ilmatiivisessä

Ilmatiivinen is a Finnish adjective meaning airtight or hermetic, describing a state or characteristic that prevents the passage of air and other gases. The inflected form ilmatiivisessä (in the inessive) is used to describe something that is in an airtight condition, for example in ilmatiivisessä astiassa (in an airtight container) or ilmatiivisessä tilassa (in an airtight space).

The term is commonly used in contexts such as packaging, laboratory vessels, vacuum systems, cryogenic storage, building envelopes, and various automotive or aerospace components. Achieving ilmatiivisyys involves sealing methods like gaskets, welding, mechanical seals, and adhesives. Materials chosen for airtight applications often have low gas permeability, including glass, metal, and certain polymers. The concept encompasses both the integrity of a single component and the overall seal of a system or enclosure.

Measurement and standards for airtightness vary by field. In vacuum technology, leak rates are expressed in units such as Pa·m³/s or mbar·l/s. In building science, airtightness is commonly assessed with tests that yield metrics like air leakage rate or air changes per hour (ACH), often via blower-door methods. A reliable ilmatiivisyys can improve content preservation, enable inert environments, and contribute to energy efficiency in buildings and systems.

Etymology and related terms: the word combines ilma (air) with tiivis (tight, sealed); the suffix -inen turns it into an adjective. Related concepts include tiiviys (airtightness), tiivistys (sealing), and tiiviste (seal or gasket).