Compact Flanges

Understanding your choice of compact flanges options

As a leading provider of oil and gas equipment, we understand that choosing the right compact flange option can be overwhelming, especially when there are so many options available in the market. It can be difficult to determine which one is the best fit for your specific application. We will provide a comprehensive guide to help you understand your choice of compact flange options.

What are compact flanges?

Compact flanges, similar to swivel ring flanges, are two-piece construction flanges widely used in offshore pipelines, offshore industrial applications, and onshore and subsea applications. Its double-sealing action prevents the release of hydrocarbons to address health and safety concerns. Compared to conventional flanges, compact flanges offer significant weight and space savings and the integrity of a leak-free joint, making them the most effective environmentally friendly pipeline joints.
The compact flange is attached to the end of a pipe and is primarily the part that interconnects the pipe and the tube. The flange has an eyelet and can be threaded with bolts to connect the two flanges tightly, and the flange is sealed with a gasket between them. They are suitable for use in harsh sealing environments with thermal expansion or cyclic fluid loads, such as risers, single-point mooring systems, pipe manifolds, oil recovery trees, subsea pipelines, heat exchangers, and various other piping systems in the process industry.

Principle and Structural Characteristics of Compact Flange

The principle of compact flanges

The design principle of the compact flange is a double-sealing system with different flange sealing surfaces.

• (1) The flange uses a sealing ring instead of a sealing gasket. The unique conical structure design of its sealing surface converts the axial bolt preload applied to the conical surface of the sealing ring into a radial sealing force.
• (2) The further loading of the bolt preload causes the entire flange outer edge to adhere tightly, and the wedge-shaped flange sealing surface and sealing ring cone surface closely fit the groove cone surface. Therefore, most of the bolt preload is converted into the pressure at the wedge-shaped flange sealing surface’s root. In this way, a slight bolt preload can achieve metal face-to-face contact, significantly reducing damage to the sealing ring.
• (3) The reduction in bolt preload results in a corresponding reduction in the number and size of bolts and a corresponding reduction in flange wall thickness. This not only reduces the size and weight of the flange but also achieves excellent zero-leakage sealing performance.

The compact flange has three seal closures.

• (1) The first seal: the root seal. This is a preliminary seal.
• (2) Second seal: sealing ring seal, which is the primary seal. The conical surface of the sealing ring forms close metal-to-metal contact under the action of the bolt preload, forming a seal. At the same time, there is a tendency for the sealing surface to return to the original inclined surface state. If the root of the sealing surface leaks, then the pressure from the inside extends toward the outer diameter, strengthening the sealing effect.
• (3) Third seal: wedge seal. This external seal mainly prevents external corrosive substances from entering the flange sealing surface.

Figure.1 Schematic Diagram of Compact Flange

Structural features of compact flanges

Structure of compact flange

The compact flange structure is shown in Figure 2.

• ① Root: The root of the compact flange is a metal-to-metal axial seal, which fits tightly without gaps.
• ② IX seal ring: Here is a metal-to-metal radial seal; because of the pressure and the tendency to return to the original bevel state, it can be self-sealing, with no lubrication, no wear, installation load will not damage the seal ring, and can be reused.
• ③ Wedge: This structure design can make the flange withstand excessive stress and prevent external impurities entry.
• ④ Bolt: The dynamic stress of the flange bolt can be ignored, and no lubrication is required.
• ⑤ Chamfering: elliptical arc transition can reduce the stress concentration.

Figure.2 Structure diagram of compact flange

Characteristics of Ⅸ sealing ring

The most commonly used seal ring of the compact flange is Ⅸ type, see Figure 2, the characteristics of this seal ring are as follows:

• (1) Smaller size and less load.
• (2) The elastic seal is achieved by the radial deformation caused by the seal groove.
• (3) No limitation on the internal pressure.
• (4) Zero leakage seal (metal-to-metal close contact).
• (5) The shape of the gasket makes the flange easy and fast to install.
• (6) The same nominal size flange corresponds to one gasket, regardless of poundage.
• (7) Made of carbon steel or duplex stainless steel.
• (8) High strength and reusable.
• (9) Meet the requirement of the NACE standard for hardness.

Advantages of compact flanges

• Space saving.

• Weight savings of 70% to 80% compared to ANSI flanges.

• Double-independent sealing is more secure.

• Positive sealing method.

• Integral sealing system (internal and external).

• Wider design temperature and design pressure range.

