When designing a building, architects have a lot to consider, such as understanding the client’s brief, budget considerations, ensuring building regulations are met, safety and environmental requirements, creating new building designs, drawing up detailed plans, and working closely with other contractors involved.

There is, however, one invisible factor that is sometimes overlooked – and that’s noise. The noise levels from, and within, a building can strongly influence whether it is judged as a success or failure. Taking steps to mitigate excessive noise brings many benefits to the environment, the economy, and the health of a building’s users and the local community.

A survey conducted by Earth5R in January 2023 by 45 volunteers from 15 Indian cities investigated noise pollution and found that noise levels were nearly 50 per cent higher than the permissible limit of 50 dBin ‘silent’ and residential areas.

Making the invisible, visible

Although noise is invisible, by using simulation software, it is possible to create a noise map. These are very visual demonstrations of where it comes from and how it propagates. The charts are color-coded so can be understood easily. This can be useful, especially when dealing with the local community or non-building professionals involved in the project. Mapping software can also break down different noise components rather than just giving an overall figure as a measurement does. With this approach, mitigation can be targeted in the most cost-efficient way.

Uncomplicating the process

If one only has an occasional requirement to undertake a project to assess noise, then mapping the noise using specialist software does not need to be complicated. Perhaps requires a one-off survey for an industrial plant, development plan, or transport infrastructure or one may need to predict the noise emissions from sound systems at an open-air event, to give a graphical overview of the expected noise during the planning of the stage setup. That’s why the developed SoundPLAN essential, software is designed to provide reliable tabular and graphical results for a standard noise calculation with the investment of minimal time. What to consider when choosing software:

Clear documentation is just as important for one-off or occasional noise projects as it is for more comprehensive noise mapping. Check that the software provides informative, standardized tables and clear graphical outputs so that one can present and document the noise map calculation results professionally and clearly in no time at all.
Does the software enable one to map different types of noise emissions from roads, railways, and industry sources effortlessly? For example, for industrial noise, is there a convenient level calculator whereby machine operating times and the emission of moving sound sources can be taken into account very easily?
Check the software is always up to date with the latest noise standards for road, rail, industry, events, parking lots, and for noise from outside sources that can affect people within a building.
Make sure it contains a large number of noise emissions data within its library, including emission of moving sound sources, to simplify noise reporting, whilst also giving one the flexibility to add their own data at any time. The information can come from manufacturers’ specifications, software libraries, and many other sources.
Choose software that enables to import and adjust geometry data. It should enable one to transfer background maps from Google Maps and Open Street Map so that one can use these as a basis for terrain models and work on projects efficiently.
Does the software include a ‘Building Acoustics-Outside‘ module? This is a very helpful tool when it comes to noise remediation or protective measures against external noise when planning buildings. It can be used to prove the acoustic properties of a room against unwanted outdoor noise. Software should conform to the updated standard EN ISO 12354-3:2017, relating to the estimation of the acoustic performance of buildings. The software should include optimization for any number of facades and components, as well as the use of a library of supplied sound insulation options.
If the requirements are changing and one needs more than occasional standard noise mapping, can they easily be upgraded to a more comprehensive noise mapping package, like SoundPLAN noise?

About Michel Rosmolen:

Michel Rosmolen, director of SoundPLAN Asia, shares tips about what to look for in noise mapping software when one only has an occasional project requirement.

Assess the impact of urban air mobility on noise propagation

New Transport Technology

In this article, Jochen Schaal and Michel Rosmolen assess the impact of urban air mobility
on noise propagation.

Our transport systems are rapidly changing, with urban air mobility expected to become a reality
within the next 3–5 years. Drones are already in use; and industry-wide reforms and manufacturer incentives through the Government’s Production-Linked Incentive (PLI) scheme for drones and drone components aim to make India a drone hub by 2030.1
Currently, drones assist a number of sectors in India. They are, for instance, increasingly common in the farming and agriculture sector, where they are used to monitor the health of crops and spray them with fertilizer. They are also used for monitoring traffic and can aid city planning and infrastructure projects by capturing images and videos.

Another benefit is the ability to access remote places and carry items including consumer goods, post, and medical supplies. For instance, the World Economic Forum’s ‘Medicine from the sky’ initiative2 is using drones to deliver vaccines and medicine to remote areas in India.

