Spectacle Blind Flanges

Size: 1/2″ thru 24″ or custom size.
Material: Nickel Alloy，Hastelloy Alloy,Monel Alloy,Inconel Allo, Anti-Corrosion Resistant Alloy, Super-Alloy, Duplex Steel, Stainless steel, Titanium Alloy, Copper Alloy, Carbon Steel, Aluminium Steel, ect.
Standard: A WWA C207, ASME B16.5, DIN, BS, JIS, EN1092-1, ASME B16.47 and GOST/ГОСТ Standard, etc..
Approved by CE, RoHs, SGS, BV
Large stock with different sizes

Spectacle Blind Flanges Solutions

In an industry that thrives on efficiency and safety, spectacle blind flanges solutions are worth their weight in gold. They allow for easy isolation of pipeline sections during maintenance, reducing the risk of spills and accidents while keeping downtime to a minimum.

Understanding your choice of spectacle blind flanges options

Spectacle blind flanges are indispensable components in various industries, offering safety and versatility for diverse applications. Understanding the different options, materials, standards, and maintenance requirements of figure-8 blind flanges can help you select the right product for your piping system and ensure its safe and efficient operation. Spectacle blind flanges are essential in piping systems, providing a safe and efficient means of isolating sections for maintenance, inspection, or repair. These specialized flanges are designed with two interconnected sections: a solid plate to block the flow of fluids and a spacer to allow fluid passage when needed.

What is a spectacle blind flange?

A spectacle blind flange, also known as a figure-of-8 blind, “spectacle flange,” is made by a steel spade and spacer, united by a welded handle: one is actually a ring (i.e., a disc with a hole of the same diameter as the pipe) and the other is a solid disc. The figure 8 blind blocks or isolates a portion of the piping system during maintenance operations and provides a firm seal when closed.
Under normal conditions, the spectacle blind is installed in the open position and does not interrupt the flow of fluid conveyed by the pipeline.
To block the pipeline and interrupt the flow, field personnel unscrew the flange bolts and rotate the eight-hole blind to the closed position.
If the spectacle blind is in the open or closed position, this is easy to understand because one of the two discs is always on the outside of the pipe (so when the ring is visible, the pipe is closed; when the solid disc is visible, the line is open). For shovels and ring gaskets, the holes in the hanger will inform the crew.

Advantages of Using Spectacle Blind Flanges

Spectacle Blind Flanges offer numerous benefits to industries requiring efficient and reliable isolation of piping sections. Some of these advantages include the following:

Safety: Spectacle blind flanges provide a safe method of isolating pipeline sections, preventing the accidental release of hazardous substances during maintenance or inspection.
Versatility: These flanges can be used in various applications, including high-pressure, high-temperature, and corrosive environments, making them suitable for multiple industries.
Ease of Use: The design of spectacle blind flanges allows for easy installation and removal, reducing downtime and labor costs associated with maintenance and repair.
Leak Prevention: High-quality spectacle blind flanges are manufactured with precision, ensuring proper alignment and sealing, thereby reducing the risk of leakage and improving overall system performance.
Cost-effective: By using spectacle blind flanges, industries can eliminate the need for additional valves, reducing overall costs and simplifying the piping system.

Types of spectacle blind flanges

There are several types of Spectacle Blind Flanges available in the market, each designed for a specific application. Some common types include:
Raised Face Spectacle Blind Flanges
Raised face spectacle blind flanges are the most common type and feature a raised surface around the bore to ensure proper sealing. They are suitable for applications with high pressure and temperature requirements.
Flat Face Spectacle Blind Flanges
Flat face spectacle blind flanges have a flat sealing surface and are typically used in low-pressure applications or when mating with other flat-faced flanges.
Ring Type Joint Spectacle Blind Flanges
Ring type joint spectacle blind flanges feature a grooved sealing surface and are used in high-pressure applications where a metal-to-metal seal is required.

How to measure a spectacle blind flange?

To measure a spectacle blind flange accurately, you should follow these steps:
Measuring Flange Diameter

Lay the spectacle blind flange on a flat surface.
Use a measuring tape or a caliper to measure the outer diameter (OD) of the flange from one edge to the other, passing through the center.

Measuring Flange Thickness

Place the measuring tool, such as a caliper or a ruler, on the edge of the flange.
Measure the thickness of the flange, ensuring that you’re measuring the thickest part.

Measuring Bolt Hole Diameter

Position the measuring tool over a bolt hole.
Measure the diameter of the hole from one side to the other.

Measuring Bolt Circle Diameter

Locate two opposing bolt holes on the flange.
Use a measuring tape or a caliper to measure the distance between the center of one bolt hole to the center of the opposite bolt hole, ensuring that the measurement passes through the center of the flange. This is the bolt circle diameter (BCD).

Standard for spectacle blind flanges

Several international standards and specifications govern the design, dimensions, and manufacturing of spectacle blind flanges. Some of the most widely recognized standards include:

ASME B16.48: This American standard covers the pressure-temperature ratings, materials, dimensions, tolerances, and marking requirements for spectacle blind flanges.
MSS SP-44: A standard developed by the Manufacturers Standardization Society, MSS SP-44 covers the dimensions, materials, and manufacturing requirements for spectacle blind flanges in the petroleum and natural gas industries.
EN 1092-1: This European standard specifies the dimensions, materials, and design requirements for spectacle blind flanges used in piping systems.

