Noise Mitigation Measures for Construction

Cities are getting noisier. Don’t believe us? Just look at Toronto, as an example. Noise complaints have been trending upwards for the past few years, and a common culprit is the construction industry. If you’re planning a project in a metropolitan area, you’re probably also researching noise mitigation measures for construction.

It can seem like a necessary evil, but there are real benefits to implementing noise control solutions on your construction site.

Of course, there are moral reasons tied to being a good corporate citizen. We can’t ignore the fact that construction activities generate a significant amount of noise pollution. This has an undeniable impact on the people who live and work in the area; prolonged exposure to excessive noise has been linked to all kinds of health problems.

But for general contractors and builders, there is also a real, tangible business upside to minimizing construction noise. The most obvious benefit is that you can avoid the penalties associated with exceeding the acceptable noise level. Your local municipal bylaws define what is considered “acceptable”. Adhering to those established levels and being mindful of local residents and businesses will reduce the number of noise complaints lodged against your project. Avoiding noise complaints means avoiding fines.

You might dismiss small fines as a “cost of doing business”. However, complaints can have a more significant impact on your project in the form of schedule delays. Noise complaints can take precious time to investigate – and we all know time equals money.

Neglecting sound abatement also comes with a real opportunity cost. A solid noise mitigation strategy can earn you the approval on a noise exemption permit, allowing you to extend working hours. Imagine the impact on your project and delivery schedule if you extend work by even just one hour each day!

Whether you’re hoping to minimize the impact of complaints on your project schedule, proactively seeking to extend working hours, or just trying to be socially responsible, it all starts with a noise mitigation plan.

What is a Noise Mitigation Plan?

A construction noise mitigation plan is an intuitive strategy to reduce the overall impact of construction noise on the surroundings. While the extent of this impact may not always be known during the early stages of the project, there are certain measures you can take during the design phase to anticipate and mitigate sources of sound. This establishes a solid foundation for your noise mitigation plan and the measures you’ll plan to take during active phases of construction.

This 21′ temporary sound barrier, composed of temporary fencing and acoustic panels, helped dampen the noise generated by drilling equipment, generators and pumps on a construction site near a residential area.

Pre-Construction Noise Mitigation Planning

There are several opportunities for sound abatement to consider during the design or pre-construction phase of any project. Some of the most common abatement measures include:

Consultation and Notification

A pre-construction noise assessment could form part of the planning in a large-scale development or major infrastructure job. This involves hiring an acoustic engineer or consultants to perform noise and vibration assessments at the development site. Following the assessment, an impact report is produced to help inform noise mitigation strategies and abatement measures.

Once you understand the potential impact, it’s a good idea to provide advance notice to the community regarding the duration of the project and anticipated noise levels. Explain the noise mitigation measures that will be applied, and when noisy periods can be expected. Communicate this information via mailbox drops, community meetings, and public signage. For particularly large-scale or long-term projects, consider establishing a web site to house this information.

Contracts and Agreements

Share the onus of sound abatement with your workers and subcontractors. Require that reasonable efforts are made to minimize noise by writing those terms into your tenders, employment contracts, subcontractor agreements, and any work method statements. All employees and subcontractors should comply with directions from site supervisors and project managers to mitigate noise.

Haul Roads, Detours, and Vehicle Entrances

An important part of any noise mitigation strategy is the identification of noise sensitive receptors. These can include buildings like residential dwellings, hospitals and schools. On a particularly large project, you may have some site areas within close proximity to sensitive receptors while other sections are more isolated. During planning, consider locating site access points away from noise sensitive receptors. By positioning vehicle entrances away from residences, you can protect community members from vehicle noise.

If your project will rely on large vehicles, heavy equipment, haul trucks or other noisy vehicles, consider creating a detour to route traffic away from noise sensitive receptors. This approach is common in the mining industry, where haul roads or haulage tracks are used for the bulk transfer of materials. For common construction projects, detours can be an effective means of minimizing the impact of vehicle noise on the surrounding area.

You can further reduce unnecessary noise by designing the site in a way that avoids the need for reversing vehicles. Reversing alarms can be disruptive to area residents. Instead, endeavour to create a site layout that allows drive-through for parking and deliveries.

Site Layout

During the design and planning phase, designate work areas and storage spaces away from noise sensitive receptors. Plant and storage area placement should be considered in conjunction with site entrances and vehicle routes as part of a holistic approach to designing the site for reduced noise impact.

Don’t discount the fact that the very items you are storing – earth, waste, or supplies – could act as a noise barrier if positioned strategically.

Noise Mitigation Measures During Construction

When we think about noise mitigation, we usually think of the sound abatement measures implemented during the construction phase. There are many different ways to minimize the impact of noise during construction, from sound dampening solutions to administrative controls like scheduling.

Scheduling

Though it is sometimes overlooked, scheduling and sequencing of construction operations can be an effective way to mitigate the impact of construction-related noise. Of course, municipal bylaws dictate when noise-generating activities, like construction work, are allowed to take place. Beyond organizing work during allowable times, consider the characteristics of the surrounding community when scheduling noisy work. You could schedule the noisiest work when neighbours are not present to minimize the risk of noise complaints.

