nonsealing

Nonsealing is a term used to describe the absence of a permanent seal at an interface, joint, or enclosure. In practice, it denotes situations where a seal is not formed, is intentionally omitted, or fails to maintain a seal under specified conditions. The concept is used across engineering, construction, packaging, textiles, and electronics to distinguish sealed from unsealed or vented configurations.

Nonsealing is advantageous when ventilation, drainage, pressure equalization, or serviceability is required. It can arise from design choices, such as gaskets with gaps, perforated seals, or intentionally loose fittings, or from practical issues like surface roughness, contamination, misalignment, insufficient compression, or environmental factors such as temperature and aging that degrade seal performance.

Examples include vented packaging that prevents condensation, breathable building envelopes, moisture-relief joints in masonry, and heat-dissipating interfaces in electronics. Nonsealing can be undesirable where sterility, weatherproofing, or containment is critical, in which case seals, sleeves, or alternative barriers are used to limit leakage or ingress while sometimes incorporating controlled venting or desiccants.

Measurement and standards focus on leak rate, moisture ingress, or pressure decay, with specifications defining acceptable levels of leakage or required ventilation. The term is often contrasted with sealing, sealing performance, or breathable design, and it intersects with related concepts such as venting, permeability, and interfacial compatibility.