Standards of Compact Flanges

NORSOK L-005 compact flanges are widely used in the offshore oil and gas industry, providing reliable connections for high-pressure, high-temperature, and critical service applications. These flanges are characterized by their small size and weight, making them ideal for space-constrained installations. Key features of NORSOK L-005 compact flanges include:

• Superior sealing performance: A metal-to-metal seal is created by the axial force applied to the flange face, ensuring a tight and leak-free connection.
• High resistance to bending stresses: The compact design reduces the bending moment on the bolted connection, increasing the flange’s ability to withstand extreme pressure and temperature fluctuations.
• Ease of installation: The simplicity of the design and fewer components of NORSOK L-005 compact flanges make them easy to install and maintain, reducing downtime and overall project costs.

Materials of Compact Flanges

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

Titanium Compact 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 Compact 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 Compact Flange	ASTM / ASME SB 61 / 62 / 151 / 152, Copper Nickel 90/10 (C70600 ), Cupro Nickel 70/30 (C71500), UNS C71640
Carbon Steel Compact 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 Compact 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 Compact Flange	ASTM A182 / ASME SA182 F5, F9, F11, F12, F22, F91
Hastelloy Compact Flange	ASTM B564 / ASME SB564, Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X
Brass Compact Flange	3602 / 2604 / H59 / H62 / etc.
Inconel Compact Flange	ASTM B564 / ASME SB564, Inconel 600, 601, 625, 718, 783, 690, x750
Monel Compact Flange	ASTM B564 / ASME SB564, Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500)
Duplex Compact Flange	S31803 / S32205 A182 Gr F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61
Super Duplex Compact Flange	S32750 / S32760 A182 Gr F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61
Alloy 20 Compact Flange	ASTM B462 / ASME SB462, Carpenter 20 Alloy, Alloy 20Cb-3
Aluminium Compact Flange	5052 /6061/ 6063 / 2017 / 7075 / etc.
Nickel Compact Flange	ASTM B564 / ASME SB564, Nickel 200, Nickel 201, Nickel 205, Nickel 205LC
Nimonic Compact Flange	Nimonic 75, Nimonic 80A, Nimonic 90
Other Compact Flange material	Tin bronze, Alumunum bronze, Lead bronze
Incoloy Compact Flange	ASTM B564 / ASME SB564, Incoloy 800, 800H, 800HT (UNS N08800), 825 (UNS N08825), 925
254 Smo Compact Flange	ASTM A182 / ASME SA182, SMO 254/6Mo, UNS S31254, DIN 1.4547

Sizes for Compact Flanges

Compact Flanges can be delivered from our product standard in pressure classes CL150 (PN20) to CL2500 (PN420) and in nominal pipe sizes ½“ to 48”.

Dimensions of Compact Flanges

These standards define the dimensions of compact flanges, including the flange size, pressure rating, bolt circle diameter, and the number and size of bolt holes.

Dimensions of Class 600 Compact Flange NORSOK L-005 (NCF5)/IS0 27509

DN	NPS	DW3 [mm]	HW3 [mm]	HW5 [mm]	BCD [mm]	A [mm]	B [mm]	NUMBER OF HOLES	DIAM. [inch]
15	1/2″	93	20	51	67,3	21,3	15,8-11,7	4	1/2″
20	3/4″	98	20	53	72,7	26,7	21,0-15,6	4	1/2″
25	1″	105	20	56	79,4	33,4	27,9-20,7	4	1/2″
40	1 1/2″	121	23	64	95,3	48,3	42,8-34,0	8	1/2″
50	2″	136	23	60	110	60,3	54,8-42,8	8	1/2″
65	2 1/2″	149	26	66	123,1	73,0	66,9-59,0	12	1/2″
80	3″	161	25	61	134,9	88,9	82,8-73,7	12	1/2″
100	4″	203	31	70	171,7	114,3	108,2-97,2	12	5/8″
125	5″	230	35	78	198,6	141,3	134,5-122,2	12	5/8″
150	6″	258	36	75	226,8	168,3	154,1-146,4	12	5/8″
200	8″	312	43	87	280,4	219,1	206,4-193,7	20	5/8″
250	10″	382	53	102	344,8	273,1	260,4-242,9	20	3/4″
300	12″	450	60	108	407,7	323,9	307,1-288,9	20	7/8″
350	14″	482	64	113	439,2	355,6	339,8-317,5	24	7/8″
400	16″	547	73	122	499	406,4	387,3-363,5	24	1″
450	18″	614	80	131	560,1	457,2	438,1-409,5	24	1-1/8″
500	20″	664	86	139	610,6	508,0	482,6-455,6	28	1-1/8″
550	22″	730	94	149	670,7	558,8	533,4-501,6	24	1-1/4″
600	24″	785	100	158	725,6	609,6	584,2-547,7	28	1-1/4″
650	26″	835	105	166	775,6	660,4	632,0-604,4	32	1-1/4″
700	28″	900	112	176	835,2	711,2	679,4-655,2	32	1-3/8″
800	32″	1016	126	195	945,7	812,8	777,8-752,8	32	1-1/2″
850	34″	1081	133	205	1004,8	863,6	828,6-799,6	32	1-5/8″
900	36″	1134	145	214	1058,4	914,4	876,3-842,4	32	1-5/8″
950	38″	1196	147	223	1115	965,2	925,2-893,2	32	1-3/4″
1000	40″	1251	153	232	1169,6	1016,0	976,0-936,0	36	1-3/4″
1050	42″	1312	165	241	1225,2	1066,8	1022,4-986,8	32	1-7/8″
1100	44″	1365	170	249	1278,5	1117,6	1073,2-1027,6	36	1-7/8″
1150	46″	1438	174	262	1345,9	1168,4	1124,0-1078,4	36	2″
1200	48″	1490	189	270	1397,4	1219,2	1169,2-1129,2	36	2″

