What Does An Acoustic Engineer Do (including Their Typical Day at Work)

I am an acoustics, noise, and vibration control engineer with 10 years of experience. My job involves looking at all acoustics, noise, and vibration aspects of any infrastructure, land development, energy, and resources projects.

Monitoring noise and vibration on a construction site

Acoustics deals with designing indoor spaces and appropriate speaker systems to ensure good speech intelligibility and loudness. An example of this is designing the Public Announcement (PA) system for a transit station. This involves developing a 3D acoustic model of the station to aid the selection of speaker types, quantities, and location, as well as identifying appropriate acoustic treatments if needed (e.g. acoustic panelling). Having a good PA system is important during emergency situations, to ensure patrons can clearly hear instructions.

I am also involved in noise assessments. These assessments look at any potential noise impacts at “sensitive receivers” both within and outside the project. Let’s look at different types of “sensitive receivers” to understand different types of noise assessments. A sensitive receiver could be:

• An office or workstation: we model noise propagation through the building from sources such as heating, ventilation, and air conditioning (HVAC) equipment or other equipment, to determine whether noise levels are acceptable. Solutions to loud rooms could include silencers, duct lining, enclosures, and treating the room with absorptive materials. In extreme cases, where workstations are located close to very loud equipment (this can occur in mines, factories, refineries, etc), we would also recommend hearing protection.
• A residential home: we build outdoor noise propagation models, to predict a project’s noise emission onto the environment. For example, a rail transit project will increase noise levels at any residences in the vicinity. High noise levels have been linked to high blood pressure, heart disease, stress, and sleep disturbances. In some cases, high noise levels have been found to impact children who live near major highways, airports, or very busy train lines. These impacts include memory impairment, attention deficit, and lower reading levels. Mitigation measures include selection of quiet trains, continuous welded rail, noise berms, noise barriers, upgraded windows and walls, amongst others.
• Wildlife areas: sensitive receivers can also include wildlife that is impacted by noise. For example, we are working on the construction of a bridge being built on the west coast. This bridge crosses a river of significant ecological importance. Fish and marine mammals are commonly found in this river. To build this bridge, impact pile driving is required. Unfortunately, impact pile driving sends large pressure waves underwater that could potentially kill or injure nearby marine wildlife. To mitigate these impacts, we have modelled underwater noise propagation and developed an air bubble curtain that will surround the pile underwater. This project is challenging because the river is deep and fast, so we had to account for the river’s current dispersing the bubbles as they rise along the water column.

By no means, this is an exhaustive list of what a noise sensitive receiver could be. A sensitive noise receiver can include hotels, classrooms, places of worship, institutional uses, etc.

Finally, we also deal with vibration. Typically, the most common major sources of vibration are train lines and construction. Similar to noise, a vibration “sensitive receiver” could be:

• A residential home: if a train line or subway line is built near a residence, vibration could propagate through the ground, from the rail line to the residence. The vibration could in turn propagate through the residence’s structural system, and could cause light partitions (e.g. windows, plaster walls) to vibrate. This creates a rattling noise that can be quite annoying. This is referred to as ground-borne noise. Vibration from trains can be mitigated by using ballasted track, high resilience fasteners, ballast mats, or floating slabs. If the rail track is existing, an existing building could be upgraded to isolate it from the ground, but this can be quite costly.
• Any structure: If vibration is sufficiently high, structural damage could occur. These higher vibration levels are usually caused by construction or demolition, especially if explosives are involved. We check for any structures that could be damaged and provide recommendations. These typically involve a revision of construction methods.

As an engineer, technical work (modelling, calculations, measurements) takes a big chunk of my time. However, report preparation is equally important as this is where we state our modelling or measurement results and provide recommendations. So even though I am an engineer, I spend a lot of time writing!

Typically, 1/3 to 1/2 of the day are meetings. During these meetings, I coordinate with other disciplines, which can be architects, mechanical engineers, structural engineers, mining engineers, biologists, transportation planners, etc. Coordinating means ensuring our models are based on the latest design and communicating our recommendations to the appropriate people to ensure they are reflected in the latest design. For example, prior to modelling, we will ask the architect for the latest architectural drawings. Based on these latest drawings, we will undertake our modelling, and then tell the architect that they need an acoustic ceiling for a certain room (for example). We want to make sure that our report recommendations and architectural drawings are ‘coordinated’.

Meeting time also includes time with Clients, typically discussing potential challenges or solutions for their project.

Providing direction to Junior Engineers or EITs also forms part of my typical responsibilities. This includes mentoring, delegating tasks, answering questions, and reviewing their work. For example, after meeting with the Client and interdisciplinary project team, I will summarize what we need to do to our junior staff, assign work, discuss expectations (budget and schedule), and then respond to questions junior staff may have. After the tasks are completed, I review the work and request updates as required.

Other responsibilities include noise and vibration measurements and monitoring. These are undertaken to calibrate the models or to show compliance with project or regulatory limits. We also take measurements to characterize noise sources. Sometimes I go on interesting site visits to measure noise/vibration levels. Locations include airports, refineries, subway systems, construction sites, mines, both within Canada or abroad.

Train vibration measurements

Pros

• Very interesting and challenging projects, always get to learn something new. Projects include major airports and rail transit lines, large infrastructure projects including bridges and highways, amongst the largest mines in the world, huge refineries and factories, and unique projects involving wildlife.
• Get to play with interesting equipment (sound level meters, digital acquisition systems) and go to very cool places very few people can access (e.g. remote airport in Iqaluit, Canada!)
• Get to learn a lot about other disciplines. I get to work with transportation engineers, mechanical engineers, electrical engineers, civil engineers, mining engineers, planners, architects, structural engineers (and others!). So throughout my career, I’ve had exposure to many disciplines which has helped me grow professionally.

Cons

• Difficult to manage emails and high workload
• Working with different time zones can be a challenge. We have offices and projects around the globe. For example, working with our Australian counterparts can be challenging, as they are sleeping when we are working! So meetings tend to be either very early in the morning or late at night!