Freeboard
Culvert, screen and outfall manual, (CIRIA C786) published by CIRIA in 2019, defines freeboard as: ‘An allowance for uncertainty in design water level and any other physical processes that may affect the ability of an asset to withstand the design water level such as wave action or superelevation.’
See also Residual uncertainty allowance.
Containment systems for the prevention of pollution, Secondary, tertiary and other measures for industrial and commercial premises (CIRIA C736), published by CIRIA in 2014 defines freeboard as: ‘An allowance in the form of increased height of a containment wall for additional capacity over and above the minimum design requirement.’
Rules of Thumb, Guidelines for building services (5th Edition) BG 9/2011, by Glenn Hawkins, published by BSRIA in 2011, defines freeboard as: ‘The vertical distance in a water tank between the maximum water level and the top of the tank’. This definition is repeated in BG 87/2024, Useful Information Guide, written by Chin Hang “Kay” Lam and published by BSRIA in 2024.
High Speed Rail (Crewe – Manchester) Environmental Statement, Glossary, abbreviations and references, published by the Department for Transport in 2022, defines freeboard allowance as:
The height from the maximum design level of a watercourse to:
- the adjacent banks of an open channel, to provide a factor of safety against flooding; or
- the soffit (underside) of any culvert or bridge above, to reduce the risk of blockage by floating debris, etc.’
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Accommodating the Victorian and Edwardian working woman. Book review.
Rethinking passive fire protection in design
PFP demands the same level of design rigour as structure or services.
38% of Gen Zs feel safe when a fire door is wedged open.
Stunning images from around the world
Shortlist for CIOB’s Art of Building photography competition.
Guidance for conversion of traditional pre-1919 stone buildings.
Industrial heritage in the Ruhr
A marked difference to the fate of industrial landscapes in the UK.
Communities will be able to build their own clean energy.
Why diversity and inclusion matters for SMEs
CIOB’s D&I Charter shows how practical changes can support long-term growth.
Cut electricity bills to power growth
Coalition sends joint letter to the Chancellor.
Gasholders: a history in pictures. Book review.
Recognition, influence and growth
SocEnv identifies three strategic pillars in new strategy to 2045.
Discover the future of roofing, cladding and insulation.