Dimensions of Class 900 Compact Flange NORSOK L-005 (NCF5)/IS0 27509

DN	NPS	DW3 [mm]	HW3 [mm]	HW5 [mm]	BCD [mm]	A [mm]	B [mm]	NUMBER OF HOLES	DIAM. [inch]
15	1/2″	93	20	51	67,3	21,3	15,8-11,7	4	1/2″
20	3/4″	98	20	53	72,7	26,7	21,0-15,6	4	1/2″
25	1″	105	20	56	79,4	33,4	26,6-20,7	4	1/2″
40	1 1/2″	121	23	64	95,3	48,3	42,8-34,0	8	1/2″
50	2″	136	23	60	110	60,3	54,8-42,8	8	1/2″
65	2 1/2″	149	26	66	123,1	73,0	66,9-53,9	12	1/2″
80	3″	161	25	61	134,9	88,9	82,8-66,6	12	1/2″
100	4″	203	31	70	171,7	114,3	108,2-92,0	12	5/8″
125	5″	230	35	78	198,6	141,3	128,2-115,9	12	5/8″
150	6″	263	40	87	231,6	168,3	154,1-139,8	16	5/8″
200	8″	330	50	98	293,2	219,1	206,4-182,6	20	3/4″
250	10″	397	60	110	354,8	273,1	257,5-230,2	20	7/8″
300	12″	462	68	119	413,9	323,9	307,1-273,1	20	1″
350	14″	497	73	127	449,3	355,6	336,5-300,0	24	1″
400	16″	567	82	140	513,8	406,4	381,0-344,5	24	1-1/8″
450	18″	633	90	153	574	457,2	434,9-398,5	24	1-1/4″
500	20″	700	99	166	635,5	508,0	482,6-442,9	24	1-3/8″
550	22″	764	107	179	693,6	558,8	514,3-488,9	24	1-1/2″
600	24″	830	115	191	754,2	609,6	581,1-531,8	24	1-5/8″
650	26″	894	124	204	812,8	660,4	620,4-588,4	24	1-3/4″
700	28″	948	141	214	866,4	711,2	666,8-631,2	24	1-3/4″
800	32″	1081	157	239	988,4	812,8	762,8-722,8	24	2″
850	34″	1160	158	254	1057,1	863,6	813,6-763,6	24	2-1/4″
900	36″	1214	176	265	1110,7	914,4	870,0-814,4	24	2-1/4″
950	38″	1291	174	279	1176,8	965,2	905,2-855,2	24	2-1/2″
1000	40″	1344	190	290	1230	1016,0	956,0-906,0	24	2-1/2″
1050	42″	1396	192	300	1282,1	1066,8	1016,8-946,8	28	2-1/2″
1100	44″	1451	211	310	1336,8	1117,6	1053,6-997,6	28	2-1/2″
1150	46″	1527	219	324	1401,9	1168,4	1096,4-1038,4	28	2-3/4″
1200	48″	1618	218	342	1482	1219,2	1147,2-1089,2	28	3″