Materials of spectacle blind flanges

Depending on the specific application requirements, spectacle blind flanges are made from a variety of metal materials, including:

Titanium spectacle blind flange	ASTM B381 / ASME SB381, Titanium Gr. 1, Titanium Gr. 2, Titanium Gr. 4, Titanium Gr. 5, Titanium Gr. 7, ASTM R50250/GR.1\| R50400/GR.2 \| R50550/GR.3 \| R50700/GR.4 \| GR.6 \|R52400/GR.7 \| R53400/GR.12 \| R56320/GR.9 \|R56400/GR.5
Copper spectacle blind flange	T1, T2, C10100, C10200, C10300, C10400, C10500, C10700, C10800, C10910,C10920, TP1, TP2, C10930, C11000, C11300, C11400, C11500, C11600, C12000,C12200, C12300, TU1, TU2, C12500, C14200, C14420, C14500, C14510, C14520, C14530, C17200, C19200, C21000, C23000, C26000, C27000, C27400, C28000, C33000, C33200, C37000, C44300, C44400, C44500, C60800, C63020, C68700, C70400, C70600, C70620, C71000, C71500, C71520, C71640, etc
Copper Nickel spectacle blind flange	ASTM / ASME SB 61 / 62 / 151 / 152, Copper Nickel 90/10 (C70600 ), Cupro Nickel 70/30 (C71500), UNS C71640
Carbon Steel spectacle blind flange	ASTM/ASME A/SA105 A/SA105N & A/SA216-WCB, DIN 1.0402, DIN 1.0460, DIN 1.0619, Die Steel, ASTM A105 / ASME SA105, A105N, ASTM A350 LF2 / ASME SA350, High Yield CS ASTM A694 / A694 (F52 F56 F60 F65 F70 F80)
Stainless Steel spectacle blind flange	ASTM/ASME A/SA182 F304, F304L, F316, F316L, ASTM/ASME A/SA351 CF8, CF3, CF8M, CF3M, DIN 1.4301, DIN 1.4306, DIN 1.4401, DIN 1.4404, DIN 1.4308, DIN 1.4408, DIN 1.4306, DIN 1.4409
Alloy Steel spectacle blind flange	ASTM A182 / ASME SA182 F5, F9, F11, F12, F22, F91
Hastelloy spectacle blind flange	ASTM B564 / ASME SB564, Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X
Brass spectacle blind flange	3602 / 2604 / H59 / H62 / etc.
Inconel spectacle blind flange	ASTM B564 / ASME SB564, Inconel 600, 601, 625, 718, 783, 690, x750
Monel spectacle blind flange	ASTM B564 / ASME SB564, Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500)
Duplex spectacle blind flange	S31803 / S32205 A182 Gr F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61
Super Duplex spectacle blind flange	S32750 / S32760 A182 Gr F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61
Alloy 20 spectacle blind flange	ASTM B462 / ASME SB462, Carpenter 20 Alloy, Alloy 20Cb-3
Aluminium spectacle blind flange	5052 /6061/ 6063 / 2017 / 7075 / etc.
Nickel spectacle blind flange	ASTM B564 / ASME SB564, Nickel 200, Nickel 201, Nickel 205, Nickel 205LC
Nimonic spectacle blind flange	Nimonic 75, Nimonic 80A, Nimonic 90
Other spectacle blind flange material	Tin bronze, Alumunum bronze, Lead bronze
Incoloy spectacle blind flange	ASTM B564 / ASME SB564, Incoloy 800, 800H, 800HT (UNS N08800), 825 (UNS N08825), 925
254 Smo spectacle blind flange	ASTM A182 / ASME SA182, SMO 254/6Mo, UNS S31254, DIN 1.4547

Selecting the Right spectacle blind flange Material

Material selection is crucial when choosing spectacle blind flanges for your piping system. Factors to consider include corrosion resistance, temperature, and pressure requirements. Common materials used for spectacle blind flanges include:
Carbon Steel: Offers excellent strength and durability, making it suitable for high-pressure applications.
Stainless Steel: Provides outstanding corrosion resistance, making it ideal for use in harsh environments or applications where chemical compatibility is essential.
Alloy Steel: Delivers enhanced resistance to heat and corrosion, making it suitable for high-temperature and high-pressure environments.
Nickel Alloys: Offer superior corrosion and heat resistance, as well as excellent mechanical properties, making them suitable for use in demanding applications such as aerospace, power generation, and petrochemical industries.

Dimensions of spectacle blind flanges

Spectacle blind flanges are available in various sizes and dimensions, ranging from 1/2″ to 60″ in diameter, with pressure ratings from 150 to 2500 Class. The size and dimensions of a spectacle blind flange depend on the pipe size, pressure, and temperature requirements.

Dimensions of ASME B16.48 Figure-8 Blanks/Spectacle Blinds RF/FF


ASME B16.48 Figure-8 Blanks/Spectacle Blinds FF	ASME B16.48 Figure-8 Blanks/Spectacle Blinds RF
Technical drawing for the figure-8 blank (spectacle blind flange) in accordance with ASME B16.48, with flat face. O: outside diameter; A: center distance; T: thickness of blank; W: web width; B: inside diameter of the open end; t: thickness of tie bar.	Technical drawing for the figure-8 blank (spectacle blind flange) in accordance with ASME B16.48, with raised face. The RF dimensions shall be furnished in accordance with ASME B16.5. The height of the raised face shall be in addition to the thickness T. For Class 150 & 300, the height of RF shall be 2 mm; for Class 600, 900, 1500 & 2500, the height of RF shall be 7 mm.

