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Vent-Axia assesses the impact of the new Building Regulations Document F - Means of Ventilation:
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In the relentless drive for better air quality and greater energy efficiency in buildings, the latest edition of
Building Regulations Document F went 'live' this October, and will begin taking real effect as from 6th April next year. That's when planning applications for all new and existing buildings will need to demonstrate compliance with the new requirements.
Why the changes?
By acknowledging the need for adequate means of ventilation and by specifying ventilation rates for the various occupied spaces within buildings, the original Document F-Means of Ventilation was an important step on the road to a healthier indoor environment. But it only prescribed minimum standards, and once you moved away from the idea of simple room-by-room extract fans and natural 'trickle' ventilation, it was all too easy to get lost in the 'Alternative Approaches'.
What's good about the new Document F is that it takes a 'performance based approach', and encourages best practice. Document F now also addresses the question of ensuring better indoor air quality by removing and preventing the ingress of gaseous and particulate pollutants, in addition to its original focus on condensation control.
More straightforward:
Each of the ventilation methods is brought into the main body of the Document. Now 'Continuous mechanical extract', Single Room Heat Recovery Products and 'Wholehouse continuous mechanical supply and extract with heat-recovery' feature alongside 'Background ventilators and intermittent extract fans' and 'Passive stack ventilation'.
All have their place as potentially acceptable solutions - the notable exception (as of October 2005) being positive input ventilation, which has concerns about controllability and 'as-installed' performance, especially in the well-sealed buildings of the future.
The design parameters, in relation to the number and type of fans, floor areas, siting of equipment and even maintenance access, are all explicitly defined for each of the specified systems. So now it's much easier to work out what's needed for a particular project, and to evaluate product choices in terms of overall cost, system performance and ongoing ease of maintenance.
As-installed performance:
Perhaps the most significant change for manufacturers relates to the 'as installed' airflow performance of ventilation equipment. It has long been a bone of contention that solutions featuring minimum spec/minimum cost fans have not been up to the job, despite test performance data suggesting their suitability.
Now Document F calls for airflow performance to be tested to a standard more relevant to actual conditions of use - to this end, the recently published suite of BS EN13141standards has been referenced, which gives a closer assessment of true volumetric performance of ventilation products in real installations.
Energy-efficient ventilation:
The new Document F also indicates a very significant shift towards energy efficiency and conservation of valuable indoor warmth during the heating season.
The 'General guidance' to Document F states that '...consideration should be given to mitigation of ventilation energy use, where applicable, by employing heat recovery devices, efficient types of fan motor and/or energy saving control devices in the ventilation system.'
This in turn points us towards Buildings Regulations Document Part L and improving building SAP Ratings through the use of these techniques, showing the joined-up thinking now underlying the Government's Standard Assessment Procedure for the Energy Rating of Buildings. Incidentally, SAP 2006 represents a 20% improvement over SAP 2002
There is also an implicit link with Building Regulations Document E, which addresses the problem of noise ingress - giving further support to whole-house ventilation, which can deliver the necessary air quality whilst shutting out neighbourhood noise.
These new Regulations are undoubtedly a strong endorsement for the leading HVAC manufacturers' work in establishing fan-drive efficiency, precise controllability and heat recovery as key characteristics of their product ranges.
It also points the way ahead in ventilation technology - Energy Saving LoWatt DC motors which can more than halve electrical power consumption and confer precise fan speed control, 'intelligent' electronic controls which minimise ventilation extraction rates whilst ensuring high indoor air quality, and heat-recovery systems which save as much as 90% of the indoor warmth that would otherwise be lost through essential ventilation.
The need for close-control:
All this is in the context of ideal buildings with a design air leakage rate down to 3 ach at 50 Pa. This is very airtight, and underlines the need for close-control of ventilation rates, so there's an obvious incentive to include powered heat recovery ventilation to achieve better SAP ratings for well-sealed houses.
Heat recovery ventilation can also bring electric heating back into the frame - combining the two can produce an 'energy-positive' solution. For developers of apartment buildings, where electric heating is the most practical option, this is good news.
And it's good news for residential social landlords faced with refurbishment projects featuring large numbers of electrically heated homes - a task made easier if the heat recovery ventilation systems and the replacement electric heaters can all be sourced with a single manufacturer as part of the overall scheme.
The pay-off:
Far from creating administrative overload for H&V manufacturers and the building industry, the new Document F is doing a great deal to clarify building design requirements and means of compliance. Previously, Document L called for the best energy-efficient solutions, but Document F didn't offer them. Now Document F is 'filling the gap' by giving developers, specifiers and contractors practical choices when it comes to ventilation and energy conservation.
It gives true scope for specifiers to set a lead in energy saving, for property managers to improve their building stock, and for developers to add value in an increasingly competitive and energy-aware marketplace. It all adds up to best practice and better choices.
The picture shows Vent-Axia's HR 100S. This delivers warmth, energy savings and high air quality, room by room.
Please click on the download button to obtain the full article, including more pictures and tables too (Word file - 1.28MB).
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Related contacts
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Vent-Axia
Fleming Way, Crawley
West Sussex RH10 9YX
Tel: +44 (0) 1293 526 062
Web: www.vent-axia.com |
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