Dimensions of Class 1500 Compact Flange NORSOK L-005 (NCF5)/IS0 27509

DN	NPS	DW3 [mm]	HW3 [mm]	HW5 [mm]	BCD [mm]	A [mm]	B [mm]	NUMBER OF HOLES	DIAM. [inch]
15	1/2″	93	20	51	67,3	21,3	15,8-6,4	4	1/2″
20	3/4″	98	20	53	72,7	26,7	21,0-11,1	4	1/2″
25	1″	105	20	56	79,4	33,4	26,6-15,2	4	1/2″
40	1 1/2″	121	23	64	95,3	48,3	40,9-28,0	8	1/2″
50	2″	136	23	60	110	60,3	52,5-38,2	8	1/2″
65	2 1/2″	149	26	66	123,1	73,0	62,7-45,0	12	1/2″
80	3″	180	30	73	148,3	88,9	77,9-58,4	12	5/8″
100	4″	224	37	86	187	114,3	102,3-80,1	12	3/4″
125	5″	261	43	92	218,6	141,3	122,2-103,2	12	7/8″
150	6″	307	50	101	258,8	168,3	146,4-124,4	12	1″
200	8″	365	60	115	317,4	219,1	193,7-169,1	16	1″
250	10″	453	75	136	393,6	273,1	247,7-215,9	16	1-1/4″
300	12″	508	83	151	449	323,9	295,4-257,3	20	1-1/4″
350	14″	558	89	162	493,1	355,6	317,5-284,2	20	1-3/8″
400	16″	626	105	180	555,2	406,4	363,5-325,4	20	1-1/2″
450	18″	704	111	198	622,3	457,2	409,5-366,7	20	1-3/4″
500	20″	778	126	217	690,7	508,0	455,6-408,0	20	1-7/8″
550	22″	850	142	234	757,9	558,8	488,9-450,8	20	2″
600	24″	933	146	253	829,3	609,6	547,7-490,5	20	2-1/4″
650	26″	990	172	269	887	660,4	596,4-540,4	20	2-1/4″
700	28″	1051	182	285	947,2	711,2	639,2-591,2	24	2-1/4″
800	32″	1155	202	311	1040,8	812,8	732,8-672,8	24	2-1/2″
850	34″	1232	214	328	1107,1	863,6	783,6-713,6	24	2-3/4″
900	36″	1339	222	352	1191,3	914,4	824,4-754,4	20	3-1/4″
950	38″	1416	226	369	1257,5	965,2	865,2-805,2	20	3-1/2″
1000	40″	1452	250	382	1305	1016,0	916,0-846,0	24	3-1/4″
1050	42″	1549	257	402	1379,5	1066,8	966,8-886,8	20	3-3/4″
1100	44″	1583	275	413	1424,2	1117,6	1007,6-927,6	24	3-1/2″
1150	46″	1666	281	433	1496,5	1168,4	1048,4-948,4	24	3-3/4″
1200	48″	1714	303	445	1544,7	1219,2	1099,2-989,2	24	3-3/4″

Dimensions of Class 2500 Compact Flange NORSOK L-005 (NCF5)/IS0 27509

DN	NPS	DW3 [mm]	HW3 [mm]	HW5 [mm]	BCD [mm]	A [mm]	B [mm]	NUMBER OF HOLES	DIAM. [inch]
15	1/2″	93	20	51	67,3	21,3	15,8-6,4	4	1/2″
20	3/4″	98	20	53	72,7	26,7	21,0-11,1	4	1/2″
25	1″	105	20	56	79,4	33,4	26,6-15,2	4	1/2″
40	1 1/2″	121	23	64	95,3	48,3	40,9-23,3	8	1/2″
50	2″	147	27	72	116,2	60,3	52,5-31,9	8	5/8″
65	2 1/2″	179	32	81	141,6	73,0	59,0-41,0	8	3/4″
80	3″	209	36	85	166,3	88,9	77,9-53,9	8	7/8″
100	4″	248	44	95	200,4	114,3	97,2-69,9	8	1″
125	5″	278	50	106	230,2	141,3	109,5-91,3	12	1″
150	6″	322	58	120	268,8	168,3	146,4-108,3	12	1-1/8″
200	8″	408	72	145	343,7	219,1	188,9-147,1	12	1-3/8″
250	10″	485	88	172	415	273,1	242,9-183,1	16	1-1/2″
300	12″	564	99	195	483,2	323,9	288,9-213,9	16	1-3/4″
350	14″	618	108	211	531,2	355,6	317,5-245,6	16	1-7/8″
400	16″	718	125	238	615,1	406,4	363,5-276,4	16	2-1/4″
450	18″	780	136	260	676,3	457,2	409,4-317,2	16	2-1/4″
500	20″	849	147	282	735	508,0	455,6-348,0	16	2-1/2″
550	22″	958	163	310	821,8	558,8	450,8-388,8	16	3″
600	24″	1039	176	334	891,3	609,6	504,9-419,6	16	3-1/4″

Manufacturing process of compact flanges

Compact Flanges can be produced by forging, casting. We mainly produce flanges by forging, cutting and rolling processes. We will take you through the step-by-step process of manufacturing compact flanges, from the materials used to the final product.