Policy Shaping
In fact, this new advanced air mobility (AAM) sector has been developed globally, with applications being trialled and tested. This includes manned or unmanned drones and eVTOLs (electrical/ hybrid vertical take-off and landing aircraft) that can take off vertically without relying on a runway. Initially with a pilot, remote piloting or autonomous services could follow. The technology offers innovative services for passenger and goods transportation, data and image collection, and aerial works.
However, internationally, policymakers are still a long way from understanding how best to approach these technologies and the challenges they will bring. A proactive policy approach that considers aspects such as congestion, noise and privacy is needed if the benefits of urban aerial mobility are to be realized.
In response, The World Economic Forum has launched an ‘Advanced and Urban Aerial Mobility Cities and Regions Coalition’3 to ensure that emerging advanced aerial mobility technologies are implemented in ways that work for cities and their communities. The coalition will build on work that has taken place in Europe under the Urban- Air-Mobility Initiative Cities Community (UIC2) of the European Union’s Smart Cities Marketplace4 to transition to more sustainable urban environments. This includes developing a regulatory framework for urban air mobility.

Factoring in Noise

Citizens’ acceptance of this technology will be essential to the successful deployment of urban air mobility globally. However, The Institute of Acoustics (IOA) published a briefing note in July 20225 highlighting that noise from drones has not yet been fully considered.
A reduction in traffic in our cities, facilitated by solutions like drone delivery, would provide planners and developers with an opportunity to adapt and enhance our urban areas while also reducing vehicle emissions. However, drones also represent sources of noise, a challenge that manufacturers, urban planners, and pollution control experts have to manage.
Studies show that long-term exposure to noise can cause a variety of health impacts including annoyance, sleep disturbance, negative effects on cardiovascular and metabolic systems, as well as cognitive impairment in children. In its 2021 ‘World Report on Hearing’, The World Health Organization indicates that there are currently 401 million people
in the South-East Asia region living with hearing loss. This costs the region USD 108 billion annually. By 2050, it estimates that 666 million people are projected to have problems with their hearing.6
As we swap our tarmac for take offs, what consideration will manufacturers give to the issue of noise as they race to beat their competition to the marketplace? How much noise does an electrical vertical take-off and landing aircraft make, and where will it be able to fly?
Drones represent a unique new community noise source that will operate and be perceived differently than traditional aircraft and ground transportation vehicles. In fact, the IOA highlight that: “Their rotating blades create a mixture of hums and whistles, that is arguably more annoying than noise from other modes of transport.”
The purpose might also contribute to people’s annoyance—for instance,
IOA highlights that a drone delivering takeaway food is less likely to be tolerated than a drone carrying medical supplies.
This is a new and unfamiliar noise source to many people, which alone may make them particularly noticeable when introduced into a community on a larger scale. The flexibility of drones means that they will also be likely to be flying over some remoter communities that currently have very limited or no exposure to commercial aircraft noise. The IA would like to see four aspects considered:

The extent of the potential adverse noise impact from drones determined. For example, how much noise do they generate, how often will they fly and at what time and day of the week,
and how will this combine with other noise sources that already exist in the area?
Control of noise at source by setting maximum sound levels
Controlling the number of flights
Control of drone flightpaths including for privacy and security and to manage the potential impact on wildlife.

Noise Prediction for Urban Air Taxi Operation

A 2021 study presented at the International Congress and Expo on Noise Control Engineering (Internoise) examined ‘Noise prediction for urban air taxi operation.’ 7 The study was undertaken by M Koehler and Dr P Brandstätt of the Fraunhofer-Institute for Building Physics (IBP) and F Baader of Wallner und Brand Ingenieurgesellschaft mbH (WBI). This examined issues related to noise protection using the specific example of an urban landing space for air taxis at the main train station in the city of Ingolstadt in Bavaria, Germany, one of the European Commission’s Urban Air Mobility initiatives.

In the study, the environmental noise impact of this air taxi operation is visualized in noise maps, using existing simulation methods, through our SoundPLAN software. This is used to simulate environmental noise and gives a very visual demonstration of how it will propagate and the volumes, helping you isolate and address problem areas. The maps are colour coded, so it can be understood easily by everyone involved.

