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What is the fraction of floor area that is required for purge ventilation in a window?
Last Updated: 23 September 2025In the UK, Approved Document F of the Building Regulations stipulates that a window used for purge ventilation must have an openable area equivalent to at least 1/20th of the room’s floor area. For instance, a room measuring 20m² requires a minimum openable area of 1m². This rapid ventilation helps remove pollutants and moisture quickly....
What is the minimum intermittent extract fan ventilation rate in a kitchen adjacent to a hob?
Last Updated: 23 September 2025The minimum intermittent extract rate for a kitchen fan adjacent to a cooking appliance in the UK is 60 litres per second (l/s). Building Regulations Approved Document F stipulates this rate specifically for cookers and hobs to effectively remove moisture, grease, and combustion products generated during cooking. Understanding Kitchen Ventilation Requirements Ventilating a kitchen properly...
Under Awaab’s Law, if a damp and mould hazard poses a health risk, when should repairs commence?
Last Updated: 23 September 2025Under Awaab’s Law, landlords must commence an investigation into repairs within 14 days of receiving a complaint. Subsequently, they must start the actual repairs within a further 7 days, meaning work should typically begin within 21 days. This strict timeline applies specifically when the damp and mould are deemed a health hazard, ensuring tenants’ well-being...
How can I test my CO2 levels at home?
Last Updated: 23 September 2025You can accurately test your home’s CO₂ levels by using a dedicated indoor air quality monitor that employs non-dispersive infrared (NDIR) sensor technology, placing it at head height away from people and draughts, and interpreting the readings in parts per million (ppm) against UK health and building ventilation guidelines. Understanding CO₂ and Its Significance in...
What are the advantages and disadvantages of using passive stack ventilation in residential buildings?
Last Updated: 16 September 2025Passive stack ventilation offers zero running costs and silent operation, making it a low-maintenance, energy-efficient choice for some UK homes. However, its effectiveness relies heavily on weather conditions, leading to inconsistent performance, potential draughts in winter, and a lack of user control, which can result in poor indoor air quality if residents block the vents....
How does wind direction influence the operation of PSV systems?
Last Updated: 16 September 2025Wind direction significantly impacts passive stack ventilation (PSV) systems in the UK, often enhancing their performance, but also creating potential issues like over-ventilation or even reverse flow. The effects are due to wind-driven pressure differences around a building, which work in conjunction with the system’s primary buoyancy-driven “stack effect.” The Fundamental Forces at Play: Stack...
What is the impact of outdoor weather conditions on PSV efficiency?
Last Updated: 16 September 2025Outdoor weather conditions, particularly temperature and wind, significantly impact passive stack ventilation (PSV) efficiency. These systems rely on natural air movement driven by the stack effect (temperature difference) and wind pressure. Efficiency peaks in cold UK winters with high indoor-outdoor temperature differentials but can drop or reverse in warmer, still conditions, potentially compromising air quality....
How does indoor temperature affect air flow in passive stack ventilation?
Last Updated: 16 September 2025Indoor temperature significantly affects air flow in passive stack ventilation. This relationship hinges on the stack effect, a natural phenomenon where warmer, less dense indoor air rises through vertical ducts, creating a pressure differential that draws cooler air in through lower-level vents. The greater the temperature difference between inside and outside, the stronger this effect...
What factors influence the air-flow rate in PSV (Passive Stack Ventilation) systems?
Last Updated: 16 September 2025The air-flow rate in a Passive Stack Ventilation (PSV) system is primarily influenced by the stack effect, which is driven by temperature differences between indoor and outdoor air, alongside wind speed and direction acting on the terminal. Other critical factors include the system’s design, such as the diameter, length, and route of the ducting, the...
How does the natural stack effect contribute to air movement in PSV systems?
Last Updated: 16 September 2025The natural stack effect, driven by temperature and density differences between indoor and outdoor air, creates a pressure differential that draws warm, moist air upwards and out through high-level Passive Stack Ventilation (PSV) terminals, simultaneously pulling fresher, cooler air into the building from lower levels to maintain a continuous, energy-free airflow cycle. Understanding the Natural...