Document JN9X9847qgo2qKZzMVzMKj3dX

SPIRAL WOUND GASKETS DESIGN CRITERIA COy*lQHT 1M2. n.gXlTAU.(C OASKCT CO INC. 02/09/9? 15:27 COBLENCE & NPRNER - 21S S9E 27^1 NO.S39 003 SPIRAL WOUND GASKETS DESIGN CRITERIA CO*VIGHT 19*2. ngXlTAlUC GaSKt CO INC. INTRODUCTION This paper has been prepared as the result of many requests received from design engineers, users and others for more detailed information on the design and use of FLEXITaLLIC spiral-wound gaskets. The concept of spiral-wound gasket construction was originated in 1912 by the FLEXITaLLIC GASKET COMPANY. With the introduction of FLEXITALLIC gaskets, a new era in safe, effective sealing of joints was inaugurated. The versatility of this design concept is now attested by the wide range of successful applications, ranging from extremely high vacuums to pressures in excess of present flange standards of 2500 psi and from cryogenic temperatures to beyond 2000s F and against virtually every known corrosive media. The FLEXITaL LIC design has not on.iy kept pace with modern trends, but has been constantly in advance of such progress 'hat combines materials and construction techniques which result in effective sealing that could not be achieved by any other known type of gasket. Since 1912. the FLEXITALLIC GASKET COM PANY has had a record of steady growth and today is the iargest organization in the world that exists solely to produce a spiral-wound gasket. Our entire efforts are directed toward producing for our customers, the highest quality and the most reliable gasket at competitive prices. TABLE OF CONTENTS __ __ Page introduction___ - .........->" fi ....................................................... *......................................... 2 What A Flexltalllc Gasket is ..w......................... ....................................................... ................ . 3 How Pie*itallie'QasPgS Are MWhfactured ................................................... .......................... 3 StyiM<0f Fiexitauic. (gaskets .. ............ ....................................................................................3. 4. 5 Criteria For Materials in Gasket .Construction ............................................... .......................... ....... 5 Metal* ........................................ "......................... j............................................................................ S. S Filler Materials...................................................................................................................................... 6. 7 Gasket Sizes and Manufacturing Tolerances ....................................................................................... 7 Sizing Spiral-Wound Components......................................................................................................... 8 Basic Gasket Design Factors.................................................................................................................. 9 Gasket Compression Characteristics..................................................................................................... 9 Gasket Density........................................................................................................................................ 9 Flange Surface Finish............................................................................................................................ 10 ASME Boiler and Pressure Vessel Code Calculations .................................................................10. if Flange Design........................................................................................................................................ '2 Information *or Special Flange Designs.............................................................................................. '2 Boiting-Up Procedures..................................................................................................................... 13. 14 Bolt Tensioning ..................................................................................................................................... 14 Conclusion.............................................................................................................................................. 14 List of Tables and Sketches: Table 1. Gasket Sizing Limitations................................................................................................ 7 Table 11. Gasket Manufacturing Tolerances ................................................................................. 7 Table III. Metal Ring Sizing Limitations........................................................................................ 8 Table IV. Gasket Seating Stresses.................................................................................................11 Ust of Charts and Sketches: Chan 1. Gasket Compression Characteristics............................................................................... 9 Sketch 1. Bolting-up Sequence .................................................................................................. 1* Chan 2. Torque Data with Various Bolts.................................................................................... IS Appendix. Corrosives wnicn induce intergranular Corrosion <n Austenitic Stainless Steel..................... 15 I 2 32/09/97 15: 2P CGBLENCE NC.639 004 WHAT IS A FLEXITALLIC GASKET Gaskets are essentially a packing designed for inclusion between rigid parts of a fluid container in an essentially stationary relationship. A FLEXITALLIC gasket consists of laminated, preformed metal strips and filler materials selected to meet the conditions of service required. Its construction provides inherent resilience enabling it to follow flange movement within reasonable limits. Unfortunately, gaskets are all too often simply accepted per se. that is. "iust another gasket." The irony of this is that one of the most costly and serious industrial problems today is leaky joints resulting in explosions, fires, loss of production and soaring maintenance costs. Much of this is due to insufficient attention to the proper application and design of closures and the gaskets that are used to effect the seal. The FLEXITALLIC gasket is not "just another gasket." It is a specifically engineered product in the FLEXITALLIC program of continuous research and development in gasket design and production control to give you assurance of quality and safety. It is our objective in the preparation of this bulletin to help prevent, through greater knowledge of the FLEXI TALLIC gasket, the serious and cosily waste of time, money and resources resulting from joint leakage. We trust the information contained herein will prove worthwhile and will benefit the equipment manuiacturer. design engineer, and the user in sealing closures, whether high or icw pressure, high or iow temperature, and regardless of the nature of the corrosive media to be sealed. HOW FLEXITALLIC GASKETS ARE MANUFACTURED A FLEXITALLIC gasket is manufactured by spirally winding a preformed metal strip and a filler on the outer periphery of metal winding mandrels. The winding man drel outside diameter forms the inner diameter of the gasket and the laminations are continually wound until the required outer diameter is attained. Normal practice is to reinforce the inner andouter diameters with several plies of metal with no soft fillers being introduced. Our method of manufacture itududes custom designed devices which provide control of gasket density that permit com pression to the operating thickness under a specified 11031 load. This engineered product is thus "tailor made" to be compatible with the flanged closure in which it is to be used. For example, a closure designed for vacuum service may require a gasket of exactly the same dimensions as a closure designed for 1500 psi service. The closure design ed for the vacuum service would have relatively light bolting indicating the necessity for a soft gasket, while the i 500 psi application would have heavy bolting indicating relatively dense gasket. It is usually within our capa bility to satisfy both requirements. Refer to paragraph on "Flange Design for Flexuallic Gaskets." AVAILABLE STYLES OF FLEXITALLIC GASKETS SSsISs> I. Style R -- This designates a round spiral-wound gasket with no accessory devices added. The notations. Ri. R3. and R4 in our catalog, apply to our standard gaskets only, so indicated for use on standard flanges, if a Style R gasket is to be used on a special flange design (other than ANSI or BS flange specification), the gasket ts usually termed a Special Style R. 3. Style CG -- A Style CG gasket is a round spiral-wound gasket with a solid metal or spiral-wound outer ring forming a complete assembly. A solid metal outer ring serves as a compression stop, anti-blowout device, and to properiy center the gasket on the flange. A spiral-wound outer ring serves mainly as a centering device, and is normally specified where there is insufficient room for a solid ring. :. Style R1R -- This isa round spiral-wound gasket fitted with an inner metal ring used to provide inner confine ment to the gasket, to act as a compression stop if of the proper thickness, and to be used to fill the annular space between the flange bore and the gasket !.D. to minimize turbulence of process fluids and erosion of flange faces. 