Standalone: The new way forward in non-domestic ventilation?

This is a BSRIA Member contribution to the BSRIA Blog, by Roy Jones, Technical Director at Gilberts (Blackpool) Ltd

Bars, restaurants and leisure venues are opening, schools have welcomed back pupils, people are heading back into work. But what, in the building services/ventilation sector, will be our new normal? One thing is already clear, things are going to change.

New Building Regulations

We have Building Regulations revisions imminent that will change the way we design ventilation strategies. The ingress of external pollutants should be minimised. Ductwork should be rigid, not flexible, and lengths kept to a minimum. Approved Document Part F is looking for not just a commissioning report to show the system works adequately, but information in operation and maintenance. The interim uplift for Approved Document Part L is looking for a 27% reduction in carbon emissions per building against the existing standard⁽¹⁾.

Inevitably, protecting against COVID, even despite the vaccination programme, will figure in specifiers’ minds. With the best will in the world, the initial Government guidance to achieve adequate ventilation re COVID of “opening windows” is not practical nor realistic as a long-term strategy alongside the global drive to cut carbon emissions and improve indoor air quality.

System evolution

Whereas on the face of it, the industry is facing a huge amount of change, the wherewithal to deliver is already widely available and in use. Legislation is just confirming what the quality manufacturers and engineers already implement. It all combines to, I believe, an increasing use of stand-alone ventilation and heat recovery systems, especially those that minimise energy usage. The latest evolution has been a hybrid- dynamic optimisation of natural ventilation, fan boosted mechanically when required. Ahead of the changes to Building Regulations, stand-alone versions have already been developed. Are these the way forward, to meet our requirements?

Some hybrid systems, such as units designed to meet current Regulatory guidance (eg. BB101 for schools), are stand-alone single-zone items, which obviates the need for ductwork, either to external or internal areas. No internal penetrations are required either, to move the air through the building, as each unit serves a dedicated zone, whether façade- or ceiling-mounted. This reduces major cost and labour in ductwork, fire dampers and silencers. The principle therefore already overcomes the potential obstacles when the revised Approved Document F comes into force. They ventilate just the one space, preventing transfer of particulates from one zone to another, and thereby minimising risk of internal cross-contamination. Some already deliver flow rates compliant with latest COVID guidance (i.e. to achieve a notional CO₂ below 1000ppm).
Carbon dioxide (CO₂) is currently the metric used to check the air is ‘fresh’ within a zone. Links have been established that higher CO₂ levels reflect higher Covid-19 risk.

Modular design

Within modular design products can be provided alongside a “mix and match” option of additions. These can be added to meet the specific use and requirements of the buildings to be ventilated.

Some options include:

• filter modules to address fine airborne particles, and maintain the IAQ within required limits
• connection modules to address site-specific installation limitations, to allow single-sided operation
• heating coils that can remove the need for ancillary supplementary heating such as radiators,
• acoustic attenuation to modulate noise below 30dBA
• control unit to enable easy management of the IAQ and temperature to facilitate any over-ride as required. This provides capable boost and purge ventilation and night-time cooling.

Get it right

The amount of change, not just in Regulations, but how we use our non-domestic buildings in future, is vast. Specifiers and designers should use the expertise of product manufacturers to their advantage. It is wise to tap this knowledge bank to ensure delivery of the best compliant solution for the project.

This blog article was written by Roy Jones, Technical Director at Gilberts (Blackpool) Ltd.

(1) https://www.gov.uk/government/publications/building-regulations-approved-documents-l-and-f-consultation-version