Dimensions for ASME B16.48 Class 150 figure-8 blanks (spectacle blind flanges) with FF or RF.

NPS	O	A	T	W	B
1/2	45	60	3.0	38	16
3/4	54	70	3.0	38	21
1	64	80	3.0	38	27
1-1/4	73	90	6.4	38	42
1-1/2	83	100	6.4	38	48
2	102	120	6.4	51	61
2-1/2	107	140	6.4	51	73
3	133	150	6.4	64	89
3-1/2	159	175	9.7	64	102
4	172	190	9.7	64	114
5	194	215	9.7	76	141
6	219	240	12.7	76	168
8	276	300	12.7	76	219
10	337	360	15.7	102	273
12	406	430	19.1	102	324
14	448	475	19.1	108	356
16	511	540	22.4	108	406
18	546	580	25.4	114	457
20	603	635	28.4	121	508
24	714	750	31.8	140	610

Dimensions for ASME B16.48 Class 300 figure-8 blanks (spectacle blind flanges) with FF or RF.

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

Dimensions for ASME B16.48 Class 600 figure-8 blanks (spectacle blind flanges) with FF or RF.

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

Dimensions for ASME B16.48 Class 900 figure-8 blanks (spectacle blind flanges) with FF or RF.

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

Dimensions for ASME B16.48 Class 1500 figure-8 blanks (spectacle blind flanges) with FF or RF.

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

Dimensions for ASME B16.48 Class 2500 figure-8 blanks (spectacle blind flanges) with FF or RF.

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

Weights for spectacle blinds in sizes NPS 1/2″ through 24″ of Class 150, 300 & 600.

NPS	150#	300#	600#
1/2	0.12	0.25	0.38
3/4	0.17	0.38	0.57
1	0.23	0.46	0.73
1-1/4	0.49	0.56	1.24
1-1/2	0.63	0.76	1.65
2	0.96	1.46	2.33
2-1/2	1.07	1.98	3.61
3	1.59	2.61	4.87
3-1/2	3.00	3.93	6.46
4	3.52	4.73	9.00
5	4.34	7.93	15.34
6	6.66	10.56	21.06
8	10.19	21.16	35.75
10	17.59	31.63	64.41
12	30.31	47.11	94.88
14	36.80	71.30	116.37
16	55.11	102.25	171.78
18	68.18	133.67	210.36
20	90.98	170.85	299.91
24	139.19	269.41	447.64

Weights for spectacle blinds in sizes NPS 1/2″ through 24″ of Class 900, 1500 & 2500.

NPS	900#	1500#	2500#
1/2	0.46	0.46	0.72
3/4	0.61	0.79	0.89
1	0.80	1.05	1.19
1-1/4	1.37	1.40	2.14
1-1/2	1.73	2.08	3.17
2	3.98	4.04	4.90
2-1/2	5.21	6.21	7.50
3	6.68	8.47	11.81
4	11.45	13.58	20.45
5	18.15	23.62	34.01
6	27.04	34.45	49.98
8	53.48	60.13	94.12
10	88.31	108.77	171.27
12	130.89	182.62	268.26
14	156.56	245.28	–
16	208.72	339.62	–
18	278.80	457.52	–
20	361.74	569.25	–
24	619.04	936.93	–

Dimensions of ASME B16.48 Figure-8 Blanks/Spectacle Blinds Female RTJ

ASME B16.48 Figure-8 Blank/Spectacle Blind Female RTJ

Technical drawing for the female ring-joint facing (F/RTJ) figure-8 blank (spectacle blind flange) made in accordance with ASME B16.48. A: centerline distance; O: outside diameter of blank flange; B: inside diameter of the open end; T: blank thickness; W: web width; t: thickness of the tie bar.

Dimensions for ASME B16.48 Class 150 figure-8 blanks/spectacle blind flanges with female ring-joint facing (F/RTJ).

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

Dimensions for ASME B16.48 Class 300 figure-8 blanks/spectacle blind flanges with female ring-joint facing (F/RTJ).

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

Dimensions for ASME B16.48 Class 600 figure-8 blanks/spectacle blind flanges with female ring-joint facing (F/RTJ).

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

Dimensions for ASME B16.48 Class 900 figure-8 blanks/spectacle blind flanges with female ring-joint facing (F/RTJ).

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

Dimensions for ASME B16.48 Class 1500 figure-8 blanks/spectacle blind flanges with female ring-joint facing (F/RTJ).

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

Dimensions for ASME B16.48 Class 2500 figure-8 blanks/spectacle blind flanges with female ring-joint facing (F/RTJ).

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

Weights for spectacle blinds in sizes NPS 1/2″ through 24″ of Class 150, 300 & 600.

NPS	150#	300#	600#
1/2	0.11	0.24	0.36
3/4	0.16	0.37	0.55
1	0.22	0.44	0.70
1-1/4	0.47	0.54	1.19
1-1/2	0.61	0.73	1.59
2	0.92	1.40	2.24
2-1/2	1.02	1.90	3.47
3	1.53	2.51	4.67
3-1/2	2.88	3.77	6.20
4	3.38	4.54	8.64
5	4.17	7.61	14.72
6	6.40	10.14	20.22
8	9.79	20.31	34.32
10	16.89	30.37	61.83
12	29.10	45.22	91.09
14	35.32	68.44	111.71
16	52.91	98.16	164.91
18	65.45	128.33	201.95
20	87.34	164.02	287.92
24	133.62	258.63	429.73

Weights for spectacle blinds in sizes NPS 1/2″ through 24″ of Class 900, 1500 & 2500.

