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Sizing Semi-Metallic Gaskets When Replacing Soft Gaskets When replacing soft gaskets with semi-metallic gaskets, it's important to understand the sizing differences and considerations. The following guidelines provide suggested dimensions based on experience to help you choose the appropriate non-metallic gasket size to replace a soft gasket. These sizings are not mandatory but serve as useful recommendations. 1. When Flange Dimensions Are Provided If the customer provides the dimensions of the flange, the following guidelines can be used to determine the appropriate gasket size: Gasket Inner Diameter (I.D.) : The inner diameter of the gasket should be the bore size of the flange plus a minimum of 1/8". Gasket Outer Diameter (O.D.) : The outer diameter can be up to the bolt hole circle diameter minus one bolt hole diameter. This applies when the proposed gasket width corresponds to the standard width of semi-metallic gaskets, which is typically 1/2", 3/4...

  In the process of gasket material selection, many inquiries point to the term “fire-safe”. Lets briefly look at the two most commonly used gasket fire testing methods: API 6FA & API 607. API 6FA: The American Petroleum Institute’s 6FA-re test is used to qualify valves for chemical process service.  The flange is assembled using proper bolt-up procedures and all parameters such as stress and torque are recorded. Thermocouples are mounted 1” away from the outside of the flange (Figure 1). The valve is enveloped in flame using four propane burners arranged symmetrically around the outside of the flange. The flame temperature should be 1400ºF to 1800ºF (average of the two thermocouples) for a burn period of 30 minutes from ignition. The temperature is maintained with no reading less than 1300ºF. An internal water pressure amounting to 75% of the flange rating is applied throughout the test and the leakage rate is continually measured. The test rig is then allowed t...

Est-ce possible qu’une fuite soit causée par une bride endommagée ? Défaillance d’une bride. D ans un système de tuyauterie, les brides sont un élément essentiel pour un confinement idéal. L ’intégrité structurelle d e la jonction ne doit jamais être affectée, cependant la défaillance due à la bride est un problème a ssez peu courant, mais peut être catastrophique. pour le confinement, C ette défaillance lié a la bride est principalement due à : • S urfaces de bride s endommagées: ou revêtement de bride incorrect, car les dentelures plus profondes que celles spécifiées empêcheront l'assise, en particulier dans les joints métalliques et semi-métalliques comme les joints enroulés en spirale s (veuillez vous reporter à notre publication précédent e : Finition de surface de bride vs type de joint ). • B rides tordues: Des mouvements de flexion excessifs sur la bride peuvent desserrer le boulonnage ou déformer les brides et entraîner des fuites. Cette situation peut également ê...

  Is it possible I have leakage because of a damaged flange? Flange failure: In a piping system, flanges are an essential element for ideal containment. The structural integrity of the junction should never be affected, however flange failure is a fairly uncommon problem but can be catastrophic. Flange failures are primarily due to: • Damaged flange surfaces or Improper Flange Facing, because the deeper serrations than specified will prevent the seating especially in metallic and semi metallic gaskets like spiral wound gaskets (please refer to previous blog entry entitled: Flange Surface Finish vs Gasket type ). • B uckling flanges: Excessive bending movements on flange s can loosen the bolting or distort the flanges and lead to leaks. This situation can also be produced by thermal s hock where the rapid temperature fluctuations can cause flanges to deform temporarily. • Non-parallel flanges: Improper flange face parallelism, causes uneven gasket compression, local ga...

What are Spray Safety Shields? Spray safety shields, are installed on pipe joints, these being the ‘weak points’ where leaks typically occur. For critical pressurised applications, they are the vital first line of defence to prevent fire, explosion and toxic release which would otherwise endanger plant and personnel. Prevent Spray-outs - Generally the most important requirement is to control the leak, create a safe release and thus avoid a dangerous spray-out, which would otherwise happen even at low pressure. Avoid oil mist formation - For certain oil & fuel applications, oil mist formation is just as hazardous as a spray-out. Furthermore, ill-fitting safety shields can actually create mist formation. Provide leak indication - It is important to identify leaks as quickly as possible, though the process will determine the urgency. For certain acid lines, some customers require that flanges must not be concealed. This is achieved using transparent shielding. Alternatively leak-indic...

