Indoor air quality: 7 contaminants to be aware of

In the UK, on average people spend more than 90% of their time indoors.

Indoor air quality is affected by outdoor pollution, but also by indoor sources and inadequate ventilation. Air pollution can have a negative impact on our health; from short term effects such as eye irritation and coughs to long term effects such as respiratory infections and cancer.

Here, we take a look at contaminants commonly found in buildings. For more information on how to manage indoor air quality, please visit the BSRIA Air Quality Hub.

Carbon Dioxide

A colourless and odourless gas resulting from combustion and breathing. At higher concentrations carbon dioxide can cause drowsiness, fatigue, and dizziness as the amount of oxygen per breath is decreased. In an enclosed environment, ventilation is key to reduce carbon dioxide build-up.

Carbon Monoxide

An odourless and colourless gas produced by incomplete combustion of fuels such as oil, wood, and gas. Carbon monoxide binds with haemoglobin in blood cells instead of oxygen, rendering a person gradually unconsciousness even at low concentrations.

Ozone

Whilst beneficial in the stratosphere, when found at ground level, ozone causes the muscles found in the respiratory system to constrict, trapping air in the air pockets, or alveoli. Ozone can be produced by certain air purifiers, laundry water treatment appliances and facial steamers.

Particulate Matter 2.5

A complex mixture of solid and or liquid particles suspended in air, where the diameter of the particles are 2.5 microns or smaller. PM2.5 sources include transportation, power plants, wood and burning and can cause airway irritability, respiratory infections, and damage to lung tissue. 

Particulate Matter 10

A complex mixture of solid and or liquid particles suspended in air, where the diameter of the particles is 10 microns or smaller. PM10 sources include construction sites, industrial sources, and wildfires. These inhalable particulates can obscure visibility, cause nasal congestion, and irritate the throat. 

Formaldehyde

A colourless gas that is flammable and highly reactive at room temperature. Formaldehyde is a carcinogen and a strong irritant. Formaldehyde can be found in building materials, resins, paints, and varnishes and can last several months particularly in high relative humidity and indoor temperatures.

Total Volatile Organic Compounds

Carbon-based chemicals that easily evaporate at room temperature, most commonly found in building materials, cleaning products, perfumes, carpets and furnishings. Long term exposure can cause, cancer, liver, and kidney damage whilst short term exposure can cause headaches, nausea, and dizziness.

Find out more about air quality at the BSRIA Air Quality Hub.

Heat Pumps and Heat Waves: How overheating complicates ending gas in the UK

by Dr Aaron Gillich | Associate Professor and Director of the BSRIA LSBU Net Zero Building Centre

We have entered what many are calling the decisive decade on climate action. Among the most critical decisions that the UK faces this decade is how it will eliminate carbon emissions from heat. Heat accounts for over a third of our emissions, and over 80% of our buildings are linked to the gas grid. There is no pathway to Net Zero that doesn’t include ending the use of gas as we know it in the UK.

Given the size of the UK gas grid, no single technology or energy vector can replace it. We will need a combination of clean electricity and carbon‐free gas such hydrogen or biogas, delivered by a range of enabling technologies such as heat pumps and heat networks. And of course an extremely ambitious retrofit agenda that reduces the demand for heat in the first place.

The UK is investing widely in low carbon heating innovation. That innovation is essential, but is also unlikely to include any blue‐sky breakthroughs that aren’t currently on the table. In other words, the menu of low carbon heating technology options is set, and this decisive decade will be about deciding what goes best where, and how to ensure a just and equitable heat transition.

Low-carbon heating options

Of all the low‐carbon heating options available, low carbon heat pumps are the most efficient and scalable option that is market ready and can respond to the urgency of climate change this decade. The UK has set a laudable target of installing 600,000 heat pumps per year by 2028. Many have criticized this figure as unrealistic, but I believe that the target is highly achievable, and represents a pace that is in line with past transitions such as ‘the Big Switch’ that put us on the gas grid in the first place.

