Half-life
Half-life is a measure of the time taken for a quantity to reduce to a half its initial value. The term is found in the medical and nuclear sciences and is expressed by the formula t by 1/2 or t1/2.
In particular it is used to describe the speed at which unstable atoms become less stable through decay, releasing radioactivity in the process, or conversely, how long atoms remain stable.
In medical science the same measure is used to describe the biological life span of drugs and other chemicals in the human body.
It is also more generally used to describe any type of exponential or non-exponential decay.
The converse of half-life (when considering exponential growth) is doubling time.
[edit] Related articles on Designing Buildings
- Chernobyl New Safe Confinement.
- Generation nuclear.
- Methane and other gasses from the ground.
- Nuclear power.
- Planning and managing Hinkley Point C.
- Radon protection for new domestic extensions and conservatories with solid concrete ground floors (GG 73 revised).
- Radon: Guidance on protective measures for new buildings BR 211
- Radon protection for new dwellings GG 74.
- Radon protection for new large buildings GG 75.
- Radon.
- Radon: Guidance on protective measures for new buildings BR 211.
- Types of radioactive material (Radionuclides)
Featured articles and news
Call for greater recognition of professional standards
Chartered bodies representing more than 1.5 million individuals have written to the UK Government.
Cutting carbon, cost and risk in estate management
Lessons from Cardiff Met’s “Halve the Half” initiative.
Inspiring the next generation to fulfil an electrified future
Technical Manager at ECA on the importance of engagement between industry and education.
Repairing historic stone and slate roofs
The need for a code of practice and technical advice note.
Environmental compliance; a checklist for 2026
Legislative changes, policy shifts, phased rollouts, and compliance updates to be aware of.
UKCW London to tackle sector’s most pressing issues
AI and skills development, ecology and the environment, policy and planning and more.
Managing building safety risks
Across an existing residential portfolio; a client's perspective.
ECA support for Gate Safe’s Safe School Gates Campaign.
Core construction skills explained
Preparing for a career in construction.
Retrofitting for resilience with the Leicester Resilience Hub
Community-serving facilities, enhanced as support and essential services for climate-related disruptions.
Some of the articles relating to water, here to browse. Any missing?
Recognisable Gothic characters, designed to dramatically spout water away from buildings.
A case study and a warning to would-be developers
Creating four dwellings... after half a century of doing this job, why, oh why, is it so difficult?
Reform of the fire engineering profession
Fire Engineers Advisory Panel: Authoritative Statement, reactions and next steps.
Restoration and renewal of the Palace of Westminster
A complex project of cultural significance from full decant to EMI, opportunities and a potential a way forward.
Apprenticeships and the responsibility we share
Perspectives from the CIOB President as National Apprentice Week comes to a close.