Practical ventilation post Part F
Written for Window Fabricator and Installer
In this report for Window Fabricator and Installer, John Mitchell - head of technical support for Carl F Petersen Ltd, looks at how the complexities of 'Part F' have been addressed and how the dust has settled regarding ventilation requirements. The role of the installer is also examined and an insight provided into the challenges that are faced on site.
"Initially, Part F was intended as an 'across the board' stipulation for ventilation. However, it has been widely accepted that the calculations are so complex that it is both impractical and unmanageable to carry out retrospective changes. A more practical way forward has therefore been adopted which means that manufacturers and installers focus on Part F regulations for new build projects.
For replacement and refurbishment projects, the installation of trickle ventilators in replacement windows is deemed as best practice to ensure good airflow and indoor air quality in existing dwellings.
In all cases the ventilation opening should be at least equivalent to what was previously provided. In instances where there was no ventilation, or where the size of the original ventilation opening is not known, the minimum recommended sizes should be adopted.
Based on a 'whole house' approach, the new requirements take indoor air quality and building performance into consideration - as a result, bespoke ventilation systems are tailored to the size of the property. Additionally, mechanical and passive ventilation solutions are integrated to ensure whole building ventilation rates and effective airflow within the dwelling.
The performance measurement for background (trickle) ventilation referenced in the new document has been adapted to reflect the new performance approach to ventilation and 'equivalent area' replaces 'free area' for measuring vents in new build and refurbishment projects.
Making life easier
At Carl F we work in partnership with Greenwood Airvac having supplied the company's ventilation products for over a decade. As a market leading manufacturer of ventilation lines with a focus on quality solutions, Greenwood has taken a practical approach to Part F. Not only does Greenwood give the option of different slot sizes but the company has taken the proactive approach of completing performance tests for all sizes of vents. Calculations are summarised in an easy-to-use chart, available from Carl F, which makes life easier for all involved in the ventilation supply and installation chain.
Through Carl F's alliance with Greenwood, we have sub-divided our ventilation range to provide three product categories, namely: standard through-frame ventilation, glazed in solutions and over-frame lines for the new-build and refurbishment markets. We also provide an attractive range of powered, 'through the wall' ventilators to meet most domestic requirements.
But what part is played by those involved in installing ventilation products?
When ventilation products have been supplied by a technically led manufacturer that considers airflow issues and supports the window manufacturer in their calculations to achieve Part F, the installer can concentrate on their part in the process.
The key challenge for installers is ensuring that matters of quality control are upheld on site. This is important for all hardware fittings, but particularly critical for ventilation products. If there has been any damage in transit it is straightforward to replace a vent before it is installed but, once the window has been fitted, problems become much more difficult to resolve. To limit any problems of damage during transportation, a new range of 'F' vents from Greenwood offer the option of screw-fitting or clip fitting which enables the installer to quickly fit the product on site.
We are acutely aware that on new build projects the installer often works in a challenging, cramped environment under pressure to complete the job as other trades are champing at the bit to finish their work. However, despite these on-site pressures, we would urge those working in the front-line to take a moment when they receive the components of a ventilation system to check these have not been damaged. This is not only a matter of aesthetics but also performance - damage can affect airflow. Naturally, we take every step to ensure products are securely packaged, but quality control needs to be followed through on site.
Misalignment of vents will impact significantly on the finished appearance of a window - a few minutes checking final measurements will be time well spent. In short, quality processes apply before the ventilation products arrive on site and include air flow calculations and this best practice approach should be upheld on site. The end user will assume adequate ventilation but the thing they will notice is a damaged or unaligned ventilator."
