GOST 12820 Flanges | PN 1-25 | Russian Standard

GOST 12820 flanges are Russian-standard steel flanges for pipeline connections made to GOST 12820-80, a specification used widely across Russia, the CIS countries, and regions that follow former Soviet engineering practice. The standard covers flat welded flanges from PN 1 to PN 25, rated for nominal pressures up to 25 kgf/cm² and diameters from DN 10 to DN 1600 and larger. It sets the dimensions, tolerances, materials, and technical requirements that keep joints leak-proof in industrial piping. Most are supplied as Type 01 plate flanges for welding, which gives a cost-effective option for low to medium pressure service. PM Industries manufactures, supplies, and stocks these flanges in popular DN sizes and pressure ratings.

We produce GOST 12820 flanges in carbon steel grades such as 20, 09G2S, and 17GS, along with stainless variants. Those grades weld well, carry good mechanical strength, and stay compatible with Russian pipe standards like GOST 8732 and GOST 8734. Standardized bolt hole patterns, flange thickness, and facing surfaces are set up for flat or raised configurations with the right gaskets. The flanges do their best work in water supply, heating networks, oil and gas distribution, chemical processing, and general industrial utilities, where pressures and temperatures stay moderate. The design holds up under mechanical load, thermal expansion, and the vibration that comes with pipeline operation.

The standard puts real weight on quality control: material certification, dimensional accuracy, and surface finish, all aimed at interchangeability and long service life. In the field, GOST 12820 flanges are favored for their simplicity, easy availability, and proven track record in harsh climates across wide territories. They go in fast and service easily, on new projects and legacy upgrades alike.

PM Industries keeps ready stock of GOST 12820 compliant flanges, backed by certification and technical documentation. Whether your project follows Russian norms or has to work alongside mixed international standards, these flanges give you dependable connectivity at a sensible price. They still carry a lot of energy infrastructure, municipal service, and industrial work across Eastern Europe and Asia. Tell us your DN size, PN rating, grade, and facing, and we will quote it.

Specification GOST 12820 Flanges

Standards	ANSI/ASME B16.5, B16.48, ANSI Flanges, GOST Flanges, DIN Flanges, EN-1092, B16.47 Series A & B, ASME Flanges, EN Flanges, AWWA Flanges, BS Flanges.
JIS Standard	5K, 10 K, 16 K 20 K, 30 K, 40 K, 63 K
DIN FLANGES	DIN 2527, 2627, 2631, 2656, 2576, 2673, 2629, 2628, 2566, 2641, 2637, 2655, 2634, 2636, 2632, 2633, 2638, 2642, 2573, 2635.
Pressure Rating	Class 150 LBS, 300 LBS, 600 LBS, 900 LBS, 1500 LBS, 2500 LBS
Types	Threaded, Plate, Screwed, Forged.
Supporting material	Gasket, Ring Joint, Flange Bolts
Size range	1/2" (15 NB) to 48" (1200NB) DN10~DN5000
Production technique	Forged, machined and Heat treated
Available Flange Type	Weld Neck Flanges, RTJ Flanges, Slip On Flanges, Spectacle Blind Flanges, Flanges Gaskets, Square Flanges, Standard Insert Flanges, High Hub Blinds Flanges, Flat Flanges, forged flanges, Weldo / Nipo Flanges, Jacket Insert Flanges, Tongue groove Flanges, Blind Flanges, Socket Weld Flanges, Large diameter Flanges, Long Weld Neck Flanges, Spacer Blinds, SWRF Flanges, SORF Flanges, Angle Face Rings Flanges, Spades Ring Spacers Flanges, WNRF Flanges, Screwed Flanges, Insert Flanges, flanges bolts, cf flange, Lap Joint Flanges, ASME B16.36 Orifice Flanges, Plate Flange, Expander Flanges, Ring Type Joint Flanges, Loose Flanges, Reducing Flanges, puddle flange, Threaded Flanges, blank flange, vacuum flange.
Connect Type/ Flange Face Type	Ring Type Joint (RTJ), Flat Face (FF), Tongue & Groove, Small Male-Female (SMF), Lap-Joint Face (LJF), Raised Face (RF), Large Male-Female (LMF), Small Tongue.
Custom design	As per your drawing
Test	Direct-reading Spectrograph, X-ray detector, UItrasonic flaw detector, Magnetic particle detector, Hydrostatic testing machine.
Origin	Indian / USA / Korean / West Europe / Japan
Pressure Class	PN 6 TO PN 100
Thickness	Normal Pipe Size ≤ 18
Bore Diameter	Normal Pipe ≤ 10
High Temperature	Above 200°C (400°F) For Class 150 Or Above 400°C (750°F)
Low Temperature	Above -29 Degree C (−20°F)
Coating/Surface Treatment:	Zinc Plated, Anti-rust Paint, Oil Black Paint, Yellow Transparent, Cold and Hot Dip Galvanized.
European/African/Russian Standard Flanges	Available
Gaskets Types	Full Face, Metallic Ring, Flat Ring Gasket
Marking Standard	Name of Manufacturer
	Schedule
	Type of Flange Facing
	Pressure Class
	Nominal Pipe Size, etc
Test Certificates	EN 10204/3.1B, NACE MR0103, NACE MR0175
	Raw Materials Certificate
	100% Radiography Test Report
	Third Party Inspection Report, etc