4. Style CGI -- This designates a CG gasket as above with the addition of an inner metal ring. The inner ring thickness is normally the same as the outer ring and serves to prevent material build-up between the flange bore and ihe gasket I D., as a protection against excessive 3 02/09/97 15:28 COBLtNCE & 'jpzkzp. NO.639 neat, to reduce process fluid turbulence and to minimize erosion of flange facings. Style CG! gaskets are frequently used on vacuum service and for PTFE gaskets. This style eliminates costly machintngin one of the flange faces if a totally contained gasket is required. A Style CGI gasket will effectively provide a totally contained gasket without the additional costly machining. 5. Style CG-RJ -- This style designates a Special CG gasket sized to be used on standard ring joint flanges as noted in our catalog. The outer ring is dimensioned to cover the ring jotnt grooves and to prevent the spiralwound portion from entering the groove. The spiralwound portion of the gasket is sized to fit between the flange bore and the ring joint groove. This type of gasket should be used only as a maintenance repair item, ff FLEXITaLUC gaskets are to be used in new construc tion. it is advisable to use standard raised face flanges and our Style CG gaskets. 6. Style D -- This consists of a spirai-wound gasket w ;h loops (usually 2) added to the O-D. of the gasket and dimensioned to fit over two diametrically opposite flange bolts for centering purposes. Style D gaskets are not generally recommended for use in applications where pressures are in excess of 600 psi. It is not as widely used or as popular as the Style CG gasket, with its outer metal ring functioning as a centering, anti-blowout device as well as a compression stop. The Style D gasket dees lend itself to ease of assembly in areas ofcongested piping plus the fact that the standard Style D's are less expensive than the CG for the equivalent size and pressure rating. When Style D gaskets are required and are not standard catalog items, special winding mandrels must be purchased. It should be noted, the spiral-wound portion of the Style D gasket is identical to the spiral-wound portion of a Style CG gasket in the same size and pressure series. Please note Style T gaskets rely on internal pressure in the boiler to properly seat the gasket. This means, when a hydrostatic test is performed on the gasket, the pressure exerted against the plate will further compress the gasket -- and it is necessary to tighten each nut to compensate for the additional compression of the gasket under load. STSaiCvtSiOEO OVAL 0IAMQN0 ?A* 3. Style M & MC -- These styles are designed for boiler manhole cover assemblies. They are usually of round, obround or oval shape, depending, of course, upon the manhole piate configuration. Style MC gaskets have a preformed spiral-wound centering ring snapped into the inner groove of the gasket proper. This centering guide re-mits the gasket to assume its correct position and to compensate for inequalities in plhte contours and fillets in ccid-pressed plates as well as to prevent shouldering and pir.chir.g caused by radial misplacement. 9 Style HE -- Style HE gaskets are for heat exchangers where pass ribs are required. The outer portion is of standard spiral-wound construction, whereas the rib portion is normally of single, or double-jacketed style, securely fastened to the l.D. of the spirai-wound portion. 7. Style T -- This designates gaskets lor boiler handhole and tube cap assemblies. They are available in round, oval, ubround. square, pear and diamond shapes. Refer to our general catalog for standard Style T gaskets. 10; Stefe HE-CG -- This style is identical to the Style H E above, except that it is fitted with an outer ring on the O D. Not* -- Sivle HE Style HE-CG gaskets have a primary seal of vjwa'-wouna construction with its inherent resiliency ond excellent selling -quality <U necea^ry that dimensional drawings locating the pa>> nbs jr.J the configurations be submitted for al* inqu.no and orders or these style gas Hen 02^09/97 15:29 COELcNCE & ijcctsjc?? - NO. S39 D06 11 Style HX* -- Style HX gaskets are suitable for standard heat exchanger flanges designed in accordance with BS 3274 and TEMA standards. The primary seal is a spiral-wound gasket construction which is fitted with a stainless steel outer wound guide so as to correctly locate the gasket m the flange recess. An inner compression stop ring is fitted and for the tubeplaie to channel connection, a compressed asbestos fiber insert with pass partition bars is incorporated. Where working conditions demand it. the compressed asbestos fiber insert can be dispensed with and the pass partition bars can be supplied in metal asbestos or solid metal as part of the inner compression Stop ring. Now -- Submil application to Engineering Depsrirr.tr.i 12. Style 625 -- Similar to Style R gaskets, exceot original thickness vs .0625'. Limited to small diameters I' =3 and narrow flange widths. Most frequently used on clamp-type closures where an extremely thin gasket >s required. 13. Miscellaneous -- On rare occasions, applications for FLEXITALLIC gaskets arise where it is necessary ta utilize a spiral-wound inner and/or outer ring. The spiral-wound inner or outer rings are used primarily as centering devices and are chosen in lieu of a solid metal ring, because of lower cost or because of limited space when the use of a solid metal ring would be prohibited because of the difficulty in fabrication. to cur Ocncrai Catalog I'e r FIEXITWLUC gjsSsij j'.a.'.di'i :cr standard Ganges and common boiler fundhy.e and manheie :'-.ur.$3. CRITERIA FOR MATERIALS USED IN GASKET CONSTRUCTION The selection of materials of construction, for FLEXITaLLIC gaskets requires consideration of the following aspects: 1. The corrosive nature and concentration of the fluid to be confined. 2. The operating temperature. 3. The expected life of the installation. 4. The relative cost of alternative materials. Specific recommendations for materials of construc tion are beyond the scope of this paper. The resistance to corrosive attack by the various materials used in FLEXITALLIC gaskets fluctuates widely, depending upon the concentration of the corrosive agent, presence of other contaminates and the operating variables of temperature and pressure. Lacking specific experience with the corrosive nature of any particular agent and those materials that would have sufficient corrosion resistance to the media, designers are recommended to contact the manufacturers of alloyed materials, who have available extensive information on the chemical resistiv ity of their products to various corrosive media. Another excellent source of corrosion resistance is contained in "Corrosion Data Survey" published by the Association of Corrosion Engineers. Houston. Texas. It is frequently necessary to conduct laboratory corrosive tests and or pilot plant operations in order to obtain factual and reliable information. When considering the choice of materials for FLEXI TALLIC gaskets, designers should be guided by the following general comments: I. Stress Corrosion -- FLEXITALLIC gaskets, when installed, are highly stressed, particularly in the area of the engineered wire formation, and adjacent to the flange seating surtaccs. The 18-8 stainless steels are particularly subject to stress corrosion or stress corrosion cracking w hen exposed to certain media. In such cases, alternative materials must be selected that are less susceptible to stress corrosion cracking. 2. Intergranular Corrosion -- When austenitic stainless steels are subjected to temperatures in the range of 300 to !500F carbides are precipitated along the grain boundaries. When exposed to certain chemicals, inter granular corrosion will occur. A list of corrosives which Induce intergranular corrosion are included in Anpendix A. When handling these media, special attention to matertal selection is necessary. 3. Expected Life of the Installation -- The trend in industry today is to lengthen the time between overhauls and consequently, the best possible material, regardless of initial cost, is frequently the most economical. Gaskets are relatively low cost items when compared to labor costs to install, downtime on equipment and loss of productivity, should premature failure occur Hence, for "permanent" installations, the cost of special gasketing materials should be equated against increased produc tivity and reliability. The FLEXITALLIC CASKET COMPANY maintains a substantial inventory of a wide variety of metals and filler materials to meet specific operating conditions and requirements. METAL WINDINGS The following materials are normally inventoried to insure prompt delivery: Type 304 Stainless Steel -- This 18-3 Chromium-Nickel Steel is the most common metal used in the fabrication of FLEXITALLIC gaskets. I'. has excellent corrosion S 02/0S/3? 