BS 1806 is a British standard for O-ring sizes, originally issued by the British Standards Institution. This standard lists all Imperial standard sizes and includes the five main cross-section groups found in AS568, plus additional sizes that fall between the AS568 sizes.
BS 1806 has been officially replaced by BS ISO 3601, which aligns British O-ring standards with the international ISO 3601 standard. However, because BS 1806 is still widely referenced in certain industries and regions around the world, it remains important for cross-reference purposes.
The sizes in BS 1806 are fully compatible with AS568, meaning the two standards can be used interchangeably for matching sizes.
ZSR Silicone manufactures silicone O-rings that fully match BS 1806 standard sizes, including both the AS568-compatible sizes and the additional in-between sizes unique to this standard. If your equipment or documentation still references the BS 1806 specification, we can supply the exact size you need in the silicone material that suits your working conditions.
Simple BS 1806 O-rings Size Chart
BS 1806 Standard No. Range | CS (mm) | ID Range (mm) | OD Range (mm) | CS (inch) | ID Range (inch) | OD Range (inch) |
|---|---|---|---|---|---|---|
BS1806-001~003 | 1.02 ~ 1.52 | 0.74 ~ 1.42 | 2.78 ~ 4.46 | 0.040 ~ 0.060 | 0.029 ~ 0.056 | 0.109 ~ 0.176 |
BS1806-004~050 | 1.78 | 1.78 ~ 133.07 | 5.34 ~ 136.63 | 0.070 | 0.070 ~ 5.239 | 0.210 ~ 5.379 |
BS1806-102~178 | 2.62 | 1.24 ~ 247.32 | 6.48 ~ 252.56 | 0.103 | 0.049 ~ 9.737 | 0.255 ~ 9.943 |
BS1806-201~284 | 3.53 | 4.34 ~ 456.06 | 11.40 ~ 463.12 | 0.139 | 0.171 ~ 17.955 | 0.449 ~ 18.233 |
BS1806-309~395 | 5.33 | 10.46 ~ 658.88 | 21.12 ~ 669.54 | 0.210 | 0.412 ~ 25.940 | 0.831 ~ 26.360 |
BS1806-400~475 | 6.99 | 34.29 ~ 658.88 | 48.27 ~ 672.84 | 0.275 | 1.350 ~ 25.940 | 1.900 ~ 26.490 |
BS1806-901~932 | 1.42 ~ 3.00 | 4.70 ~ 59.36 | 7.54 ~ 65.36 | 0.056 ~ 0.118 | 0.185 ~ 2.337 | 0.297 ~ 2.573 |