Head Depths Reference Chart - Wisconsin Stainless Heads Mfg. Inc. The radius of the dish is 80% of the diameter of the cylinder ( and "Can you provide a material finish will keep my product safe and within regulatory guidelines?" ASME 80-10 Flanged & Dished Tank Heads Sizes 14 to 240 inches in diameter. The actual shape can be approximated by a spherical radius of 0.9D and a knuckle radius of 0.17D. The full calculation set is linked below. The inside diameter (ID) ends up at 47. We fabricate ASME flanged and dished tank heads that will meet the needs of your business and your customer. Skip to content. o Dished Head Calculator - Conrex Steel or O.D. In practice the fabricator will often make the SE head from 3 radii that approximate an ellipse large in the crown, smallest at the outside diameter, with an intermediate radius in the middle. Twelve Professional Engineers on staff licensed to stamp and sign off on designs for use in all Canadian jurisdictions. Designing 80-10 Torispherical Heads rather than standard shapes can be achieved by lowering the material costs. Baker Tank Head manufactures semi-elliptical tank heads, ASME flanged and dished tank heads, ASME 10-10 flanged and dished tank heads, ASME high crown flanged and dished tank heads, flanged and conical dished tank heads, standard flanged and dished tank heads, flanges and shallow dished tank heads, flanged only tank heads, dished only tank heads, flared and dished tank heads. The ASME code design formulas for a 2:1 SE are very close to that of the cylinder in this case resulting in a required thickness of 0.4947 for the SE vs 0.500 for the cylinder. Solution: Dished Torispherical Heads with L = Di and r/L = 0.06, use equation 2.7. t = 0.885 (350) (78) / (11,200)(0.85) 0.1(350) = 2.54. ASME code heads are required in a wide range of processing industries to ensure safety and quality standards are a top priority. For the required thickness of a Non-Standard 80-10 Head, use equations 2.7 and 2.8. Tank Heads - Tank Components | Paul Mueller Company Non-ASME I.D. . The material is SA 285 Grade A. Since 1910, Boardman has been a respected custom fabricator. CHART - Head Depths CHART - Head Volume (920) 921-1899 Volume of Heads Reference Chart Volume of head does not include straight flange. Internal pressure only! Y = 2 [(15,000)(1.0) + 10,000] / 2 [(15,000)(1.0)] 10,000 =, t = R (Y1/3 1) = 18.0 (2.51/3 1) + 0,125 = 6.5 in. The radius (r) of the head equals the radius of the cylindrical part of the vessel. ). 2:1 Semi-Ellipsoidal dished heads are deeper and stronger than the more popular torispherical dished heads. The internal design pressure is 100 psi at 450F. ASME heads are available in both OD and NPS sizes and often provide an economical alternative to caps. Inside Crown Radius (L): (18.0 x 0.9Di) in; Inside Knuckle Radius (ri): (18.0 x 0.17Di) in; Material: SA-202 Gr. Fast and professional assistance from our team. What is the Difference between ANSI and ASME Flanges? r Paul Mueller Company HeadquartersMissouri, USA, Europe, Africa, Middle East:+31 (0)88-6830000. ASME Flanged and Dished Tank Head - Paul Mueller 242 To cast a little light on these subjects see the resume below: a) When t < 0.356R or P < 0.665SE - (Thin Spherical or Hemispherical Heads): A pressure vessel is built of SA-516-70 material and has an inside diameter of 96 in. Have a project in mind? 1 PDF Letco Industries Llc 851 North Belcrest; Springfield, Mo 65802 For more information about ourproducts,heavy plate&custom fabricationservices orfabrication capabilitiescontact ustoday! Tolerances comply with ASME requirements. Browse head types below for more detailed information about the tank head you're looking for. Internal pressure only! FEA Team Lead From 18 to 144 inches in diameter. Dish Radius = 1/2 Head Inside Diameter. < 21.3 in., use equation 2.2. This cylinder and the seams joining it to any attached heads are fully radiographed, and there is no corrosion allowance. From 14 to 260 inches in diameter. Designers are particularly cautioned about putting large nozzles in the knuckle region, SE (left) and F&D head the knuckle stresses are higher, especially in the F&D head. The inside radius in a corroded condition is equal to, R = 48 + 0.125 = 48.125 in. Tolerances comply with ASME requirements. Flanged and dished heads can be formed from carbon steel, stainless steel, and other ferrous and nonferrous metals and alloys. (In addition to tank heads, we fabricate Segmented Domes with virtually no size limitations.) The most common configurations are spherical, hemispherical, elliptical (or ellipsoidal) and torispherical shapes. It is commonly used in large diameter or high pressure applications where material savings are important. Hemispherical. 