Spectacle blind flanges are forged products used to blind pipelines (temporarily or permanently). These devices are cost-effective alternatives to isolation valves. A spectacle blind combines, in one single product, a flange spade and a ring spacer.

Spectacle blinds are available in standard sizes up to 24 inches and in forged material grades like ASTM A105 (high-temperature carbon), A350 low-temperature carbon), and various ASTM A182 grades (alloy, stainless steel, duplex). Click on the link to learn about the chemical and mechanical properties, and the selection criteria, of these common spectacle blind grades (which are the same as flanges).

• Class 150 Spectacle Blind Flange
• Class 300 Spectacle Blind Flange
• Class 600 Spectacle Blind Flange
• Class 900 Spectacle Blind Flange
• Class 1500 Spectacle Blind Flange
• Class 2500 Spectacle Blind Flange

Acero has 3 warehouses in Wenzhou, Wuxi and Hebei. As one of the piping solution providers, Acero has been committed to providing one-stop solutions for projects in the fields of oil and gas, water, renewable energy and infrastructure. With years’ consistent dedication and innovation, our reliable, cost-effective and environment-friendly solutions have won clients’ wide recognition.

China spectacle blind flanges manufacturer Acero supplies spectacle blinds, spectacle blind flanges, Special Flanges made in forged steel, Stainless Steel, alloy steel, etc.

Size
1/2″ – 56″ (DN15 to DN1,400)
Pressure
America Series:Class 150 ,Class 300, Class 600, Class 900A ,Class 1500,Class 2500.
Europe Series:PN2.5,PN6,PN10,PN16,PN25,PN40,PN63,PN100,PN160,PN250,PN320,PN400.
Flange Facing Types
America Series:Flat face(FF),Raised face(RF),Tongue(T),Groove(G),Female(F),Male(M),Ring type joints face(RJ/RTJ)
Europe Series:Type A(Flat Face),Type B(Raised Face),Type C(Tongue),Type D(Groove),Type E(Spigot),Type F(Recess),Type G(O-Ring Spigot),Type H(O-Ring Groove)
Material
Carbon steel: ASTM A105,ASTM A105N,GB 20,C22.8.
Alloy steel: ASTM/ASME A182 F1-F12-F11-F22- F5-F9- F91
Stainless steel: ASTM/ASME A182 F304-304L-304H-304LN-304N
ASTM/ASME A182 F316-316L-316H-316LN-316N-316Ti
ASTM/ASME A182 F321-321H, F347-347H
Low temperature steel: ASTM/ASME A350 LF2.
High performance steel: ASTM/ASME A694 F42 , F52, F56, F60, F65, F70
Standards
ASME ANSI B16.5,ASME ANSI B16.47.
API 605,API 6L.
MSS SP 44
CSA Z245.12
EN1092-1,EN1759-1.
DIN2565, DIN2566, DIN2567, DIN2568, DIN2569
BS1560,BS 4504,BS 10.
AFNOR NF E29-200-1
ISO7005-1
AS2129
JIS B2220
UNI 2276. UNI 2277.UNI 2278 .UNI 6089 .UNI 6090

Dimensions Spectacle Blinds – ASME B16.48

Pressure Class 150

NPS	Outside Ø A	Inside Ø 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
1.1/4	73	42	90	6.4	38
1.1/2	83	48	100	6.4	38
2	102	61	120	6.4	51
2.1/2	107	73	140	6.4	51
3	133	89	150	6.4	64
3.1/2	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 Ø A	Inside Ø B	Center Line C	THK t	Web Width W

Pressure Class 300

NPS	Outside Ø A	Inside Ø 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	38
1.1/4	79	42	100	6.4	38
1.1/2	92	48	115	6.4	38
2	108	61	125	9.7	51
2.1/2	127	73	150	9.7	51
3	146	89	170	9.7	64
3.1/2	162	102	185	12.7	64
4	178	114	200	12.7	64
5	213	141	235	15.7	76
6	248	168	270	15.7	76
8	305	219	330	22.4	76
10	359	273	385	25.4	102
12	419	324	450	28.4	102
14	483	356	515	31.8	108
16	536	406	570	38.1	108
18	594	457	630	41.1	114
20	651	508	685	44.5	121
24	772	610	810	50.8	140
NPS	Outside Ø A	Inside Ø B	Center Line C	THK t	Web Width W

Pressure Class 600

NPS	Outside Ø A	Inside Ø 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
1.1/4	79	37	100	9.7	57
1.1/2	92	43	115	9.7	67
2	108	55	125	9.7	57
2.1/2	127	67	150	12.7	67
3	146	83	170	12.7	67
3.1/2	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	105
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 Ø A	Inside Ø B	Center Line C	THK t	Web Width W

Pressure Class 900

NPS	Outside Ø A	Inside Ø 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
1.1/4	86	37	110	9.7	57
1.1/2	95	43	125	9.7	67
2	140	55	165	12.7	57
2.1/2	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 Ø A	Inside Ø B	Center Line C	THK t	Web Width W

Pressure Class 1500

NPS	Outside Ø A	Inside Ø 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
1.1/4	86	35	110	9.7	64
1.1/2	95	41	125	12.7	70
2	140	53	165	12.7	70
2.1/2	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 Ø A	Inside Ø B	Center Line C	THK t	Web Width W

Pressure Class 2500

NPS	Outside Ø A	Inside Ø 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
1.1/4	102	35	130	12.7	64
1.1/2	114	41	145	15.7	70
2	143	53	170	15.7	70
2.1/2	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 Ø A	Inside Ø 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 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.

RAISED FACE JOINT BLANKS

• 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.

Source: Werner Sölken