insulator

An insulator is a material or device that resists the transfer of energy between bodies or within systems. In everyday use, the term covers electrical, thermal, and acoustic insulation. A material may function as an insulator for one form of energy while not for others; many products combine different insulating properties to reduce unwanted transfer of heat, electricity, or sound.

Electrical insulators are materials with high electrical resistivity and high dielectric strength. They prevent current from leaking between conductors, protecting equipment and people. Common electrical insulators include porcelain, glass, rubber, and various polymers. Their performance is described by properties such as volume resistivity, dielectric constant, and breakdown voltage. They must tolerate environmental conditions (moisture, temperature, UV exposure) and mechanical loads.

Thermal insulators have low thermal conductivity and contain trapped air or other low-density structures to reduce heat transfer by conduction, convection, and radiation. Materials include fiberglass, mineral wool, polyurethane foams, aerogels, wood, and air gaps. Used in buildings, refrigerators, pipelines, and apparel, they improve energy efficiency and comfort.

Acoustic insulators reduce sound transmission and vibration through barriers and enclosures. Common materials include fiberglass, mineral wool, acoustic foams, and dense mats. They are used in walls, ceilings, automotive cabins, and machinery enclosures to yield quieter operation.

Select insulators are chosen for durability, aging, moisture resistance, and compatibility with other materials. Insulation performance can decline with moisture ingress, mechanical damage, or thermal cycling. Proper specification and installation are essential to ensure safety and effectiveness.