224 From 3/16 to 1-3/8 inches thick. The manufacturing of such an end is easier than that of a hemisphere. Calculate the required wall thickness or the maximum allowed working pressure of an ASME VIII-1 Flanged and Dished Head. Engineering Technologist The sizes of these projects are up to 200 in length, 350 tons, 16 diameter and 4 thick. Let's get started, Privacy Policy | The hemi heads will not change. ASME code heads are required in a wide range of processing industries to ensure safety and quality standards are a top priority. Digital E-Star HiPerForm EVC Refrigeration Unit, HiPerForm III with Robotic Interface Control, Air-Cooled Refrigeration Unit for Remote Condenser, Temp-Plate Inflated Heat Transfer Surfaces, Heat Transfer Manufacturer Representative Locator, Temp-Plate Inflated Heat Transfer Surface, Stamped Dimple Jacket Heat Transfer Surface, Tank Volume Calculator/ 3D Model Generator. r The knuckle has a toroidal shape. These ends, which in upright vessels are the bottom and the top, use less space than a hemisphere (which is the ideal form for pressure containments) while requiring only a slightly thicker wall. ASME 80-10 Flanged & Dished Tank Heads Sizes 14 to 240 inches in diameter. The VIII-1 formulation for 2:1 SE heads results in required thicknesses equal to that of the shell. Standard Flanged and Dished Head (F&D Head) - TCI or O.D. Tank Head Information Fort Worth F&D Head Company The discontinuity zone shows the highest stresses (thin shell beside the transition). Sizes 14 to 300 inches in diameter. Finding the right equipment that fits within your budget can be daunting. Assume joint efficiency E = 0.85. 2 Ben Vanderloo, P.Eng. D In the next issue we will discuss more ASME Section VIII Code, Source: ASME International Boiler & Pressure Vessel Code. D Products - Brighton Tru-Edge Cold-form Tank Head Manufacturers From solar milk coolers in rural Africa, to lifesaving medical technology we are making an impact across the globe. This is presented to you as a service from BOARDMAN, LLC located in Oklahoma City, Oklahoma. F&D Head Design Tool - Pressure Vessel Engineering [emailprotected] endobj Canadian Registration Number (CRN) We are Canadas largest independent registrar of fittings, vessels and piping under the CRN program registering for more than a thousand customers. V[P2W@=z7\ZKWe2En F&D heads are known to be safe, but if the heads were invented today, the required thickness for some would be higher. The required thickness of 2:1 heads with pressure on the concave side is given below: Example 14 - Elliptical or Ellipsoidal Heads, or, Semi-Elliptical or Semi-Ellipsoidal Heads 2:1: Calculate a semi-elliptical head thickness considering the dimensions given below: t = PD / 2se - 0.2p + corrosion allowance, t = 200 x 18.0 + 0.010 / 2(20,000)(0.85) 0.2(200). 4.1.5.1 Design Thickness. Springfield, Missouri 65803, 2000 North Alliance Avenue Springfield, MO 65803, Material Thicknesses available from 14 gauge 1/2 Plate (diameter dependent). Sizes 6-5/8 to 192 inches in diameter. Our contact information is to the right. We are proud to partner with tank fabrication companies all around North America to help continue the legacy of quality stainless steel manufacturing in the industry. Download the Compress ASME calculation set for the four heads and cylindrical shell. Not all input dimensions are suitable for manufacturing. A0?3_3Edc 3\23epy}*ydc5JcSy[6SBFmfD;0; w$jpY_;Bh5Ad4ak3['W9t:c+D,WFc1#)f7y5c-Cp>x4PN\C(]`wW RrG/:lc7"QTus#FA Hu+4FJerQbb1r Thus, as 9975 psi < 10,000 psi, use equation 2.3. Knuckle Radius = N/A. ASME Dimensional Standards - The Piping Engineering World Paul Mueller Company can provide a wide range of custom tank heads with custom