NPS	900#	1500#	2500#
1/2	0.44	0.45	0.69
3/4	0.58	0.76	0.85
1	0.77	1.00	1.14
1-1/4	1.31	1.34	2.06
1-1/2	1.66	2.00	3.04
2	3.82	3.88	4.70
2-1/2	5.00	5.96	7.20
3	6.42	8.13	11.34
4	10.99	13.04	19.63
5	17.42	22.68	32.65
6	25.95	33.07	47.98
8	51.34	57.73	90.35
10	84.77	104.42	164.42
12	125.66	175.32	257.53
14	150.30	235.47	–
16	200.37	326.04	–
18	367.65	439.22	–
20	347.27	546.48	–
24	594.27	899.45	–

Dimensions of ASME B16.48 Figure-8 Blanks/Spectacle Blinds Male RTJ

ASME B16.48 Figure-8 Blanks/Spectacle Blinds Male RTJ

Technical drawing for the male ring-joint facing figure-8 blank (spectacle blind flange) made in accordance with ASME B16.48. B: inside diameter of the open end; t: thickness of tie bar; A: centerline distance; W: web width; T: blank thickness.

Dimensions for ASME B16.48 Class 150 figure-8 blanks/spectacle blind flanges with male ring-joint facing (M/RTJ).

NPS	A	T	W	B
1	80	6.4	51	34
1-1/4	90	6.4	51	42
1-1/2	100	6.4	57	48
2	120	6.4	57	61
2-1/2	140	9.7	57	73
3	150	9.7	57	89
3-1/2	175	9.7	64	102
4	190	9.7	64	114
5	215	12.7	70	141
6	240	12.7	83	168
8	300	15.7	95	219
10	362	19.1	102	273
12	432	22.4	121	324
14	476	22.4	127	356
16	540	25.4	127	406
18	578	28.4	127	457
20	635	28.4	127	508
24	749	35.1	152	610

Dimensions for ASME B16.48 Class 300 figure-8 blanks/spectacle blind flanges with male ring-joint facing (M/RTJ).

NPS	A	T	W	B
1/2	65	6.4	38	21
3/4	80	9.7	45	27
1	90	9.7	51	34
1-1/4	100	9.7	51	42
1-1/2	115	9.7	57	48
2	125	12.7	57	61
2-1/2	150	15.7	57	73
3	170	15.7	57	89
3-1/2	180	15.7	64	102
4	200	15.7	64	114
5	235	19.1	76	141
6	270	22.4	83	168
8	330	25.4	95	219
10	390	28.4	102	273
12	450	35.1	121	324
14	515	38.1	127	356
16	570	41.1	127	406
18	630	44.5	127	457
20	685	50.8	127	508
24	810	57.2	152	610

Dimensions for ASME B16.48 Class 600 figure-8 blanks/spectacle blind flanges with male ring-joint facing (M/RTJ).

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

Dimensions for ASME B16.48 Class 900 figure-8 blanks/spectacle blind flanges with male ring-joint facing (M/RTJ).

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

Dimensions for ASME B16.48 Class 1500 figure-8 blanks/spectacle blind flanges with male ring-joint facing (M/RTJ).

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

Dimensions for ASME B16.48 Class 2500 figure-8 blanks/spectacle blind flanges with male ring-joint facing (M/RTJ).

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

Weights for spectacle blinds in sizes NPS 1/2″ through 24″ of Class 150, 300 & 600.

NPS	150#	300#	600#
1/2	0.11	0.23	0.34
3/4	0.15	0.34	0.51
1	0.21	0.42	0.66
1-1/4	0.44	0.51	1.11
1-1/2	0.57	0.68	1.49
2	0.86	1.32	2.10
2-1/2	0.96	1.78	3.25
3	1.43	2.35	4.38
3-1/2	2.70	3.54	5.81
4	3.17	4.26	8.10
5	3.91	7.14	13.80
6	6.00	9.51	18.95
8	9.17	19.04	32.17
10	15.83	28.47	57.97
12	27.28	42.40	85.39
14	33.12	64.17	104.73
16	49.60	92.03	154.61
18	61.36	120.31	189.33
20	81.88	153.77	269.92
24	125.27	242.47	402.87

Weights for spectacle blinds in sizes NPS 1/2″ through 24″ of Class 900, 1500 & 2500.

NPS	900#	1500#	2500#
1/2	0.41	0.42	0.64
3/4	0.55	0.71	0.80
1	0.72	0.94	1.07
1-1/4	1.23	1.26	1.93
1-1/2	1.55	1.87	2.85
2	3.59	3.63	4.41
2-1/2	4.69	5.59	6.75
3	6.02	7.62	10.63
4	10.31	12.22	18.40
5	16.34	21.26	30.61
6	24.33	31.01	44.98
8	48.13	54.12	84.71
10	79.48	97.90	154.15
12	117.80	164.36	241.44
14	140.91	220.76	–
16	187.84	305.66	–
18	250.92	411.77	–
20	325.57	512.32	–
24	557.13	843.24	–

Difference between the blind flange and spectacle blind flange

A blind flange and a spectacle blind flange are integral components of piping and process systems. They serve distinct purposes and possess different features. This technical document aims to elucidate the primary differences between the two in terms of design, function, and applications.

Design:

Blind Flange: A blind flange is a solid, flat, circular plate devoid of any opening in its center. It is designed to be bolted to a pipe, valve, or another flange, effectively sealing the end of a pipe or system. The outer edge of the blind flange is equipped with bolt holes that align with those on the mating flange, facilitating easy installation and removal.