Step 1: Material Selection
The first step in our manufacturing process is material selection. We use only the highest quality materials, including carbon steel, stainless steel, and alloy steel. Each material has its own unique properties and is selected based on the specific needs of the customer.
Step 2: Cutting
Once the materials are selected, they are cut to the desired size using a cutting machine. We use state-of-the-art cutting machines to ensure precision and accuracy in every cut.
Step 3: Heating
After the materials are cut, they are heated to the desired temperature. This helps to reduce any stresses in the material and makes it easier to shape the flange.
Step 4: Forming
The next step in our manufacturing process is forming the flange. We use a hydraulic press to shape the heated material into the desired shape. This ensures that each flange is formed with precision and accuracy.
Step 5: Solid solution
Make the structure and composition of the blank flange uniform, which is particularly important for raw materials. At high temperatures, atomic activity intensifies, σ Phase dissolution, the chemical composition tends to be uniform, and a uniform single-phase structure is obtained after rapid cooling.
Eliminate work hardening to facilitate continuous cold work. The distorted lattice is recovered through solution treatment, the elongated and broken grains are recrystallized, the internal stress is eliminated, the tensile strength of stainless-steel forgings decreases, and the elongation increases.
Restore the inherent corrosion resistance of the flange blank. Due to carbide precipitation and lattice defects caused by cold working, the corrosion resistance of the flange blank is reduced. The corrosion resistance of forgings recovered to the best state after solution treatment.
Step 6: Machining
Once the flange is formed, it undergoes machining to ensure that it is smooth and free from any imperfections. We use CNC machines to achieve the highest level of accuracy in our machining process.
Step 7: Inspection
Before the flange is considered complete, it undergoes a thorough inspection process to ensure that it meets industry standards. Our team of experts inspects each flange to ensure that it is free from any defects and meets the specifications of the customer.
Step 8: Coating
Once the inspection process is complete, the flange is coated to protect it from corrosion and other environmental factors. We offer a variety of coating options, including epoxy, zinc, and galvanized coatings.
Step 9: Packaging and Delivery
Finally, the flange is packaged and prepared for delivery to the customer. We take great care in packaging our products to ensure that they arrive at their destination in pristine condition.
At Guanxin, we take great pride in our manufacturing process of compact flanges. We are committed to producing high-quality flanges that meet the needs of our customers. Contact us today to learn more about our products and services.

Marking of compact flanges

The marking of compact flanges is essential to their manufacture and use. The marking aims to provide information about the flange’s material, size, pressure rating, and other relevant details.
Compact Flanges are typically marked by industry standards, such as NORSOK L-005 (NCF5)/IS0 27509. These standards specify the required information that must be included on the flange, as well as the format and location of the markings.
The required information typically includes the following:

• Flange size
• Pressure rating
• Material specification
• Orifice plate bore diameter
• Tag number
• Manufacturer’s name or trademark
• Heat number or lot number
• Date of manufacture

The standard also specifies the location of the marking on the flange. Typically, the marking is placed on the raised face of the flange near the bolt holes. In some cases, the marking may be located on the flange hub or the orifice plate itself.

Packing of compact flanges

How to package compact flanges? To pack the compact flange, follow these steps:
When it comes to packaging compact 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 compact flanges.
Step 1: Clean and Inspect the Flanges
Before packaging the compact 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 compact 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 compact 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 compact 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 compact flanges properly, and label the package accurately to avoid any mishaps during transportation.

Manufacturing – “Value and Protect”

1. Pay attention to the sealing surface

• Do not use chains to pass through flange or bolt holes.
• Do not allow welding chips to damage the sealing surface.
• Do not use a grounding clip on the sealing surface.
• Be careful when inserting and removing objects through holes.
• Polish the sealing surface after heat treatment.

2. Protect the sealing surface

• Protect the base before and after machining.
• When required and reinstalled, carry out anti-corrosion protection treatment.

3. Corrosion prevention
Compact flanges and bolts have their own protective coatings. Additional anti-corrosion treatment may be required on assembled flanges to adapt to specific environmental conditions and/or to supplement coating damage during assembly.

Inspection and measurement of compact flanges

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

Material
The first thing to inspect in a compact 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 compact 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 compact 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.