15:29 COBLENCE & 36 3741 NO, S39 007 resistance to a wide variety of chemicals. U is. however, subject to stress corrosion cracking when exposed to certain media, and to intergranularcorrosion at tempera tures between 800 F and 1500 F in the presence of certain media. Under these conditions, alternative materials should be selected. Due to the precipitation of carbides along grain boundaries, its use is normally limited to a maximum continuous temperature of 800'' F if any danger of the materials that would cause inter granular corrosion are expected to be present. Type 347 Stainless Steel -- The addition ofcoiumbium to this 18-10 Chromium-Nickel serves to keep carbides in solution, and hence, inhibits carbide precipitation along the grain boundaries. Type 3*7 Stainless Stee' has corrosion resistant qualities comparable to Type 30`* Stainless Steel. It is not as subject to intergranular corrosion as is Type 30* Stainless Steel, and can be used at continuous temperatures up to the 1*00 -- 1500 F range. Type 3*7 is subject to stress corrosion cracking, however, as is Type 30*. Type 316L Stainless Steel -- The 2% molybdenum added to this 18-12 Chromium-Nickel alloy increases its creep strength at elevated temperatures. Carbon content is held at a maximum of .03% which inhibits the tendency toward carbide precipitation. Type 3I6L is subject to stress corrosion cracking and also to intergranular corrosion, but to a lesser degree than Type 30* Stainless Steel. Its continuous maximum temperature exposure would be in the range of 1*00 -- 1500 F. Type 321 Stainless Steel -- This austenitic CSromeNickel. Steel is stabilized by the addition of Titanium, thereby eliminating carbide precipitation and conse quently intergranular corrosion. The higher chromium content of this grade givey impVcved-dkidailon resistance and so it can be used at temperatures' up to' MOO -- 1500* F. Type 3<ML Stainless Steel -- This 18-8 stainless steel alloy has the same excellent corrosion resistance as does Type 30*. but its carbon concent is maintained at a maximum of .03$, which tends to reduce the precipitation of carbides along grain boundaries, and as a consequence, would be less subject to intergranular corrosion than is the Type 304 stainless steel. U is. however, subject to stress corrosion cracking. Plated Low Carbon Steel -- In FLEXITALLIC gasket construction, the use of this metal is normally limited to low pressure steam applications at maximum tempera tures in the range of 500* F. Monel Metal -- This Nickel base alloy contains 67% Nickel and 30% Copper. It is widely used as a gasketing material due to its excellent resistance to most acids and alkalis, except the strong oxidizing acids. In combination with PTFE. it is widely used in FLEXITALLIC gaskets for hydrofluoric acid service. Maximum upper tempera ture limit for Monel metal is in the range of 1500 F. Monel metal is subject to stress corrosion cracking when exposed to fluorosilic acid, mercuric-chloride and mercury, and should not be used with these media. Inconel 600 -- This metal is a Nickel base alloy containing 77% Nickel. 15% chromium and 7% iron it has excellent high temperature strength and can be used at temperatures up to the 2000 F range. Inconel 600 has little tendency ioward stress corrosion cracking and is frequently used as a gasketing material to overcome this problem. OTHER METALS AVAILABLE MATERIAL MAX, TEMPERATURE* *30 S.S................... Carpenter 20.......... 1*00, i500e F 1*00. I500c F Phosphor Bronze .. ........ 500F Nickel..................... .... I*00F Titanium................. .... 2000 F Hastdloy C-276 4 B .... 2000s F Inconcel X............. .... 2000s F Copper................... .... 300 F 310 S.S.................... .. . . '.?C0F On special order, gaskets can be fabricated from gold, zirconium, platinum and tantalum. Maximum ;mperaiu?e ratings are based upon hoi air jt caftan! 's:np*?3iufcs. Ths presence oi contaminating 'IuhJn and cyclic condition* may drastically at'fect ihe maximum temperature range. FILLER MATERIALS 1. PLEXITF* -- A new. non-asbestos, chlorite mineral paper especially developed for use in FLEXITALLIC spiral-wound gaskets. The chlorites are a group of minerals with a layered structure, in many respects resembling the micas. The nominal composition of FLEXITE Filler (Patent Applied For) is: 90% minimum chlorite mineral. 2% -- 5% nitrile latex binder, less than 1% green dye for identification, with balance cellulose pulp. In additiorfthe paper is coated with acrylic latex and. a paraffinic wa'jir. FtEX+TE can be used at temperatures fro'm cryogenic to *I050F in steam, hydrocarbons, heat transfer fluids, alkaline solutions, solvents, aqueous and .salt solutions, fuel oil, hydraulic oil. halogens, and general service in mild acids, k is available in all sizes, styles and pressure ratings, with compressibility and recovery being equivalent to asbestos filled spiral-wound gaskets. FLEXITE Filler is tested for teachable chlorides and meets the 200 parts per million requirements for total soluble chlorides. 2. Canadian Asbestos Paper (Chrysolite) -- Canadian Asbestos Paper is the most common filler material used in the fabrication of FLEXITALLIC gaskets. Canadian Asbestos is a hydrated magnesium-silicate. The form, as we use it. is composed of approximately 90% Canadian Chrysciile Asbestos. 7% vegetable rubber latex binder and 3% water-proofing binder. This material has poor acid resistance and strong mineral acids dissolve out all magnesia, leaving a residue of nearly pure insoluble silica. It docs, however, show excellent resistance against alkaline solutions, such as sodium-hydroxide or caustic soda and can be used against solvents, aqueous and salt solutions, and gases (except oxygen). Canadian Asbestos has a very high melting point fusing at approximately 2770 F. However, it loses 11% by weight of water at 1100F and about 13 5% at l*00F. From this point to the fusion temperature, it has turned to a powder with very tittle tensile strength left. In spue of this, it can continue to produce a satisfactory sea! since u is com 6 02/09/37 15=30 COBLENCE ?, URR^ER - 216 636 3^41 NO.639 708 f r pletely confined between the metal windings of the gasket and the seating surfaces of the flange. Our standard Canadian Asbestos Paper contains . blue vegetable dye for identification purposes. This material is available without the dye added if the dossibilily of color contamination is a problem. Not= All oapet used by FLE.XITaLUC GASKET COM PANY .* tested lor Isaehable chloride* end meets ihe 100 pari* per million reijuirrmenii lor total soluble chlorides. 3. Compressed Asbestos Fiber Type Special -- This is a grade of compressed asbestos liber specially developed for use in spiral-wound gaskets. The homogeneous struc ture of the material allows it to more readily conform to the spiral-wound steel protile than conventional com pressed asbestos fiber materials. The material contains an asbestos content of 70c and a binder content of 12this being a blend of NR and SBR. The material shows good performance in steam and hydrocarbon service at high temperatures. 4. Potytetrafluoroethylene (PTFE) -- PTFE is used as a filler material in FLEXITALLIC gaskets where extreme chemical inertness is required for temperatures ranging from cryogenic to 500 F. PTFE is unaffected by any known chemicals except molten alkali metals and fluo rine precursors. Because of its low permeability. PTFE is also frequently used as a filler material on FLEXITAL LIC gaskets in vacuum applications. Gaskets wound with PTFE should be fully confined either by fitting in a groove or providing both an external and internal ring. 5 Ceramic Fiber Paper -- Consists of aluminum silicuie fiber with an organic binder. This material has excellent high temperature stability to 2300 F. It resists attack from most corrosive agents (except hydrofluoric and phosphoric acids! as well as concentrated alkalies. 6. Flexicarb -- This material is a pure pyrolytic graphite with no binder which exhibits excellent resistance to a wide variety of chemicals. Flexicarb can be used -,n the temperature range from -350CF to 90CCF m an oxidizing atmosphere and up to 6000s F in a reducing or neutrai atmosphere*. Its unique combination of iow permeability, inherent lubricity, and compressibility make Flexicarb suitable for critical gas services. Not* -- We suggest applications for oxidising atmosphere* be submitted to Engineering Deportment. 7. Other Materials -- FLEXITALLIC gaskets are also available with various compressed asbestos sheet packings utilizing Buna S. Neoprene, or Buna N as a binder for special applications. AVAILABLE GASKET SIZES AND MANUFACTURING TOLERANCES 'CTA*MN. , .. .. . r- Gasket Tbfctnesa Maximum. Iflpxmuim tnslda " Fionas OtmanMon fetam Recomflisfldad Comprasaad Thlcknesa" 0.0625" 0.0625" '' 0.100" 1 0.12S" 0.125"' 0.175" 0175"' 0.17S"' 0.175"' 0.250" 0.259" Up to 6" 1 r'te 9" 10*Up to 20" 20" to *0" Up to 40" *0" 10 60" 60" to 70" 70" to 75" 90" 185" ;r**' 1/4" <"f/2*' 1" 3/4" 1" f 7/8" 3/4" 1" 1" 0.05C'70.0SS" 0.05C"/0-055" n0.075'70.Q80" 0.090"/0.100" C.090'70 100" 0.125V0.135" 0.12SV0.135" 0.12S-70.135" 0.125-70.13S" 0.180-/0.2W 0.200-/0.230" Not* i -- Preferred x/.c rang* in relation to thickness shown in bold type. Nose 2 -- "PTFE filled FLEXITALLIC gaskets in this <i7e range are unstable and art subject 10"spongingapart"in shipping and handling. Specify next gasket thickness up. Note 3 - The recommended compressed thickness is ha: experience has indicated to he me optimum range in order to achieve maximum resiliency of the gasket. Ar adoiuonal spread of 0IC in cither direction may be tolerated on si! gasket thicknesses with the exception of the 0*25 and -re . UK)* thick gasket. This tv on the a*umpi'.on '.hjt the (lanee Nurface finishes arc relatively >mooih. Rclcr 13 "Flange Surface Finish" on page 10 When attempting to contain hard to hold fluids, or pressures above IOOO ?v. it 1* suggest ed (hat compression be maintained at the lower range uf me recommended compressed thickness. FLEXlTAiJU gskets-air available in=*Rr from 3, 8* i.D. to approximately 135' l.D. depending upon gasket thickocu. Table 1 indicates size ranges^atlabie in various tnicknessea. maximum flange- wtBtfis Jnd the recommended compressed thickness. FLEXITALLIC gaskets are subject. tQ,standard manufacturing, tolerances listed in Table II. If tighter tolerances are-required, consult our Engineering Department. TABLE II Gaskai Diameter -- tnalda Oiamatar Ou1s44* Ofsnwter t'o to 10" 10" to 24" 24" to 50" 50" & ADOvP * 1/64" i 1/32" i 3/64" i 1/16" i 1/32" i 1/16" i 1/16" - 1/16" roisMiscs on gssket thickness is plus 0.010'. minus O.OOS" (mkaiured acrotc metal winding) on all thicknesses. 