Flange Type Available

ГОСТ 12820 Pipe Flanges Dimensions

Pressure PN = 0.6 MPa (6 kgf/s m²)
Name	D, mm	D1, mm	dv, mm	b, mm	d, mm	resp., pcs.	Mass, kg.
Flat flange GOST 12820-80 (01) 1-15-6 st.3 (20)	80	55	19	10	11	4	0,33
Flat flange GOST 12820-80 (01) 1-20-6 st.3 (20)	90	65	26	12			0,53
Flat flange GOST 12820-80 (01) 1-25-6 st.3 (20)	100	75	33	12			0,64
Flat flange GOST 12820-80 (01) 1-32-6 st.3 (20)	120	90	39	13	14		1,01
Flat flange GOST 12820-80 (01) 1-40-6 st.3 (20)	130	100	46	13			1,21
Flat flange GOST 12820-80 (01) 1-50-6 st.3 (20)	140	110	59	13			1,33
Flat flange GOST 12820-80 (01) 1-65-6 st.3 (20)	160	130	78	13			1,63
Flat flange GOST 12820-80 (01) 1-80-6 st.3 (20)	185	150	91	15	18		2,44
Flat flange GOST 12820-80 (01) 1-100-6 st.3 (20)	205	170	110	15			2,85
Flat flange GOST 12820-80 (01) 1-125-6 st.3 (20)	235	200	135	17		8	3,88
Flat flange GOST 12820-80 (01) 1-150-6 st.3 (20)	260	225	161	17			4,39
Flat flange GOST 12820-80 (01) 1-200-6 st.3 (20)	315	280	222	19			5,89
Flat flange GOST 12820-80 (01) 1-250-6 st.3 (20)	370	335	273	20		12	7,67
Flat flange GOST 12820-80 (01) 1-300-6 st.3 (20)	435	395	325	20	22		10,28
Flat flange GOST 12820-80 (01) 1-350-6 st.3 (20)	485	445	377	22			12,58
Flat flange GOST 12820-80 (01) 1-400-6 st.3 (20)	535	495	426	24		16	15,2
Flat flange GOST 12820-80 (01) 1-500-6 st.3 (20)	640	600	530	25			19,72
Flat flange GOST 12820-80 (01) 1-600-6 st.3 (20)	755	705	630	25	26	20	26,24
Flat flange GOST 12820-80 (01) 1-800-6 st.3 (20)	975	920	820	27	30	24	46,14
Flat flange GOST 12820-80 (01) 1-1000-6 st.3 (20)	1 175	1 120	1 020	31		28	64,36
Flat flange GOST 12820-80 (01) 1-1200-6 st.3 (20)	1 400	1 340	1 220	34	33	32	99,03