polishing, beveling, inspection, heat transfer, and other options. B (Room Temperature); Head Longitudinal Joint Efficiency: 0.85; IKR Inside Knuckle Radius (At least 60% of diameter if code Typically 3 x THK if non code), Typical Thin Out Allowance and under add 0.03125 to the minimum thickness, Over Add 0.0625 to the minimum thickness. ASME 80/10 Flanged & Dished Head - Tank Components If dimensions are not especially critical, just specify an F&D head, a minimum tank volume, and let the fabricators work it out. "Brighton Tru-Edge asme-flanged-dished", " : Login to the site", https://en.wikipedia.org/w/index.php?title=Head_(vessel)&oldid=1067001016, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 21 January 2022, at 05:53. or O.D. Flanged and dished heads can be formed in a size range from 4 inches to 300 inches diameter and in thickness range of 1/8 in. Attract and retain customers by providing superior tank components, focusing on our commitment to building mutually beneficial partnerships. ASME F&D head[edit] Commonly used for ASMEpressure vessels, these torispherical heads have a crown radius equal to the outside diameter of the head (r1=Do{\displaystyle r_{1}=Do}), and a knuckle radius equal to 6% of the outside diameter (r2=0.06Do{\displaystyle r_{2}=0.06\times Do}). ). 2 Tolerances comply with ASME requirements. Standard Flanged & Dished Bottom dimensions - Eng-Tips Forums With a 47 ID, the required wall thickness is 0.2474, about half the thickness of the shell. Language links are at the top of the page across from the title. Fort Worth, Texas 76177, Toll Free: 866-232-8030 PDF Stainless Steel Heads and Caps - alaskancopper.com All available polished Inside/Outside from 80 Grit to 320 Grit (5-10 Ra). ASME UG-32 (e) I.D. Heads manufactured as Inside Diameter (ID) or Outside Diameter (OD). Review Engineer o Special tolerances, trimming or machining can be supplied as required. Without the straight flange. We specialize in the fabrication ofstainless steel,aluminum, andcarbon steel tank headsfor many different industries. 2 We work to many ASME standards to design and validate pressure vessels, boiler, fittings and piping systems. Ferrous Pipe Plugs, Bushings, and Locknuts With Pipe Threads. Pressure Vessel Design Tools - Pressure Vessel Engineering Heat treatment may be required after cold forming, but not for heads formed by hot forming.[7]. Diameters available from 9 - 120. Types of dished heads - Fondeyur The shape of this head is more economical, because the height of the head is just a fraction of the diameter. 0.8 Available for next day shipment, Brighton's stainless stock heads range from 6.625"OD to 36"OD in the 2:1 Elliptical and 12"OD to 36"OD in the ASME Flanged & Dished. Here is a comprehensive list of such piping dimensional standards. b) When t > 0.356R or P > 0.665SE (Thick Spherical or Hemispherical Heads): Calculate the required hemispherical head thickness of an accumulator with a design pressure of P = 10,000 psi, R = 18.0 in, S = 15,000 psi, and E = 1.0. {\displaystyle r_{2}=0.154\times Do} Phone: 817-232-8030, document.write(new Date().getFullYear()); Baker Tankhead, Incorporated Email: [emailprotected]Phone: 519-880-9808, Pressure Vessel Engineering Ltd.120 Randall Drive, Suite BWaterloo, Ontario, CanadaN2V 1C6, How Permissible Cycle Life (or Fatigue Life) is Calculated using FEA, The Nuts and Bolts of Stress Linearization, Heat Exchanger FEA with Thermal Loads Sample, Sample Seismic Analysis of a Propane Storage Sphere, Tower with Wind, Seismic and Vacuum Loads, Comparison Between Head Types: Hemi, SE, F&D and Flat, Screenshots of Pipe Stress Analysis In Action, Design Optimization with Pipe Stress Analysis, Thermal Design of Shell and Tube Heat Exchanger and Mean Metal Temperatures Calculation, Waste Heat Recovery Shell and Tube Heat Exchangers For Gas Turbine, Compress, PV Elite, DesignCalcs and our own in-house software, ASME VIII-1, VIII-2, I, IV, B31.1, B31.3, B31.5, Pressure, thermal, wind and seismic load analysis, Analysis to many piping codes including B31.1 and B31.5, Design, review and registration with P.E. . * Volume (US gal) V=.000263 D3 These thinner heads will have more rotation at the head to shell junction requiring the