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

October 5, 2021 by Leave a comment

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

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What makes a good PICV?

September 22, 2020 by Leave a comment

by Andrew Pender, National Sales Manager at FloControl Ltd.

Over the last 5 years, PICVs have been widely accepted as the best method of terminal control in variable flow systems due to their energy saving potential.  The surge in popularity has led to an influx of products with varying designs, features and functionality.  This article reviews some of the mechanical PICV design elements and how they can impact on the PICV’s performance in an applicational context.

Where do we start?

To help specifiers and project engineers assess which PICV is best suited for an application, the BSRIA BTS1/2019 standard has been developed to provide a consistent test method for PICV manufacturer’s products to be benchmarked against.

Manufacturers should be able to provide test results in line with this technical standard which covers:

  • measured flow vs nominal flow
  • pressure independency or flow limitation
  • control characteristics, both linear and equal percentage
  • seat leakage test

Repeatability & Accuracy are central to the tests and they are key to good temperature control and realising the full energy saving potential of a PICV installation.

An accurate PICV means the measured results will be equal or very close to the manufacturer’s published nominal flow rate each time it is measured, known as low hysteresis.

Accuracy has a positive impact on a building’s energy consumption.  “Measured over time, a 1% increase in the accuracy of a PICV can result in a reduction of around 0.5% in the building’s overall hydronic energy consumption” (FlowCon International).

Valve accuracy is driven by the design, manufacturing process and material used for the internals of the valve.

  • The design of the PICV should allow for Full Stroke Modulating Control at all flow settings without any stroke limitation.  The flow setting and temperature control components should operate independently.  Some PICV designs use the stroke of the actuator stem to set the flow rate resulting in limited stroke and control.  This can cause issues at low flow rates whereby the PICV effectively becomes on/off irrespective of actuator selection.  
  • The manufacturing process and the component materials also contribute to accuracy. For example, injection-moulded, glass-reinforced composite materials cope better with water conditions that valves can be exposed to.  They also have less material shrinkage than other materials, delivering higher accuracy than valves that use alloy components.

What else should be considered?

The importance of accuracy and repeatability are paramount when selecting a PICV however there are other factors that should be considered:

  • Wide flow rate range – including low flow rates for heating applications, ideally covered by a small number of valves.
  • Setting the flow rate – setting the PICV can influence the accuracy. There are various scales used including set points related to flow rates and percentages. PICVs with very detailed scales with small increments between set points are more difficult to set accurately, leading to higher tolerances than the BSRIA standard recommended + 10%.
  • Wide ΔP Range – low start up pressure. To operate satisfactorily, the PICV requires a minimum pressure differential to overcome the initial spring resistance within the PICV, enabling the spring to move and take control. Care should be taken to ensure the minimum pressure differential is as low as possible to maximise the energy saving potential of the system.  The maximum DP should also be considered to ensure the PICV operates effectively under part load conditions.
  • Dirt tolerance – the Valve Control Opening Area [A] on all PICVs, irrespective of the manufacturer, is identical for each flow rate. The shape of the Control Area can be different depending on the valve design. A Rectangular flow aperture is more tolerant than an Annular flow aperture. Debris will pass through the rectangular aperture more easily.
  • Removable inserts – deliver the greatest flexibility and serviceability.  Products can be easily serviced in line without disruption. This is especially of value when water quality is poor or when flow requirements change due to changes in space usage.  Inserts can also be removed during flushing.  Valve bodies can be installed with blank caps eliminating the risk of damaging or contaminating the PICV element, whilst having a full-bore flushing capacity.
  • Installation – PICVs in general have no installation restrictions however in line with BSRIA BG29/20, it is recommended that PICVs should be installed in the return branch as small bore PICVs will have a high resistance which will hinder the flushing velocity during the forward flushing of terminal units.

Making the right choice

There are many aspects for specifiers and project engineers to consider when selecting the right PICV for an application.  The BTS1/2019 standard provides an excellent benchmark, but the individual designs also need to be carefully considered.  A correctly selected PICV will ultimately lead to a more comfortable indoor climate with better control of the space heating and cooling as well as potentially reducing the pump energy consumption in a building by up to 35%.

