EPDM Rubber Gaskets

Water, steam and outdoor flat seals for flanges, manways and enclosures. Cut from sheet or to your drawing.

Overview

EPDM rubber gaskets are the default choice for flat static joints exposed to water, steam, ozone and outdoor weather. The saturated polymer backbone of ethylene propylene diene monomer gives EPDM excellent heat-aging and UV stability, while its polar structure makes it unsuitable for petroleum oils and fuels. For gasket service, EPDM is typically supplied in 40–90 Shore A, with 70 Shore A being the most common for bolted flanges. The temperature window spans approximately −50°C to +150°C continuous, with short-term steam exposure up to +160°C possible in peroxide-cured compounds. EPDM flat gaskets are widely used in water treatment, HVAC, food-grade washdown equipment, solar thermal systems and outdoor electrical enclosures. Common forms include full-face pipe flange gaskets, inner-bolt-circle (IBC) rings, sheet stock for in-house fabrication, and die-cut custom profiles. Standard thicknesses run from 1/32 in to 1/4 in, with 1/16 in and 1/8 in most popular for ANSI/ASME Class 125/150 flanges. We stock commercial, WRAS-approved potable-water and FDA 21 CFR 177.2600 EPDM grades. When ordering, specify compound grade, hardness, thickness, and flange standard or drawing. EPDM gaskets are single-use: once compressed they take permanent set and should be replaced at each disassembly.

Types

Full-Face Flange Gaskets

Gasket extends to the outer bolt circle, protecting the flange face and providing a wide sealing area. Common for plastic and cast-iron flanges.

Best for: Water treatment flanges, pump housings, tank nozzles

Ring Gaskets (IBC)

Sealing ring inside the bolt circle, leaving bolt holes exposed. Lower material cost and easier alignment on large flanges.

Best for: Steel flanges, manways, equipment covers

Sheet Stock

Uncut EPDM sheet for fabrication shops and MRO blanket orders. Supplied in 60–70 Shore A as standard.

Best for: In-house cutting, prototype panels, large gaskets

Materials

Material	Properties	Best For
Commercial EPDM 70 Shore A	General purpose water and weather resistance; −50°C to +150°C	HVAC, irrigation, industrial water
WRAS / NSF 61 EPDM	Potable water approved; low odor, low extractables	Drinking water, food processing, plumbing
FDA EPDM (peroxide cured)	21 CFR 177.2600 compliant; steam and CIP tolerant	Food equipment, pharmaceutical washdown
High-Temp Steam EPDM	Peroxide cure; up to +160°C intermittent steam	Steam valves, autoclaves, boiler fittings

Sizing

EPDM gaskets are made to drawing or matched to common flange standards. Provide ID, OD or bolt circle, thickness and quantity for fastest quoting.

Thicknesses

• 1/32"
• 1/16"
• 3/32"
• 1/8"
• 3/16"
• 1/4"
• Custom

Common standards

• ASME B16.21
• DIN EN 12560
• Custom drawing

Applications

Water Treatment

Filter vessels, pump flanges, valve bonnets, UV reactor heads

HVAC

Chiller headers, coil connections, air handling unit doors

Food & Beverage

Washdown equipment, CIP manways, potable water fittings

Outdoor Equipment

Electrical enclosures, solar thermal collectors, cabinet doors

Frequently Asked Questions

Can EPDM rubber gaskets be used for oil or fuel?

No. EPDM swells and degrades in petroleum oils, fuels and mineral hydraulic fluids. For oil or fuel flange service, use NBR or FKM gaskets.

What is the maximum temperature for EPDM gaskets in steam?

Standard EPDM handles up to +150°C continuous; peroxide-cured steam grades can tolerate +160°C intermittent. For higher steam temperatures, consider AFLAS or FKM depending on other media.

Are EPDM gaskets UV and ozone resistant?

Yes. EPDM has excellent ozone and UV resistance, making it the default choice for outdoor enclosures, solar equipment and exposed roof-level piping.

What hardness should I specify for a water flange gasket?

70 Shore A is the standard compromise between conformability and bolt-load retention. Softer 50–60 Shore A grades conform better to uneven flanges; 80–90 Shore A grades resist extrusion in higher-pressure systems.

Do you supply potable-water-approved EPDM gaskets?

Yes. WRAS and NSF 61 approved EPDM grades are available for drinking water and food-contact applications. Request the compliance certificate with your order.

Can EPDM gaskets be reused after disassembly?

No. Like all compressed flat gaskets, EPDM takes permanent set and should be replaced at every reassembly to avoid leakage.