Gaskets

Dimensions: Flange Gaskets

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 Holes	Full 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 Holes	Full 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)
0.5	0.878	3.50	4	0.625	2.375	3.750	4	0.625	2.625	1.875	2.125
0.75	1.062	3.88	4	0.625	2.750	4.625	4	0.750	3.250	2.250	2.625
1	1.313	4.25	4	0.625	3.125	4.875	4	0.750	3.500	2.625	2.875
1.25	1.683	4.63	4	0.625	3.500	5.250	4	0.750	3.875	3.000	3.250
1.5	1.943	5.00	4	0.625	3.875	6.125	4	0.875	4.500	3.375	3.750
2	2.375	6.00	4	0.750	4.750	6.500	8	0.875	5.000	4.125	4.375
2.5	2.875	7.00	4	0.750	5.500	7.500	8	0.875	5.875	4.875	5.125
3	3.500	7.50	4	0.750	6.000	8.250	8	0.875	6.625	5.375	5.875
3.5	4.000	8.50	8	0.750	7.000	9.000	8	0.875	7.250	6.375	6.500
4	4.500	9.00	8	0.750	7.500	10.000	8	0.875	7.875	6.875	7.125
5	5.563	10.00	8	0.875	8.500	11.000	8	0.875	9.250	7.750	8.500
6	6.625	11.00	8	0.875	9.500	12.500	12	0.875	10.625	8.750	9.875
8	8.650	13.50	8	0.875	11.750	15.000	12	1.000	13.000	11.000	12.125
10	10.750	16.00	12	1.000	14.250	17.500	16	1.125	15.250	13.380	14.250
12	12.750	19.00	12	1.000	17.000	20.500	16	1.250	17.750	16.130	16.625
14	14.000	21.00	12	1.125	18.750	23.000	20	1.250	20.250	17.750	19.125
16	16.000	23.50	16	1.125	21.250	25.500	20	1.375	22.500	20.500	21.250
18	18.000	25.00	16	1.250	22.750	28.000	24	1.375	24.750	21.630	23.500
20	20.000	27.50	20	1.250	25.000	30.500	24	1.375	27.000	23.880	25.750
22	22.000	29.50	20	1.375	27.250	33.000	24	1.625	29.250	26.000	27.625
24	24.000	32.00	20	1.375	29.500	36.000	24	1.625	32.000	28.250	30.500
26	26.000	34.75	24	1.375	31.750	38.250	28	1.75	34.5	30.5	32.875
28	28.000	36.50	28	1.375	34.000	40.750	28	1.75	37	32.75	35.375
30	30.000	38.75	28	1.375	36.000	43.000	28	1.875	39.5	34.75	37.5
32	32.000	41.75	28	1.625	38.500	45.250	28	2	41.5	38	39.625
34	34.000	43.75	32	1.625	40.500	47.500	28	2	43.5	39	41.625
36	36.000	46.00	32	1.625	42.750	50.000	32	2.125	46	41.25	44
38	38.000	48.75	36	1.625	45.250	52.250	32	2.25	48	43.63	46.125
40	40.000	50.75	36	1.625	47.250	54.250	36	2.25	50.25	45.63	48.75
42	42.000	53.00	36	1.625	49.500	57.000	36	2.25	52.75	48	50.75
44	44.000	55.25	40	1.625	51.750	59.250	36	2.25	55	50.13	53
46	46.000	57.25	40	1.625	53.750	61.500	40	2.25	57.75	52.13	55.25
48	48.000	59.50	44	1.625	56.000	65.000	40	2.25	60.75	54.5	58.5

  Notes:

• Dimensions per ANSI B 16.5 and AWWA C110 standards for pipe flanges and flange 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) or Non-Asbestos (Green), but Neoprene, EPDM, Buna N, Silicone, Viton Teflon and other compounds are readily available.
• Standard thicknesses are 1/16” and 1/8”, but other thicknesses are available.
• Sizes above 24″ are available upon request (minimum order quantity may apply).

 

Basic Compounds and Properties for Flange Gaskets

Common Name(s)	Designation	Composition	General Properties	General Chemical Resistance To:	General Chemical Resistance Attacked By:
Neoprene	CR	Chloroprene	Good 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.
EPDM	EPM	Ethylene-propylen-diene-molimers	Excellent 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-N	NBR	Nitrile-butadiene	Excellent 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.
Silicones	Q, Si	Polysiloxane	Excellent 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)	SBR	Styrene-butadiene	Good 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)	FPM	Hexafluoropropylene-vinylidene flouride	Excellent 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)	TFE	Polytetra-flouroethylene	Excellent 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-Asbestos	NA	Aramid fiber and synthetic fibers bonded with NBR.	General service water & oil gasket. Pressures to 1595 psi, temp to 750? F.	Mild acids, alkalis, oils, general chemicals & petroleum derivatives and steam.	Consult customer service for chemical compatibility.

  Notes:

• The chemical guidelines in this table are offered as a general indication of the compatibility of various materials with chemicals and fluids listed.
• When in doubt, a sample of the compound should always be tested with the particular chemical it is to handle.
• API stocks Non-Asbestos (GNA Series) and SBR (GRR Series) flange gaskets, but others are available upon request (minimum order quantity may apply).