Seals

Module from the Storage Tank Engineering Curriculum curriculum.

Module 6 - Seals and Emissions · Learning Objectives · 1. Design primary seal (mechanical shoe or liquid-mounted) per API 650 C.3 · 2. Add secondary seal to reduce emissions (required under 40 CFR 60 Subpart Kb) · 3. Apply rim space temperature monitoring and gaps per API 653 · 4. Calculate standing and withdrawal losses per API 42/TANKS 4.0 · 5. Inspect seals semi-annually (visual) and annually (gap measurement) · Emission Reduction by Seal Configuration

Configuration	Emission Reduction vs Fixed	Subpart Kb Compliant	Application	Notes	Ref
Fixed roof (baseline)	0% (baseline)	No	All	Breathing + working loss	AP-42
EFR mechanical shoe primary only	90%	No	Legacy	Very old	AP-42
EFR liquid-mounted primary only	95%	No	Legacy	Older	AP-42
EFR mechanical shoe + rim-mounted secondary	99%	Yes (Kb: 80ppm)	Standard refinery	Meets current	40 CFR 60 Kb
EFR liquid primary + rim-mounted secondary	99%+	Yes	Preferred	Best practice	40 CFR 60 Kb
IFR with seals	98% vs fixed	Yes	Geodesic dome + IFR	Crude + gasoline	40 CFR 60 Kb

Source: Storage_Tank_Engineering_Curriculum_v1.xlsx · Sheet: Seals

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