Can flanges of various shapes be used together? Lotfi Grine, Eng. – Product Specialist at Robco Flat face flanges should never be bolted to a raised face flange. ASME B31.1 states that when connecting flat face cast iron flanges to carbon steel flanges, the raised face of the carbon steel flange must be removed and a full gasket is required. This is to prevent the cast iron flange (a thin, brittle material) from hanging in the space caused by the raised face of the carbon steel flange.   But there's a solution: if the flanges cannot be remanufactured, add a center ring between the raised face flange and the flat face flange. This ring carries one side with a raised face and another side with a flat face, and uses two gaskets. (Preferably a Maxiprofile type for the raised face).

  Peut-on utiliser ensemble des brides de diverses formes ?   Lotfi Grine, Eng. – Spécialiste de produit chez Robco Les brides à face plate (flat face) ne doivent jamais être boulonnées à une bride à face surélevée (raised face). L'ASME B31.1 indique que lors du raccordement de brides en fonte à face plate à des brides en acier carbone, la face surélevée de la bride en acier carbone doit être retirée et qu'un joint d'étanchéité complet est requis. Cela permet d'éviter que la bride en fonte (un matériel fin et cassant) ne soit suspendue dans l'espace provoqué par la face surélevée de la bride en acier carbone.   Mais il existe une solution :   Si les brides ne peuvent être réusinées, ajouter un anneau central entre la bride à face surélevée et la bride à face plate. Cet anneau porte un côté avec une face surélevée et un autre côté avec une face plane, et utilisent deux joints d'étanchéité, préférablement de type Maxiprofile.

What gasket material to use on sheet metal flanges for ventilation systems Jocelyn Vachon - VP B.Dev / Product Specialist Gasket materials require to be compressed, in order to achieve a seal. What materials should you use when flanges are simply made of thin sheet metal? Ventilation systems assembled on-site require gaskets between sections. Sheet metal flanges cannot create a high, evenly dispersed mechanical load on gasket materials, even if internal pressures are low (6 to 12 inch of water on average).   Here are a few suggestions: Closed cell sponges with a durometer of 20 to 60 (shore 00 scale) are good options Neoprene-based sponges (Robco SC-41 soft / SC-42 medium / SC-43 firm) are the most popular. Self-adhesive strips can be formed (round flanges) or cut in lengths (square flanges) for a quick and wasteless assembly PTFE saturated woven glass tapes (Robco GW-305) can be used where temperatures are above 250°F (130°C) and where a ...

  ASME PCC1-2019 : technical notes about sealing performance Lotfi Grine, Eng. – Product Specialist at Robco   In the following technical notes, you will find valuable technical extracts from the ASME PCC1 2019 ( bolted flange joint assembly (BFJA) guidelines) to help better understand sealing behaviour and produce a positive seal. - Calculating Target Torque Values are based on the root area. The root areas are based on coarse-thread series for sizes 1 in. and smaller with 8-pitch thread series for sizes 1 1/8  in. and larger (Section H). - The major long-term value of coated bolts is to protect against corrosion of the exposed threads and to minimize break-out and nut-removal torque, thereby promoting ease of joint disassembly (Section 7). - Section VIII, Division 1 of the ASME Boiler and Pressure Vessel Code requires that nuts engage the threads for the full depth of the nut (Section 8.2).   - Start-up re-torque is performed when the temperature of ...

Style Selection Guide of Metallic Serrated Maxiprofile Gasket: Lotfi Grine, Eng. – Product Specialist at Robco Standard core design is parallel, which offers the advantage of even stress distribution across the gasket face. The LA2 type is used for Male & Female and Tongue & Groove type flanges without outer ring type. LA1 and LA2 types are used for flat face and raised face type flange. Sizes: Standard sizes are offered to fit ASME B16.20 to suit ASME B16.5, ASME B16.47 series A and B pipe flanges. Other non-standard gasket sizes are also available.       Maxiprofile STYLE Cross Section Flange Type Flat Face  Raised Face  Male and Female Tongue and Groove  LA2 Core only-without outer ring.     √ √ LA1 Integral outer ring √ √ ...