100	6.4	57
2	61	120	6.4	57
21⁄2	73	140	9.7	57
3	89	150	9.7	57
31⁄2	102	175	9.7	64
4	114	190	9.7	64
5	141	215	12.7	76
6	168	240	12.7	83
8	219	300	15.7	95
10	273	362	19.1	102
12	324	432	22.4	121
14	356	476	22.4	127
16	406	540	25.4	127
18	457	578	28.4	127
20	508	635	28.4	127
24	610	749	35.1	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 300 Male Oval Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

T_h = T + t where T is the ring gasket height specified in ASME B16.20.

NPS	Inside Diameter – B	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	65	6.4	38
3⁄4	27	80	9.7	45
1	34	90	9.7	51
11⁄4	42	100	9.7	51
11⁄2	48	115	9.7	57
2	61	125	12.7	57
21⁄2	73	150	15.7	57
3	89	170	15.7	57
31⁄2	102	180	19.1	64
4	114	200	15.7	64
5	141	235	19.1	76
6	168	270	22.4	83
8	219	330	25.4	95
10	273	390	28.4	102
12	324	450	35.1	121
14	356	415	38.1	127
16	406	570	41.1	127
18	457	630	44.5	127
20	508	685	50.8	127
24	610	810	57.2	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 600 Male Oval Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

T_h = T + t where T is the ring gasket height specified in ASME B16.20.

NPS	Inside Diameter – B	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	65	6.4	38
3⁄4	27	80	9.7	45
1	34	90	9.7	51
11⁄4	42	100	9.7	57
11⁄2	48	115	9.7	57
2	61	125	12.7	51
21⁄2	73	150	15.7	57
3	89	170	15.7	67
31⁄2	102	180	19.1	67
4	114	215	19.1	73
5	141	265	22.4	73
6	168	290	28.4	73
8	219	350	35.1	83
10	273	430	41.1	121
12	324	490	47.8	121
14	356	525	50.8	121
16	406	605	57.2	127
18	457	650	63.5	133
20	508	720	69.9	127
24	610	840	82.6	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 900 Male Oval Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

T_h = T + t where T is the ring gasket height specified in ASME B16.20.

NPS	Inside Diameter – B	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	80	9.7	38
3⁄4	27	90	9.7	45
1	34	100	9.7	51
11⁄4	42	110	12.7	54
11⁄2	48	125	12.7	54
2	61	165	15.7	51
21⁄2	73	190	19.1	54
3	89	190	19.1	67
4	114	235	25.4	73
5	141	280	28.4	73
6	168	315	31.8	73
8	219	395	41.1	79
10	273	470	47.8	121
12	324	535	57.2	121
14	356	560	60.5	121
16	406	615	69.9	127
18	457	685	76.2	133
20	508	750	85.9	127
24	610	900	98.6	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 1500 Male Oval Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

T_h = T + t where T is the ring gasket height specified in ASME B16.20.

NPS	Inside Diameter – B	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	83	9.7	38
3⁄4	27	89	9.7	45
1	34	102	12.7	54
11⁄4	42	111	12.7	54
11⁄2	48	124	15.7	57
2	61	165	19.1	54
21⁄2	73	191	22.4	57
3	89	203	28.4	73
4	114	241	31.8	76
5	141	292	38.1	76
6	168	318	41.1	79
8	219	394	50.8	86
10	273	483	63.5	133
12	324	572	73.2	133
14	356	635	79.2	140
16	406	705	88.9	146
18	457	775	98.6	152
20	508	832	108.0	165
24	610	991	127.0	178

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 2500 Male Oval Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

T_h = T + t where T is the ring gasket height specified in ASME B16.20.