designer to give this area much deserved attention. or O.D. r * Volume (US gal) V = .000586 D3 These heads have a dish with a fixed radius (r1), the size of which depends on the type of torispherical head. These torispherical heads have a crown radius equal to 100% of the outside diameter of the head, and a knuckle radius approximately equal to 5 . The stainless steel plate thickness can be up to a half inch. ASME Flanged and Dished Heads ALASKAN Formed shape conforms to the requirements of the ASME Code for torispherical heads. Mechanical Engineer However, the cost is offset by a potential reduction in the specified thickness due to the dished head having greater overall strength and resistance to pressure. I.D. Von Mises stress in the cylinder and hemi head the cylinder stress is now 12% below the VIII-1 code. {\displaystyle r_{1}=Do} {\displaystyle r_{2}=0.06\times Do} At Paul Mueller Company, we understand your needs. As FEA methods from VIII-2 part 5 gradually replace code rules as found in VIII-1 and VIII-2 part 4, reduced cylindrical thicknesses will be seen. or O.D. A.S.M.E. Tank Heads | Standard tankhead * Volume (US gal) V=.000346 D3 <>/XObject<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Corrosion allowance is 0.125 in. The F&D head, even with its thicker construction, has much higher stress in the knuckle region. The tight knuckle radius results in high forming stresses in this case post forming heat treatment (stress relief) is required. While tank head details like style, dimensions, and polish requirements typically come from your customer, you often offer guidance that can only come from an experienced vessel fabricator. ). FLANGED AND DISHED AMay be subject to minimum 3x nominal thickness B2:1 elliptical head finished inside depth (not including straight flange) to be 25% of inside diameter. 0.06 If it holds liquid, we can help, to the tune of 1800 heads a month. Tank heads are a critical piece of your tank fabrication, whether it's ASME flanged and dished, 2:1 elliptical, standard flanged and dished only, or any other style. Many stainless steel tank fabricators are asked to build ASME pressure vessels every day. 519-880-9808 Ext. The ASME design code does not allow the knuckle radius to be any less than 6% of the outside diameter.[4]. Thickness: 10 GA - up to 1-1/4 NOM. Also calculates the volume and weight. 2:1 elliptical flanged and dished heads are ASME compliant. We stock stainless steel heads in both ASME 2:1 Elliptical and ASME Flanged & Dished styles. From 3/16 to 1-3/8 inches thick. Flanged & Dished Heads. Vessel dished ends can also be welded together from smaller pieces. ASME F&D Tank Volume Calculator - NearlyFreeSpeech The inside radius (L) of an 80-10 is 0.8 Di and the knuckle radius (ri) is 10% of the head diameter. @b|2Hs,q[8m%J%+-J,Irzutqr> ''nGh+I0Ud1vv ! From 24 to 240 inches in diameter. (the width of the head is 4x the head depth). Stock Tank Heads - Brighton Tru-Edge Tank Head Manufacturers ( D = ID in inches ). o VIII-1 nozzle reinforcement rules account for this requiring more reinforcement in the knuckle region. endobj Corrosion allowance is 0.125 in. We fabricate ASME flanged and dished tank heads that will meet the needs of your business . FEA results are required to be done to VIII-2 methods, including the use of von-Mises stress reporting, however VIII-1 stress equations that are derivable are done to Tresca methods. Code rules also exist allowing a two radius crown and knuckle which would normally be considered as a F&D head, to be considered a SE head if special values are used (Ug-32(c):An acceptable approximation of a 2:1 ellipsoidal head isone with a knuckle radius of 0.17D and a spherical radiusof 0.90D.). Stress Intensity (P1-P3) in a Cylinder and Hemi Head equaling the code design target stresses. The dish has a radius that equals the diameter of the cylinder it is attached to ( Thats why we offer Leasing options that give you more flexibility. Home - B & W Heads Weight calculation is theoretical, based on Carbon steel material, which may not be same as actual head weight. When calculated by FEA using a Tresca formulation, the stress is 20,484 psi Tresca or Stress Intensity P1-P3. 