Acoustics in the workplace – What’s the “new normal”?

Rebecca Hogg
Acoustic Consultant, BSRIA

Wooden blocks spelling 'new normal'

There is no denying global events this year have turned every aspect of our lives upside down, and as we all start to try and get back to normal while lockdown restrictions ease, we realise it is a “new normal”.

Workplaces have changed, some almost unrecognisable from before, and there is a myriad of requirements to consider beyond the essential health and safety measures. Occupant wellbeing was a prominent consideration prior to lockdown, and this included provision of a good acoustic environment, but how are new COVID-secure workplaces affecting the acoustic environment?

For many years there have been acoustic standards and guidelines on internal noise levels in offices, determining sound power levels of building plant, and predicting the sound absorption of materials. Well designed open-plan offices have allowed large groups of people to collaborate and communicate effectively, and noise regulations have ensured factories and construction sites operate without disturbing neighbours.

In recent months, the workplace has been turned on its head. Following government guidelines many people began working from home. Suddenly the familiar hum of the workplace was replaced in some instances with squabbling children or impatient pets, and if you live alone maybe unwelcome silence replaced your usual face-to-face conversations.

As people are gradually allowed to return to a place of work, new COVID-secure offices have changed the acoustic environment. The installation of screens, the partitioning of open plan spaces, wearing of face coverings, and a lower level of occupancy have created acoustic challenges. For example, speech intelligibility is affected by the reverberation time of a space. Fewer people and more reflective materials, such as plastic screens, will decrease the sound absorption and increase the reverberation time, resulting in poorer speech intelligibility.

Building services have been specified, installed, and commissioned for a particular set up of a workplace layout and building occupancy. If a space is divided into individual offices to allow for social distancing, then the building services provision also needs to be reconsidered. Changing the control settings of a system will have an impact on the internal noise levels and subsequently on levels of occupant annoyance.

Not everyone works in an office, so, what about situation in different workplaces? Factories, shops, and construction sites have been redesigned to allow for social distancing, and often operating hours have been extended to allow for shift patterns, potentially increasing noise nuisance for neighbours.

In these environments the noise levels are also often higher and communication between people can therefore be harder. People working further away from each other and wearing face coverings will inhibit successful communication and influence performance, and if someone must shout to be heard does this have the potential to spread virus droplets further? There should also be consideration of the highly overlooked 12 million people in the UK who suffer from some level of hearing loss. Being unable to lip read because someone is wearing a face covering, or unable to hear the conversation over a bad video conferencing link is incredibly frustrating and isolating.

The acoustic challenges within a COVID-secure workplace may seem overwhelming but there are several simple solutions. Firstly, identify noise sources in the workplace and maintain them appropriately to minimise background noise.

Something as simple as cleaning filters inside a fan coil unit can increase airflow and capacity, meaning the fan speed can be reduced and subsequently the noise level.

Secondly, examine acoustic specifications of any new products being installed – ask to see test reports and consider how a new product could influence the acoustic environment.

Finally, consider the occupants of your workplace and how they use the space. Tailoring the acoustic environment to the needs of the occupants can increase productivity, decrease annoyance and overall improve the wellbeing of all. The focus on workplace safety is paramount, but long-term considering other design parameters, such as the acoustic environment, will ensure workplaces not only survive but thrive.

BSRIA acoustic experts publish guidance, and support our members and clients with a range of acoustic testing solutions. Read more about our UKAS-accredited laboratory for acoustic testing to BS EN ISO 3741, BS EN 12102 and BS EN ISO 354 here.

Clean Indoor Air for Healthy Living – New Air Filter Standards

 

Breathing air is a fact of life. We all do it. Unfortunately the air that comes into our bodies often carries unwelcome pollution. This air pollution comes in the form of a mix of toxic particles and acidic gases.

Urban traffic air pollution has been a rising public concern especially since the recent VW scandal demonstrated car manufacturers have been more interested in dodging emission tests than providing clean running diesel engines.

The government is also slow to take action to remedy the situation having been responsible for previously promoting use of polluting diesel engines. If you live in a polluted urban area or close to a source of air pollution such as an arterial road, industrial plant or power station then you will be exposed to this invisible health hazard.

These airborne contaminants can penetrate in your lungs and can enter your bloodstream causing damage to health and diseases. The recent study from Lancaster University shows that ultrafine combustion particles generated from high temperature fuel combustion have been found in heavy concentrations in the brains of people suffering from early onset of Alzheimer disease and dementia.

This is a concern because it indicates that traffic air pollution can not only damage our health physically but also mentally. A real and current problem; what is the solution?

What measures can we as individuals take to protect ourselves and minimise our exposure to outdoor sourced air pollution? Well it is not all bad news there are things that can be done and actions taken.

For a start we spend typically about 90% of our time indoors so our direct exposure to outdoors air is reduced as a result. The buildings we occupy at work and at home to some extent act as a haven against this threat to our health.