GOST 12820-80 Flange PN0.6MPa Dimensions Chart

Conditional passage Dy	Py  0.6 MPa (6 kgf/cm2)
	d n	d in	b	Mass, kg
				with a connecting projection	with a ledge	with a depression
10	14	15	10	0,31	0,31	0,30
15	18	19		0,33	0,33	0,32
20	25	26	12	0,53	0,53	0,51
25	32	33		0,64	0,64	0,62
32	38	39	13	1,01	1,02	0,98
40	45	46		1,21	1,19	1,16
50	57	59		1,33	1,30	1,27
65	76	78		1,63	1,60	1,55
80	89	91	15	2,44	2,40	2,35
100	108 (A)	110		2,85	2,81	2,72
	114 (B)	116		2,73	2,66	2,60
125	133 (A)	135	17	3,88	3,84	3,70
	140 (B)	142		3,68	3,59	3,50
150	152 (A)	154		4,63	4,65	4,43
	159 (B)	161		4,39	4,36	4,19
	168 (B)	170		4,09	3,98	3,89
(175)	194	196	19	5,36	5,33	5,14
200	219	222		5,89	5,86	5,65
(225)	245	245		6,60	6,60	6,29
250	273	273	20	7,67	7,64	7,34
300	325	325		10,28	10,18	9,74
350	377	377	22	12,58	12,45	12,00
400	426	426	24	15,20	15,07	14,53
(450)	480	480		17,25	17,04	16,52
500	530	530	25	19,72	19,57	18,86
600	630	630		26,24	25,91	24,96
(700)	720	720	27	36,68	36,27	35,28
800	820	820		46,14	45,66	43,65
(900)	920	920	29	55,10	-	-
1000	1020	1020	31	64,36
1200	1220	1220	34	99,03
1400	1420	1420	43	161,45
1600	1620	1620	48	203,05

Dimensions Of ГОСТ Gost 12820-80 Flange

Pressure PN = 1.0 MPa (10 kgf/s m²)
Name	D, mm	D1, mm	dv, mm	b, mm	d, mm	resp., pcs.	Mass, kg.
Flat flange GOST 12820-80 (01) 1-15-10 st.3 (20)	95	65	19	10	14	4	0,51
Flat flange GOST 12820-80 (01) 1-20-10 st.3 (20)	105	75	26	12			0,74
Flat flange GOST 12820-80 (01) 1-25-10 st.3 (20)	115	85	33	12			0,89
Flat flange GOST 12820-80 (01) 1-32-10 st.3 (20)	135	100	39	14	18		1,4
Flat flange GOST 12820-80 (01) 1-40-10 st.3 (20)	145	110	46	15			1,71
Flat flange GOST 12820-80 (01) 1-50-10 st.3 (20)	160	125	59	15			2,06
Flat flange GOST 12820-80 (01) 1-65-10 st.3 (20)	180	145	78	17			2,8
Flat flange GOST 12820-80 (01) 1-80-10 st.3 (20)	195	160	91	17			3,19
Flat flange GOST 12820-80 (01) 1-100-10 st.3 (20)	215	180	110	19		8	3,96
Flat flange GOST 12820-80 (01) 1-125-10 st.3 (20)	245	210	135	21			5,4
Flat flange GOST 12820-80 (01) 1-150-10 st.3 (20)	280	240	161	21	22		6,62
Flat flange GOST 12820-80 (01) 1-200-10 st.3 (20)	335	295	222	21			8,05
Flat flange GOST 12820-80 (01) 1-250-10 st.3 (20)	390	350	273	23		12	10,65
Flat flange GOST 12820-80 (01) 1-300-10 st.3 (20)	440	400	325	24			12,9
Flat flange GOST 12820-80 (01) 1-350-10 st.3 (20)	500	460	377	24		16	15,85
Flat flange GOST 12820-80 (01) 1-400-10 st.3 (20)	565	515	426	26	26		21,56
Flat flange GOST 12820-80 (01) 1-500-10 st.3 (20)	670	620	530	28		20	27,7
Flat flange GOST 12820-80 (01) 1-600-10 st.3 (20)	780	725	630	31	30		39,4
Flat flange GOST 12820-80 (01) 1-800-10 art.3 (20)	1010	950	820	37	33	24	79,16
Flat flange GOST 12820-80 (01) 1-1000-10 st.3 (20)	1220	1160	1020	43		28	118,43
Flat flange GOST 12820-80 (01) 1-1200-10 st.3 (20)	1455	1380	1220	51	39	32	197,44

