Page 281 - ACEL 2024-2025 Catalogue

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Ventilation & Heating
PART F and PART L Compliant Energy Saving Ventilation
Part F and L of the Building Regulations placed much greater emphasis on effective design, installation and operation of ventilation systems. The objective is to maximise carbon reduction through correctly specified and designed systems, competent installation minimising losses of the systems, verified performance once installed and correct operation by the home owner.
Part L
Target Emission Rates (TER’s) have been set to deliver 25% over the previous regulations, in line with the Code for Sustainable Homes Level 3. The regulations require a maximum Specific Fan Power (SFP) as minimum energy efficiency. This is measured in watts per litre a second of airflow (w/l/s) extracted and covers both new build AND refurbishment.
The table below shows the maximum Specific Fan Powers required to comply with the new building regulations.
SPECIFIC FAN POWER
• Intermittent extract fans – specify a maximum of 0.5w/l/s
• Continuous extract fans – specify a maximum of 0.7w/l/s
• Continuous supply and extract with heat recovery - 1.5w/l/s
The Heat Recovery efficiency of balanced mechanical ventilation systems incorporating heat recovery should not be worse than 73%.
You can be reassured that ALL Acel products in the Whole House Ventilation and Part L compliant domestic ventilation ranges comply with these regulations.
Part F
Airtightness – There are different ventilation requirements depending on the airtightness (permeability) of the building. This is measured by how much air (m3) leaks through the external surface of a building (m2) in an hour: (m3h/m2)
Ventilation Rates
A) For properties leakier than 5m3h/m2, continuous extract fans (MEV or dMEV) do not require background (trickle) ventilators.
B) Traditional intermittent extract fans require significantly increased trickle ventilators at any air permeability, so favouring continuous systems.
C) Mechanical Ventilation with Heat Recovery (MVHR) ventilation rates can be reduced if the building air permeability is greater than 5m3h/m2
Installation – Installed performance of ventilation is now verified through commissioning
There will also be post-completion testing and if you have designed to 5m3h/m2 at 50 Pa and achieve down to 3 then the ventilation will still be considered adequate.
MVHR systems will have higher airflows in properties above 5m3h/m2.
For more information visit www.electric-center.co.uk
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