This race to replace gas in the UK has been widely discussed. As have the many barriers that face heat pump deployment in the UK. What I’ve heard discussed far less are the links between heating in the winter and overheating in the summer. Over the next decade, the end of gas will present both a threat and an opportunity to improve both the winter and summer performance of our building stock.

The threat of climate change is clear. The end of gas increases this threat because gas has allowed the UK to obscure poor building performance, and poor building knowledge for so long. Cheap gas has enabled a ‘set it and forget it’ approach to many building systems, and allowed us to maintain reasonable standards of comfort in most buildings despite very poor fabric performance. The irony is that this poor winter performance actually helps reduce the risk of overheating in the summer, as the leaky and poorly insulated buildings can more easily shed excess heat. It has been widely reported that many newer, better insulated buildings actually face an increased risk of summer overheating.

Replacing gas with heat pumps, or any other low carbon heat source, should be accompanied by ambitious retrofit to improve energy efficiency and reduce heat loss. There are many that argue heat pumps in fact require extensive fabric retrofit in order to function in most UK buildings. This is highly debatable and will be explored in detail in follow-up writings. Regardless, demand reduction and a fabric first approach is a good idea for its own sake.

Replacing gas with heat pumps, or any other low carbon heat source, should be accompanied by ambitious retrofit to improve energy efficiency and reduce heat loss.

But reducing the heat loss in winter will likely trap heat in the summer, presenting a conflict. The UK currently experiences over 20,000 excess winter cold deaths and around 2,000 heat related deaths in summer. It was previously thought that the increased temperatures from climate change would decrease winter cold deaths, but more recent work has shown that due to the increases in extreme weather events at both ends of the spectrum, it is far more likely that winter cold deaths will remain at similar levels, and summer heat deaths will increase dramatically under climate change.

We must use the transition from gas to low carbon heating as an opportunity to better understand our buildings. Many of 600,000 heat pumps we install by 2028 will be in new build, but up to half will need to be from existing homes.

Retrofitting a heat pump is also the time to think about not only how to improve energy efficiency for the winter but how to reduce summer overheating as well. Despite much effort towards a whole‐house approach to retrofit, most work remains quite siloed. Energy efficiency and heating installations are largely in separate supply chains, and the building physics knowledge to carry out an overheating risk assessment is even less likely to sit with the same project team. Overheating is also very poorly captured by the building regulations and planning process.

A holistic approach

The last few years has seen a growing awareness of overheating risk and an emergence of increasingly easy to use assessment tools. A very small fraction of UK homes have comfort cooling. Retrofitting a comfort cooling solution typically requires costly and complex changes to distribution systems. However, there are a range of low cost options, including using local extract fans to create interzonal air movement, or using night purges and thermal mass. Blinds are also incredibly useful, but often misused in summer, and can also help reduce heat loss in winter. There are also ways to use local microclimate features such as shaded areas or the North side of the building to bring in slightly cooler air from outside and reduce peak temperatures.

Improving the air tightness and fabric performance of our buildings to address heating in the winter will change how we implement these solutions for the summer. They require not only careful thought at the design stage, but also strong communication to help end users operate them properly. Simply opening a window is unlikely to help if the outside air is warmer than inside.

A significant problem is that there are insufficient drivers to force this type of holistic approach to design, performance, and communication. It is so often said that we need stronger policies in the area of heat and retrofit, and this is no doubt true. But while we await these policies it is incumbent upon each of us in this sector to share and collaborate as widely as possible, and use whatever influence we have over a given project to encourage a fair and forward looking solution.

In summary, the availability of cheap gas has allowed us to escape having to understand our buildings in much detail. Climate change is the catalyst for an untold level of change in our lives that we are going to start to truly experience in the coming decade. Heating and overheating are coupled issues that must be solved together. We must use the end of gas as an opportunity to understand our buildings better, and implement solutions to climate change that work across seasons, or we risk trading one problem for another.

In summary, the availability of cheap gas has allowed us to escape having to understand our buildings in much detail.

