B16.5 Silicone Gasket
Manufacturer & Custom Solutions

Pipe Flanges and Flanged Fittings


Are you looking for gaskets for ASME B16.5 flanges? ZSR can help. We make silicone gaskets that match ASME B16.5 pipe flanges from NPS 1/2 inch to 24 inch, Class 150 to Class 2500. For these flanges, buyers usually choose compressed fiber, PTFE or rubber gaskets. Silicone is a better choice for food pipelines, outdoor lines and places with big temperature changes, because it works from -60°C to +200°C and resists ozone and weathering. The gasket dimensions follow ASME B16.21, so installation is easy and sealing is reliable. Tell us your flange class and size, and we will send a price within 24 hours.

  • MOQ: Flexible / Low MOQ Support
  • Lead Time: Prototype in 3–7 Days
  • Certifications: FDA, LFGB, ISO 9001, ROHS, REACH
  • Material: VMQ, FVMQ, LSR, HCR / HTV
  • Hardness: 30 to 80 Shore A
  • Temperature: -60°C to 230°C
  • Standard: ASME B16.5 Flange Gaskets
  • Custom Sizes: Per flange spec
  • Tooling: In-house mold machining
  • Samples: Free samples available
Request a Free Quote & SampleTalk To Our Expert Directly

FDA 21 CFR 177.2600

Rubber Articles Intended for Repeated Use

LFGB 30&31

EU Food Contact Materials

USP Class VI / ISO 10993

Biocompatibility of Medical Devices

RoHS / REACH

Environmental Compliance

UL 94

Flammability of Plastic Materials

More

Built to Your Exact Spec

Custom Silicone Gaskets Options

ImageProductTypeShort InfoAction
DIN 32676 Silicone Gasket DIN 32676 Silicone Gasket Standard & Size DIN 32676 tri-clamp silicone gaskets, FDA food grade, full size range in stock at ZSR factory. View Details
AS568 Standard Silicone Gaskets AS568 Standard Silicone Gaskets Standard & Size AS568 standard-size silicone gaskets for groove-based sealing applications. View Details
DIN 3869 Silicone Sealing Ring DIN 3869 Silicone Sealing Ring Standard & Size DIN 3869 profile sealing rings in silicone for hydraulic ports, working from -60°C to +200°C. View Details
EN 1514-1 Silicone Gasket EN 1514-1 Silicone Gasket Standard & Size EN 1514-1 silicone flat gaskets for PN flanges, IBC and FF types, standard and custom sizes. View Details
Custom Die Cut Silicone Gaskets Custom Die Cut Silicone Gaskets Standard & Size Flat silicone gaskets cut to any shape from sheet stock. Precision cutting for exact fits. View Details
ISO 7483 Silicone Gasket ISO 7483 Silicone Gasket Standard & Size Silicone gaskets to ISO 7483 for ISO 7005 flanges, made for international projects and tenders. View Details
Custom Molded Silicone Gaskets Custom Molded Silicone Gaskets Standard & Size Three-dimensional silicone gaskets made by compression or injection molding. For complex sealing shapes. View Details
ISO 1127 Silicone Gasket ISO 1127 Silicone Gasket Standard & Size Sanitary silicone gaskets matched to ISO 1127 stainless steel tube sizes for food and pharma lines. View Details
Standard Flange Silicone Gaskets Standard Flange Silicone Gaskets Standard & Size Silicone gaskets cut to fit pipe flanges. Matches ANSI, DIN and JIS bolt patterns. View Details
B16.21 Silicone Gasket B16.21 Silicone Gasket Standard & Size ZSR makes silicone gaskets to ASME B16.21, ring type and full face type, for Class 150 to 2500 pipe flanges. View Details
ISO 2852 Silicone Gasket ISO 2852 Silicone Gasket Standard & Size ISO 2852 silicone clamp gaskets for food industry couplings, FDA grade, factory direct from ZSR. View Details
Tri-Clamp / Sanitary Silicone Gaskets Tri-Clamp / Sanitary Silicone Gaskets Standard & Size Hygienic silicone gaskets for food and pharmaceutical pipe connections. CIP and SIP compatible. View Details
B16.5 Silicone Gasket B16.5 Silicone Gasket Standard & Size Silicone gaskets from ZSR sized to fit ASME B16.5 flanges, NPS 1/2 to 24 inch, Class 150 to 2500. View Details
