Gaskets
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Gaskets

Gaskets-Drawing
API strives to supply the highest quality gaskets of all materials. Rubber NBR & BUNA, Teflon®, Viton, graphite, silicone, compressed sheet and spiral wound.

ALL DIMENSIONS ARE IN INCHES UNLESS OTHERWISE STATED
Nominal Pipe Size I.D. (old style) ANSI Size I.D. (new style) Full Face Gaskets - (125/150#) Outside Diameter (OD) Full Face Gaskets - (125/150#) # Of HolesFull Face Gaskets - (125/150#) Bolt Hole Diameter Full Face Gaskets - (125/150#) Bolt Circle Diameter (BC) Full Face Gaskets - (250/300#) Outside Diameter (OD) Full Face Gaskets - (250/300#) # Of HolesFull Face Gaskets - (250/300#) Bolt Hole Diameter Full Face Gaskets - (250/300#) Bolt Circle Diameter (BC)Ring Gaskets 125/150# Outside Diameter (OD) Ring Gaskets 250/300# outside Diameter (OD)
1/20.8783.504.6252.3753.7504.6252.6251.8752.125
3/41.0623.884.6252.7504.6254.7503.2502.2502.625
11.3134.254.6253.1254.8754.7503.5002.6252.875
1 1/41.6834.634.6253.5005.2504.7503.8753.0003.250
1 1/21.9435.004.6253.8756.1254.8754.5003.3753.750
22.3756.004.7504.7506.5008.8755.0004.1254.375
2 1/22.8757.004.7505.5007.5008.8755.8754.8755.125
33.5007.504.7506.0008.2508.8756.6255.3755.875
3 1/24.0008.508.7507.0009.0008.8757.2506.3756.500
44.5009.008.7507.50010.008.8757.8756.8757.125
55.56310.008.8758.50011.008.8759.2507.7508.500
66.62511.008.8759.50012.5012.87510.638.7509.875
88.65013.508.87511.7515.00121.00013.0011.0012.125
1010.7516.00121.0014.2517.50161.12515.2513.3814.250
1212.7519.00121.0017.0020.50161.25017.7516.1316.625
1414.0021.00121.12518.7523.00201.25020.2517.7519.125
1616.0023.50161.12521.2525.50201.37522.5020.5021.250
1818.0025.00161.25022.7528.00241.37524.7521.6323.500
2020.0027.50201.25025.0030.50241.37527.0023.8825.750
2222.0029.50201.37527.2533.00241.62529.2526.0027.625
2424.0032.00201.37529.5036.00241.62532.0028.2530.500
2626.0034.75241.37531.7538.25281.75034.5030.5032.875
2828.0036.50281.37534.0040.75281.75037.0032.7535.375
3030.0038.75281.37536.0043.00281.87539.5034.7537.500
3232.0041.75281.62538.5045.25282.00041.5038.0039.625
3434.0043.75321.62540.5047.50282.00043.5039.0041.625
3636.0046.00321.62542.7550.00322.12546.0041.2544.000
3838.0048.75361.62545.2552.25322.25048.0043.6346.125
4040.0050.75361.62547.2554.25362.25050.2545.6348.750
4242.0053.00361.62549.5057.00362.25052.7548.0050.750
4444.0055.25401.62551.7559.25362.25055.0050.1353.000
4646.0057.25401.62553.7561.50402.25057.7552.1355.250
4848.0059.50441.62556.0065.00402.25060.7554.5058.500

Note:

  • Dimensions per ANSI B 16.5 and AWWA C110 standards for pipe flanges and gaskets.
  • Dimensional tolerances (unless otherwise stated): Up to 1” @ +/- .0325”; 1.25” thru 12” @ +/- .0625”; 14” thru 24” @ +/- .0975”; 24” and above @ +/- .25”.
  • Standard gasket material is SBR (Red Rubber), but Neoprene, EPDM, Buna N, Silicone, Viton Tefl on and other compounds are readily available.
  • Standard thicknesses are 1/16” and 1/8”, but other thickness are available.

Gaskets – Basic Compounds & Properties

Common Name(s)DesignationCompositionGeneral PropertiesGeneral Chemical Resistance To:General Chemical Resistance Attacked By:
NeopreneCRChloropreneGood weathering resistance and flame retarding. Good resistance to petroleum based fluids.Moderate chemicals and acids, ozone, oils, fats, greases and many solvents.Strong oxidizing acids, esters, ketones, chlorinated aromatic and nitro hydrocarbons.
EPDMEPMEthylene-propylen-diene-molimersExcellent ozone, chemical and aging resistance. Excellent heat resistance. Poor resistance to petroleum based fluids.Heat, ozone, strong oxidizing chemicals and acetone.Petroleum based fluids, animal fats, solvents and greases.
Buna-NNBRNitrile-butadieneExcellent resistance to petroleum based fluids. Good physical properties.Many hydrocarbons, fats, oils, hydraulic fluids and chemicals.Ozone (except PVC blends), ketones, esters, aldehydes, chlorinated and nitro hydrocarbons.
SiliconesQ, SiPolysiloxaneExcellent high and low temperature properties. Good oil resistance. FDA compound. Good physical properties.Moderate chemicals and acids, ozone, oils, fats, greases and concentrated sodium hydroxide.Many solvents, high aromatic hydrocarbons, concentrated acids, dilute sodium hydroxide.
SBR
(Red Rubber)
SBRStyrene-butadieneGood physical properties and abrasion resistance. Poor resistance to petroleum based fluids.Most moderate chemicals wet or dry, organic acids, alcohols, ketones and aldehydes.Ozone, strong acids, animal fats, oils, greases and most hydrocarbons.
Viton
(Flouro-elastomer)
FPMHexafluoropropylene-vinylidene flourideExcellent oil and air resistance at low and high temperatures. Excellent chemical resistance.All aliphatic, aromatic and halogenated hydrocarbons, acids, animal and vegetable oils.Ketones, low molecular weight esters and nitro containing compounds.
Teflon®
(Flourocarbon resin)
TFEPolytetra-flouroethyleneExcellent chemical and solvent resistance. Resistant to very high temperatures.Inert to most chemicals, smooth anti-adhesive surface. easily cleaned.Acetates, NA-K and some amino acids.
Non-AsbestosNAAramid fiber and synthetic fibers bonded with NBR.General service water & oil gasket. Pressures to 1595 psi, temp to 750⁰ F.Mild acids, alkalis, oils, general chemicals & petroleum derivatives and steam.Consult customer service for chemical compatibility.

Notes:
a. The chemical guidelines in this table are offered as a general indication of the compatibility of various materials with chemicals and fluids listed.
b. When in doubt a sample of the compound should always be tested with the particular chemical it is to handle.