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

UK heat pump market has weathered Covid-19 challenges. Coherent policy support is now needed to unlock its full potential.

by Krystyna Dawson, BSRIA Commercial Director

BSRIA has released its latest global heat pump market reports, including the eagerly awaited report on the status of the UK heat pump market.

Last spring, deep uncertainty set in across the markets as lockdowns in many countries disrupted trading. There was fear within the heat pump industry of a significant slowdown in what had previously shown dynamic market growth.

Indeed, the global heat pump market posted a decrease of 1.5% in 2020. However, performance varied across regions: with 12% market growth year-on-year, Europe has been at the forefront; the UK also saw positive development with heat pump sales increasing by 9.2% in 2020.  

Green Homes Grant

UK heat pump market sales were helped by the RHI and the Green Homes Grant scheme in 2020. The latter has proven to be important for the market, which has seen sustained growth in the refurbishment segment despite the number of installations in new buildings stalling due to the lower level of new home completions.

However, heat pump installation still represents a major challenge in existing homes. The ongoing review of Part L and Part F of building regulations offer hope that refurbishments in homes and buildings will be conceived with low carbon heating in mind, but the review’s outcomes are yet to become a legal requirement.

Moreover, even though there is market potential for a higher number of heat pump installations in existing homes, the government has, so far, been unable to unlock it. The Saturday 27th March announcement of the closing of the Green Home Grant scheme to new applicants by 31st March 2021 has been yet another example of the disappointing approach to deployment of energy efficiency measures and heat pumps.

UK heat pump market: Achieving a net zero carbon economy

Heat pumps are among the technologies the government has identified as key to achieving a net zero carbon economy by 2050. The Prime Minister’s 10 Point Plan for the UK Green Industrial Revolution includes the target to deploy 600,000 heat pumps a year by 2028.

The UK saw around 37,000 heat pumps sold in 2020. The extra £300 million in funding, moved from the soon-to-be defunct Green Homes Grant to local authorities to enable energy efficiency upgrades for lower income households, may bring additional installations. But even if all 30,000 applicable homes were fitted with heat pumps, the numbers are insufficient to sustain hope of reaching the PM’s ambitious target.. There is potential for more heat pump installations in existing homes, and the interest in heat pumps is growing among home and building owners. The heat pump industry is also working at full speed to deliver innovative products that respond to end-user expectations and environmental challenges.

HVAC industry skills gap

However, unless demand from existing homes and buildings is unlocked at full scale, and until real attention is paid to the sufficient availability of a skilled workforce, the heat pump market will struggle to see the acceleration needed to reach the government target and make a difference in the level of carbon emissions from UK homes and buildings.

Coherent policy and financial support are needed to match the readiness to act on both industry and consumer sides. Integration of heat pumps in a home or a commercial building requires a holistic approach where design and affordability should be considered to deliver carbon savings, cost savings and a healthy and comfortable environment.

“Clean Energy Revolution” puts building and product standards back on the Federal agenda

by Krystyna Dawson

The inauguration of the new President-elect, Joe Biden, marks the start of a period that could bring a substantial shift in US building-related markets. Air conditioning, heating, ventilation and controls are likely to face requirements from policy and market demand that will change dynamics in several segments.

Net Zero Emissions

With the President-elect’s Clean Energy Revolution announced during the campaign, the federal green agenda is set to make a strong comeback. President Biden signalled his intention to re-join the Paris Agreement, notably on the first day of his presidency, and outlined a national goal of net-zero emissions across the economy by 2050. Although less ambitious than the progressive Green New Deal target (net-zero emissions by 2030), with Congress now on his side he can venture putting his intention into law.

The President has promised a nearly USD 2 trillion investment plan, much of which is due to support green initiatives. He also promised to work towards achieving decarbonised electricity by 2035. Although during the campaign he was careful not to promote the ban of gas and oil fracking, his Clean Energy Revolution includes plans to improve energy efficiency in buildings and houses, and promises high investment in R&D related to zero carbon technologies to produce cutting-edge equipment for internal markets and export.

Even if not all of it might come to fruition, there is certainly a significant change of direction ahead in all industry sectors, including energy and HVAC in buildings.