7 02/09/97 COBLENCE S, NE* 7` NO. 639 509 SIZING SPIRAL-WOUND COMPONENTS FOR FLEXITALLIC GASKETS Regardless of the type of flange facing in use. FLX(TaLLIC gaskets must be sized to insure the spiraiwound element is seated against a flat surface. This is of utmost importance. If the spiral-wound element pro trudes into the flange bore or extends beyond a raised face, mechanical damage will occur to the gasket during initial compression, and ultimate failure will resuit. In addition, should the gasket protrude into the flange bore, the windings can possibly enter the process stream with severe damage to other equipment resulting. V*':th recessed flange facings, limiting dimensions of the gasket are established by dimensions of the groove. On flat or raised face flanges, considerable leeway is available. Note that due to radial growth and clearance requirements, spiral-wound gaskets are normally sized differently than other types of gaskets The following rules wili be generally applicable for. limiting dimensions of spiral- wound components. 1. Gasket confined on both l.D. & O P -- This is the type facing encountered in tongue and groove joints, and groove to Hat joints. Standard practice is to allow ; lbnominal diametrical clearance between the l.D. of the groove and the l.D. of the gasket and h 16" nominal diametrical clearance between the 0 D. of the gasket and the O.D. of the groove.* 2. Gasket confined on the O.D. only -- This is the type ot facing encountered with male and female facings and female :o-flat facingss-Standard practice is to allow 116' nominal diametrical.clearance between the O.D. of the gasket and the O.D. of the groove.* If possible, allow a minimum l/4'diamewicai clearance between the l.D. of the seating surface and the l.D. of the gasket. Not* -- l 16' nominal 0 D clearance for gaskets up io 6C' O.D.; from 60' O.D io SO* O.D.. allow 5 6a". above SO' O.D . allow 3 32' nominal 0.0. clearance. 3. Gasket unconfined on both the l.D. k O.D. -- Allow i minimum I 4" diametrical clearance between the gasket l.D. and the I D. of the seating surface. The O.D. should be kept as close as possible to the bolt circle to minimize flange bending moments. If the gasket is used with raised face flanges, allow a minimum 1: 4*diametrica! clearance between the gasket O.D. and the raised face O.D. and determine the l.D. on the basis of the desired flange width. Important -- Please note the above ruies establish general limits for sizing FLEXITALLIC gaskets, it is frequently necessary to adjust dimensions in order to achieve a proper balance between gasket area and bolt area to maintain a reasonable compressive force on the gasket and a minimum gasket factor "m" of three. Please refer to section covering AS ME Boiler and Pressure Vessel Code. 4. Metal Gauge Rings-- When Flexitallie gaskets arc required to be equipped with outer metal rings or with inner metal rings, limitations on the minimum flange widths of the solid metal ring are necessary due to the availability of machining facilities and rigidity of completed assemblies. Table 111 indicates the minimum flange width for solid metal rings based on the ring l.D. TABLE lit Olemeter o< Ring Minimum Flange Width* Uo to iC" inside Diameter 10" to 24" inside Diameter 24" to SO" Inside Ciameter SO" to 70" inside Diameter ?0" and Larger 3/8" 7/16" 1/2" 5/8" 3/4" Not* -- space : Kmue;* and r.arrf.anze width* are nccosarv. :nay be pohstfcie to au?i?K inner an*: cuter ypaecr nngi 01 mcul N?iral**ound wonsiruc.ivft Cvnvw'i our Hniireerme Depart* rr.ent i'er advice Standard practice is to size outer rings with the outside diameter equal to the diameter of the bolt circle less the diameter of one bolt for rings up to 60" O.D. Above 60* 0. D.. rings are sized to the diameter of the bolt circle less the diameter of one bolt holt. Inner rings are normallysized with an outside diameter equal to the flange bore plus 1. S'. 3. Non-Circular Gaskets -- FLEXITALLIC gaskets can be fabricated in non-circular shapes within limitations. As a genera! rule, if the ratio of the long l.D. to the short 1. D. exceeds 3 to I and should any of these sides approach a straight line, it may not be possible to manufacture . FLEXITALLIC gasket that would be suitable. Ou: product requires a definite radius or curvature to give . inherent strength and stability and to prevent it froc springing apart. Any application requiring a non-circula gasket should be submitted to our Engineering Depart meni for review to determine the feasibility of producir. a satisfactory gasket as early as possible in the desig: stage. The comments above relating to availability of sizes and recommended clearances for proper sizing of FLEXITALLIC gaskets are general in nature. Many applications will arise where the recommend ed clearances are impractical due to space limita tion on the flange. Frequently, clearances between gasket sealing member and grooves must be reduced in order to effectively maintain a seal under operating conditions, particularly when the higher pressures are encountered, Lnder such circumstan ces. FLEXITALLIC GASKET COMPANY en gineers should be consulted prior to finalizing j designs. a 02/03yg7 COELENCE i 510 BASIC GASKET DESIGN FACTORS The same basic fundamentals of FLEXITALLIC spiral-wound gasket design and construction that base been used successfully for ANSI flanges have been extended to cover a wtde range of applications in installations tor which there were no industry-wide equipment standards. When special joint assemblies are designed in which spiral-wound gaskets can be applied. FLEXITaLLIC'S variable compression characteristics and wide range of materials embodied in gasket construc tion can usually be adapted to solve ail problems related to achieving a satisfactory joint assembly. The designing of a spiral-wound gasket can be compared to the design problem of a heavy-duty spring supporting a compressive force. Both are structures engineered to withstand calculated loads and shock, in the design of any gasket, the gasket engineer must consider three factors: type of joint, bolting load and operating conditions. Type of Joint. The joint design ;s the basis for determin ing the gasket thickness as well as the inside and outside dimensions. The gasket is dimensioned so that i: is totally confined between two flat faces without any overhang and is proportioned to the joint in which a safe sea! is to be made. Bolting Load. The available compressive force is the basis for calculating the density of the gasket structure to support specific boll loading. Operating Conditions. As the basis for specifying gasket materials, consideration is given to the nature of the confined fluid, temperature and pressure of the fluid, thermal shocks, vibration, abrasion, erosion and corrosion. Selection of a suitable joint assembly is the function of the piping or pressure vessel designer. FLEXITALLIC gasket design is coordinated closely with a wide range of join: assemblies. Whether a joint assembly is designed originally for soft sheet packings or for high load values requiring harder gaskets, the proper FLEXITALLIC construction can usually be selected to meet the require ments. W hen a joint assembly is placed in service, three basic forces become active and affect iis sealing qualities. 1. End Force -- which originates wnh the pressure of confined gas es or liquids and tends to separate the flange faces. 2. Casket Load -- the function of bolting or other means which applies force upon the flange faces to compress the gasket. 3 Internal Pressure -- which tends to move, permeate or bypass the gasket. Because these forces are operating variables in any joint assembly, a gasket of resilient construction, such as the FLEXITALLIC construction, is more smtaole for the vartabie conditions than is a gasket of so 'C construc tion which cannot adjust to the varying cand.t-ons. The char; below illustrates an interesting study in gasket design. A FLEXITALLIC Style CG Gasket for use with a 6" raised face flange assembly is described. For each series considered, the gasket contact area is the same, be; the bolting varies with each series. With bolting calculated at a constant stress of 30.000* lbs. per sq. in., the resulting unit gasket loads vary. A constant terminal (hickness is retained within the elastic limits of the gasket body by designing a specific construction for each case. This is determined by FLEXITALLIC engineers. This procedure ;S of the utmost necessity (t is imperative that FLEXITALLIC engineers be furnished complete and accurate flange design data to ensure that the gasket construction Is correct. - This char; below illustrates the variable compression characteristics FLEXITA.LLIC -cam design, into their spiral-wound gaskew. with identical l.D. anc O D d'msnsions. Similar variable consTpictfOns can be- provided for most sizes andrfnaten'als.