Blind Flange

Blind flanges are an essential component in piping systems, designed to seal off the ends of pipes, valves, or pressure vessel openings. These flanges play a critical role in industries such as oil and gas, petrochemicals, power generation, water treatment, and construction. In this comprehensive guide, we will explore everything you need to know about blind flanges, including their specifications, materials, applications, and benefits.

What are Blind Flanges?

A blind flange is a solid disk-shaped component used to block the end of a piping system or vessel. Unlike other types of flanges, blind flanges do not have a central bore, making them ideal for isolating sections of a pipeline or terminating a flow. Blind flanges are manufactured to meet various pressure ratings and material standards, ensuring reliability in even the most demanding environments.

Applications of Blind Flanges

• Blind flanges are used across various industries for applications such as:
• Pipeline Isolation: Sealing off pipeline ends during maintenance or system testing.
• Pressure Testing: Ensuring pipelines can handle designated pressure levels by blocking one end.
• Flow Termination: Closing the end of pipes or pressure vessels in permanent or temporary setups.
• Safety Measures: Preventing leakage or spillage in hazardous environments.
• Inspection and Cleaning: Allowing easy access to pipeline interiors by removing the blind flange.

Industries that frequently use blind flanges include:

• Oil & Gas
• Petrochemicals
• Pharmaceuticals
• Food Processing
• Water Treatment
• Power Generation
• Construction

Blind Flange Dimensions and Weight Chart
NPS	A	C	G	H	I	J	W
	inch	inch	inch	No. of holes	inch	inch	kg/pc
	mm	mm	mm		mm	mm
1/2	3.500	0.440	1.380	4	0.620	2.380	0.42
	88.90	11.20	35.10		15.70	60.45
3/4	3.880	0.500	1.690	4	0.620	2.750	0.61
	98.60	12.70	42.90		15.70	69.85
1	4.250	0.560	2.000	4	0.620	3.120	0.86
	108.0	14.20	50.80		15.70	79.25
1-1/4	4.620	0.620	2.500	4	0.620	3.500	1.17
	117.3	15.70	63.50		15.70	88.90
1-1/2	5.000	0.690	2.880	4	0.620	3.880	1.53
	127.0	17.50	73.15		15.70	98.60
2	6.000	0.750	3.620	4	0.750	4.750	2.42
	152.4	19.10	91.90		19.10	120.7
2-1/2	7.000	0.880	4.120	4	0.750	5.500	3.94
	177.8	22.40	104.6		19.10	139.7
3	7.500	0.940	5.000	4	0.750	6.000	4.93
	190.5	23.90	127.0		19.10	152.4
3-1/2	8.500	0.940	5.500	8	0.750	7.000	6.17
	215.9	23.90	139.7		19.10	177.8
4	9.000	0.940	6.190	8	0.750	7.500	7.00
	228.6	23.90	157.2		19.10	190.5
5	10.00	0.940	7.310	8	0.880	8.500	8.63
	254.0	23.90	185.7		22.40	215.9
6	11.00	1.000	8.500	8	0.880	9.500	11.3
	279.4	25.40	215.9		22.40	241.3
8	13.50	1.120	10.62	8	0.880	11.75	19.6
	342.9	28.40	269.7		22.40	298.5
10	16.00	1.190	12.75	12	1.000	14.25	28.8
	406.4	30.20	323.9		25.40	362.0
12	19.00	1.250	15.00	12	1.000	17.00	43.2
	482.6	31.75	381.0		25.40	431.8
14	21.00	1.380	16.25	12	1.120	18.75	58.1
	533.4	35.10	412.8		28.40	476.3
16	23.50	1.440	18.50	16	1.120	21.25	76.0
	596.9	36.60	469.9		28.40	539.8
18	25.00	1.560	21.00	16	1.250	22.75	93.7
	635.0	39.60	533.4		31.75	577.9
20	27.50	1.690	23.00	20	1.250	25.00	122
	698.5	42.90	584.2		31.75	635.0
24	32.00	1.880	27.25	20	1.380	29.50	185
	812.8	47.80	692.2		35.10	749.3