Tips & How-To

CIBSE Guide B — What It Covers and Why It Matters

CIBSE Guide B is the system design bible for building services. If Guide A is about what conditions to achieve, Guide B is about how to achieve them.

Structure breakdown

B1: Heating — LTHW systems, radiators, UFH, heat pumps. Design approaches and sizing methods.

B2: Ventilation and ductwork — AHU selection, duct sizing, controls. The bridge between occupancy requirements and installed systems.

B3: Ductwork — Detailed specification, DW144 reference, fan selection. Where engineers check velocity limits and pressure drop.

B4: Refrigeration and heat rejection — Chillers, cooling towers, VRF. Refrigeration cycle design and heat rejection sizing.

B5: Noise and vibration control — NR criteria, duct attenuation, vibration isolation. The acoustic requirements that affect mechanical design.

How engineers use it

Not as a textbook but as a reference during design — checking velocity limits, selecting attenuation, verifying system configurations. Always verify against the current published edition; CIBSE updates guides periodically.

Where to access it

CIBSE Knowledge Portal (paid), university libraries, or through employer CIBSE membership. Access for non-members typically requires a subscription.

Track the current edition of Guide B and 62+ other standards with the free Standards Tracker.

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