Metric Size Silicone Gaskets Metric Size Silicone Gaskets Standard & Size Metric dimension silicone gaskets for international equipment standards. View Details
DIN 7603 Silicone Sealing Ring DIN 7603 Silicone Sealing Ring Standard & Size Flat silicone sealing rings made to DIN 7603 for screw plugs, banjo bolts and threaded fittings. View Details
DIN 2690 Silicone Gasket DIN 2690 Silicone Gasket Standard & Size Silicone flat gaskets to DIN 2690 / EN 1514-1 dimensions for PN6 to PN40 flanges, food grade available. View Details
DIN 2691 Silicone Gasket DIN 2691 Silicone Gasket Standard & Size Silicone gaskets made to DIN 2691 for tongue and groove flanges PN10 to PN160, ideal for plant repair. View Details
DIN 11851 Silicone Gasket DIN 11851 Silicone Gasket Standard & Size Food grade silicone gaskets for DIN 11851 sanitary unions, DN10 to DN150, FDA material. View Details
FDA Food Grade Silicone Gasket FDA Food Grade Silicone Gasket Grade Food-safe silicone gaskets for processing equipment. FDA-compliant and taste-neutral. View Details
Medical Grade Silicone Gasket Medical Grade Silicone Gasket Grade Biocompatible silicone gaskets for medical devices. Sterilizable with full documentation. View Details
Industrial Grade Silicone Gasket Industrial Grade Silicone Gasket Grade General-purpose silicone gaskets for industrial sealing. Reliable, durable and cost-effective. View Details
High Temperature / Heat Resistant Silicone Gaskets High Temperature / Heat Resistant Silicone Gaskets Special Function Heat-resistant silicone gaskets rated for continuous use above 200°C. For ovens and furnaces. View Details
Flame Retardant Silicone Gaskets Flame Retardant Silicone Gaskets Special Function Self-extinguishing silicone gaskets meeting UL 94 V-0. For fire-safety applications. View Details
Solid Silicone Rubber Gaskets Solid Silicone Rubber Gaskets Materials Solid silicone rubber gaskets with excellent compression set resistance and long service life. View Details
Fluorosilicone (FVMQ) Gaskets Fluorosilicone (FVMQ) Gaskets Materials Fuel and solvent-resistant silicone gaskets for chemical processing and automotive applications. View Details
Transparent / Clear Silicone Gaskets Transparent / Clear Silicone Gaskets Color Clear silicone gaskets for visible sealing and light-transmitting applications. View Details
Black / White Silicone Gaskets Black / White Silicone Gaskets Color Standard black and white silicone gaskets. Fastest delivery from stock. View Details

How B16.5 Relates to Gaskets

Buyers often search for "B16.5 gaskets" — but technically, ASME B16.5 is the flange standard, not the gasket standard. It defines the flange itself: the outside diameter, the bolt circle, the number and size of bolt holes, the flange thickness, and the pressure-temperature ratings for each class. The gasket that sits inside that flange is defined by a partner standard, ASME B16.21.

This split matters for one practical reason: the gasket must match the flange geometry exactly. At ZSR Silicone Parts, we work from B16.5 flange dimensions to make sure of two things — the gasket OD fits inside the bolt circle (for ring gaskets) or follows the full bolt pattern (for full face gaskets), and the gasket ID matches the pipe bore, so nothing sticks into the flow path.

Common B16.5 flange face types:

  • Raised Face (RF) — the most common type; the sealing surface is a raised ring. Silicone ring gaskets fit here.
  • Flat Face (FF) — the sealing surface is flat across the whole flange. Silicone full face gaskets fit here.
  • Ring-Type Joint (RTJ) — uses a machined groove for a solid metal ring gasket. Silicone gaskets are not used on RTJ flanges — this facing is designed for high-pressure metal sealing, and we will always tell you so.

