GOST 12621-78 PDF

Full title and description

GOST 12621-78 — "Днища конические неотбортованные с углом при вершине 140°. Основные размеры" (English: Conical heads without knuckle, apex angle 140 degrees. Basic dimensions). National standard that specifies the basic overall and manufacturing dimensions, nominal sizes and dimensional tables for unwelded (non-flanged) conical heads with a 140° apex intended for use on horizontal vessels and apparatus.

Abstract

This standard defines standardised basic dimensions, geometric parameters and recommended dimensional tolerances for conical (non-knuckled) dished ends with an apex angle of 140°. It provides tables and rules designers and fabricators use to select and make conical heads for low-pressure horizontal vessels and tanks, ensuring interchangeability and correct fit with skirts, flanges and shells.

General information

• Status: In force / active (действует).
• Publication date: 1978 (GOST designation year); put into effect 01 January 1979.
• Publisher: State Committee for Standards of the USSR (Gosstandart); current custodian — Rosstandart (Russian Federation).
• ICS / categories: 23.020 — Fluid storage devices (pressure vessels and related components), commonly cited under pressure-vessel design codes.
• Edition / version: GOST 12621-78 (original 1978 edition). Amendments were issued and integrated (notably amendment introduced in 1984).
• Number of pages: 3 (concise dimensional standard with tables and figures).

Scope

Applies to non‑flanged (non‑knuckled) welded conical heads having an apex angle of 140°, made of carbon, alloy and clad (two‑layer) steels. Intended for horizontal vessels and apparatus filled by gravity or operating at low internal pressures (typical limit given is up to 0.07 MPa). The standard excludes heads intended for vessels for liquefied gases and other specialized services where different rules apply.

Key topics and requirements

• Standard geometric definition of a conical head with apex angle 140° and associated nomenclature (diameter, cone height, skirt, blank dimensions).
• Tabulated basic dimensions for common nominal diameters and wall thicknesses, with corresponding cone heights and blank sizes.
• Dimensional tolerances and manufacturing allowances for blank and formed heads.
• Material scope (carbon, alloy and two‑layer steels) and intended pressure/temperature service limitations (low‑pressure horizontal vessels).
• Notes on applicability and explicit exclusion for liquefied‑gas vessels; references to related head types and standards for other apex angles or knuckle designs.

Typical use and users

Used by mechanical and pressure‑vessel designers, tank and vessel manufacturers, metal fabricators, procurement specialists and quality/inspection engineers who need standardised dimensions for conical heads during design, specification, fabrication and acceptance of horizontal tanks and low‑pressure vessels. Also used by technical libraries and standards offices as a reference for compatibility with other GOST mechanical standards.

Related standards

Companion and related GOSTs for vessel heads and shell components, for example: GOST 12620-78 (conical heads with apex angles 60, 90 and 120°), GOST 12622-78 and GOST 12623-78 (other types of heads). Related international pressure‑vessel design codes and standards frequently consulted alongside GOST 12621-78 include ASME Boiler & Pressure Vessel Code (Section VIII) and EN/ISO standards for unfired pressure vessels (for design and construction practice), and more recent national GOST/R and GOST R‑series documents covering tank heads and fabrication requirements.

Keywords

GOST 12621-78, conical head, dished end, apex angle 140°, basic dimensions, pressure vessel head, tank head, non‑knuckled head, vessel components, ГОСТ, dimensional tables.

FAQ

Q: What is this standard?

A: GOST 12621-78 is a national (USSR / Russian) standard that prescribes the basic dimensions and nominal sizes for non‑knuckled conical heads with an apex angle of 140° used on horizontal vessels and tanks.

Q: What does it cover?

A: It covers the geometric definitions, tabulated basic dimensions and manufacturing tolerances for conical heads (apex 140°), applicable materials (carbon, alloy, two‑layer steels) and the intended low‑pressure horizontal vessel applications; it does not cover heads for liquefied‑gas service or special pressured applications requiring other rules.

Q: Who typically uses it?

A: Vessel and tank designers, fabricators and manufacturers, procurement specialists specifying standard heads, and inspection/quality engineers who verify dimensional compliance during manufacture and assembly.

Q: Is it current or superseded?

A: The standard is designated GOST 12621-78 and is listed as in force (active). Amendments were issued and integrated (an amendment from the mid‑1980s is recorded). Users should check the national standards registry or the custodian body (Rosstandart) for the absolute current legal status before using it for regulatory or safety‑critical work.

Q: Is it part of a series?

A: Yes — it belongs to a family of GOST standards that define basic dimensions for various types of vessel heads (for example GOST 12620-78 for other cone angles and GOST 12622‑78 / 12623‑78 for other head shapes), allowing coordinated selection of head geometry across designs.

Q: What are the key keywords?

A: Conical head, apex 140°, dished end, basic dimensions, GOST 12621-78, pressure vessel head, non‑knuckled, ГОСТ.