Gost Flange Dimensions

Conditional passage Dy	Py  1.0 MPa (10 kgf/cm2)
	d n	d in	b	Mass, kg
				with a connecting projection	with a ledge	with a depression
10	14	15	10	0,46	0,46	0,44
15	18	19		0,51	0,51	0,49
20	25	26	12	0,74	0,75	0,71
25	32	33		0,89	0,89	0,84
32	38	39	14	1,40	1,39	1,34
40	45	46	15	1,71	1,72	1,67
50	57	59		2,06	2,03	1,99
65	76	78	17	2,80	2,77	2,69
80	89	91		3,19	3,13	3,08
100	108 (A)	110	19	3,96	3,94	3,76
	114 (B)	116		3,81	3,76	3,61
125	133 (A)	135	21	5,40	5,38	5,18
	140 (B)	142		5,15	5,08	4,93
150	152 (A)	154		6,92	6,97	6,62
	159 (B)	161		6,62	6,62	6,33
	168 (B)	170		6,24	6,17	5,95
(175)	194	196		7,32	7,31	7,02
200	219	222		8,05	8,04	7,71
(225)	245	245		9,30	9,30	9,05
250	273	273	23	10,65	10,66	10,22
300	325	325	24	12.90	12,89	12,21
350	377	377		15,85	15,79	14,96
400	426	426	26	21,56	21,51	20,49
(450)	480	480		22,76	22,68	21,67
500	530	530	28	22,70	28,02	26,86
600	630	630	31	39,40	39,26	37,48
(700)	720	720	34	59,46	58,58	56,45
800	820	820	37	79,16	77,89	76,08
(900)	920	920	40	94,13	-	-
1000	1020	1020	43	118,43
1200	1220	1222	51	197,44
1400	1420	1420	60	278,92
1600	1620	1620	70	422,65

GOST 12820-80 Flange Dimensions in mm

Pressure PN = 1.6 MPa (16 kgf/s m²)
Name	D, mm	D1, mm	dv, mm	b, mm	d, mm	resp., pcs.	Mass, kg
Flat flange GOST 12820-80 (01) 1-15-16 st.3 (20)	95	65	19	12	14	4	0,61
Flat flange GOST 12820-80 (01) 1-20-16 st.3 (20)	105	75	26	14			0,86
Flat flange GOST 12820-80 (01) 1-25-16 st.3 (20)	115	85	33	16			1,17
Flat flange GOST 12820-80 (01) 1-32-16 st.3 (20)	135	100	39	16	18		1,58
Flat flange GOST 12820-80 (01) 1-40-16 st.3 (20)	145	110	46	17			1,96
Flat flange GOST 12820-80 (01) 1-50-16 st.3 (20)	160	125	59	19			2,58
Flat flange GOST 12820-80 (01) 1-65-16 st.3 (20)	180	145	78	21			3,42
Flat flange GOST 12820-80 (01) 1-80-16 st.3 (20)	195	160	91	21			3,71
Flat flange GOST 12820-80 (01) 1-100-16 st.3 (20)	215	180	110	23		8	4,73
Flat flange GOST 12820-80 (01) 1-125-16 st.3 (20)	245	210	135	25			6,38
Flat flange GOST 12820-80 (01) 1-150-16 st.3 (20)	280	240	161	25	22		7,81
Flat flange GOST 12820-80 (01) 1-200-16 art.3 (20)	335	295	222	27		12	10,1
Flat flange GOST 12820-80 (01) 1-250-16 st.3 (20)	405	355	273	28	26		14,49
Flat flange GOST 12820-80 (01) 1-300-16 st.3 (20)	460	410	325	28			17,78
Flat flange GOST 12820-80 (01) 1-350-16 st.3 (20)	520	470	377	30		16	22,88
Flat flange GOST 12820-80 (01) 1-400-16 st.3 (20)	580	525	426	34	30		31
Flat flange GOST 12820-80 (01) 1-500-16 st.3 (20)	710	650	530	44	33	20	57,01
Flat flange GOST 12820-80 (01) 1-600-16 st.3 (20)	840	770	630	45	39		80,03
Flat flange GOST 12820-80 (01) 1-800-16 art.3 (20)	1020	950	820	49		24	104,41
Flat flange GOST 12820-80 (01) 1-1000-16 st.3 (20)	1255	1170	1020	58	45	28	179,37
Flat flange GOST 12820-80 (01) 1-1200-16 st.3 (20)	1485	1390	1220	71	52	32	297,78