Professional noise simulation software is already used widely as a tool to solve noise problems including road, rail, air, industrial and leisure noise, or room acoustics. Each noise map is unique, according to project size, geography, objectives, the relevant noise sources, but most of all, on what data is available and can be readily acquired to be imported and used.

The data can come from multiple sources, graphical information systems or other mapping services, counts of traffic mix for road and railroads, manufacturers’ specifications, software libraries or any other source.

Different noise components, from a range of locations and from multiple sources, can be broken down, including machinery and equipment. This means that the impact can be evaluated across a range of locations, to show the sources of the loudest noise, and propagation across the area. It can also help show how well mitigation factors, such as a noise protection wall or soundproofing of equipment, may work.

The software gives you the option of developing ‘what-if scenarios’ so that
the impact of developments or activities can be assessed in advance. Different options can be trialled and costed on the computer, avoiding expensive retrofit noise mitigation measures. Future noise levels can be predicted and pre-emptive steps taken to control it. With this approach, mitigation can be targeted in the most cost-efficient way.

Increased Noise Pollution

In the urban air taxi study, the noise maps indicate that the operation of the air taxi line can lead to additional noise pollution locally. However, the study highlights that, if the flight routes are carefully planned, the additional noise pollution is extremely low. However, future development might mean drone noise is on a larger scale.

The authors concluded that “in order to calculate the sound propagation in the environment of a drone airport (vertiport), it must first be clarified fundamentally which methods and regulations are to be used for the calculations. A large number of regulations exist that can be used as a guide, but some of them also have to be adopted for the new types of transport.” For instance, the consideration of urban aircraft noise with particularly low flight altitudes is new, and shielding the noise by, for example, buildings, plays an important role in its propagation.

This study also indicates that air taxi noise is likely to be perceived as more annoying to residents than regular traffic noise, with calculations based on the 2007 Frankfurt aircraft noise index.

Fresh Challenges

Developments such as urban air mobility, which can lead to noise pollution, must be carefully managed. Worldwide,
there are numerous guidelines for the calculation of different types of noise in the environment, including road, railway, aircraft, and industrial noise. It is important that regulation is developed for this new technology, as each type of noise must be assessed separately, and analysis based on recognized standards
and fixed legislation.

From SoundPLAN’s point of view, we believe it is very important to limit drones to certain flight paths that are identified at the start of the planning process. Their location should be assessed in direct relevance to individual localities, to avoid creating a noise carpet over an entire city. Identifying transportation corridors with optimal drone noise masking potential, and choosing corresponding distribution hub locations, may minimize community noise exposure in urban areas.

Modern technologies will bring fresh regulatory and noise mapping challenges to help protect residents and communities. As engineers,
we are excited by these transport advancements, which could turn out to be the most significant development since the industrial revolution. We are confident that noise mapping software will be able to meet the multitude of forthcoming challenges that arise.

Jochen Schaal is managing director of SoundPLAN GmbH and Michel Rosmolen is director of SoundPLAN Asia. For more information about SoundPLAN visit: www. soundplan.eu, email SoundPLAN Asia at info@soundplan.asia or contact the team at SoundPLAN’s headquarters at marketing@soundplan.de

1 Government of India, Ministry of Civil Aviation. Details available at https://pib.gov.in/PressReleaseIframePage.aspx?PRID=1755157
2 World Economic Forum. Details available at www.weforum.org/impact/drones-delivering-vaccines/
3 World Economic Forum. Details available at https://www.weforum.org/press/2022/03/local- leaders-join-new-coalition-to-advance-urban-air- mobility-around-the-world/
4 European Commission. Details available at https://smart-cities-marketplace.ec.europa.eu/
5 Institute of Acoustics. Details available at https:// www.ioa.org.uk/news/managing-drone-noise-
%E2%80%93-new-ioa-briefing
6 World Health Organization ‘World Report on Hearing’ infographic for WHO South-East Asia region. Details available at https://www.who.int/ images/default-source/health-topics/deafness- and-hearing-loss/world-report-on-hearing/ world-report-on-hearing—infographic-searo. jpg?sfvrsn=ccb90120_7
7 Noise prediction for urban air taxi operation – 50th International Congress and Expo on Noise Control Engineering (internoise2021.org). Details available at https://internoise2021.org/abstract/noise- prediction-for-urban-air-taxi-operation/