Application of compact flanges

Compact flanges are suitable for use in harsh sealing environmental conditions with high thermal expansion or fluid cyclic load strength, such as riser, single point mooring systems, manifolds, Christmas trees, subsea pipelines, heat exchangers, and other pipeline systems in various process industries.

Assembly procedure of compact flange

1. Protection
Keep the protection of the flange from damage for as long as possible. After checking all sealing surfaces of the compact flange for mechanical damage and rust (step 2), restore the protection cap to its original state again before further processing and installation.

2. Component verification and inspection
Verify that all components are of the correct material, type and size. All conventional bulk flanges are marked on the outside face with the size, material and type of seal ring required for the flange; markings may vary on flanges that are connected to the unit as a whole. Ensure that the seal ring is of the correct size and material type (see Table 1), and that the seal ring material is marked as shown. Inspect all sealing surfaces for mechanical damage and rust. Touch the seal faces with your fingertips to probe for the presence of dents, scratches, knocks, etc.

Table.1 Seal Ring Material Guidelines

Sealing ring material type	•••	：：•	Low alloy	Stainless steel	High strength steel/stainless steel	Duplex / Superduplex	Nickel alloy
The grade is marked on the sealing ring		：：•	AISI 4130 AISI 4140	A182 F44 6Mo stainless steel	A564 630 (17/4 PH)	A182 F51 A182 F55	Alloy 625 Alloy 718
▼Hub material	▼Labeling data (material grade)
Carbon steel/low alloy steel	A694 F52, F60, F65, A350 LF2		■	■	■ (2)	■   (4)	■   (4)
	Ditto+alloy 625 cladding		■	■	•	■   (4)	•
Stainless steel	A182 F316, F304, F321		■	■ (1)	•	■   (3)	•
	A182 F44 (6Mo)		■	■ (1)	•	■   (3)	•
Duplex + S.Duplex	A182 F51, F53, F55, F61		■	■	■ (2)	•	•
Nickel alloy	Alloy 625, 800,825		■	■	•	(3)	•

■Stop: Avoid using this material!
■Use with caution: Check specifications or metallurgical recommendations.
■Conduct: Selection of good materials.

Remarks:

• 1. Recommended for use in environments below – 100 ° C;
• 2. Not recommended for use in acid containing environments;
• 3. Not recommended for environments below – 50 ° C;
• 4. Related applications to H₂S (hydrogen sulfide).

Please refer to NACE MR0175

3. Check the reference distance of the seal
Check the reference distance of the IX-seal ring by following the steps below: Place the seal ring into the groove.
If the seal ring can be shaken slightly: good.
If the seal ring cannot be shaken (touches the bottom of the groove): Replace!

4. Lubrication
Lubrication is not necessary for the groove of coated sealing rings. For uncoated sealing rings, use lubricant in the groove of the sealing ring. If using a torque tool, lubricate the threads of the double-headed bolt and the force surface of the flange and nut on the tool side.

• If torque tools are used, the bolt and nut bearing surfaces on the tool side need to be lubricated.
• If the seal is not coated with polytetrafluoroethylene (PTFE), the groove seating surface needs to be lubricated.

5. Alignment of flange
Before installing the sealing ring, perform flange alignment so that the double-headed bolt can be easily inserted into the bolt hole. The allowable error guideline values for alignment are approx:

• Flange diameter <ø300mm:a=1.5mm.
• Flange diameter >ø300mm:a=1mm per ø200mm.

6. Insert sealing ring
Using the lower part of the double-headed bolt at the appropriate position, separate the flange and insert the sealing ring. If washers or locating tabs are required, they can be fitted to the already inserted double-headed bolt. The use of a seal ring mounting rope (or similar item) is recommended. With the seal ring in place, carefully close the flange until the seal ring is held in the flange groove. Tighten the bolts by hand to prevent flange separation and prevent the seal ring from falling off. At this point, remove the seal ring mounting rope. Install all other bolts, nuts and washers. At this stage, the nut tightening force should not exceed 10% of the preload force, and for smaller nuts hand tightening is sufficient.

7. Installation
Insert the bolt. The double-headed bolt must extend beyond the outer 2 grommets of the nut. Tighten the bolt from the point of maximum clearance to eliminate the final alignment error of the flange. (The maximum tightening force is 15% of the final preload force!) .

8. Final preload force

The operator should be a skilled and qualified mechanic. The pre-tightening procedure of the bolts must be in accordance with the requirements in the test. The tools and equipment used must be consistent with those used in the calibration test. For details on qualification and calibration, refer to the full version of the installation and assembly procedures. In the final preload operation, the nut should be tightened until it is immovable. The gap between the flanges at the wedge must be completely closed to show that the correct preload is achieved. For more information on the final bolt tightening force and torque values, refer to Table 2.