Flange Face and Gasket Fit

The flange face decides the gasket shape. Get this right, and installation is easy:

Flange Face

Gasket Style

Gasket OD Rule

Recommended Thickness

Raised Face (RF)

Ring type

Slightly larger than the raised face, but smaller than the bolt circle

1.5 / 3 mm

Flat Face (FF)

Full face, with bolt holes

Covers the entire flange face, matching the bolt pattern

1.5 / 3 / 5 mm

Ring-Type Joint (RTJ)

Metal ring gasket (R / RX / BX types)

Set by the groove — no silicone option

–

Why the OD rule matters: on an RF flange, the raised face is only about 1.6 mm high (Class 150/300). If the gasket is too small, it slips off the raised face and seals poorly; too large, and it hits the bolts. On an FF flange, the gasket must cover the whole face — this spreads the bolt load and protects brittle flanges like cast iron, plastic, or glass-lined steel from cracking.

Bolt holes on request: ZSR cuts bolt holes into full face gaskets to match your flange's exact bolt pattern — standard B16.5 patterns or custom drilling from your drawing.

Pressure-Temperature Ratings

B16.5 flanges carry pressure-temperature ratings: each class (150, 300, 600, and up) has a maximum working pressure that drops as the temperature rises. A Class 150 flange that holds 19 bar at room temperature may only hold a fraction of that at 200°C. Two ratings must both be respected — the flange's, and the gasket material's.

Maximum service temperature for silicone B16.5 gaskets, by material grade:

Material Grade

Continuous Service

Short-Term Peak

Standard VMQ

+200°C

+230°C

High-Temp VMQ (heat-stabilized)

+230 – 250°C

+300°C

Extreme High-Temp VMQ (iron oxide / cerium stabilized)

+260°C

+315°C

Why so many names?
  • Hydrocarbon service: standard silicone swells in fuels and oils. For any line carrying fuel, oil, or solvents, specify fluorosilicone (FVMQ) — or choose a different gasket material entirely.
  • Pressure: silicone is a soft gasket. It performs best on Class 150 and Class 300 flanges. For Class 600 and above, use our fiberglass reinforced silicone, or let us recommend a more suitable gasket type.

Tell us your medium, temperature, and flange class — we will confirm the right material before you order, free of charge.

Contact us now ➔

What Is ASME B16.5?

ASME B16.5 — Pipe Flanges and Flanged Fittings — is the most widely used pipe flange standard in the world. Published by the American Society of Mechanical Engineers, it defines everything about a steel pipe flange: its size, its shape, its bolt holes, its materials, and how much pressure it can safely hold at any given temperature. When engineers anywhere on the planet say "a 4-inch Class 150 flange," they are speaking the language of B16.5.

Key Points of the Standard
  • A Complete Flange Definition — B16.5 covers flanges from NPS 1/2" to 24", in pressure classes from Class 150 to Class 2500, across a wide range of flange types (weld neck, slip-on, blind, threaded, and more).
  • Pressure-Temperature Ratings Built In — The standard includes rating tables for different material groups, so designers know exactly how much pressure a flange can hold as temperatures climb.
  • The Partner of B16.21 — B16.5 defines the flange; B16.21 defines the nonmetallic gasket that seals it. Together they form a complete, interchangeable sealing system.
  • A Global Common Language — Even outside North America, B16.5 dimensions are the reference point for equipment built to U.S. codes — oil and gas, chemical plants, power stations, and OEM machinery worldwide.
  • Why It Matters for Gasket Buyers — If your equipment uses B16.5 flanges, your gaskets must follow B16.5-matched dimensions. One standard reference is all a factory needs to make a gasket that fits the first time.

At ZSR Silicone Parts, we keep B16.5 flange data on file for every size and class — so your silicone gasket arrives matching your flange, your bolt pattern, and your service conditions. Tell us the class and NPS size; we handle the rest.