`" Stress rt JO.OOfi psi i* *e!i wuiv-n (he viciC pome el alloy bating Pui .a sometimes to or apove the yield points oi iH.H Cr. Ni and other aus'.srtilis 'tcels When yield point metal i* employee either t\ir tta.'.ttcj or soltv special gasket construction may fie necessary. (or reason. *ncn Mch metal s used. FLEXITALLIC engineer! whou'.d be consulted. GASKET DENSITY CHART NO. 1 GASKET COMPRESSION CHARACTERISTICS laMd oa Devout 0rap*4 6 CC GU# Meet A?i lelt*nq Comoc* j 7 Sever* Csikfr' Q 17 (ton o^ortiHW* v JO n'4*' <**u o' 3O.9C0 s* >1*44 The service conditions under which a FLEXITALLIC spiral-'Aouftd gasket > expected to hold us sen dictate the density ot the gasket. Gaskets that hass identical inside and outside diameters can e either hard or .ott as -.ho^n jfiove. The available compressive toree % the lorc3lcu!aimg:heden> *.v or -.hu gasket structure to suppgr; spend* bourn* loads 9 02/09/3? 15:32 COBLENCE i 'j-ES'E? - 216 S96 iwo^ NO. 639 pa FLANGE SURFACE FINISH FLEXITALLIC gaskets rely on the combined reaction of the metal and filler material to ef fect a seal. When the gasket is compressed, the filler material flout into minute imperfections and the metal serves to completely trap the filler material and provide the necessary strength and resilience to the gasket assembly. Obviously, the deeper the serrations, or the rougher the flange surface finish, the higher the force required to flow the gasket into the imperfections. Although FLEXITaLLIC gaskets may seal against virtually any commercial flange surface finish, abnormally high bolt loads may be required to obtain a seal against rough flange finishes, while excep tionally smooth surfaces may destroy the inherent resiliency of the gasket. Surface finish is one of the major factors to consider when attempting to seal a joint with a FLEXITaLLIC spiral-wound gasket! Surface finish as specified in ANSI BI6.5 (19S 11 has proven satisfactory under a wide range of service conditions. ANSI 316.5 -specifies a circular lay (either concentric or phonoaraohic) produced by a .06 minimum radius round nose tool. The resultant surface finish shall be 125 to 500 .aaRH. For difficult service conditions dictated by iow specified leak rates, light gas scaling, narrow gaskets or minimal available bolt load. FLEXITALLIC recommends tighter limits be considered. Optimum results have been obtained with a finish as described :n ANSi B16.5. wnh the resultant surface limited to the 125 to 250 AARH range. Surface finishes significantly smoother than 125 AARH can present a sealing problem. A spiral-wour.d gasket may creep or slide radially or. a smooth finish if unconfirmed by a groove or inner and outer r.rgs. Important -- L-nder no circumstances in.au.d fiance sealing surfaces be machined in a manner that tool marks would extend radially across ihe sealing surtace. Such tooi marks arc practically impossible to seal regard,ess of the type of gasketing material used. ASME BOILER AND PRESSURE VESSEL CODE CALCULATIONS Section VIII. of the ASME Boiler <& Pressure Vessel Code, establishes criteria f?r flange design and suggests values of ~m" (gasket factor) and "y" (minimum gasket seating stress) as applied to spiral-wcund gaskets. For the most part, the defined values have proven successful in actual applications. However, much confusion exists regarding these values, primarily due to a misunderstand ing of the definitions of the terms and their significance in practical applications. Mandatory. Appendix II. ip Section v;n of the Boiler Code, requires m the design of a bolted flange connec tion. complete calculations shaii be made for no separate and independent sets of conditions. determined to scat the gasket regardless of internal pressure and utilizes a formula: (2) wm, s 3.t4bC.V The *'b " in this formula is defined as the effective gasket width and "y" is defined as the minimum seating stress in psi that depeffils upon the type of gasket material. Table 'JA--19.!. Section V|M of the Boiler Code suggests a minimum "y" value for a spiral-wound gasket of 10.000 psi (Winter 1976 Addenda). These design values are suggested and-not mandatory. The term "b" is defined as: b = On when b,, 2 . wnen on ^ i a 1. Operating Conditions Condition one (I) requires a minimum load be determin ed in accordance with the following equation: (I) wm, e-liifiiL* 2b 3.l4CmP 4 This equation states the minimum required bolt load for operating conditions is the sum of the hydrostatic end force plus a residual gasket load on the contact area of the gasket times a factor times internal pressure. Stated another wav. this equation requires the minimum bolt load be such that it will maintain a residua': unit compressive load on the gasket area tha: is greater than internal pressure u-hen the total icad is reduced by the hydrostatic end force. [t should be noted that Tabie L'A-W I suggests a gasket factor "m" for a spiral-wound gasket of 2.5 for carbon steel and 3.0 for stainless or monel. It is important to note the gasket factor "m~ is suggested and is not mandatory. Not* -- See paragraph on gasket factor "m ' on page M for a more detailed discussion. 2. Casket Seating Condition two (2) requires a minimum bolt load be In the case of a spiral-wound gasket, bo1 T in all casts where \ is the radial flange width of the sciral-wound portion of the gasket. No#* -- In applications where exceeds W<n;. we <uggi; that the actual ga*kc< siting tre$* be determined as ;aicuuied in equation (5K (f Sg is less than 6COO psi. we *ygcst contacting aur technics; service department. After Wm, and Wm; are determined, the minimum required bolt area. Am is determined as follows: w Arn, = where 5() is the allowable boll stress at ODeratir.i temperature, and WfTT where Sa is the Pa allowable bolt stress at atmospheric temperature. Then Am is equal to the greater of Am, or Am:, Boitsare then selected so the actual boil area. Ab. is equal to or greater than AmAt this point, it is important to realize the gasket must be capable of carrying the entire compressive lorce applied by the bolts when prestressed unless provisions are made to utilize a compression stop m me fiange design or by the use of a compression gauge ring. For this 10 I 02/09/5? 33 COBLENCE & wfi^NES - 216 36 3741 NO.639 312 _ !v::u in T tass-sif ins 'a^UiS -either a wioer gskui'reqtS| mst be utilized." OTE -- it a D'estresa g?at*map Sgis to beuaeotaa iinoonaa grict.ce in order is successful paaa-e nycrostafie tastj ;ra - actual presses* waiue will be used >n fie? at 5*air eeweftcw i3i;: ; G A SKET_S EATING STRESS.-^,.;-.. FLEXlTA&LlCjs'Vast paSiudS fea>tdlag~i^e unreif-~^ 3jst,c of. "y'Jrai^iefined IM-49.1 has ~ Jjecr^aBPgnized by die Wi^ir 1976 AtidCnla change ter' 000 psi minimum (lohaprly *y''^.25G$5fc for tecl and "y~ = 4500 ^sineeKXOuV _e isHuvfS s .twin pskeT^Table'^^ESri be used as a^jule to "y (minimum seating stress) and Sg (actual stress). The actual seating stress is a function of flinge surface finish, gasket material, density. ihicknesijg.fluid to be sealed and allowable leak rate. Rough or irregular flange finishaja^ESjl to contain fluids and specified low allowable IgilBSQrill indicate the need for different "y" valtresiSljpBSSpl work to determine the effect of these variables is indicated and is presemly being sponsored by a sub-group of the Pressure Vessel Research Committee. Welding Research Council. work is also being done to this end oy AST.M Committee F-J and Flexitallic Gasket Compa-iv, <,, jnc "y are normally considered to be the unit load required j~_Appenfih| ~ ihe.SSilcE-Code under ''paragrapRC S3aed&`the `tiv1factor is a funettop. oCtfi'gas%t material and construction-" W*do f oot agree-cauttly with tHitinterpreution'of Vlm". Actually, the gasket docs not create any forces and can only react-to external forces--We.bcjjeve amaparealktic 'uatcompresiiVe contact area must be sur^wWewSTcompriisr/e foe ro*t||jciS^iorce." It is t0 cohtabV pressure to intern ej than unity otherwise, en. the use of a hi. ?sTgn"wuti T greater factor of safety. Experience has indicated a value of 3 for "m" is satisfactory for flanged designs utilizing FLEXITALLIC gaskets regardless of the materials of construction. In order to maintain a satisfactory ratio of gasket contact pressure to internal pressure, two points must he considered. First, the flanges must be sufficiently rigid to prevent unloading the gasket due to flange rotation when internal pressure is introduced. Secondly, the bolts must be adequately prestressed. The Boiler Code recognizes the importance of pre- itrssstng bolls sufficiently to withstand hydrostatic lest pressure. Appendix S. in the Code, discusses this problem in detail. notations as = Actual total cross-sectional root areiotbonsorseetion d least diameter under stress: sausrs incr.es. * Tow required cross-sectiontl area of Sous, taken as 9'eater ot Am,. or Am2; square menes. ni' 1 Total required cross-section jl area of Sous required lor A _ operating conditions; square menes. *: 5 rotai requirederosa-sactronal iraaol bolts reouired for s _ 9ast sealing; square inenes ^ eifeciive seating widtn; inches. - i'5in|`cor"act*surfaee pressure width: menes q - Sasic gasket seating width: inches. Diameter of location of gasket toad reaction menes m N ? Si So w w_, qc o,' Gasket factor. Radial flange width ot sstral-wound component; menes. Ces<gn pressure: ps>. Allowable boll stress ai atmospheric temperature os Aiiowso'e bon stress at eesign temoerature. osi riange design bolt load, pounds. Minimum required Bon aid tor oseratmg esnd nons. pounds. M mmum requirec Bolt isad tor gaset seating: pounds Minimum gasket seating stress: osi Actual unit stress at gasket bearng surface psi Outside diameter of gasket, inches. ms.ee diameter oi gasaet. menes 11 02/03^5? 