Spectacle Blind Flange: A spectacle blind flange, also known as a figure-8 blind, comprises two interconnected discs – one solid and one with an opening matching the pipe’s inner diameter. The reliable and holed discs resemble an “8” shape, hence the name. This unique design allows easy switching between the open and closed positions by rotating the spectacle blind flange.

Function:

Blind Flange: The primary function of a blind flange is to provide a secure, leak-proof closure at the end of a piping system, isolating it from the rest of the process. This is particularly useful during maintenance, testing, or decommissioning activities, ensuring a safe working environment for personnel and equipment.

Spectacle Blind Flange: The spectacle blind flange serves a dual purpose – isolation and flow control. In the closed position (solid disc covering the pipe), it isolates a section of the piping system for maintenance or repairs, similar to a blind flange. The open position (holed disc aligned with the pipe) allows for the unobstructed flow of fluid or gas through the pipeline, thus enabling regular operation.

Applications:

Blind Flange: Blind flanges are widely used across various industries, such as oil and gas, petrochemical, chemical, power generation, and water treatment plants, to isolate or terminate pipelines, pressure vessels, or equipment during maintenance, inspection, or repairs.

Spectacle Blind Flange: Spectacle blind flanges are commonly employed in industries with stringent safety and operational requirements, such as oil refineries, chemical plants, and offshore platforms. They offer quick and easy flow control without disassembling the piping system, reducing downtime and increasing overall efficiency.

The primary differences between a blind flange and a spectacle blind flange lie in their design, function, and applications. While a blind flange is a solid, flat plate used for isolating sections of a piping system, a spectacle blind flange comprises interconnected solid and holed discs, allowing for both isolation and flow control. Depending on the application’s specific requirements, these distinct features dictate their respective usage in different industrial settings.

How to use a spectacle blind flange?

The Spectacle Blind is usually used on the oil line with two different functions:

If the spade is put in between the flanges, it stops the fluid’s passage;
The fluid path is allowed if the spacer is placed between the flanges.

The Spectacle Blind is inserted between two flanges: to guarantee a perfect watertight, two gaskets usually are mounted, one on each side of the spectacle blind.
Spectacle blind flanges are a type of flow control device used in piping systems to isolate sections or regulate fluid flow. They consist of two circular plates, one with a hole (spacer) and the other without (spade), connected by a handle or web. The spacer and spade can be rotated to allow or block the flow through the pipe.

Manufacturing Process of spectacle blind flanges

Spectacle blind flanges are crucial components in piping systems, utilized to provide flexibility in managing flow and isolating specific sections when needed. These flanges are designed with a unique figure-eight shape, consisting of one solid and one open section. This configuration allows for easy flow manipulation through the piping system, depending on the operational requirements.

Section 1: Raw Materials and Spectacle Blind Flange Composition

The manufacturing process of spectacle blind flanges begins with selecting high-quality raw materials. Commonly used materials include carbon steel, stainless steel, alloy steel, and various other metals, depending on the specific requirements and application. The material selection is crucial to ensure the flanges’ durability, resistance to corrosion, and ability to withstand the operating conditions they will be subjected to.

Section 2: Cutting and Shaping the Spectacle Blind Flange

Once the appropriate material is selected, the manufacturing process moves to the cutting and shaping stage. The raw material is precisely cut to the desired figure-eight shape using advanced machinery, such as CNC, plasma, and water jet cutting machines.

The cutting process must be accurate, ensuring that the dimensions of the solid and open sections of the spectacle blind flange meet the required specifications. Additionally, the edges of the flange must be smooth and burr-free to ensure proper sealing when installed in the piping system.

Section 3: Drilling and Machining the Bolt Holes

After cutting the flange to its unique shape, the next step involves drilling and machining the bolt holes. These holes allow the spectacle blind flange to be securely fastened to the adjacent flanges in the piping system, ensuring a leak-free connection. The drilling process must be precise, guaranteeing that the bolt holes are evenly spaced and aligned.

Section 4: Heat Treatment and Surface Finishing

To enhance the mechanical properties of the spectacle blind flange, heat treatment processes, such as normalizing, annealing, or quenching and tempering, may be employed. These treatments improve the flange’s strength, ductility, and resistance to wear and corrosion.

Once the heat treatment is complete, the spectacle blind flange undergoes surface finishing. This step involves sandblasting, pickling, or electro-polishing, which remove any surface imperfections and enhance the flange’s appearance and corrosion resistance.

Section 5: Quality Assurance and Testing

Quality assurance and testing are vital stages in the manufacturing process of spectacle blind flanges. Various tests ensure that the flanges meet the required standards and specifications. These tests may include the following:

Dimensional inspection: Verifying that the flange’s dimensions, such as thickness, diameter, and bolt-hole spacing, are within the specified tolerances.
Visual inspection: Checking for surface defects, such as cracks, pits, or other imperfections.
Material analysis: Confirm that the flange’s composition matches the required material specifications.
Mechanical and physical testing: Evaluating the flange’s mechanical properties, such as tensile strength, yield strength, and elongation, to ensure it meets the required standards.

Section 6: Marking and Packaging

Once the spectacle blind flange passes all quality assurance tests, it is marked with essential information, such as material grade, size, pressure rating, and the manufacturer’s name or logo. This marking ensures traceability and confirms that the flange meets the required standards.