NPS	Inside Diameter – B	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	90	12.7	41
3⁄4	27	95	15.7	48
1	34	110	15.7	54
11⁄4	42	130	19.1	54
11⁄2	48	145	22.4	61
2	61	170	25.4	57
21⁄2	73	195	28.4	61
3	89	230	31.8	76
4	114	270	38.1	83
5	141	325	47.8	89
6	168	370	57.2	95
8	219	440	69.9	95
10	273	540	82.6	95
12	324	620	98.6	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 150 Female Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1	34	64	80	19.1	51
11⁄4	42	73	90	19.1	51
11⁄2	48	83	100	19.1	57
2	61	102	120	19.1	57
21⁄2	73	121	140	22.4	57
3	89	133	150	22.4	57
31⁄2	102	154	175	22.4	64
4	114	172	190	22.4	64
5	141	194	215	25.4	70
6	168	219	240	25.4	83
8	219	273	300	28.4	95
10	273	330	360	31.8	102
12	324	406	430	35.1	121
14	356	426	475	35.1	127
16	406	483	540	38.1	127
18	457	546	580	41.1	127
20	508	597	635	41.1	127
24	610	711	750	47.8	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 300 Female Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	51	65	15.7	38
3⁄4	27	64	80	19.1	45
1	34	70	90	19.1	51
11⁄4	42	79	100	22.4	51
11⁄2	48	90	115	22.4	57
2	61	108	125	25.4	57
21⁄2	73	127	150	28.4	57
3	89	146	170	28.4	57
31⁄2	102	159	185	28.4	64
4	114	175	200	31.8	64
5	141	210	235	35.1	70
6	168	241	270	35.1	83
8	219	302	330	41.1	95
10	273	356	385	44.5	102
12	324	413	450	50.8	121
14	356	457	515	53.8	127
16	406	508	570	57.2	127
18	457	575	630	60.5	127
20	508	635	685	69.9	127
24	610	749	810	79.2	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 600 Female Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	51	65	19.1	38
3⁄4	27	64	80	22.4	45
1	34	70	90	22.4	51
11⁄4	42	79	100	22.4	51
11⁄2	48	90	115	22.4	57
2	61	108	125	28.4	57
21⁄2	73	127	150	31.8	57
3	89	146	170	31.8	57
31⁄2	102	159	185	35.1	64
4	114	175	215	35.1	64
5	141	210	265	38.1	70
6	168	241	290	44.5	83
8	219	302	350	50.8	95
10	273	356	430	57.2	102
12	324	413	490	63.5	121
14	356	457	525	66.5	127
16	406	508	605	73.2	127
18	457	575	655	79.2	127
20	508	635	725	88.9	127
24	610	749	840	104.6	152

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 900 Female Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	61	80	22.4	38
3⁄4	27	67	90	22.4	45
1	34	71	100	22.4	51
11⁄4	42	81	110	25.4	51
11⁄2	48	92	125	25.4	64
2	61	124	165	31.8	51
21⁄2	73	137	190	35.1	67
3	89	155	190	35.1	67
4	114	181	235	41.1	73
5	141	216	280	44.5	73
6	168	241	315	47.8	73
8	219	308	395	57.2	80
10	273	362	470	63.5	121
12	324	419	535	73.2	121
14	356	467	560	82.6	121
16	406	524	615	91.9	127
18	457	594	685	101.6	133
20	508	648	750	111.3	127
24	610	772	900	133.4	140

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 1500 Female Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	61	80	22.4	38
3⁄4	27	67	90	25.4	45
1	34	71	100	25.4	54
11⁄4	42	81	110	25.4	54
11⁄2	48	92	125	28.4	57
2	61	124	165	35.1	54
21⁄2	73	137	190	38.1	57
3	89	168	205	44.5	73
4	114	194	240	47.8	76
5	141	229	290	53.8	76
6	168	248	315	60.5	79
8	219	318	395	73.2	86
10	273	371	480	82.5	133
12	324	438	570	101.6	133
14	356	489	635	111.3	140
16	406	546	705	124.0	146
18	457	613	775	133.0	152
20	508	673	830	142.7	165
24	610	794	990	168.1	178

All dimensions are in “mm” unless noted otherwise.

Dimensions of Class 2500 Female Ring-Joint Facing Figure-8 Blanks as per ASME B16.48.

NPS	Inside Diameter – B	Outside Diameter – O	Centerline Dimension – A	Thickness – t	Webwidth – W
1⁄2	21	65	90	25.4	38
3⁄4	27	73	95	28.4	45
1	34	83	110	28.4	54
11⁄4	42	102	130	35.1	54
11⁄2	48	114	145	38.1	61
2	61	133	170	41.1	57
21⁄2	73	149	195	47.8	61
3	89	168	230	50.8	76
4	114	203	270	63.5	83
5	141	241	325	73.2	89
6	168	279	370	82.6	95
8	219	340	440	98.6	95
10	273	425	540	117.3	91
12	324	495	620	133.4	152

Spectacle Blind Flange

Dimensions of Class 150 RF Figure-8 Blanks

Dimensions of Class 300 RF Figure-8 Blanks

Dimensions of Class 600 RF Figure-8 Blanks

Dimensions of Class 900 RF Figure-8 Blanks

Dimensions of Class 1500 RF Figure-8 Blanks

Dimensions of Class 2500 RF Figure-8 Blanks

Dimensions of Class 150 Male Oval Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 300 Male Oval Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 600 Male Oval Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 900 Male Oval Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 1500 Male Oval Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 2500 Male Oval Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 150 Female Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 300 Female Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 600 Female Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 900 Female Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 1500 Female Ring-Joint Facing Figure-8 Blanks

Dimensions of Class 2500 Female Ring-Joint Facing Figure-8 Blanks