15:34 :OBLtNC & UPRNER - 216 696 0741 FLANGE DESIGN FOR FLEXITALLIC GASKETS NO. 013 1 1. Determine the required bolt load for operating conditions W'mi. Equation (I), i Approximate gasket size by referring to Table I. and use an "m" value equal to three.) 2. Determine the required bolt ioad to effect a sea: t a:' by solving Equation (2). Use a minimum seating stress "y" per Table IV. ). Determine the minimum bolt area by dividing Vr'mi by the allowable bolt stress at operating temperature and by dividing Wm; by the allowable bolt stress at atmospheric temperature. The greater of these two vaiues becomes Am, the minimum bolt area. Select the number and size of bolts that will give an actual total cross-sectional area equal to or greater than Am. a. Substitute the larger Wm, and Wn: into the numerator of Equation i3) and soK-e tar '5;'~ If "SV'falls within the ranges showa-an Table ^5fFjXLT.\fc-~g LIC gasket can bmj8*rgBt^tqferaijij5EB&jEl9Bfe^ resulting^ is jzreareistiaahhek maaamsn-'hBggfrd ;n Tabic IV. u is necessary to provide a compression stn,, either by utilizing a ring on the inside or the outside of ;he gasket or by designing into the flange, a compression step that would bring the flanges metal to metal. 5. If W'm; 4 substantially greater than Wmi resulting ma greater bolt load than required for operating conditions it is possible to reduce wm: by reducing the flange w.dih of the gasket. If this is the case, we suggest you coma:; FLEXITALLIC engineers for recommendations as [0 minimum flange widths for the diameter and pressure temperature conditions. 6. Proceed strictly to the flange design procedures m Appendix ll of the Boiler Code. 7 After all flange dimensions have oen determir.eg. determine flange rotation at the gasket interlace a: test conditions. If the flange rotation is excessive, extraordi nary precattTons must be tauH^o insure a sat.sfactcrv rostantfFeaL .fRefecjadfiliSfecovenniz "8ohmg L? 6. Hydrostatic Test pressure 7. Initial~Vg^CtBTOTner^refereaeew.ijtflefjBatenafs-j^--- F L EXlTALLlCTtniplieieag^npSgfifiia^a^c-n o costBK"ctTtAis-i nfotmajiomjag^tfTu'?'! As *-"g*aket manufa review ay* rotation a defined u|he design eni L'Hh* atiet _ _ _ _ . ______ ___HeHaSfe-Hnritrree,*?*r t'rWrir.ige?aaitBtHiug>gin tfie" ~ "^nSsiflCshe d<5gn criteria estafc. _ lished by Ufe Siler Co3c and that theilafttf a r sufficiently rigid "Wider-the most severe condition tq.._ preclude the possibility the gasket could become1' - unloaded either during operating condifcons'ar hydefc -I*._____: viatic.test conditions. We are aware'that most flange '*7 t and wemiggest AS M E r*Ntodern Steel Bolting authored by C M. prior to finaliring^higjiesipt. JBiSifflo^of iTKitmckl ""TVogrm-. Fwnk SrflTwftteunsand John S. Worth, be necessity, must assume the bolt.material being dSeinx - -- ^cnsultdti fopguidaricein the proper sefecffSti df'bolcr.g adequate for all conditions inchidmg ^aerating pressure- ma.tertal for^Mping agd pressure vessel applications, at operating temperature and hydramatic test'pretaure at ' ` ~ " " -. ambient temperature. The~we of the.optimum m*lrjpF-" :: -*- -- ` 12 32^9/S? X5:-'t CQBLENCE a L'O^NER - 21? ?3S 3~41 NO. 639 514 BOLTING-UP PROCEDURES FLEXITALUC GASKET COMPANY supplies thousands of different gaskets for special flange designs-* that must successfully pass a hydrostatic test and maintain a satisfactory seal under operating v'Oj)jMfS.s. Our experience Has indicated that virtually overtime a leaky lomt is encountered, the actual cause relates to something other than the gasket d of these causes arc itemized below: 1. On low pressure applications, flange d followed the Code suggestions for a mmimui stress (V value) that e know from taper' impractical and hence, neither the bolting nor of the flanges are adequate to initially scat the obtain a seal. : 2. Fiange designers do not take into con; rotation of the flanges, and the necessity fo' and the bolting to maintain a sufficiently high residual unit load on the gasket contact surface to contain .nternal pressure. 3. The insistence of some inspection personnel that hydrostatic test conditions must be carried out at stress values for initial pretensioning of bolts at the allowable design stresses specii ;d in the Code. Appendix S. in the Code, specifically cot -rs this irea and must be taken into consideration anytime a hydrostatic test is to be performed. From a practical s.andpoint. when a flange is designed for pressure conditions of 600 psi and the hydrostatic test pressu e is to be performed at 900 psi: it is obvious chat a higher prestress must be applied to the bolts if a satisfactory est is to be achieved. 4. The use of low yi-.Id bolting material, such as the austenitic stainless -teels or ordinary carbon steel machine bolts. With both of these materials, it is relatively easy to stress the bolts beyond their yield point with eventual failure occuring using a standard wrench for the nominal bolt diameter, in order to successfully pass a hydrostatic tesc. it is often desirable and permissi ble to utilize a high strength alloy bolt for hydrostatic testing purposes. When this procedure is followed, the following steps are recommended: a. For hydrostatic testing, use ASTM B 193. Grade B 7 bolting material, or equivalent, to initially seat the gasket and perform the hydrostatic test, a. After achieving a successful hydrostatic test, relieve the tension on the bolts to approximately S0?t of the allowable bolt stress and replace the bolts one at a time with the required bolting material, c. When replacement is made, the bolts should be stressed to the allowable stress for operating conditions. 5. On high temperature applications, considerable relax ation of bolt stress can occur due to creep of the bolt material. The level of relaxation depends upon the bolt material and the temperature to which the belt is subjected. In applications where a bolt is operating near the upper extremity of its recommended temperature range, it is highly feasible that the relaxation will be so * great that leakage will occur after a period df time on a ttnge that has successfully passed the hydrostatic test. It is therefore essentia! to prestress a bolt to a degree that layupee maintenance of a stress level at operating ton* that will ensure a leak-tight joint. uslv discussed under the heading of "Flange sh". the ability of a gasket to seal depends, to degree, on the condition of the fiange face, ar attention should be given to the reccmdetailed under this heading. THERMAL EXPANSION jits are initially prestrtssed. consideration n to stresses induced by thermal expansion ting conditions. In extreme cases, when par.sion is a serious problem and excessive bolt Stresses or gasket loading can result, it may be practical for the gasket co be compressed only to a point that will permit further compression of the gasket as the loading due to thermal expansion is applied. This is not a recommendation by FLEXITALUC. bur rather a suggestion to be considered in extreme cases by the designer. DEVELOPING PRESTRESSES IN BOLTING In order to achieve and maintain a sea! on a flange connection, it is extremely important to provide adequate bolt stress to meet both operating and hydrostatic test conditions. Although the correct level of bolt strt*s can be determined as detailed under the section headed "ASME Boiler and Pressure Vessel Code Calculations" and with due consideration to the comments already made in this section, it is the inabiWtv to adequately achieve the correct level oi stress that is another common cause of joint leakage. The most frequent method of stressing bolts is by utilizing torque wrenches. The use of torque wrenches, however, introduces many variables, and are not normally reliable methods of determining the actual bolt stress developed Some of the factors that enter into the actual developed bolt stress are: 1. The class of fit of the bolt and nut 2. Presence of burrs 3. The degree of lubrication achieved 4. The presence of grit, chips and dirt in the threads m the bolt and nut 5. Vicks 6. The relative condition of the seating surtace or. the flange against which the nut is rotated All of these variables have a marked effect on the amount of torque required to produce a given stress. When conditions are fairly constant and reasonably controlled, it is possible to give nuts a certain torque aiue and obtain stresses that are constant within reasonable limits. The tables on page IS reflect the results of many tests to determine the relationship between torque and bolt stress and the values are based on steel 13 32 ''39/37 C03LENCE 8. iUEENEE - 215 596 3741 NO.53S 515 boiling well lubricated with a heavy graphite and o! mixture. It is important to realize, however, that ar.v deviation in lubrication will have a considerable eltec: on imple^JHjy.