Packing of spectacle blind flanges

How to package spectacle blind flanges? To pack the spectacle blind flange, follow these steps:

When it comes to packaging spectacle blind flanges, it’s important to ensure that they are properly protected and secured during transportation to prevent any damage. We will walk you through some of the key steps to follow when packaging spectacle blind flanges.

Step 1: Clean and Inspect the Flanges

Before packaging the spectacle blind flanges, it’s essential to clean them thoroughly to remove any dust, dirt, or debris that may have accumulated on them. You can use a cloth or brush to clean the flanges and inspect them to ensure they are free from any defects or damages.

Step 2: Choose the Right Packaging Material

The packaging material you choose should be sturdy and able to provide adequate protection to the flanges during transportation. Ideally, you should use a strong cardboard box or wooden crate that can withstand the weight and size of the spectacle blind flanges.

Step 3: Secure the Flanges

Once you have the packaging material ready, you need to secure the flanges to prevent them from moving around or getting damaged during transit. You can use bubble wrap, foam, or any other suitable cushioning material to protect the spectacle blind flanges from impact or shock.

Step 4: Label the Package

Labeling the package correctly is crucial to ensure that it reaches the intended destination without any confusion. You should clearly label the package with the recipient’s address, contact information, and any other necessary details.

Step 5: Arrange for Shipping

After the package is fully prepared and labeled, it’s time to arrange for shipping. You can use a reliable courier or shipping company to ensure that the package is delivered on time and in good condition.

Packaging spectacle blind flanges requires careful planning and attention to detail. By following the above steps, you can ensure that your flanges are properly protected and arrive at their destination safely. Remember to use high-quality packaging materials, secure the spectacle blind flanges properly, and label the package accurately to avoid any mishaps during transportation.

Inspection and Measurement of spectacle blind flanges

There are several factors that need to be considered when inspecting and measuring spectacle blind flanges, including:

Material

The first thing to inspect in a spectacle blind flange is the material. The standard specifies that the flanges should be made from materials such as carbon steel, stainless steel, or alloy steel. The material should be free from any defects such as cracks, porosity, or inclusions that can affect the integrity of the flange.

Dimension

The next thing to inspect in a spectacle blind flange is its dimension. The standard specifies the dimensions of the flanges based on their nominal size and pressure rating. The flanges should be inspected for their inside and outside diameter, thickness, and overall dimensions to ensure they meet the requirements of the standard.

Surface Finish

The surface finish of a flange is also important. The standard specifies that the flanges should have a smooth and even surface finish to ensure proper sealing of the gasket. Any roughness or irregularities on the surface of the flange can lead to leaks in the piping system.

Bolt Hole Alignment

The bolt holes in a flange should be aligned properly to ensure the bolts can be inserted and tightened correctly. The bolt holes should be inspected to ensure they are in the correct position and are not misaligned.

Bolt Hole Size

The size of the bolt holes is also important. The standard specifies the size of the bolt holes based on the nominal size and pressure rating of the flange. The bolt holes should be inspected to ensure they are the correct size and are not damaged.

Bolt Hole Thread

The threads in the bolt holes are important to ensure the bolts can be screwed in and tightened properly. The threads should be inspected to ensure they are clean and free from any damage or defects.

To inspect and measure spectacle blind flanges, you will need a set of calipers or a micrometer to accurately measure the dimensions of the flange. It is also a good idea to have a torque wrench on hand to ensure that the bolts are tightened to the correct torque specification.

Installation and Maintenance of Spectacle Blind Flanges

Proper installation and maintenance of spectacle blind flanges are crucial to ensure their optimal performance and longevity. Follow these guidelines to maintain the integrity of your piping system:
Installation of figure 8 blind flanges
Proper installation of the figure 8 blind flange is critical to the safe and efficient operation of the piping system. For a successful installation, perform the following steps:

Inspect the flange: Prior to installation, inspect the figure 8 blind flange for any visible defects such as cracks, dents or warpage.
Prepare the pipe: Make sure the pipe is clean and free of debris. In addition, make sure the flange faces are clean and undamaged.
Position the flange: Align the figure 8 blind flange with the mating flange on the pipe or equipment, making sure the bolt holes are properly aligned.
Install Gasket: Place a suitable gasket between the flange faces to create a tight seal and prevent leakage. Ensure that the gasket material is compatible with the piping media and operating conditions.
Insert Bolts: Insert the appropriate bolts through the bolt holes and secure with nuts. Tighten bolts and nuts evenly in a crisscross pattern to ensure proper pressure distribution across the flange.
Rotate flange: Rotate the figure-of-8 blind flange to open (gasket side) or close (spade side) the pipe, depending on the desired flow configuration.
Verify installation: After installation, visually inspect the flanges for proper alignment and ensure that all bolts are tightened evenly.

Inspection of figure 8 blind flange
Periodically inspect the figure 8 blind flange for signs of wear, corrosion or damage. Monitor for any leaks and address them promptly to prevent further damage to the system.
Maintenance of figure 8 blind flange
Perform routine maintenance on the figure 8 blind flange, including cleaning, tightening bolts and replacing gaskets as necessary – shut down periodically for thorough inspection and maintenance of the entire piping system.
Replacement of figure 8 blind flange
Replace worn or damaged figure 8 blind flanges with new flanges that meet the original flange specifications. Ensure proper installation and alignment to maintain the integrity of the piping system.

Application of spectacle blind flanges

ASME B16.5 spectacle blind flanges are known to deliver exceptional performance and are generally developed to meet the demands. We offer a broad range of spectacle blind flanges through a worldwide network of stock-keeping branches.

