Set point
In the construction industry, the term ‘set point’ (or sometimes set-point or setpoint) typically refers to the point at which a building system is set to activate or deactivate.
For example, a heating system might be set to switch on if the internal temperature falls below 20°C, an extract fan might be set to switch on if the relative humidity in a room exceeds 65% and so on.
Set points can be fixed, adjustable or variable. An adjustable set point might be controlled for example by a manually-operated thermostat. A variable set point might be controlled by some form of calculation, for example, set points for air conditioning systems may be programmed to be higher when outdoor temperatures are higher as people are more conditioned to, and dressed for those higher temperatures. Alternatively, if a building is unoccupied, the set point for the heating might be programmed to reduce to just 5°C to prevent pipework from freezing.
The set point at which something is activated may be different from the set point at which it is de-activated. This prevents continually switching on and off if the conditions are very close to the set point.
Set points may be fine-tuned during the commissioning process, and building occupants may be given control of some set points, perhaps within prescribed parameters.
Set points should be monitored, and checked regularly to ensure that they are correctly set and that they are delivering the required result. Seemingly small changes in set points can have a significant impact on performance and energy use. In addition, some building spaces may house critical operations requiring very specific, closely-controlled set points.
It is important therefore that building operators and occupants are provided with an explanation of set points, their operating ranges, and the impact of adjustments on performance and energy use.
NB Guide to Controls (BG 83/2023) written by John Marrow and published by BSRIA in June 2023, defines setpoint as: ‘An adjustable level of a parameter, such as temperature, humidity or pressure, which a control system aims to achieve.’
[edit] Related articles on Designing Buildings
Featured articles and news
Electrotechnical excellence, now open for entries.
Net zero electricity grids BSRIA guide NZG 5/2024
Outlining the changes needed to transition to net zero.
CIOB Global Student Challenge 2024
Universitas Indonesia wins for second year running.
New project and cultural district described in detail.
The nature of EPCs, crticism and inaccuracies.
History, issues and redesign.
From waste recycling to energy performance the hierchy.
An introduction to WERCS and WEEE responsibilities
Dealing with 2 million tonnes of waste equipment a year.
Global BACS Market: analytics and optimisation
A BSRIA glance at building automation and control systems.
What it is and how to use it.
Types of insulating plaster by binder and insulant.
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.