Spectacle Blinds

Dimensions Spectacle Blinds – ASME B16.48

NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W
1/2	45	16	60	3	38
3/4	54	21	70	3	38
1	64	27	80	3	38
1¼	73	42	90	6.4	38
1½	83	48	100	6.4	38
2	102	61	120	6.4	51
2½	107	73	140	6.4	51
3	133	89	150	6.4	64
3½	159	102	175	9.7	64
4	172	114	190	9.7	64
5	194	141	215	9.7	76
6	219	168	240	12.7	76
8	276	219	300	12.7	76
10	337	273	360	15.7	102
12	406	324	430	19.1	102
14	448	356	475	19.1	108
16	511	406	460	22.4	108
18	546	457	580	25.4	114
20	603	508	635	28.4	121
24	714	610	750	31.8	140
NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W

NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W
1/2	51	16	65	6.4	38
3/4	64	21	80	6.4	38
1	70	27	90	6.4	57
1¼	79	37	100	9.7	57
1½	92	43	115	9.7	67
2	108	55	125	9.7	57
2½	127	67	150	12.7	67
3	146	83	170	12.7	67
3½	159	96	185	15.7	76
4	191	108	215	15.7	76
5	238	135	265	19.1	86
6	264	162	290	22.4	86
8	318	212	350	28.4	95
10	397	265	430	35.1	105
12	454	315	490	41.1	10
14	489	346	525	44.5	114
16	562	397	605	50.8	124
18	610	448	655	53.8	133
20	679	497	725	63.5	133
24	787	597	840	73.2	152
NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W

NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W
1/2	60	16	80	6.4	38
3/4	67	21	90	6.4	41.
1	76	27	100	6.4	57
1¼	86	37	110	9.7	57
1½	95	43	125	9.7	67
2	140	55	165	12.7	57
2½	162	67	190	12.7	67
3	165	83	190	15.7	67
4	203	108	235	19.1	76
5	244	135	280	22.4	86
6	286	162	320	25.4	86
8	356	212	395	35.1	95
10	432	265	470	41.1	105
12	495	315	535	47.8	105
14	518	346	560	53.8	114
16	572	397	615	60.5	124
18	635	448	685	66.5	133
20	696	497	750	73.2	133
24	835	597	900	88.9	152
NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W

NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W
1/2	61	16	80	6.4	38
3/4	67	21	90	9.7	41
1	76	27	100	9.7	64
1¼	86	35	110	9.7	64
1½	95	41	125	12.7	70
2	140	53	165	12.7	70
2½	162	63	190	15.7	76
3	172	78	205	19.1	76
4	206	102	240	22.4	89
5	251	128	290	28.4	89
6	279	154	320	35.1	89
8	349	203	395	41.1	102
10	432	255	480	50.8	114
12	518	303	570	60.5	114
14	575	333	635	66.5	127
16	638	381	705	76.2	133
18	702	429	775	85.9	146
20	752	478	830	95.3	152
24	899	575	990	111.3	178
NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W

NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W
1/2	67	16	90	9.7	38
3/4	73	21	95	9.7	41
1	83	27	110	9.7	64
1¼	102	35	130	12.7	64
1½	114	41	145	15.7	70
2	143	53	170	15.7	70
2½	165	63	195	19.1	76
3	194	78	230	22.4	76
4	232	102	275	28.4	89
5	276	128	325	35.1	89
6	314	154	370	41.1	89
8	384	198	440	53.8	102
10	473	248	540	66.5	114
12	546	289	620	79.2	114
NPS	Outside � A	Inside � B	Center Line C	THK t	Web Width W

General Notes:

Dimensions are in millimeters unless otherwise indicated.
D = Hole size (where required) should be the same as the flange bolt hole. In practice, these dimensions have been rounded round off upwards.
Wt = Thickness of the web (or tie bar) should be 6 mm minimum, or equal to Thickness (t) if less than 6 mm. Spectacle Blinds should be made from a plate or forging specification, approved for use by ASME B31.3, of essentially the same chemical composition as the mating flanges and piping involved
Spectacle Blinds according to ASME B16.48 may be used for installation between ASME B16.5 flanges
Depending on a customer specification, some dimensions can be different from what on this page is defined.

ASME B16.48 says: The gasket seating surface finish and dimensions for raised face line blanks shall be in accordance with ASME B16.5. A raised face may be specified at the option of the purchaser.
A Raised Face would add machining time and complexity so the price would be higher. Call this the Bugatti or Rolls Royce of the line blind world.
Personally, I have seen that version once or twice somewhere. The version without Raised Face is the default and is used everywhere.