ABSTRACT
Static seal applications are the major use of elastomeric O-ring seals. Most static seals are employed as face seals, but male and female radial seals are becoming more common. This author prefers radial squeeze applications over axial squeeze face-seal applications for two reasons: radial seals depend on the dimensions of the parts to maintain O-ring squeeze, whereas face seals depend on external fasteners such as screws and bolts to maintain O-ring squeeze; and radial seals are usually easier to employ when modifying existing parts, whereas face seals usually require additional radial space and flange protrusions. Industrial specifications are designed for an overall average 20. 5% O-ring squeeze: 27% squeeze for 0.070-in. cross sections to 18% squeeze for 0.275-in. cross sections. The military specification requires approximately one-half the O-ring squeeze specified by the industrial specification, because it incorporates dynamic applications together with static applications. The industrial specification requires more stretch on the inside diameter of the O-ring than the military specification.