80:10 Flanged & Dished. The hemi head is the most efficient, containing the pressure in pure tension. From solar milk coolers in rural Africa, to lifesaving medical technology we are making an impact across the globe. D ASME Flanged and Dished Tank Head - Paul Mueller The calculated pressure 460 psi is < 0.665SE (9213 psi); therefore, equation 2.2 is acceptable. Paul Mueller Company tank heads are made to fit your fabrication processes. The designer will get a thinner cylindrical shell when designing to VIII-2 part 5 than VIII-2 part 4. We are proud to partner with tank fabrication companies all around North America to help continue the legacy of quality stainless steel manufacturing in the industry. i=X|&hf(Yv;5dnG3J) *b9l?YwrIhqC'W nx36d0' Shallow heads, commonly referred to as flanged and dished heads (F&D heads), are according to paragraph UG-32 (e), with a spherical radius L of 1.0D and a knuckle radius r of 0.06D. These heads have a crown radius of 80% of outside diameter, and a knuckle radius of 10% of outside diameter. Standard . Pipe Stress AnalysisPipe stress analysis is mandatory for British Columbia registration and it is recommended practice for many other systems. Tolerances comply with ASME requirements. mvPfc2|JP3OiM.ncP@t 24J_X;(gXL=84}f ! *4? 4 0 obj VIII-2 has rules for the design of cylinders which match the Tresca stress methods, however, VIII-2 allow the use of Part 5 FEA rules to replace Part 4 design rules. Maximize your time with online documentation downloads and an expert sales team that knows your needs. All heads manufactured from Stainless Steel, Aluminum, Copper, and exotic alloys such as Hastelloy, AL6XN, Duplex 2205, and Inconel. Tolerances comply with ASME EG 32 (d). This is also called an elliptical head. Need help? Non-ASME I.D. ASME UG-32 (e) I.D. Knuckle Radius = 10% of Head Diameter. Standard and intermediate sizes between 14 to 248 inches in diameter. The solution to the integral is complicated and is provided courtesy of online integration solvers. The ASME Section VIII - Division 1 determines the rules for dished heads. ASME flanged & dished heads are available in diameters ranging from 4-1/2 to 168; material thickness ranges from 3/16 to 1. ), hence its alternative designation "decimal head". Since P > 0.665SE = P > 9975 psi. From 12 gauge to 5/16 inches thick. Pouring a flat concrete floor in SE or F&D heads. Since P > 0.665SE = P > 11,305 psi. Calculate the required wall thickness or the maximum allowed working pressure of an ASME VIII-1 Flanged and Dished Head. Need help? 228. Determine the design pressure if the allowable stress is 16,300 psi. SF Circumferences IDD KR IDD KR IDD KR 24 4 5/16 2 4 5/16 2 3 7/16 2 1/2 6 - 3 13/32 26 4 5/8 2 4 5/8 2 3 A flat plate with tie rods or rings connected to the SE or F&D head it is mounted in. [3] The transition between the cylinder and the dish is called the knuckle. The commonly used semi-ellipsoidal head has a ratio of base radius to depth of 2:1 (shown below). With these dimensions, MARKS can manufacture a flanged and dished head for almost every need. The dish radius is approximately 90% of the diameter and the knuckle radius is approximately 17% of the diameter. Qualification Highlights, Evan Habermehl, B.A. Standard and intermediate sizes 12 to 275 inches in diameter can be readily supplies. From 3/16 to 1-3/8 inches thick. The diagrams show the basic shape of the semi-elliptical and flanged & dished heads along with the dimensional data required for Clark . This calculator page is provided for your convenience. 2 0 obj The radius of the knuckle is ( The actual stress in the SE head is higher in the knuckle region and equal to the design stress in the crown. ). This website or its third-party tools process personal data.In case of sale of your personal information, you may opt out by using the link. A cylindrical shell made of 0.500 inch thick Sa-516 70 material (rated to 20,000 psi at 100F) is rolled to 48 OD. I.D. HEAD THICKNESS STANDARD STRAIGHT FLANGE MINIMUM STRAIGHT FLANGE 12 gauge or less 11 2 10 gauge or greater 11 212 If the standard straight flange length must be held, please notify your salesperson of the requirement prior to fabrication and Paul Mueller Company will apply a tolerance of 1 The stress is