It’s easy to look at noise mitigation components in isolation. A silencer, an acoustic plenum or roof screens could all be regarded as a standalone solution to a sound emission problem. In some cases, they are. But mostly they’re critical parts of a wider noise control system. That’s especially true of roof screens, which are being used in an increasing number of industrial, institutional, commercial and residential applications—particularly in crowded urban areas where mechanical noise can easily exceed acceptable limits as defined by state/provincial or municipal ordinances.
We should note that when implementing any set of noise mitigation solutions, it’s critical to first look at a project holistically to avoid the potential for unintended consequences and costly overruns. This is a key consideration for general contractors, for whom on-time, on-budget product delivery is essential.
The reason is that some noise control solutions can impact the proper functioning of existing mechanical componentry (e.g., when applied to a legacy HVAC or CHP system). Avoiding that kind of outcome requires a detailed understanding of manufacturer specifications and various mechanical tolerances. Take an acoustic enclosure, as just one example. If an enclosure isn’t designed properly (e.g., to integrate with an HVAC system or to include an adequate number of maintenance access points, among many other considerations), the solution could create more avoidable (and potentially costly) challenges than it resolves.
Roof screens are no different. Whether structure-mounted or floating—such as our signature Gravity Barrier systems—their design must take everything from structural limits to wind loads into account. They also need to accommodate the architect’s technical specifications to ensure complete aesthetic alignment with the building’s façade. That could be in a commercial or institutional application such as a university or a long-term care facility, for temporary use on a construction site or anchored on a high-rise office tower. The application may change, but the engineering principles remain the same.
The advantages of a system-wide approach
Perhaps most importantly, roof screen solutions should be regarded as an integral component of a standard building design. As such, it takes detailed analysis, engineering, implementation and maintenance to ensure that a single (or set of) roof screen(s) functions as required. That’s where a system-wide approach is best applied. It’s also a strategy that makes roof screening more accessible and user-friendly for architects and general contractors—and it’s a process best managed by an engineering firm specializing in noise control.
At Parklane, for example, our team manages roof screen solutions in their entirety, providing flexibility for architects that need to implement a specific façade cladding (our roof screen solutions offer the flexibility to integrate cladding from any commercial supplier), while also managing all relevant mechanical acoustic considerations. Case in point: our team has the expertise to design and engineer adaptive anchorage systems for virtually any roof structure type, be it a connection to a concrete slab, or an open-web steel joist, to name only two examples. Whether the roof screen is floating or fixed, our products are easily specified and adaptable to suit architects’ requirements.
We also deliver turnkey design, fabrication and implementation services for a complete, end-to-end service experience. Full roof screen solution management under one roof—including the ability to engineer all necessary supplemental acoustical and custom building-envelope solutions—provides single-source liability and complete modularization for simpler, more efficient installations. That level of in-house expertise and adaptability significantly reduces the risk of project delays and cost over-runs.
The roof screen-as-a-system in practice
We were recently engaged to work on a complex noise mitigation project at a municipal transit centre in Southern Ontario, where the facility owner was facing the threat of legal action due to sustained mechanical sound emissions.
Working in conjunction with the acoustical consultant assigned to the project, our team assessed the problem using our Parklane360 service approach. The objective was to highlight the source of the unwanted emissions and to determine an effective engineered solution—eventually identified as a noisy HVAC unit. The fully-managed solution will eventually include the design, fabrication, supply and installation of multiple floating Gravity Barriers™, various structure-mounted acoustic screens and a new silencer arrangement, along with detailed structural engineering and sealed design packages, and all necessary fittings and structural support. We will also deliver complete on-site installation including the coordination of crane freight and placement, offloading and hoisting of all assemblies to the roof and administrative coordination to secure and manage road closures.
When looking at the roof screen solution for this project as a system, our process accounts for a range of engineered considerations, which include the:
- Design of all ballast restraints to resist applicable environmental loads
- Design of all ballast/roof interfaces to yield optimal frictional coefficient
- Design of integral steel barrier wall structures to withstand local loading conditions
- Final calculation of vertical and horizontal transfer loads to roof structure
- General arrangement of the various Gravity Barriers™ and structure-mounted screens
The project will be completed over a span of about a week, and the expectation is that the noise emission problem will be fully addressed and mitigated. The solution will also relieve the threat of fines and other legal action against the facility owner.
This upcoming project speaks to the engineering complexity that can influence the design of a successful noise control measure. More importantly, it underscores the fact that roof screens should never be regarded as a standalone solution to a sound emission problem. They’re invariably a single (albeit essential) component of a much wider noise mitigation system.
The Parklane Team
For assistance with your noise or vibration control challenges, contact a member of our team.