Building Regulations and ventilation: it’s time to make Part F work harder

With Approved Document F – or Part F, as it is often referred to – of the Building Regulations under review again, it’s time to review how well our legislation addresses Indoor Air Quality (IAQ) and adequate ventilation. Rupert Kazlauciunas of Zehnder Group UK, reports

It’s still not clear what the scale of changes and amendments will introduce.

However, one thing is abundantly clear: only a complete overhaul of the standards set in Part F, the powers given to those who regulate it and the ongoing education of those using ventilation units will be enough to prevent the damage that is occurring to the UK’s health from poor IAQ.

Let’s take a look at what’s currently wrong – and suggest some fixes. And let’s hope they are picked up as part of the current review of Part F.

What is Part F?
Part F of the Building Regulations covers the ventilation and air quality requirements for all buildings.

It considers three ventilation types:

  • Whole building ventilation – to provide fresh air that can dilute and disperse low levels of water vapour and other pollutants, usually via mechanical supply ventilation
  • Local extract ventilation – for rooms, like bathrooms or kitchens, where most water vapour or concentrated pollutants are released, usually via extract fans
  • Purge ventilation – to rapidly dilute and remove high concentrations of pollutants from occasional activities, usually via opening windows

To ensure that the minimum standards that are set in Part F are met, a flow rate test is required and the results must be submitted to Building Control via a Commissioning Notice.

What is the current state of play with ventilation and IAQ?
In its review of the state of our ‘unhealthy homes’, the recent White Paper from the All Party Parliamentary Group for Healthy Homes and Buildings noted that the recent single-minded focus on energy efficiency – at the expense of other critical areas such as ventilation – was leading to renewed risks of poor IAQ.

VOCs released into our thermally-efficient homes – from items such as carpets, lino, paints, furnishing fabrics and plastics lino – no longer have the many escape routes provided by drafty, older buildings.

Unless, that is, adequate ventilation is also being supplied.

We have raised similar issues and concerns in the past and now is the time to try and push these more forcefully onto the agenda. The issue is not that ventilation is not addressed by Part F currently – it’s that the checks in place are woefully inadequate.

Self-certification is an obvious starting point for improvements – with a clear case for an independent body being used to check installations for air flow rates. And, beyond this, there also needs to be checks made to ensure that ventilation systems continue to perform to required standards beyond that initial check.

Let’s look at what needs addressing in a bit more detail.

1. Ventilation installation

The BRE recently argued that:
‘Improving legislation is all well and good, but you have to ensure that there are an adequate number of people … that understand the issues to ensure that buildings are both designed and built correctly. Currently this is not the case.’

Put simply, if the ventilation units aren’t commissioned properly to the required flow rates – and this is comprehensively checked – then this will continue to contribute to an increased risk.

‘The Government should ensure the competency of installers is improved, for example by requiring that all installers are members of a registered competent person scheme, and ensuring they have the necessary skills and knowledge.’ Healthy Homes and Buildings

2. Ventilation use

The issue of ventilation systems being used correctly has also been raised as an ongoing concern. But, although Appendix A of Part F mentions that mould growth can occur if the performance criteria for reducing moisture is not met at all times, there is no provision for the fact that:

  • Intermittent fans may not be used by residents
  • MEV or dMEV units may be turned off
  • Filters in MVHR units may not be cleaned or maintained by landlords or owners
  • Constant volume motors in MVHR units are not required to be fitted to ensure minimal flow rates are always met

And the result of any of these could be poor IAQ, condensation and health-harming mould.

3. Ventilation and overcrowding

There are more than half a million overcrowded households, affecting one child in ten in England. The problem is at its most acute in London, but overcrowding nationally in the private and social rented sector is at its highest level ever.

Overcrowding is one of the most significant risk factors for condensation: with more occupants in a home, the building has more moisture to contend with.

Ventilation is critical to prevent damp. Homes need to be better ventilated, especially those which are overcrowded. But most ventilation systems are designed to the minimum level that the building regulations set, and so, when houses have higher than minimum levels of occupancy, the ventilation is not sufficient to the excess moisture from the air.

Ventilation and energy efficiency
The incentivisation of building and retrofitting energy efficient homes is currently taking place without adequate provision or incentives for issues such as ventilation that affect IAQ.

The concentration on insulation and making homes more airtight can lead to condensation if they are installed badly or without enough additional, continuous ventilation.

And, as the Healthy Homes White Paper reports:

‘Ventilation is rarely a consideration when energy efficiency measures are installed and competency issues (caused by a lack of standards required of installers) are leading to unintended consequences.

There should be greater enforcement and quality control of home renovation standards with a shift towards measuring ‘in use’ performance standards, not just design performance, to ensure that improvements made … do not negatively impact on health and wellbeing.’

IAQ, Part F and wider industry initiatives
It is hoped that, as part of the upcoming Part F review, issues of self-certification by installers, compliance and a closer focus on ventilation in use will be considered.

We welcome the fact that ventilation and IAQ are increasingly receiving the attention they have long-deserved and that many different working groups are actively seeking to address these issues.

Alongside the Part F review there is also a potential SAP change (SAP 11): it is likely that IAQ will form part of its focus. In addition, the European Ventilation Industry Association (EVIA) is discussing an IAQ rating on its products.

While these pincer movements look like moving things in the right direction, we are still left with two issues that must be resolved if we are to tackle IAQ issues effectively.

The first is theoretical.

We need to define exactly what constitutes poor IAQ if we are to adequately test and regulate solutions.

The second is practical.

There is an ongoing clash – as yet unresolved – between achieving lower energy consumption levels and achieving a high-standard of IAQ. These are issues that the industry as a whole – rather than regulatory bodies – must solve.

Rupert Kazlauciunas is Technical Product Manager at MVHR, Zehnder Group UK