HVAC Industry

During the Trump presidency, the federal government kept progress in energy efficiency standards for appliances and equipment at a low level. This has been countered by initiatives in several states, like California, Vermont, Washington, Colorado Texas and Hawaii, which have been setting their own efficiency standards for a variety of products. Federal standards nevertheless cover a wide range of HVAC products. Hence, the re-activation of ambitious federal efficiency programs will be important for industry and consumers.

California will likely increase its influence on federal decision making, not only as Kamala Harris’ home state, but because of its leading set of environmental regulations and standards. Its Title 24 Building Standards Code that sets requirements for “energy conservation, green design, construction and maintenance, fire and life safety, and accessibility” that apply to the “structural, mechanical, electrical, and plumbing systems” in buildings might provide a template for wider adoption. The experience the state is gathering on the application of a variety of solar and heat pump combinations can support the uptake of these technologies on a larger scale.

Green Agenda

With the push towards energy efficiency in buildings, technologies that support their smart operation are likely to see dynamic uptake. Currently, smart buildings represent a niche market across the US, with just some cities in the North-East, Texas or California seeing their increased emergence. They usually belong to corporations who are keen to emphasise their green credentials, aspiring to achieve high sustainability certificates through building sustainability assessments like LEED or WELL.

The impact of the federal policy change on the building HVAC and controls market will not be instant, but waiting for it to become obvious might have serious consequences for market players.  The unfolding of the green agenda by the federal government will strengthen ongoing efforts of market stakeholders and demand from consumers as environmental awareness creates favourable conditions for the shift towards efficient, environmentally friendly products.

Taking action on Climate Change

by Michelle Agha-Hossein, BSRIA Building Performance Lead

Most nations now recognise climate change as an established, perturbing fact that needs immediate attention. We can see the effects in the worsening and more frequent extremes of weather: flash floods, droughts, strong winds, heavy snow, heat waves, etc.

UK temperatures in 2019 were 1.1°C above the 1961-1990 long-term average and it was a particularly wet year across parts of central and northern England. Still fresh in the memory are storms Ciara and Dennis in February 2020 with strong winds and heavy rain that caused significant damage to homes and commercial buildings. There is growing evidence that periods of intensely strong winds and heavy rain are likely to increase in the future.

The UK is not the only country affected by climate change. Many other countries are (and will be) suffering disproportionately. The world’s leading climate scientists have warned that we might have just 12 years to keep global warming at a maximum of 1.5°C. After this point, the risk of extreme weather conditions will significantly increase. The increased frequency and intensity of extreme weather will affect all but is most likely to bring catastrophic consequences in many less economically developed countries, where food shortages and water scarcity can trigger deep social changes.

Immediate radical action is required to limit carbon emissions, and the built environment industry can play a crucial role by changing the prevailing culture.

Most building-related carbon emissions are generated from energy use in buildings. However, there are choices that building owners/operators can make and initiatives that they can undertake to lessen the related negative impact on the environment:

In brand new buildings, the most effective way for addressing emissions is reducing consumption through energy efficient design. In existing buildings, the issue can be addressed by efficient retrofitting and effective maintenance strategy. Adopting renewable energy technologies in both cases can significantly reduce building emissions.

Steps building owners and operators can take today.

There are several initiatives/activities that can help building owners/operators combat climate change:

