Overview
ISO 7483:1991 specifies dimensions of gaskets for use with flanges to ISO 7005. It defines the geometric dimensions and size ranges for a range of gasket forms - not the materials - so manufacturers, specifiers and end‑users can select gaskets that correctly fit steel, cast‑iron and copper‑alloy/composite flanges manufactured to ISO 7005 series.
Key gasket forms covered:
- Non‑metallic flat gaskets (full‑face, IBC, tongue‑and‑groove, spigot‑and‑recess, segmental)
- Spiral wound gaskets
- Metallic ring‑joint gaskets
- Non‑metallic envelope gaskets
- Corrugated, flat or grooved metallic and filled metallic gaskets
Annex A (informative) lists flange facing types; Annex B (informative) lists purchaser information to be supplied when ordering.
Key topics and requirements
- Dimensional tables and plans: The standard contains detailed tables and plan views giving outside/inside diameters, bolt circle diameters, hole sizes and numbers, and thickness ranges to suit nominal sizes (DN) and nominal pressures (PN).
- Gasket thickness selection: Thickness options for non‑metallic flat gaskets are specified and cross‑referenced to typical material categories.
- Gasket types and designs: Defines acceptable gasket designs for each flange facing type (A–F) and for different PN/DN ranges.
- Ring‑joint specifics: Includes dimensions, tolerances and typical hardness values for metallic ring‑joint gaskets and requirements for surface texture and marking.
- Normative references: Uses ISO standards such as ISO 7005 (flanges), ISO 6708 (nominal size DN), ISO 7268 (nominal pressure PN) and ISO 468 (surface roughness) for consistency.
- Scope limits: Materials and detailed performance properties are explicitly outside the scope; selection should consider operating conditions and supplier guidance.
Practical applications
- Specifying gasket geometry in piping, pressure‑vessel and pipeline design to ensure correct fit with ISO 7005 flanges.
- Creating procurement and inspection documents that reference correct DN/PN gasket dimensions.
- Guiding manufacturers in producing standardized gaskets (dimensions, marking, identification).
- Supporting maintenance, repair and operations (MRO) teams in selecting replacement gaskets that match flange geometry.
Who uses this standard
- Piping and mechanical engineers
- Gasket and flange manufacturers
- Procurement/specification writers
- Plant maintenance and reliability teams in oil & gas, chemical, water, power and industrial process sectors
Related standards
Practical note: Because ISO 7483 does not cover gasket materials or performance limits, always confirm material, temperature and pressure compatibility with gasket suppliers when specifying gaskets for actual service.
