Designing Buildings - The Construction Wiki

Search

Subjects

Tools / info

Edit this article

Last edited 30 Dec 2022

Exposure

In its broadest sense, the word ‘exposure’ refers to a state of being vulnerable to something harmful, or the degree of protection of something from negative impacts – such as the weather, or economic changes.

A Guide To Climate Change Impacts, On Scotland’s Historic Environment, published by Historic Environment Scotland in October 2019, defines exposure as: ‘The natural features of an asset’s position within the landscape that render it vulnerable to harm or damage.’

Water safety in buildings, published by the World Health Organization in 2011, defines exposure as the: ‘Concentration or amount of a particular agent that reaches a target organism, system or (sub)population in a specific frequency for a defi ned duration (WHO, 2004a).’

Advice for Building Owners of Multi-storey, Multi-occupied Residential Buildings, published in January 2020 by the Ministry of Housing, Communities and Local Government, states: ‘There is no prescribed definition of an exposed location but typically this would include buildings in an elevated or hill-top location, sea side locations, areas where the surrounding terrain will not provide sheltering from wind, or a combination of these factors. In dense cities, funnelling will need to be considered which could increase the wind effect.’

Global Warming of 1.5 ºC, Glossary, published by the Intergovernmental Panel on Climate Change (IPCC) in 2018, defines exposure as: ‘The presence of people; livelihoods; species or ecosystems; environmental functions, services, and resources; infrastructure; or economic, social, or cultural assets in places and settings that could be adversely affected.’

The English Housing Survey captures data regarding site exposure of the dwelling. This is different to exposure zones, which indicate the approximate amount of wind driven rain which the building may be subject to. In the EHS, 4 categories of site exposure are recorded as:

Not exposed: The dwelling is in a sheltered position, possibly surrounded by other buildings or trees or tucked away in a valley.
Slightly exposed: The dwelling is quite sheltered but may be buffeted by winds from time to time.
Exposed: The dwelling is open to the elements, possibly on all 4 sides with little shelter provided by other buildings or natural obstacles.
Very exposed: The dwelling is permanently exposed to the worst that the English elements can offer. Cliff top houses and isolated hill farms might fall into this category.