GOST12820-80 Plate Flange Dimension Table

Pressure PN = 2.5 MPa (25 kgf/s m²)
Name	D, mm	D1, mm	dv, mm	b, mm	d, mm	resp., pcs.	Mass, kg
Flat flange GOST 12820-80 (01) 1-15-25 st.3 (20)	95	65	19	14	14	4	0,7
Flat flange GOST 12820-80 (01) 1-20-25 st.3 (20)	105	75	26	16			1
Flat flange GOST 12820-80 (01) 1-25-25 st.3 (20)	115	85	33	16			1,2
Flat flange GOST 12820-80 (01) 1-32-25 st.3 (20)	135	100	39	18	18		1,8
Flat flange GOST 12820-80 (01) 1-40-25 st.3 (20)	145	110	46	19			2,2
Flat flange GOST 12820-80 (01) 1-50-25 st.3 (20)	160	125	59	21			2,7
Flat flange GOST 12820-80 (01) 1-65-25 st.3 (20)	180	145	78	21		8	3,2
Flat flange GOST 12820-80 (01) 1-80-25 st.3 (20)	195	160	91	23			4,1
Flat flange GOST 12820-80 (01) 1-100-25 st.3 (20)	230	190	110	25	22		5,9
Flat flange GOST 12820-80 (01) 1-125-25 st.3 (20)	270	220	135	27	26		8,3
Flat flange GOST 12820-80 (01) 1-150-25 st.3 (20)	300	250	161	27			10,1
Flat flange GOST 12820-80 (01) 1-200-25 st.3 (20)	360	310	222	29		12	13,3
Flat flange GOST 12820-80 (01) 1-250-25 st.3 (20)	425	370	273	31	30		18,9
Flat flange GOST 12820-80 (01) 1-300-25 st.3 (20)	485	430	325	32		16	23,9
Flat flange GOST 12820-80 (01) 1-350-25 st.3 (20)	550	490	377	38	33		34,4
Flat flange GOST 12820-80 (01) 1-400-25 st.3 (20)	610	550	426	40			44,6
Flat flange GOST 12820-80 (01) 1-500-25 st.3 (20)	730	660	530	48	39	20	67,3
Flat flange GOST 12820-80 (01) 1-600-25 st.3 (20)	840	770	630	49			90,87
Flat flange GOST 12820-80 (01) 1-800-25 art.3 (20)	1075	990	820	63	45	24	181,43

GOST 12820-80 Flange Pressure rating

ASME/ANSI B 16.36	Welding Neck Flange, Slip on Flange, Threaded Flange
PRESSURE CLASS	300, 400, 600, 900, 1500, 2500
ASME/ANSI B 16.5	Welding Neck Flange, Slip on Flange, Blind Flange, High Hub Blind Flange, Socket Weld Flange, Lap Joint Flange, Threaded Flange, Ring Type Joint Flange
PRESSURE CLASS	150, 300, 400, 600, 900, 1500, 2500
ASME/ANSI B 16.47	Welding Neck Flange, Blind Flange [Series A & B]
PRESSURE CLASS	75, 150, 300, 400, 600, 900
BS 4504 SEC 3.1	Welding Neck Flange, Hubbed Slip on Flange, Hubbed Threaded Flange, Lapped Pipe End Flange, Plate Flange, Loose Plate Flange, Loose Plate With Weld Neck Flange, Blank Flange
PRESSURE CLASS	PN 2.5 TO PN 40
BS 4504[PART 1]	Welding Neck Flange, Hubbed Slip-On Hubbed Threaded, Plate Flange, Loose Plate With Weld On Plate Collar, Blank Flange
PRESSURE CLASS	PN 2.5 TO PN 400
BS 1560 BOSS	Welding Neck Flange, Socket Welding Flange, Slip-On Flange, Blind Flange, Screwed Boss Flange, Lapped Flange
PRESSURE CLASS	150, 300, 400, 600, 900, 1500, 2500
BS10	Welding Neck Flange, Plate Slip-On Flange, Screwed Boss Flange, Slip-On Boss Flange, Blind Flange
TABLE	D, E, F, H
FROM FLANGES	DIN 2527, 2566, 2573, 2576, 2641,2642, 2655, 2656, 2627, 2628, 2629, 2631, 2632, 2633, 2634, 2635, 2636, 2637,2638, 2673
PRESSURE CLASS	PN 6 TO PN 100

Weight chart of Gost 12820-80 Weld Neck flange

Standard	Class	Diameter	Bolt Circle Diameter	Number of Bolts	Bolt Size	Diameter of Bolt Hole
AS4087 Flanges	PN14	95	67	4	M12	14
AS 2129 Flange	Table C	95	67	4	13	14
	Table D	95	67	4	13	14
	Table E	95	67	4	13	14
	Table F	95	67	4	13	14
	Table H	114	83	4	16	17
	Table J	114	83	4	16	17
ANSI B16.5 Flanges	ANSI 150	89	60	4	13	16
	ANSI 300	95	67	4	13	16
	ANSI 600	95	67	4	13	16
	ANSI 900	121	83	4	19	22
	ANSI 1500	121	83	4	19	22
ISO 7005 (DIN) Flange	PN6	80	55	4	M10	11
	PN10	95	65	4	M12	14
	PN16	95	65	4	M12	14
	PN20	90	60.5	4	M14	16
	PN25	95	65	4	M12	14
	PN40	95	65	4	M12	14