-g^Uarque boeacrfSBgtfjrm tlixant of that given iaS>e disuI^TtTde"gi Cajth^rSy'bi.suressed t el^TIS an those-^Micatfd; btrSppfjjmygru oi the recommended torques. In order to effect a seal, ir is s-reqirf#meni of any gasketed joint to apply an even compressive force. a practical standpoint." in order to achieve this, artery definkfc-boluup procedure mnst-pe fallowed <hen -etj^tneni^sa PfasVge using torque met heads Iiy4 procedure r]r'dctaflW as follows. " ,j I ..lnsialtjhc gasket on the gdSXet seating surface and ' i;(he'covmii^*i*C)ntacr with the gasket. *::3Hzafoll ainfefts. making sure they are free of dirt and grn.'1ff?S_ artf^teO lubricated. ;=. lu&iy-UB alt nuts linger tight. 4.` PCTffeSihe required bolt stress in a minimum of lour 7a#tf foVgpting a tightening up procedure as recomfSttd^fS^ketch 1. It is important to matte certain *hat - no-more than 30Tr of the required boltqiress is achieved 'onffcs initial set. Should this occur seriowdamage cai^je. done, tq, the FLEXITaLLIC gasket and subsequent innot offset the ua final tightening fboit-to-bolt sequej evenly stressed..; [lowing the above seq re&i ve fores can be e%rte ; of the varying frici Us and the lluct occur as the bo' around a flange, the final level of stress in all bolts around 1 i !\ ;\ O . \ ' $ : / 3 : , .! BOLT FLANGE 1 BOUT FLANGE IS BOLT SKETCH l . BOLTING-UP SEQUENCE->- i the flange can vaTv considerably. Even under. idea'E*- .cortdioaw-wher&tjgH bcjJ^pjiV-e been lubricated to the . '-^same'^pyee and-rtw recommended bolting-us sequence rt^is f^DVd-using controlled torques, tests na-e iiiqwn . that"ni@nwl stStt levels in bolts around a zrge-can --<iuy as much orqjfcus 20? from the average, if i dkcubolcs are stressed bj^d uncontrolled method. eff.. *Ti;immer watches, etc., them the final siressltvelain bolts ill varv cnormouslv. .* r- BOLT TENSIONING hi view of these.biaceuracies asociited torque' jj. wrenches..it.m*r itperttnem to consider* twafv accurate ;* meiXiil of presaging bolts on liangss wTichaaatmtplly,. - ^Cufler fronerrJfcge problems or :lunf)mflMjt is'^%scal._ ynr?seal from a safety standpoint One mcttudtaiF^t ~ sing bolts, which is independent of varying fnclionar i litiona-Ji the use of nydraatUe b.oUaBf-*.rening A FLEXITALLIC spiral-wound gasket will provide a reliable seal if properly installed;in the application for which it was designed. PleBiiiijSj^embcr that the performance of FLEXITALLIC spffal-wound gaskets is not solely dependent on the gasket itself but on a combination of variables, many of which are outside the control of FLEXITALLIC. It'joint leakage or failure occur duringte.storsubsequemuse.it is most often due to something other (Ban failure of the gasket. Ifjeakage does occur, the following items should be checked: 1. Is the correct new gasket being usee? 2. Are flanges clean and true, and free of surface damage.' 3 Do Hanses have the correct surface finish.' 4. Are nuts and bolts of the correct material, and well lubricated'? 3. Has a proper bolt-up procedure beer, followed and sufficient preload applied'? If you have any problems, contact our technical serv ice department..^-- they are there to assist you! Please have the following information available when'calling: - a. style, dimensions. andMIBiq^rirof jpsket b, -flange details, i.e * tfimefi^ns. boittngdata. etc. r^cjTapplication details, i.e.. pressure, temperature. medium being sealed - The information contained in this bulietietis not to be uriten as a warranty or_representation fd'r which we mssume legal responsibility. It is offered solely for your consideration, investigation, and verification. Comments, criticisms, and discussion on its contents are cordially invited. Please write Flexitallic Casket Company Inc.. P.O. Box 848. Beltmawr. New Jersey 08031. U S.A..or Flexitallic Caskets Ltd . Station Lane. Heckmondwikc. Yorkshire. England. The authors are appreciative of the assistance freely given by their co-workers and others outside the company in preparing this bulletin and the extremely helpful suggestions and criticisms offered. CAUTION -- Wf. jnali be unoer no liability tar toss barrage cr rivjty incurred oy any parson are resulting ai'ectiy or moireciiy from mcor-ee: processing or use ot asbestos oasec croauets soia oy as. in drawing ygu> attention to tne dangers 10 neaun trom exposure 10 asoestosous: or libers, we would pomi Oul that most at Cur producis containing aspestos libers are produced sending agents coatings or binders mat render tr.em sa'e rcr normal i-xndhrg anp usage _________ ________ ^___ 14 32/0S/97 15:38 COBLENCE 8. UP8NE8 - 21S 38 3741 CHART NO. 2 TORQUE DATA FOR USE WITH MACHINE BOLTS ANO COLO ROLLED STEEL STUD BOLTS Load In Pounds on Bolts and Stud Bolts whan Torqua Loads ara Applied IOWIIAL OlANETER ofikt lleeheil !;4 5i H 3/8 7/IB i'2 3nS 5/8 3/A 7/8 1 M/8 M/4 1-3/8 i.t/2 1-5/8 1-3/* 1-7/8 2 linWEB OF THREABS [Per liesAI 20 18 16 14 13 12 11 10 9 a 7 V 6 8 S-i/2 5 5 *1/2 OlANETER AT MOT OF THREAD ftndMI 18S 2*0 29* 3*5 400 *5* 507 520 731 838 939 1 36* MSI 1.283 1 389 1 *90 1615 1 711 AREA AT MOT OF TRREAO So. me* 027 0*5 068 .093 i2 l2 202 302 *19 S5l 693 .890 1.054 129* 1.515 1.7*4 2.0*9 2.300 STRESS 7.S0DPS1 . Ttrqu* if i Ceaarvtel**^ 'w Fl/lSa. LBi. . ISABPSI Targe* Ft/lft*. CaewaaiM Lie. 1 203 2 ' SB 3 510 5 866- 8 9*5 2 4 8 TO 15 *05 675 1020 1395 <890 '2 15 25 *0 62 98 - 137 183 219 121$ :u. TSiB 2265 31*3 *133 5<90 6675 7905 9705 * 23 30 SO 80 123 195 273 365 *37 2430 3030 *530 6285 82SS 10360 133SO 15810 19*10 300 11363 600 22725 390 13060 775 21160 525 15366 1950 30735 563 17250 ' '*125 3*500 30.000 P5I Tif*ti Ft/lt*. 4 8 12 20 30 *5 60 100 160 2*5 390 5*5 730 875 1200 1550 2100 22S0 Cameramen 16*. B'O 1350 20*0 2790 3790 *660 6060 9060 zv: 5S3C 20'M 26?X 31520 38820 *5*50 S2320 51*70 59000 TORQUE DATA FOR USE WITH ALLOY STEEL STUD BOLTS Loads in Pounds on Stud Bolts whan Torque Loads ire Applied ROIRMAL BUURCTER OF MIT llnctnai 1/4 5/16 3/8 7/16 1/2 9/16 5/9 3/4 7/8 * M/8 M/4 1-3/8 1-1/2 1-5/8 V3/4 U7/i 2 2-1/4 2-1/2 2-3/* 3 IUMIE* OF THREADS fPar hmH| 20 18 16 14 '3 12 11 10 9 6 8 6 8 8 9 S 9 a 8 8 8 8 BIAMETES AT RHt Of TKffCAO nnchml .115 2*0 .29* 3*5 400 aiu AT MOT OF THREAD U. laen .027 4*5 068 12$ 30.000 PSI Tirade Fi/LRi 4 8 12 CaMnaMi 19a. HO 1350 -- 30 3760. STRESS *000 PSI Taraa* Ft/ta* 6 - 1J 30 45 Ceqmiim 16*. 1215 2025 3060 4185 5670 15* 162 . *5 *660 58 7290 .507 .202 60 6060 90 9090 .620 302 100 9060 150 13590 .731 419 160 12570 240 18655 838 .551 2*5 16530 368 24796 963 1.066 1213 1,338 1 *63 728 321 MS 1*05 1680 355 '1840 533 32790 soo 27870 750 41805 680 34650 1020 51975 600 *2150 1200 63225 1100 50400 1650 75600 1.566 1.713 1.836 2.016 1.910 2.30* 2.652 3*23 1500 59400 2250 89100 2000 S9120 3000 103690 2200 '9560 3300 U9340 3180 102690 4770 154005 2336 2.586 2.838 *292 5.259 *00 128760 6800 193140 5920 :57770 8880 236655 7720 99720 11580 284580 Reprinted *m orfni)ion o* Crane Co |Pag* 383. Cura No. SO verve Catalog.) 60000 PSI Tirana Ft/lta 8 16 24 40 50 SO 120 200 320 *90 710 1000 1360 1600 2200 3000 *000 4400 6360 9600 11640 15440 Caminialon LM !0 2700 4C80 5580 7560 9720 12120 18120 25140 33060 43680 557*0 69300 6*300 '00800 116800 1382*0 159120 205380 257520 3155*0 379**0 518 APPENDIX A "ecri-tea iron '96' Carroaton Data Surv*y. naCE. 2*00 w coos S . Houston T< ""02? CORROSIVES WHICH iROUCE !NTERGRA?IUUR CORROSION |R AUSTENITIC STMNUSS STEEL *iie Add Actrie Add -f Salierfie Acid Ammonium Nitrau Ammonium Sullata Ammonium Sulfate * H,S0. Boat Juice Calcium Ni*-f*ti Chromic Acid Chromium Chlonde Cogoar Sulfaii Ctuda Oil fatty Acids Ferric Chloride Farric Sulfate Formic Acid Hydrocyanic Acid Hydrocyanic Acid * Sulfur Dioxide Hydrofluo-x Acid + Fame Sulfate lactic Acid Ucfie Acid *- Nitric Acid Maleic Ac.d a Nitric Acid Nitric Acid * Hydrochloric Acid Nitric Acid * Hydrofluonc Acid Cialic Acid Phenol Naohtnenic Acid Phosphone Acid a Phihahc Acid Salt So'ay Sea Water Silver Nitrate * Acetic Acid Sodium Bisultate Sodium Hydroxldi + Sodium Sulfida Sodium Hyoochlerte Sulfite Cootm; liquor Sulfite Solution Sulfite Oi|ester Acid (Calcium Bisulfite * Sulfur Oioaida) Sulfamic Aeid Sulfur Oio>de (Wet) Sulfuric Acid Sulfuric Acid * Acetic Acid Sulfuric Acid - Cooper Sulfate Sulfuric Acid + Ferroua Sulfate Su.forte Acid * Methanel Sulfuric Acid v Nitric Acid Sulluroul Acid Water + Starch * Sulfur Oioudo Water Aluminum Sulfate IS Find it fast in the "Yellow Pages" under gaskets There's a listing for your nearest Master Fiexitallie Stocking Distributor in the Yeow Page Telephone Directory ;n more man 120 strategically located cities across tne nation FUEXITAUIC GASKET COMPANY INC. Main Office A Factory: P O. Sex M. i5i Heller Place. Sef'mawr. NJ 03031 Phone !609> 931-2500 Tiex 831660 * TWX 7106390125 Houston Ptam: P O. So* 760. Doer Pant. TX 77536 Pnone (7131 179.3491 0* Angeles Plane - : .".j C2 Spruce 1 t Qj*, Hatfinf.CaBuCAJOT1^ laeawg^ijB^JpruftlTs. Sngtane Ten* S5718S ITHEA AfpiUlATSO COMPANIES >n Australia. Mexico. low Zeatena, Scotiane South Africa. Venezuela, wej: Gtrmi->y 3l.