Bolted Tanks for Storage of Production Liquids

API SPECIFICATION 12B: Specification for Bolted Tanks for Storage of Production Liquids

For professionals in the oil and gas sector, ensuring the safe and reliable containment of production liquids is paramount. API Specification 12B provides the essential, industry-leading framework for the design, fabrication, and erection of bolted steel tanks, offering a proven standard for critical storage applications. Adherence to this comprehensive document is key to mitigating risks and maintaining operational integrity.

What is API SPECIFICATION 12B?

API Specification 12B, developed by the American Petroleum Institute (API), is the definitive standard for bolted steel tanks used to store crude oil, condensate, natural gasoline, and other production liquids. It establishes minimum requirements for materials, design, fabrication, and erection, ensuring tanks are built to withstand the loads and environmental conditions they will encounter. Its primary purpose is to promote safety, reliability, and interchangeability in tank construction.

Scope & Purpose

This specification governs the design, materials, fabrication, and erection of atmospheric and low-pressure bolted steel tanks intended for the storage of production liquids. It covers tanks with capacities from 100 barrels to 10,000 barrels and includes guidance on shell plate thickness, roof design, bottom construction, and appurtenances. Importantly, API 12B does not cover the design of foundations, painting, or the installation of specialized equipment beyond basic connections and vents.

Who Must Comply?

• • Primary audience: Petroleum Engineers, Mechanical Engineers, Tank Designers, Quality Inspectors, and Operations Managers involved in the upstream and midstream sectors of the oil and gas industry.
• • Industries affected: Oil and Gas Exploration and Production, Petrochemical Storage, and Midstream Operations.
• • Compliance nature: While the use of API standards is generally voluntary, compliance is often mandated by contractual agreements, regulatory bodies, or chosen by companies to ensure adherence to proven, safe engineering practices.
• • Enforcement: Compliance is typically verified through internal quality control processes, third-party inspections, and audits by regulatory agencies or clients. Manufacturers seeking API Monogram certification must adhere to this standard.

Key Requirements Overview

• • The standard requires careful consideration of all applicable loads, including liquid, wind, snow, and seismic forces, in the tank's structural design.
• • Professionals must ensure that materials used for tank components, such as plates, sheets, structural shapes, and bolting, meet the specified mechanical and chemical properties.
• • Key provisions include detailed guidance on calculating shell plate thickness to safely contain the stored liquid and withstand external loads.
• • The specification mandates proper design and installation of roofs, bottoms, and bolted joints to ensure structural integrity and prevent leakage.
• • It outlines requirements for essential appurtenances like inlet/outlet connections, cleanouts, and venting systems to ensure safe operation and maintenance.

Related Standards & References

API 12B often works in conjunction with other industry standards. For instance, API 650 (Welded Tanks for Oil Storage) provides a parallel, more comprehensive standard for larger welded tanks, and API 1104 (Welding and Testing of Pipelines and Related Facilities) may be referenced for specific welding procedures if any welded components are involved in appurtenances. Understanding these complementary standards ensures a holistic approach to tank farm design and safety