BSRIA BG30/07 Guide to HVAC Building Services Calculations (BSRIA/CIBSE) This second edition has been expanded to include new and revised sections and provides practical, easy to follow methodologies for a range of calculations used in the design and sizing of heating, ventilating and air conditioning. The guidance is primarily based on data and procedures contained within the CIBSE Guides, together with other sources such as Building Regulations, with cross-referencing to data sources. Presented in the form of calculation sheets including design watchpoints, design tips and rules of thumb, the Guide is intended to aid the design process and reduce errors. Calculation sheets are presented in five sections: heating loads, cooling loads, water flow distribution, air flow distribution, and acoustics. Each section is introduced via flowcharts providing an overview of the system design process.