higher in the discontinuity zone of the head to shell junction (23,060 psi). D ASME F&D Head Capabilities MARKS produces domed tank heads up to 120" in diameter. However, VIII-2 changed from using Tresca (P1-P3 stress) to von Mises formulation. The remainder of this article uses von Mises reported stress. ASME UG-32 (h). Many stainless steel tank fabricators are asked to build ASME pressure vessels every day. * Volume (US gal) V=.000488 D3 Dish Radius is equal to 100% of Diameter. Metallic Gaskets for Pipe Flanges: Ring-Joint, Spiral-Wound, and . No corrosion allowance is stated to the design pressure. nozzle reinforcement configuration) in lieu of the design-by-rules in Part 4 for any geometry or loading conditions (see 4.1.5.1). D We offer our products in the following materials: Carbon Steel: SA36, SA516-70, SA387 Grade 5 Class 2 (Forming Only), SA285 Grade C (Forming Only) Stainless Steel: SA240T304/304L, SA240T316/316L, SA240T304H (Forming Only), SA240T904/904L (Forming Only) We have experience designing thousands of vessels and fittings to multiple codes. Many, Inspected for compliance by an ASME authorized inspector, Digital E-Star HiPerForm EVC Refrigeration Unit, HiPerForm III with Robotic Interface Control, Air-Cooled Refrigeration Unit for Remote Condenser, Temp-Plate Inflated Heat Transfer Surfaces, Heat Transfer Manufacturer Representative Locator, Temp-Plate Inflated Heat Transfer Surface, Stamped Dimple Jacket Heat Transfer Surface, Tank Volume Calculator/ 3D Model Generator, Polishing for sanitary applications and aesthetics, Built to match your production processes and techniques, Useful for moderate to high-pressure applications, Bevel, taper, and landing zone weld preparation available, Assembly with heat transfer can be provided, MTRs and other quality documents available. Flanged and dished heads can be formed in a size range from 4 inches to 300 inches diameter and in thickness range of 1/8 in. This custom profile is not a ASME standard but serves beverage tank needs well. Diameters 14" to 180"Thicknesses 14 ga to 1/2" ELLIPITICAL FLANGED AND DISHED HEADS variety of sizes availableThicknesses 12 ga to 8 ga0.190" to 0.250" for aluminum DISHED ONLY HEADS Diameters 10" to 162"Thicknesses 18 ga to 1/2" FLANGED & REVERSE DISHED HEADS Diameters 24" to 152"Thicknesses 14 ga to 1/4" CONICAL HEADS Usually a hemi head cannot be formed from a flat sheet, instead it is made from welded pieces, making this, the thinnest head, sometimes the most expensive. = stamping for all provinces, Specific knowledge of what needs registration and what is exempt by province. ASME Conical Heads Dished Only Flanged Only Flanged & Flued Flanged and Reversed Dished Edge Prepped Trimmed Untrimmed Beveled Tapered Diameter 6 5/8 to 220 in Thickness 3/16 to 1 1/4 in Material SA516-70 Carbon Steel Clad Steel High Strength Low Alloy Steel Titanium* Stainless Steel Stainless-Clad Steel Alloy Steels Aluminum* Form As-Rolled Finite Element Analysis (FEA) We use FEA to design and validate fittings and vessels that cannot be designed by rule-based codes like VIII-1 or B31.3. Finite Element Analysis (FEA)We use FEA to design and validate fittings and vessels that cannot be designed by rule-based codes like VIII-1 or B31.3. ASME Flanged & Dished Tank Heads Standard and intermediate sizes 14 to 250 inches. Knuckle Radius is equal to 6% (minimum) of Diameter. Alternatively, the design thickness may be established using the design-by-analysis procedures in Part 5, even if this thickness is less than that established using Part 4 design-by-rule methods. Stock heads are offered in SA240 304/304L dual-certified and SA240 316/316L dual-certified, and they are . The required thickness of the Conical or Toriconical Head (knuckle radius > 6% OD) shall be determined by formula using internal diameter of shell, 30. The Semi Elliptical head has an elliptical form the most common ratio is 2:1 or the width of the ellipse is twice the depth. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. TANGENT LINE: The tangent line describes the point on the head where the knuckle radius meets the straight flange. ASME Section VIII Div.1 for further detail. or O.D. ASME Flanged & Dished Head - Tank Components Industries