-S35.5H Pfirtao r 02/0S/9'7 COBLENCE 3, -jRRNER 219 59b 0741 NO.639 518 The nuclear navy ...where gaskets must not fail For critical seal-mg applications in the Nuclear Navy, engineers depend on Flexitalhc Gaskets. in Flexitalhc Spiral-Wound Gasket con struction, type of metal, type of filler, relationship of metal to filler -- all are variables in the nanos of the Flexitalhc engineer. Every Flexitai'.ic Gasket is designed for the specific ;ob <t has to do, based on the flange geometry, temperature and pressure or the con'mec fluid, bolt load, corrosion, vibration, unusual joint stress. Style CG Gasket, illustrated, has Flexile Finish to inhibit corrosion. Give us the facts about your most seri ous sealing requirement -- n chemical processing, petroleum, power, marine, aircraft and missiles, diesel, or any other field. There's a Flexitalhc Gasket to meet your needs -- or rlaxitallie will design one. Rexitallic Gasket Company. Camcen 2. New Jersey. Stocking D.strbutors icr Standard Flexitauic Gasnets in pnr,c osi cities. 22'09-'97 15:39 COBLENCE S- ~~ 51c 996 0741 WE BUILD "PEACE OF MIND" INTO EVBRY GASKBT WE MAKE NC. 639 019 7ft,i */* i#f#f $ fLSXlTALUC SOifil'WMl Qitkit wft/eft atfAisrj internment)/ to efti/ty#* in Inmpnntyrt*fffMuf eyefi. It's a big plus in valves, pumps, com* pressors. heat exchangers, engines, and fluid processing lines when you know that the gaskets you used are not going to let you down. A FLEXITALLIC Spiral-Wound Gasket will not fall when used in the application for which It was designed. The engineers at FLEXI TALLIC help you select the proper metal, the proper filler, and the gasket density so that the gasket wifi have an extra margin of safety to compensate for emergency.loads. Nor every spiral-wound gasket, of course. Is a FLEXITALLIC. But every FLEXITALLIC Spiral-Wound Gasket is engineered to provide a leak-proof seal even under severe sealing conditions in all practical pressure/temperature ranges Irom vacuum to 15.000 psl and higher; and from cryogenic tempera tures to 1900 F. and higher. How can FLEXITALLIC be so sure? Because we've constructed more spiral-wound gaskets than anyone else in the world and we provide the engineering skill required to assure a safe seal. We'll be glad to share that engineering know how with you on your design problems. We are ready to serve you at any of three plant locations or f-pm any authorised FLEXITALLIC distributor -- consult Yellow Pages. Send for a General Catalog or Bulletin 171 on Design Criteria today. FLEXITALLIC CASKET COMPANY 9.0. |i SM. camdan. N. J. 9#l#1 urra; *t* iwo<i of rv*. tx "* ISS instil*! MJ Se!K 2r . Mirtar c.lr C SO,10 End corrosion in gosket inventory The gold Flexite Finish* for the metal gauge rings in Flexitallic Compression-Gauge Gaskets is new. It is highly corrosion resistant when exposed to severest weathering in open construction projects or in stock. The Flexite Finish provides for ease of identification and a clean, long-lived installation. Write for samples. FLEXITALLIC GASKET CO., Sth & Bailey Sts., Camden 2, N. J. Representatives in Principal Cities t'U*r t..ilivr Flexile it > of the CtOri<:rt4toM M >|w.*l `.Vmift-J AOptivd toe PiftH tnsi F11` < > r a I; i c Bl'ie ix jur e^elun** .u,,.Kpms.xto\x.%a :hv n.eik at (oFrUalhs*t>allhtvlxriu,imUel*. iOld SHIUl-WOYN GASKETS WITH d FINISH CONSIDER THE PRICE OF GASKET FAILURE! Jointfailure Cause* 3-Day Refinery Shutdown- --- (,-wu ^pUPTjT" ' power PU8tf$nunwif \TRACED TO LEJUUNSJOSflr I*M. r*< TiJ f*W> - - -j i|4 *--yefc* IW ,** I*<k fr-"4' -*-*- y IU ***-**>. if* h. ,4m tf** ,Mk> 'yeM. * .; ++* <r*i **mm \<C 4A, >*, IW <A|-- <*J j *.+>. v*. "* |*fc. .* %* .Wm r, Aw.. *' i - *- * ' consider the price of gasket lure ... in danger to personnel.. downtime of equipment... in loss fluid... in labor costs for replace ments. you H specify Flexitalilc. Flexltaliic Spiral-Wound Gaskets are constructed with an extra margin of safety. That's why engineers spec ify Flexitalilc where gaskets must not fail. Available in almost any pressure/ ; temperature combination -- limits* only by the materials used In their construction. The application engineering pro vided by Fiexitaliic and the extra care w# take in manufacturing re sults In the right gaefept, for the right flange, to makg^gie right seal. We ^Jieve 3 manw(ietur(ng plants and auttoiaed'~3htributors in principal ee your local yellow pages. SMULWOOMO 048M7 Pl.axlTAU.IC OASKtT COMPANY INC. *.o. ***. cn>a. m j Him mrsts-nso MUST**.' tu>i3/M.76*.mf inri. rj r753* ISSiiMIlISi Wl$*ruc>Llt*0r.,KirbarCi<Y.CAI071S JU/S.7lM I* (HUM; nmuiiic Sutili limit** NkMM'U, Tors**** Ttlal: JS74SS 521 02/0S/S7 15:42 COBLENCE S. `-^.RNER - 21? 535 2741 NO. 539 STYLE CG-RJ Himmumnmmnn iiiiHiiiiiiiimiiiiiiiii fltiibliic Style CG4U ComprwiiHJ*ige 6akt with outer rin|. Hw eampreaion(mgs confines me gaktt on me ouUMe. Typical position ot Style CfrW Casket. Olmwsion A and P O era controlKne fac tors of the application of Stylo CS4U Gasket. The maiimuffl nailable packet setting surface is the area between '.he flange orifice and the ID of the ring groove. Use ol this lull space is not always necessary. The Flexitallic Style CG-RJ Gasket in effect converts a ring-type joint into a male-and-female type joint, with the outer ring of solid steel providing a compression stop and centering device. When the groove in a ring-type joint is worn or scored, more bolt stress is a temporary solution, but there is a dan ger of overstressing the bolts. Eventually, the flange has to be cut out of the line, and then welded back after the groove has been re-machined. Style CG-RJ Gaskets prevent this costly maintenance expense. Style CG-RJ Gaskets are especially suitable for joints where there is close manifolding of the piping. With the Style CG-RJ Casket, the making and breaking of ring-type joints is accomplished with minimum delay and mainte nance expense. Only 1/16-inch breakaway is required, as compared with y2-inch to 34-inch with conventional ring gaskets. It's the spiral winding of the V-crimped metal plies, alternating with plies of filler, that gives Flexitallic Gas kets the spring-action or resiliency which is so valuable where thermal shocks occur. Standard Style CG-RJ Gaskets are manufactured of Type 304 stainless steel with Cana dian asbestos filler. Many other metals and fillers are avail able-check with the factory. Standard gauge rings are of carbon steel. Standard gasket thickness before compression is .175". Standard thickness of the gauge ring is Mf. 02/09/97 15:42 CQBLENCE l Uh=NER - 21= 596 3r'41 NO.639 D24 ZmxUaffic, STYLE CG-R1 FOR STANOARO A. S. A. RING-JOINT FLANGES Tyoa 304 Stamtess Steal tM Fteiitame "INm" Canadian UMiUt Orl(>nal SiMt TMctnti* .175's .005*. 3/32' Ttiicl Carton Steal Outer line (V%~ tfuca carton stool rw(s may to autatituttd at no additional cost.1 (IUMA) 9<iw' 4 % 9a9 I1fVl : 74 19 1tvR9 ><4* ISJIA SUIIS QmMI 9u llIMMI___ O.O. (Iu*m 2*4 Jil4 3'S *\* S;i* 91^ I'x IO*,* IVH J7l, 19'. 23 3N 3`S is v. 21. 19t^S US 14'S It'S It 11', 2SS n o.o. (IKM.1 4T, S', f, 4:. 7'. f. 11 U', lt`, tr. MS IV, O', N 400 !>. SttltS O^M fllmwa-- 1.0.1'MMI 04.1KMN.1. 2\ 3*, J" V, J*a J" IS * v. r. 10>,, 12', 14W ll>( 11'. 7* t"fc 12 M'V IS1'. its-; MS 22'. 24'i **% 14'i 2tK. mn 0.0. S'S ss *N 7 i'1 *, 12 1*' it 23H MS 271-i as too II. suns. i.Q. (in I1.. IN VV. 1'i 1 i' rs. 2*h J* ' ss lisi n*i ir, its in, IV, a O.O. (lnSLi. I'm Hi m r. is. tH is. IK \K a* V, *M SS. !!S ,r 14H US, 17*fc It'S a11>`Ss nmio.A llinto.1 JN J'S *s 2K ' IK JK JK a a" . *1 . s ns U'J IT', its as MS S* 04MU Wint--r RJ-1H RJ-U RJ-1K Rj-iU R3.IN RJ.IR RJ.'O Rj-tR RJ.tS Rj.tT RJ1U RJ-IV Rj.lW AI-IX Gaa*M RJ-*h RMJ AMK AMI AMN amp AMO AJ-4R AM* AMT AMU RJ-4V RJJW AMWA AMI RJ4A RJ-tC AI40 A-te Ai-tn A)-Q Al4 RJ-tC AI40 Ai-ac RJ-tf RJ-SO Rj.tM Al-U AML AI.M rj-jr AI-IQ Al-IR Al-tt AI4T AMU AI4V rmw RJ4X tj im tmn 1 1 1 r In Wtl* 3 l1 --um <!*> 2S 1 is 4 s 1 t 10 12 14 It It 22 24 300 U. SUIU QwMt OilMBM 1.0. <M 04. (IMM.) :si JS JR, J'S J1** 4S, SN V ', '2Ti 14'. ll'-i 1'4 20'-, 22', 24 '< !> 7, t% 11 14'* If, ITS, 10S 22' 24', 2t* ! 3 i i ) NW 3 JL MO l. SdlU i4o(t0) i.a (iwi._ 2H 1 JM 4 s t 10 12 14 11 11 20 22 20 2>. 3S. J'S. w. . *,, ts UK. ir. 14S Its ____ US_______ as 22s 24*4 3h "* 71, v,. 12 MS IS. 1, 20', 2ii to-. A- Mpo.0. S', S', H 7', U-. 141, .IV, IV li ' , ,8' IS' 27'1 MS V..04. tUMMI sS'',, r-, `i ios u. IS'* II iOt's-. 141. a*. Cmm Rj-IH R14J RJ-3K RJ-JC Rj-lte RJ4R RJJS RJ-3T RJ-1U RJ-3V RJJW RJ-3X i I 0<*m nrnnMr HJ-4H RJ-4J RJ4K RJ-OL RJ4N AI-4P RJ4Q RJ4A RM* RJ4T RJ-4U RJ4V RJ4VU RMWR AI4X .T.SOOJUA ______ C-R-i. _ O-O-JL"*"1. *kJM. *T Urn 1 s & 0 i IS is 1 ____ IS is IS IT-, *s v\...... 2H 2'* J'l ft S*4... f Sm Mnn K S I K. 4 'K. tK m IK. i .. . i'K 22H 2SK*I 4 S t 4S1 K*. Itt 7S SKA. 12 11* 14 It iI2*H6 2I2t40 its ITS 22s IK. IK `*Vi. 2K. IV. JS 4>S 'S 5? n'a.._. Il'S 1SS 17 t*H US MS IK 2K IK it s It 11* i IJ'l 17', 22*s. S *71* MS MS GmO* RJ-IJ4 RJ-15C RJ-IJO Rj-ise AMSF RJ-1SO Rj-iat RJ.IJC RJ-U0 AI-ISC RJ-UF RJ-ISC AI-ISH RJ.IU RJ-1SU RJ-TSN AI-ISR RJ-IS0 Rj-ISR ARJI--1ISSTS Al.lSU RJ-ISV RJ-UW RJ.'SX tc **'" *" a oipo tore eeual '.s Wat of seftoOmo *o >m m 3D. ton eoual 1 (Ml of scfteOula ^",w- "'t ol lor tlipon llanfti. te* ' !"'"N 'l ><* *** "*** "Kl1 P,B* **1***1- ml eW" 10 10 Rote l For new nect toe an kalM > t<a bare WV to teat ol Khto.' 40 piM 0 Ktot4f. tat not (or tiipan Iona*- Rote A For void noct tea lata nain| a 9<pe tor* aouoi to tint o( uhtO"' 10 pipe or howler. Ml not for slip.on MRgts. Rttl 7. for oM MCI WO tan(OS h*i P*a tor* eoual la that ol KhtO"! tOO pia or ntavwr. but not tor siivon Ram. Note A for *ld hoot typ* tonffi hpin* a P<P boro Huai to teat o' i*"*4''1 160 *<a a* hepntr. tut not for Suva ftehtci. . ,, wntoerioA* foa oratam . ^5,.. "a *'** sim and prtssart j*n*o for your aaiicaiion. Mite ten informotioo. fiaaktts can tt te'pow erompt'y 't " 0.U Forms tinul.r io te* on# on pap 4 iwn.snto Hpontoly a rwist.