  • Consider ‘net-zero carbon’ targets for your building: UKGBC launched its Advancing Net Zero programme in 2018 and published the ‘Net Zero Carbon Buildings: A Framework Definition’ in 2019. The framework provides the construction industry with clarity on the outcomes required for a net zero carbon building.
  • Ensure the required outcomes for a ‘net-zero carbon’ building are achieved: As advised by UKGBC in the framework definition, initiatives like BSRIA Soft Landings should be adopted in new build as well as in refurbishment projects to ensure a net zero carbon building will be achieved. The BSRIA Soft Landings framework provides a platform for project teams to understand the required outcomes for their project and ensure all decisions made during the project are based on meeting those outcomes.
  • Maintain your net zero carbon building effectively: Business-focused maintenance is a methodology developed by BSRIA that can be adopted to help building operators maintain critical assets effectively and efficiently to sustain a net zero carbon building within budget.
  • Investigate failure quickly: Is the energy bill for your building higher than it should be? Investigate the problem as soon as you can. The first and easiest step would be looking at the energy end use breakdown to see which areas are using more energy than expected. If the issue is related to the HVAC system, check the system’s setting points and monitor the indoor air temperature and relative humidity. Thermal imaging of the fabric of the building can also help to identify, thermal bridging, missing/damaged insulation and areas of excessive air leakage.
  • Promote a healthy diet among building occupants: This is a non-technical initiative that building owners/operators can adopt in their buildings. Eating less meat and gradually shifting to more plant-based foods is vital for keeping us and our planet healthy.  It is important to think about initiatives such as using signage or lunchtime talks, to educate building occupants about healthy diets and encourage them to eat more fruit and vegetables. Research has shown that adhering to health guidelines on meat consumption could cut global food-related emissions by nearly a third by 2050. Healthy diet is also supported by Fitwel and the WELL building standard.

Building owners and operators, to play their role in combating climate change, should ensure their decisions and the way they create and run their buildings contribute positively to the wellbeing of our planet and its citizens.

So, make a start today and choose the first thing you are going to assess/change in your building to help combat climate change.

To find out more about how BSRIA can help you improve building performance, visit us here.

The wellbeing and environmental effects of agile working

by David Bleicher, BSRIA Publications Manager

How many times in the last few months have you started a sentence with “When things get back to normal…”? For those of us whose work mostly involves tapping keys on a keyboard, “normal” implies commuting to an office building five days a week and staying there for eight or more hours a day.

When lockdown restrictions were imposed, things that were previously unthinkable, such as working from home every day, conducting all our meetings by video call, and not having easy access to a printer, became “the new normal”.

One thing the pandemic has taught us is that changes to our work habits are possible – we don’t have to do things the way we’ve always done them. Since lockdown, agile working has been high on companies’ agendas; but agile working has a broader scope than flexible working. It is defined as “bringing people, processes, connectivity and technology, time and place together to find the most appropriate and effective way of working to carry out a particular task.”

Working from home with a cat

The triple bottom line

Agile working is indeed about much more than changing people’s working hours and locations. It’s about how people work – becoming focused on the outcome rather than the process. It’s about making the best use of technology to achieve those outcomes and it’s also about reconfiguring workplaces to better suit the new ways of working. But, when considering these outcomes, we should be looking further than the financial bottom line. The term triple bottom line is a framework that also brings social and environmental aspects into consideration.

How, when and where people work has a major impact on their wellbeing. The past few months have served as an unintentional experiment in the wellbeing effects of mass home working. Some people are less stressed and more productive working from home, providing they have regular contact with their colleagues. Other people – particularly those who don’t have a dedicated home working space – returned to their offices as soon as it was safe to do so. It depends on the individual’s preferences, personal circumstances and the nature of the work they do.

On the face of it, it would seem that increased working from home or from local coworking spaces would be a win-win for the environment. Less commuting means fewer CO2 emissions and less urban air pollution. But a study by global consulting firm and BSRIA member, WSP, found that year-round home working could result in an overall increase in CO2 emissions.

In short, it reduces office air conditioning energy use in the summer, but greatly increases home heating energy use in the winter – more than offsetting carbon savings from reduced commuting. Perhaps what this highlights most is just how inefficient the UK’s housing stock is. If we all lived in low energy homes with good level insulation and electric heat pumps, the equation would be very different. Perhaps a flexible solution allowing home working in summer and promoting office working in winter would be best from an environmental perspective.

A possible long-term effect of increased home working is that some people may move further away from their offices. For example, someone might choose to swap a five-days-a-week 20 km commute for a one-day-a-week 100 km commute. If that is also a move to a more suburban or rural location with more scattered development, less public transport and fewer amenities within walking distance, then (for that individual at least) there’ll be an increased carbon footprint. Not very agile.

