Rise and fall method
The rise and fall method is a technique used in surveying to determine the difference in elevation between two points. It is commonly used in design and construction to create accurate site plans.
A levelling instrument such as a dumpy level or a theodolite is set up at one point (the benchmark) and a staff is placed at a point whose elevation is to be determined. The instrument is then sighted on the staff and the vertical distance between the instrument and the staff is measured. This is known as the backsight.
The staff is then moved to the next point and the instrument is sighted on the staff again. The vertical distance between the instrument and the staff is measured once more, and this is known as the foresight.
If the foresight is higher than the backsight, it means that the point being surveyed is higher than the benchmark. The difference between the foresight and the backsight is known as the rise. If the foresight is lower than the backsight, it means that the point being surveyed is lower than the benchmark. The difference between the backsight and the foresight is known as the fall.
The process is repeated for multiple points, with the rise and fall measurements being added and subtracted as appropriate.
[edit] Related articles on Designing Buildings
Featured articles and news
New Great British Energy partnership launched
Crown estate help to turbocharge energy independence.
ECA Industry Awards 2024 shortlist revealed
22 leading businesses from across the electrotechnical and engineering services sector.
Government unveils Skills England strategy
Skills England to transform opportunities and drive growth.
New Government Hub for York Given Planning Green Light
For up to 2,600 civil servants, due for completion by 2028.
Construction Skills Certification Scheme cards
July update on Professionally Qualified and Academically Qualified Person Cards.
BSRIA Briefing 2024, November 22
Sustainable Futures: Redefining Retrofit for Net Zero Living.
The CLC on driving competency in the retrofit sector
Previously published roadmap on skills for net zero.
The first labour government King's speech in fifteen years
Construction industry reactions, support and some concern.
CIOB Retrofit of Buildings Technical Information Sheet
What retrofit is, the approach to be taken and processes to be followed.
Adapting Historic Buildings for Energy and Carbon Efficiency
Historic England advice note 18, free download published.
10 retrofit projects revisited 10 years after completion.
Information orders, building liability orders and SPVs
Key BSA terms and how they impact special purpose vehicles.
Listed despite problems with its design.
Zen and the art of cycling exploration.
Design Council Homes Taskforce launched
To support government 1.5 million homes target within UK climate commitments.
Comments
[edit] To make a comment about this article, or to suggest changes, click 'Add a comment' above. Separate your comments from any existing comments by inserting a horizontal line.