There are also air monitoring and measuring devices that are relatively affordable coming onto the market. As Lord Kelvin the distinguished scientist once stated. ‘To measure is to know.’ It is now possible to use newly available and affordable devices to measure pollutants of concern and compare them with published World Health Organisation limits. Some of these measuring devices also have the capability to control air purifiers and air cleaning devices.

The two outdoor urban air pollutants most commonly identified as health hazards are PM1 combustion particulate and nitrogen dioxide. The World Health Organisation and Royal College of Physicians recent report ‘Every breath you take’ go into detail about the health implications. PM1 is a mass measurement of particulate matter one micron diameter and below in size range. A micron is one thousandth of a millimetre.This is very small as any particle below 10 micron dia. cannot be seen unaided by the human eye. A human hair is typically 70 micron dia.

Once the seriousness of the problem of polluted indoor air has been established then action can be taken. Although a relatively airtight building will offer some protection against urban traffic pollution there will be penetration into the building by opening windows, doors, passage of people and ventilation air systems. Typically the penetration for PM1 and nitrogen dioxide will be in the range 30% to 70%.

The only effective solution currently available to reduce this level is to use mechanical air filtration.

There are two new ISO World standards to test air filters recently published that offer filter testing and classifications to aid effective selection of HVAC air filters.

ISO 16890:2016 is running alongside EN779:2012 in the UK during the transition period until June 2018 at which point EN779:2012 will be withdrawn by BSI.

ISO 16890:2016 enables selection of filters to remove PM1 particulates to a high level of efficiency. In the new classification system ePM1 85% would equate to a good F9 filter but is more useful and informative notation to the end user because it actually says what the filter will achieve. Filtration efficiency ‘e’ will remove PM1 size range particles to an efficiency of 85%.

For the removal of molecular gas contaminants such as nitrogen dioxide the new World filter test standard is ISO 10121:2013. A good nitrogen dioxide removal test reading for a single supply air pass would be 80% – 90% initial efficiency.

These high filter removal efficiencies (80% – 90%) are necessary when air pollution levels are routinely higher than WHO limits by a factor of four or five times in UK city centres.

This is fine for filters in large air handling unit systems in central London but what about me at home? Is there another option available apart from keeping windows and doors shut on bad air pollution days?

The answer is that a good recirculation Air purifier unit positioned close to the person needing clean air will give the healthy solution needed. A well designed unit can provide E11 – H13 Hepa particulate filtration with molecular gas filtration for the removal of nitrogen dioxide, but also the commonly encountered indoor sourced air pollutants such as volatile organic compounds (VOC’s) and aldehydes such as Formaldehyde. These units are especially valued by asthmatics and allergy sufferers.

This blog was written by Peter Dyment, Technical Manager at Camfil Ltd. To find out more information about IAQ please check out BSRIA’s website.

 

University of Reading Research Study: Indoor Environmental Quality and occupant well-being

Gary Middlehurst is a post-graduate student at the University of Reading's School of Construction Management and the Technologies for Sustainable Built Environments

Gary Middlehurst is an Engineering Doctorate (EngD) student at the University of Reading’s School of Construction Management and the Technologies for Sustainable Built Environments (TSBE)

Looking at a new approach for determining indoor environmental quality (IEQ) factors and their effects upon building occupants, BSRIA has provided the University of Reading’s School of Construction Management and the Technologies for Sustainable Built Environments (TSBE) Centre access to their Bracknell office building known as the “blue building”.

 IEQ factors are proven to affect occupant well-being and business performance, however, for the first time, actual environmental and physiological field measurements will be compared. New research therefore has been developed by the University of Reading, which will seek to understand these relationships and the potential impacts of known IEQ factors on perceived levels of occupant satisfaction and well-being.

Understanding fundamentally how IEQ factors can affect building users, will allow system designers to finally visualise occupant well-being, personal satisfaction and productivity as part of a holistic business performance model. Based upon empirical measured IEQ factors and surveyed occupant data, the research hypothesis proposes that high-density occupation can reduce office workplace environmental footprints significantly when physiological impacts are understood.

The research methodology brings together measured environmental characteristics, physiological performance measurements, POE survey responses, and then uses an Analytic Hierarchy Process (AHP) to assess existing workplace designs.

Gary Middlehurst blogReducing operational costs and increasing occupant satisfaction and well-being is seen as a distinct competitive advantage, however, businesses remain focused towards meeting the challenges of energy security, demand side management and carbon commitments. The research, therefore, will provide empirical data to create informed business decisions focused upon these challenges. This is done by increasing the importance of well-being and by defining performance as a key metric.

Field research is currently underway on the top floor within the “blue building”, where 4 willing volunteers are participating in physiological sensory measurements and POE response surveys. The project will be running for 12-months, with the initial current 2-week data acquisition period being repeated a further 3 times during winter, spring and summer of 2015/16.

The research is also being conducted at two other similar office environments in Manchester and London, and seeks to support the hypothesis that hi-density workplaces are a further sustainable step in designing and operating more efficient and effective intelligent buildings.

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