Impact of technology

There’s another aspect that may not yet come high up in public awareness. Remote working is dependent on technology – in particular, the video calls that so many of us have become adept at over the past few months. All this processing burns up energy. The effect on home and office electricity bills may be negligible because the processing is done in the cloud. This isn’t some imaginary, nebulous place. The cloud is really a network of data centres around the world, churning data at lightning speed and, despite ongoing efforts, still generating a whole lot of CO2 emissions in the process. Videoconferencing definitely makes sense from both an economic and environmental perspective when it reduces the need for business travel, but if those people would “normally” be working in the same building, isn’t it just adding to global CO2 emissions?

We don’t yet know what “the new normal” is going to look like. Undoubtedly, we’re going to see more remote working, but responsible employers should weigh up the pros and cons economically, environmentally and socially. Terminating the lease on an office building may seem like a sensible cost saving, but can a workforce really be productive when they never meet face-to-face? Does an activity that seemingly reduces CO2 emissions actually just increase emissions elsewhere? Any agile working solution must take all of these things into account, and not attempt a one-size-fits-all approach to productivity, environmental good practice and employee wellbeing.

For more information on how BSRIA can support your business with energy advice and related services, visit us here: BSRIA Energy Advice.

What makes a good PICV?

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

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

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

Maintenance of drainage systems to prevent flooding and water pollution

By David Bleicher
BSRIA Publications Manager

Every building has a drainage system. In fact, most have two – a foul drainage system that takes waste from toilets, showers etc. and a storm/surface water drainage system that takes rainwater from roofs and paved areas. Older buildings may have a combined system, and in some locations the infrastructure buried under the street is a combined sewer – a legacy from the pioneering days of city sewerage systems.

As with maintenance of any building services systems, the first step is to know what you’ve got. Every site should have a drainage plan, showing which drains are located where, what direction they flow in and what they connect to. If there isn’t one, it’s not hard to create one – even though the pipes are buried, there’s plenty of evidence above ground in the form of manholes.

When there is a drainage plan, it’s worth checking how correct and up-to-date it is. Sometimes, the exercise of doing this brings up evidence of mis-connections, such as a new loo discharging into a storm manhole. It’s also worth marking drain covers with the service (F for foul or S for storm) and a direction arrow.

Drainage manhole over showing 'S' arrow to indicate storm drainage and direction of flow.

In foul drainage systems, the biggest headaches are caused by things going down the drain which shouldn’t – like wet wipes, sanitary products and hand towels. So the best form of preventative maintenance is to keep building occupants informed, with polite notices and clearly-marked bins in strategic places. Then there is the fats, oils and greases (FOG) that go down the plughole in catering establishments. If these find their way into the drains and sewers, they’re pretty much guaranteed to solidify and cause blockages – sometimes known as ‘fatbergs’. That’s why there should always be an interceptor in place, also known as a grease trap. This needs maintenance – the generic frequency for cleaning out a grease trap, stated in SFG20 (a common approach to planned preventative maintenance), is monthly. But this will be highly dependent on how the facility is used.

If blockages go unchecked, they may also go unnoticed. That is until sewage starts backing up into the building, or overflowing into storm sewers, which eventually discharge into lakes and rivers. These are delicate ecosystems, and the introduction of detergents and faecal matter can be very harmful to aquatic life and of course humans.

Rain, can pick up contaminants from both the air and the land, so once it has reached a storm/surface water drainage system, it has picked up dirt, oil and chemicals from air pollution, roofs and paved areas. Traditional systems have no means of dealing with this, and also must be sized for occasional extreme storm events, so the pipes are very large and mostly used at a fraction of their capacity. Sustainable drainage systems, or SuDS, attenuate the flow of rainwater to watercourses and emulate the way natural ecosystems treat this water. But they need maintenance. For example, any tree routes that could block a soakaway should be trimmed annually, and green roofs may require weeding on a weekly basis during the growing season.

For more information on the maintenance of drainage systems, please explore the BSRIA Information Service

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