Globe temperature
The globe thermometer was introduced by Vernon in 1930 as a means of assessing the combined effects of radiation, air temperature and air velocity on human comfort.
It consists of a hollow copper sphere painted matt black to absorb radiant heat, with a temperature sensor at its centre. When it reaches a steady state (after 15 minutes or so depending on the size of the globe and the environmental conditions) the heat exchanges by convection and radiation will be in equilibrium, and the temperature recorded by the sensor will be somewhere between the air and radiant temperature. This is referred to as the globe temperature (tg) or black globe temperature and resembles the thermal conditions felt by the human body.
The standard sphere has a diameter of 150 mm. Other sizes do exist, but the smaller the diameter of the globe, the greater the effect of convection on the temperature recorded.
From the temperature recorded, the mean radiant temperature (mrt) in can be calculated:
MRT = tg + 2.42 x air velocity in m/s (globe temperature – air temperature)
(equation ref Novalynx Corporation 2010 - this equation is dependent on the size and emissivity of the globe thermometer, and the units they show for air velocity are incorrect - cm/s, rather than the correct m/s shown above)
Mean radiant temperature is a measure of the average temperature of the surfaces surrounding a body.
[edit] Find out more
[edit] Related articles on Designing Buildings Wiki
Featured articles and news
Commissioning Responsibilities Framework BG 88/2025
BSRIA guidance on establishing clear roles and responsibilities for commissioning tasks.
An architectural movement to love or hate.
Don’t take British stone for granted
It won’t survive on supplying the heritage sector alone.
The remarkable story of a Highland architect.
The Constructing Excellence Value Toolkit
Driving value-based decision making in construction.
Meet CIOB event in Northern Ireland
Inspiring the next generation of construction talent.
Reasons for using MVHR systems
6 reasons for a whole-house approach to ventilation.
Supplementary Planning Documents, a reminder
As used by the City of London to introduce a Retrofit first policy.
The what, how, why and when of deposit return schemes
Circular economy steps for plastic bottles and cans in England and Northern Ireland draws.
Join forces and share Building Safety knowledge in 2025
Why and how to contribute to the Building Safety Wiki.
Reporting on Payment Practices and Performance Regs
Approved amendment coming into effect 1 March 2025.
A new CIOB TIS on discharging CDM 2015 duties
Practical steps that can be undertaken in the Management of Contractors to discharge the relevant CDM 2015 duties.
Planning for homes by transport hubs
Next steps for infrastructure following the updated NPPF.
Access, history and Ty unnos.
The world’s first publicly funded civic park.
Exploring permitted development rights for change of use
Discussing lesser known classes M, N, P, PA and L.
CIOB Art of Building photo contest 2024 winners
Fresco School by Roman Robroek and Once Upon a Pass by Liam Man.