CIBSE TM40 addresses key environmental parameters that impact well-being in the design, construction and operation of buildings, specifically thermal conditions, humidity, air, light, acoustics, electromagnetic fields and water.

This revision updates the original version of TM40, published in 2006. A significant change in the document is the focus on performance outcomes. The revised document summarises existing health-based guidance and regulations and proposes recommended levels for each key environmental parameter. These may then be used as targets in new buildings, fit-outs and refurbishments, or as benchmarks in existing buildings to define priorities and improvement programmes.

This technical memorandum suggests that a useful approach to designing for health and well-being is to develop a design strategy for the people in a space and not for the space itself – which may result in a scheme meeting the desired environmental conditions only in the occupied space (rather than in the whole volume).

Looking ahead, CIBSE TM40 acknowledges that health and wellbeing is an evolving subject and that there is still much debate, research and development in numerous areas. To ensure professionals are aware of the current limits of knowledge, the document has collated these as emerging themes in each chapter of the TM.