prechambers

Prechambers are spaces that precede a main chamber, functioning as an antechamber or transitional area. The term applies to architectural spaces as well as to technical components in engineering, and its plural form, prechambers, can refer to multiple such spaces or devices within a system.

In architecture, prechambers serve to regulate access, climate, acoustics, and security between the exterior and the primary interior room. They often appear as antechambers, vestibules, or entry halls adjacent to great halls, chapels, or audience chambers. Design features may include a sequence of doors, screens, steps, and controlled lighting, creating a formal progression from outside to inside and helping to mask movement, drafts, and noise.

In engineering, a prechamber or prechamber is a small auxiliary chamber used to prepare or ignite fuel before it enters the main combustion chamber. In some diesel engine designs, a prechamber contains a pilot flame or rich mixture that is ignited and then jets into the main chamber, promoting more reliable ignition and improved emissions at certain operating conditions. The concept also appears in burners and certain gas-turbine or industrial combustion systems where early ignition or mixing occurs in a dedicated chamber.

Because the term spans architecture and engineering, its exact meaning depends on context, but in all cases it denotes a temporary or transitional space that precedes a larger primary chamber.