Table.2 Final bolt tightening force and torque values (1)

Specification of stud bolt	Remaining target preload (Notes 2 and 4)	Applicable tightening force, pre tightening tool (Notes 2 and 4)	Applicable torque values, torque tools
			p = 0.10	p = 0.12
Inch	kN	kN	Nm	Nm
1/2-UNC	44		84	98
5/8-UNC	71		164	192
3/4-UNC	106	134	291	341
7/8-UNC	147	186	465	544
1-UNC	193	244	697	816
1 1/-8UN	255	323	1016	1194
1 1/-8UN	325	412	1420	1671
1 3/-8UN	405	512	1918	2261
1 1/-8UN	492	623	2532	2989
1 5/-8UN	589	745	3250	3840
1 3/-8UN	693	878	4108	4859
1 7/-8UN	807	1022	5085	6020
2-8UN	929	1177	6205	7352
2 1/-8UN	1199	1519	8943	10611
2 1/-8UN	1503	1904	12348	14666
2 3/-8UN	1667	2111	14947	17768
3-8UN	2004	2539	19538	23243
3 1/-8UN	2373	3006	24982	29739
3 1/-8UN	2773	3512	31285	37262
3 3/-8UN	3204	4058	38646	46051
4-8UN	3666	4643	46987	56014

Remark:

• 1. Bolt material: A193B7, B16 and A320L7
• 2. The target minimum pre-stress is 75% of the yield stress, so a minimum of 70% pre-stress is considered unreliable during installation. Use root diameter bolts
• 3. The prestressing force on the bolt is 95% of the yield stress.
• 4. For some CL2500 and 5K, 7.5K (original CL4500i) and Rigid Interface (RI) flanges may require washers to ensure the minimum required bolt length to obtain sufficient residual preload.
• 5. The relevant reference values for L7M bolts can be found in the assembly section of the SPOCF Designer’s Manual.

Disassembly Procedure for Compact Flanges

1. Follow the standard code to relieve the pressure of the pipeline
Remember to operate with caution!
Never assume that the pipeline has been depressurized. Due to many reasons, the pipeline may be pressurized again before or during disassembly.
Refer to the relevant health and safety regulations for instructions on protective measures.

2. Start gradually loosening the bolts, in a symmetrical cross pattern, at a maximum angle of 60 degrees per step

Continue to operate in this mode until you can confirm that the seal has been broken and that the sealing ring is loose. When you feel that the seal has been released, continue to loosen the bolts and remove the necessary bolts to retract the seal ring.

The bolt tightening sequence is a cross pattern Ex 1 – Use 4 tools

The bolt tightening sequence is a cross pattern Ex 2 – Using 2 tools

Comparison of compact flange and ANSI flange

Flange sealing surface comparison

The flange sealing surface of the compact flange has an independent double sealing system, as shown in Figure 1. The root of the wedge flange face forms the first seal due to the pressure brought by the bolt preload force; the main seal is still the Ⅸ seal ring, and the sealing force mainly comes from the elastic energy of the seal ring under its own stress state. If the root of the wedge flange side seal leaks, then the pressure from inside expands in the direction of the outer diameter, thus strengthening the sealing effect.
The sealing principle of ANSI (common flange) is extremely simple, as shown in Figure 3.

• (1) The sealing surface of two flanges is sealed by squeezing the flange gasket with the tightening force of the bolt (but it is easy to lead to the destruction of the gasket).
• (2) In order to ensure the seal, the larger the poundage of the flange connection, the larger the bolt force (so the bolt nut size will be larger).
• (3) As the bolt load becomes larger, ANSI’s design is to thicken the thickness of the flange to ensure the strength of the flange (so the size of large, heavy weight).
• (4) ANSI flange can not guarantee zero leakage, it needs to be 50% of the bolt load for squeezing the gasket, and only 50% of the load for maintaining pressure (and the connection is dynamic, and such as thermal expansion and undulating cycle load will cause movement between the flange face, thus compromising the integrity of the flange, and ultimately lead to leakage).

Comparison of weight and size

(1) The compact flange of 16 inches 1500Lb with the same material and ANSI flange for comparison, as shown in Figure 3.