This post was authored by Andrew Pender, National Sales Manager at FloControl Ltd. All views expressed are those of the author. If you belong to a BSRIA Member company and wish to contribute to the BSRIA Blog, please contact marketing@bsria.co.uk

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Shift in Construction Technology for a ‘post-Covid, pre-vaccine’ era

September 3, 2020 by 2 Comments

by Amy Butler, JB Associates

In 2017, McKinsey Global Institute slated construction for evolving at a ‘glacial pace’ due to its ranking as the least-digitised industry in Europe. While plenty of technological advances were pitted as ‘on the horizon’, many companies were reluctant to take the necessary steps to push forward with digitisation. Critics warned that a lack of innovation would lead to companies folding, although it took a global pandemic before this prophecy materialised and those without suitable digital infrastructure in place were shaken.

The pandemic is now considered a catalyst for industry improvement, propelling construction out of its ‘glacial’ evolution and deep into the digitised era. A recent study undertaken by Procore found that two thirds of the surveyed construction companies had rolled out new technology during the lockdown, with 94% of these seeing an improvement to productivity and teamwork. However, what exactly are these technologies and where do we go from here?

Smart Buildings

While we are all now experts in the world of Zoom and Microsoft Teams, the challenge lies in returning safely to offices and various other workspaces. With many UK companies pushing for their teams to be back in work physically, how do we ensure that commercial buildings remain safe? Smart Building technology is reshaping the workplace and ensuring safety as well as energy optimisation. Buildings with integrated BMS systems and IoT sensors were already an option before the pandemic. Now, they are a wise choice for business owners.

Essential for a post-Pandemic and pre-Vaccine era, IoT systems can control air quality and ventilation. High-performance air filters and moisture controls will now be key due to Covid-19’s airborne nature. OKTO Technologies (Smart Buildings specialists) have even launched an Artificial Intelligence-led air filtration solution that is reportedly so advanced it can eliminate 99.98% of SARS-CoV-2 (the virus that causes Covid-19) from the air in 10 minutes.

Similarly, density control counters and heat detection cameras can be incorporated into BMS systems to ensure that viruses are less likely to spread or enter into a facility. Airports have been trialling infrared cameras to measure body temperatures for a fever and several companies offer leases or installations for these cameras. While they are not a definitive medical diagnosis, they add a level of reassurance. This may be the aim of much of this technology; a form of due diligence in protecting staff.

BIM & VR

Technological advances are also prominent on site. Construction News reported that contractors employed for the Nightingale Hospital projects found huge value in Autodesk programs. A vital tool for tracking constant streams of updates in rapid working conditions, construction management software proved its worth in recognisably challenging projects across the UK.

As social distancing measures remain in place, it is imperative that technology is prioritised; virtual communication is still far safer than face-to-face. Software like BIM is also providing insights and tools to manage projects during a more challenging time. Even more impressively, companies are merging BIM models with the cloud, GPS and Virtual Reality software. This development means a ‘digital twin’ of a facility can be created and it opens a world of opportunities for Project Management and Design efficiency.

Remote working could even be a trend that stays long past pandemic precautions. Drones have been used previously to reduce safety hazards for technicians and now may be utilised in future remote inspections. Similarly, researchers at the University of Strathclyde have been given £35,000 in funding to create a remote inspection system. The 3D immersive building environment program aims to reduce risks by eradicating the need for Quantity Surveyors or Health and Safety Inspectors to be physically present on site.

Whether enabling remote working, improving the health and safety of commercial buildings or aiding on-site processes, technology has become a necessary tool for construction in the last 6 months. The companies that had embraced digitisation long before 2020 were undoubtedly the ones able to continue thriving in the tough lockdown period. The next step is for many companies is to streamline their management processes or workplace systems to ensure technology works for them as efficiently as possible. Breaking out of its inertia, construction’s ‘glacial evolution’ is firmly in the past and technological advances are here to stay.

This post was authored by Amy Butler of JB Associates – building consultancy specialists. The views expressed are those of the author.

BSRIA Members wishing to make a guest contribution to the BSRIA Blog should please contact marketing@bsria.co.uk

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