This spectacle blind flange is used in various industries:

Spectacle blind flanges used in Oil and Gas Pipelines;
Spectacle blind flanges used in Chemical Industry;
Spectacle blind flanges used in Plumbing;
Spectacle blind flanges used in Heating;
Spectacle blind flanges used in Water Supply Systems;
Spectacle blind flanges used in Power Plants;
Spectacle blind flanges used in the Paper & Pulp Industry;
Spectacle blind flange uses in General Purpose Applications;
Spectacle blind flanges used in Fabrication Industry;
Spectacle blind flange uses in Food Processing Industry;
Spectacle blind flanges Use in Structural Pipe.

How do I choose between a spectacle blind flange, weld neck flange, and slip-on flange?

The choice between these flanges depends on your specific application requirements, such as pressure and temperature conditions, installation ease, maintenance needs, and budget constraints. Understanding the advantages and disadvantages of each flange type will help you make an informed decision.

How to purchase the correct spectacle blind flanges?

Are you in the market for spectacle blind flanges but don’t know where to start? Don’t worry, you’re not alone. With so many options available, it can be overwhelming to choose the right flanges for your project. We’ll go over some key factors to consider when purchasing spectacle blind flanges to ensure that you make the right decision.

Determine the Material Needed

The first step to purchasing the correct spectacle blind flanges is to determine the material you need. These flanges are available in a variety of materials, including carbon steel, stainless steel, and alloy steel. The choice of material will depend on the specific application and environmental conditions. If you’re unsure which material to choose, consult with a qualified engineer or supplier to help guide you in making the right decision.

Identify the Flange Face Type

Flange face types refer to the surface finish of a flange, and there are many different types of flange face finishes, including flat face (FF), raised face (RF), ring-type joint (SO), tongue and groove (T&G), male and female face (M&F). Each type of flange face has its unique characteristics and is suitable for different applications.

Flat face (FF): This type of flange face has a flat, smooth surface that is perpendicular to the axis of the pipe. It is typically used for low-pressure applications and when the sealing is achieved by a gasket.
Raised face (RF): This type of flange face has a raised ring on the surface that surrounds the bolt holes. The ring provides a surface for the gasket to rest on, which helps to create a better seal. It is commonly used in applications with moderate pressure.
Ring joint face (RTJ): This type of flange face has a specially designed groove to accommodate a metallic ring gasket. The groove is cut into the surface of the flange, and the gasket sits in the groove to create a tight seal. This type of flange face is typically used in high-pressure applications.

To identify a specific flange face type, you need to provide me with more information, such as the flange’s application, dimensions, and material.

Determine the spectacle blind flange Size and Pressure Class

Once you have identified the material and spectacle blind flange type, the next step is to determine the size and pressure class of the spectacle blind flange. spectacle blind flanges are available in various sizes and pressure ratings, and it’s crucial to select the correct size and pressure class to ensure that the flange can withstand the intended operating conditions. You should consult the system specifications and design to determine the appropriate size and pressure class.

Surface Finish

The flange face’s surface finish directly impacts the seal’s quality between the flanges. Common surface finishes include smooth, serrated, and grooved. Consult with the gasket manufacturer and consider the specific requirements of your application to select the most appropriate surface finish for your spectacle blind flanges.

Look for Quality and Certifications

It’s essential to ensure that the spectacle blind flanges you purchase are of high quality and come with the necessary certifications. Look for suppliers that have a reputation for delivering high-quality products, and check for relevant certifications, such as ISO 9001, API, and CE, to ensure that the flanges meet industry standards.

Consider the Price

While the price should not be the only factor to consider when purchasing spectacle blind flanges, it’s important to compare prices from different suppliers to ensure that you’re getting a fair price. However, remember that the cheapest option may not always be the best quality, so ensure that you’re not compromising on quality in pursuit of lower costs.

Purchasing the correct spectacle blind flanges can be challenging, but by considering the factors outlined in this post, you can ensure that you make an informed decision that meets your project requirements. Remember to consult with experts and compare suppliers to ensure that you’re getting a high-quality product at a fair price.

How to select spectacle blind flanges manufacturer?

Selecting the right manufacturer for spectacle blind flanges can be a daunting task. With so many options available, it’s easy to get overwhelmed and make the wrong choice. However, choosing the right manufacturer is critical to ensure that you get the best quality flanges that meet your specific needs. We provide some tips to help you select the right spectacle blind flanges manufacturer.

Quality of Products

The first factor to consider when selecting a spectacle blind flanges manufacturer is the quality of their products. You should look for a manufacturer that uses high-quality materials and follows strict quality control processes to ensure that their products meet the required standards.

Industry Experience

Another factor to consider is the manufacturer’s industry experience. Look for a manufacturer that has been in the industry for a significant period and has a proven track record of delivering high-quality products to their customers. An experienced manufacturer will have a better understanding of the market and the needs of their customers.

Production Capacity

It is also essential to consider the production capacity of the manufacturer. You should look for a manufacturer that has the capacity to produce the required quantity of flanges in a timely manner to meet your project’s needs.

Pricing

Pricing is another crucial factor to consider when selecting a spectacle blind flanges manufacturer. While it is essential to look for a manufacturer that offers competitive pricing, it is equally important to consider the quality of their products. Don’t compromise on the quality of the products for the sake of saving a few dollars.