Figure.3 Comparison of compact flanges of the same material and ANSI flanges
By checking the standard NORSOK STANDARD L-005 and ANSIB16.5 to obtain the data shown in the figure, it can be seen that such specifications of the compact flange (NCF5) size than ANSI flange is much smaller, saving 760kg.
(2) with the same material of 28 inches 1500Lb compact flange and ANSI flange for comparison, as shown in Figure.4.

Figure.4 The same pounds of compact flange and ANSI flange comparison chart
By checking the standard NORSOK STANDARD L-005 and ANSI B16.5, it is calculated that the compact flange of this specification (NCF5) saves 3800kg than the ANSI flange.

Comparison of economic benefits

• (1) From the weight comparison between traditional ANSI flanges and compact flanges in section 2.2, it is clear that the weight advantage of compact flanges is very obvious, especially for large size and large poundage flanges, compared to the compact flanges will save 70%-80% of the mass.
• (2) For duplex stainless steel and other relatively expensive metal materials, the economic benefits of cost reduction due to mass reduction will be more significant.
• (3) As the size of the flange is reduced, the installation will be very fast and easy. This in turn reduces installation costs.
• (4) Compact flange has higher size range and higher pressure pounds than ANSI flange, which can greatly save the design cost and reduce the design risk.

The compact flange is better than the ordinary ANSI flange in terms of sealing performance, size, weight, and comprehensive cost. The use of compact flanges will increase the safety and stability of large steel structures in offshore oil projects and save the cost, which is necessary for large steel structures standing in the sea, and this paper also provides theoretical support for future flange selection.

Analysis of the application prospects of compact flanges in offshore petroleum engineering

Offshore oil engineering is a high-input, high-risk engineering field, the pipelines in large steel structures such as offshore oil platforms, FPSO, drill ships, etc. are used in a large number of flange connections, if the compact flange with small size, light weight and good sealing performance is used, it will reduce the material cost, installation labor cost and also reduce the risk of leakage. Most importantly, the weight of the entire structure will be significantly reduced.
For example, the total mass of ANSI flanges used in the Modec PB GAS Project was calculated to be 330t, but if all of them were replaced with compact flanges, it would only take about 84t, a saving of 246t.
Another typical example is the “Sinopec Puguang Project” whose economic comparison table (4″\2500LB\WN\THK14.2\Incoloy825 flange comparison), as shown in Table 1.
Table.3 Flange economy comparison table

Design Criteria	Sealing method	Flange outer diameter/mm	Flange thickness/mm	Total flange height/mm	Flange mass/kg	Unit price per kilogram (RMB/kg)	Single piece price/(RMB)	Total mass/t	Unit price/10000 yuan
ASME B16.5	RTJ	355	76.2	190	69	790	54510	50	3950
RCF (Compact Flange)	IX	248	44	95	15	1050	15750	11	1155

From Table 1, it is clear that the total weight saved by only one flange in this project is 39t, which can save 27.95 million Yuan.

How to purchase the correct compact flanges?

Are you in the market for compact 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 compact flanges to ensure that you make the right decision.
Determine the Material Needed
The first step to purchasing the correct compact 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 (RTJ), 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.
• Tongue and groove face (T&G): This type of flange face has a raised tongue on one flange and a matching groove on the other flange. The tongue fits into the groove, creating a tight seal without the need for a gasket. This type of flange face is often used in applications where high pressure and temperature are involved.
• Male and Female Face (M&F): This type of flange face is similar to the tongue and groove face. However, it has a male and female end which creates a face to face contact between two flanges. This type of flange is mainly used for low pressure and low temperature 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 Compact Flange Size and Pressure Class
Once you have identified the material and compact flange type, the next step is to determine the size and pressure class of the compact flange. compact 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.
Look for Quality and Certifications
It’s essential to ensure that the compact 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 compact 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 compact 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 compact flanges manufacturer?

Selecting the right manufacturer for compact 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 compact flanges manufacturer.
Quality of Products
The first factor to consider when selecting a compact 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 compact 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 compact 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 Guanxin to Be Your Compact Flange Supplier?

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

• High-quality products: Guanxin is committed to providing high-quality compact 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: Guanxin offers competitive pricing on its products, which means you can get high-quality compact flanges at an affordable price.
• Wide range of products: Guanxin offers a wide range of compact 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: Guanxin 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: Guanxin understands the importance of timely delivery and works hard to ensure that all orders are shipped out quickly and efficiently.

Guanxin is a reliable and trustworthy supplier of compact flanges that can meet your needs and exceed your expectations.

Export Country For Compact Flanges

MIDDLE EAST	AFRICA	NORTH AMERICA	EUROPE	ASIA	SOUTH 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
			Ireland
			Croatia
			Slovenia
			Malta