Noisy activities can also be scheduled to coincide with other background noise. For instance, schedule noise-generating work when local road traffic is at its peak or other local noise sources are active. This creates a masking effect whereby the environmental noise helps to reduce the awareness or intrusion of the construction noise.

Finally, when planning concurrent operations, you may be able to schedule the noisiest operations to occur at the same time. In theory, the aggregate noise levels created by multiple noisy operations may not be significantly higher than the level of noise produced by each individual operation. This means you can operate at a slightly noisier level for a shorter period of time, versus scheduling noisy work in consecutive stages over a longer period of time – which may be more difficult for sensitive receptors to tolerate.

Noise Barriers

There are several sound dampening solutions on the market today, including acoustic panels, sound blankets, and other physical noise barriers. There are several different ways to implement noise barriers. A common approach is to install acoustic panels or sound blankets on your perimeter fencing. This is is a good way to broadly apply sound dampening measures on the construction site as a whole.
You could take this one step further by isolating specific noise-generating activities or equipment. This can be done instead of, or as a supplement to, broader sound dampening measures. For instance, there are companies that design and install acoustic sheds (sometimes called acoustic warehouses) to enclose particularly noisy equipment or activities. Acoustic sheds are ideal for long-term projects as they can be expensive to implement. They are also best suited for stationary work and equipment.

The good news is that it’s possible to isolate a noise source on a smaller and more temporary scale. As an example, Echo Barrier offers portable, quick-to-install acoustic enclosures built from a purpose-designed steel pipe frame and PVC-clad composite acoustic panels. In fact, a simple compound or enclosure using temporary fence and acoustic panels can be reasonably effective in mitigating noise from a specific source.

This temporary acoustic enclosure was constructed around a noisy generator located immediately next to a hospital. The sound wall helped to dampen the sound produced by the generator and reduce the impact on the patients.

Shielding

Consider that temporary site buildings, natural landforms and material stockpiles can also have an impact on noise levels. Depending on their composition, they may have a sound dampening effect. You could use this to your advantage by placing noisy equipment near these existing features for a noise shielding effect. Furthermore, consider scheduling permanent walls to be built as early as possible so that they, too, can serve as sound barriers.

Conversely, some surfaces can actually exacerbate the problem by reflecting noise. Take note of the surfaces on site that might increase noise levels, and avoid locating noise-generating machinery where sound could be reflected.

Alternate Construction Methods

There is no doubt that construction is a generally noisy activity. However, advancements in technology over the years have yielded quieter alternatives to some traditional construction work methods.

Pile drivers are a great example. Hydraulic or vibration insertion techniques are effective and less noisy alternatives to using pile drivers. Alternatively, you can avoid using a pile driver by auguring or drilling holes for cast-in-place piles. Though drilling is still noisy, this option can produce noise levels that are lower than the traditional pile driver method.

Do your research and consider whether one of these alternate construction methods could work to reduce noise on your construction project.

Equipment Controls

One of the easiest and most effective noise mitigation methods involves controlling noise at the source – your construction equipment.

You can start simply by using less noisy equipment. Let’s consider compressors as an example.  Most compressors are powered by gasoline or diesel engines. While some gas-powered compressors have baffles specially designed to reduce noise levels, electric compressors are an even quieter alternative.

Prioritize the use of equipment enhanced with sound dampening products to further reduce noise. For instance, muffler or silencer systems help reduce noise emission from internal combustion engines in common equipment like vehicles, chainsaws, generators, and pressure washers. Installing physical shields or sound aprons on stationary equipment is another effective way to control noise.

Dampeners can also be used to minimize noise caused by vibration. For example, lining metal chutes and bins with damping material can help reduce the sound of debris being disposed.

Finally, backup alarms on large vehicles are a common annoyance for neighbours of construction sites. On a recent transit project in Toronto, broadband backup alarms were used to help mitigate this problem. Unlike traditional “tonal” backup alarms, broadband alarms can only be heard within the immediate hazard area. According to project stakeholders, the broadband backup alarms were found to be less annoying than the beeping of a traditional alarm.

One final tip: turn off equipment when it is not in use!

Monitoring, Communication and Enforcement

Assign responsibility for noise mitigation to someone on site. This individual should be accountable for monitoring sound levels and ensuring noise mitigation protocols are respected. Give them the authority to stop or reduce the noise of an activity, if necessary.

Hopefully you’ve established a good rapport with the local community through your communications in the pre-construction phase. Maintain this level of communication by ensuring someone is available to professionally respond to public complaints at the site. This could be handled by the person responsible for monitoring and enforcement, or by your site manager(s).

Consider periodically checking noise levels at nearby residences or other sensitive receptors to identify and address any concerns. Post hours of operation and regular updates on a communications board at the front of the site to keep neighbours informed. Consider also posting contact details to provide a channel for any noise-related concerns or complaints.

Finally, when it comes to noise attenuation on your construction site, the internal communications strategy is just as important as your external outreach efforts. This includes training for employees, contractors and sub-contractors on municipal noise bylaws and the conditions of your noise exemption permit, if you have one. Use frequent communication and enforcement to ensure the conditions and expectations of your noise mitigation plan are met.