Customer Service

The final factor to consider is the manufacturer’s customer service. Look for a manufacturer that has excellent customer service and is willing to assist you with any queries or concerns you may have. A manufacturer that values their customers will provide a better overall experience.

Choosing the right spectacle blind flanges manufacturer is essential to ensure you get high-quality products that meet your needs. Look for a manufacturer with quality certifications, experience, a good reputation, customization capabilities, and a competitive price. By following these tips, you will be able to find the right manufacturer for your flange needs.

Why Choose Jihua to Be Your Spectacle Blind Flange Supplier?

Jihua is a well-established and reputable manufacturer and supplier of spectacle blind flanges that has been providing high-quality products to customers worldwide for many years. Here are some reasons why you might choose Jihua to be your spectacle blind flange supplier:

High-quality products: Jihua is committed to providing high-quality spectacle blind flanges made from the best materials and manufactured to the highest standards. The company has strict quality control procedures in place to ensure that each product meets or exceeds customer expectations.
Competitive pricing: Jihua offers competitive pricing on its products, which means you can get high-quality spectacle blind flanges at an affordable price.
Wide range of products: Jihua offers a wide range of spectacle blind flanges, including ANSI, DIN, JIS, EN, and other international standards. This means you can find the right product to meet your specific needs.
Excellent customer service: Jihua is committed to providing excellent customer service and support to all of its customers. The company has a team of experienced professionals who are available to answer any questions or concerns you may have.
Fast delivery: Jihua understands the importance of timely delivery and works hard to ensure that all orders are shipped out quickly and efficiently.

Jihua is a reliable and trustworthy supplier of spectacle blind flanges that can meet your needs and exceed your expectations.

Export Country For spectacle blind flanges

MIDDLE EAST	AFRICA	NORspectacle blind AMERICA	EUROPE	ASIA	SOUspectacle blind AMERICA
Saudi Arabia	Nigeria	Usa	Russia	India	Argentina
Iran	Algeria	Canada	Norway	Singapore	Bolivia
Iraq	Angola	Mexico	Germany	Malaysia	Brazil
Uae	South Africa	Panama	France	Indonesia	Chile
Qatar	Libya	Costa Rica	Italy	Thailand	Venezuela
Bahrain	Egypt	Puerto Rica	Uk	Vietnam	Colombia
Oman	Sudan	Trinidad And Tobago	Spain	South Korea	Ecuador
Kuwait	Equatorial Guinea	Jamaica	Ukraine	Japan	Guyana
Turkey	The Republic Of Congo	Bahamas	Netherland	Sri Lanka	Paraguay
Yemen	Gabon	Denmark	Belgium	Maldives	Uruguay
Syria			Greece	Bangladesh
Jordan			Czech Republic	Mayanmar
Cyprus			Portugal	Taiwan
			Hungary	Cambodia
			Albania
			Austria
			Switzerland
			Slovakia
			Finland
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FAQs

Q1: Can spectacle blind flanges be custom-made?

A1: Many manufacturers offer custom-made spectacle blind flanges to meet specific application requirements, such as unique sizes, materials, or pressure ratings.

Q2: How often should I inspect my spectacle blind flanges?

A2: The inspection frequency depends on system operating conditions, the environment, and the manufacturer’s recommendations. Generally, inspect spectacle blind flanges during scheduled maintenance or shutdowns.

Q3: Can I use a spectacle blind flange in a high-pressure application?

A3: Spectacle blind flanges are available in various pressure ratings to accommodate high-pressure applications. Choose a flange with a pressure rating suitable for your system.

Q4: How do I know if my spectacle blind flange needs to be replaced?

A4: Replace a spectacle blind flange if you notice signs of wear, corrosion, or damage during inspection or if it no longer meets the system’s pressure or temperature requirements.

Q5: Can I use a spectacle blind flange for isolation and flow control?

A5: Yes, spectacle blind flanges are versatile and can be used for isolation and flow control purposes, depending on the position of the spacer and spade. By rotating the spacer or spade, you can allow or block fluid flow through the piping system, making it an effective solution for both purposes.

Q6: Are there any alternatives to spectacle blind flanges for isolating sections of a piping system?

A6: Yes, alternatives to spectacle blind flanges include ball valves, gate valves, and line blinds. Each has advantages and disadvantages, so consider your application requirements and constraints when selecting the best solution.

Q7: What tools and equipment are needed to install and maintain spectacle blind flanges?

A7: Common tools and equipment for installing and maintaining spectacle blind flanges include torque wrenches, gaskets, bolt tensioners, flange spreaders, and lifting equipment. Always follow the manufacturer’s guidelines and safety precautions when working with these tools.

Q8: How do I determine the size of my spectacle blind flange?

A8: The size of the spectacle blind flange depends on your piping system’s pipe size, pressure, and temperature requirements. Consult the manufacturer’s guidelines or seek the advice of an experienced engineer to determine the appropriate size for your specific application.

Q9: Can spectacle blind flanges be used in extreme temperature conditions?

A9: Yes, spectacle blind flanges made from materials capable of withstanding extreme temperatures, such as stainless steel and alloy steel, or exotic materials like Inconel, Monel, and Hastelloy, can be used in high-temperature applications. Ensure that the chosen flange material meets the temperature requirements of your system.

Q10: How can I prevent corrosion on my spectacle blind flanges?

A10: To prevent corrosion, choose a spectacle blind flange material that offers adequate corrosion resistance for your specific application. Additionally, perform regular inspections and maintenance to detect and address any signs of corrosion early on.

Spectacle Blind Flanges