AM10: Natural Ventilation in Non-domestic Buildings
About this book
CIBSE AM10, "Natural Ventilation in Non-domestic Buildings," is an Application Manual published by the Chartered Institution of Building Services Engineers (CIBSE) that provides comprehensive guidance for engineers and designers on the design and implementation of natural ventilation strategies in commercial, institutional, and public buildings. First published in 1997 and substantially revised, AM10 is the primary UK reference document for natural ventilation design practice. The manual covers the full spectrum of natural ventilation from fundamental principles to detailed design guidance.
It begins by establishing the environmental and energy performance case for natural ventilation: buildings that can be effectively naturally ventilated typically consume 50 to 80 percent less energy for space conditioning than equivalent mechanically ventilated and air-conditioned buildings, while research consistently shows that occupants in naturally ventilated buildings report higher satisfaction with their environment when given adaptive control. The physics section covers the two driving forces for natural ventilation: buoyancy (thermal stack effect), where temperature differences between indoor and outdoor air create pressure differentials that drive airflow through openings; and wind pressure, where the distribution of positive and negative pressure zones around a building created by wind creates flow through openings on different facades. AM10 provides the fundamental equations governing both mechanisms and explains how they interact, which is essential for predicting performance in real buildings where both forces act simultaneously.
The manual addresses the principal ventilation strategies in detail: cross-ventilation (flow through openings on opposite facades), stack ventilation (vertical flow through atria, light wells, or wind towers), single-sided ventilation (flow through openings on one facade, limited to approximately 2.5 times the floor-to-ceiling height in depth), and mixed-mode systems (combinations of natural and mechanical ventilation). Each strategy has different applicable building depths, occupancy types, and climate suitability profiles. A substantial section addresses building form and planning for natural ventilation: narrow floor plates to enable cross-ventilation, atria for stack-driven ventilation in deeper plans, the integration of operable windows and facades, and the design of ventilation openings including their sizing, placement, and control.
The manual provides guidance on computational fluid dynamics (CFD) and network modeling approaches for predicting ventilation performance, and on physical model testing in wind tunnels. Later sections address performance-based design: setting ventilation targets based on indoor air quality and thermal comfort requirements, assessment methods for predicting whether targets will be met, and post-occupancy evaluation to verify actual performance. The relationship with noise, security, and weather exclusion is also covered, as these practical constraints often determine the feasibility of natural ventilation in urban locations.
AM10 is referenced by the UK building regulations, BREEAM assessment methodology, and numerous other CIBSE and professional body guidance documents. Its influence has extended internationally, with similar approaches adopted in guidance documents in Australia, Singapore, and elsewhere. Sources: CIBSE (cibse.org); CIBSE AM10 official publication; CIBSE Journal technical articles; UK Department for Energy Security and Net Zero building regulations.