Seal Related Factors for External Floating Roof Vessels

Seal type Welded vessels Riveted vessels K S N K S N Metallic shoe seal: Primary seal only 1.2 1.5 1.3 1.5 With shoe-mounted secondary seal 0.8 1.2 1.4 1.2 With rim-mounted secondary seal 0.2 1.0 0.2 1.6 Liquid mounted resilient seal: Primary seal only 1.1 1.0 a NA NA With weather shield 0.8 0.9 NA NA With rim-mounted secondary seal 0.7 0.4 NA NA Vapor mounted resilient seal: Primary seal only 1.2 2.3 NA NA With weather shield 0.9 2.2 NA NA With rim-mounted secondary seal 0.2 2.6 NA NA a NA = Not applicable.