Comprehensive Vibration Isolation Solution for Rooftop Evaporators and Energy Centre

We were approached by Thomas Leach of Sol Acoustics to provide a vibration isolation solution for large evaporators intended for the roof of a luxury apartment building in Clapham. This development also includes a substantial number of modern, well-furnished council flats, showcasing a blend of high-end and affordable housing.

Noise measurements of similar evaporators were conducted by Thomas in Denmark to ensure accurate modelling. This was to drive an appropriate specification which included the need for an intermediate support framework as well as the correct spring isolator selections.

This project highlighted Mason UK’s unique capability to manage the entire process—from design and manufacturing to on-site installation—ensuring compliance with all required specifications.

Design and Engineering Excellence
Our team provided a full-service solution for the vibration isolation strategy. The best design approach involved rigidly fixing the evaporators to a robust steel frame, which minimised the number of anti-vibration mounts and upstands required and minimising risk of further resonances.

Anti-vibration mounts were placed beneath the steel frame, and the design incorporated restrained mounts, Mason type SLRSO, with 50mm deflection springs to limit movement due to wind loads which is a crucial factor given the rooftop location.

The fans are typically supplied with simple folded steel legs but these are not suitable for mounting on top of a spring mount and thus a more robust frame solution was required. The initial design concept involved maintaining the standard legs with a low level steel frame. However, in collaboration with our client, it was decided to replace the legs entirely with a full height steel frame which the fans could be bolted to.

The design evolved in line with airflow requirements which affected placement and profile of stiffening members and together with the client we were able to come up with a suitable design solution.

Steel Frame Design, Manufacturing, and Installation
Every aspect of the steel frame supporting the evaporators was handled by our engineering team, from design to structural calculations, fabrication, and delivery. Our expertise extended beyond supplying the materials; we managed the entire installation of all steelwork on-site. Tom, Senior Project Engineer at Mason UK, was present during the frame assembly and setting of all the spring mounts and ensured the highest standards were maintained throughout the installation.

Once on-site, we verified that all anti-vibration mounts performed as designed, meeting the acoustic specifications set by Sol Acoustics. Our firm commitment to quality and precision ensured that the solution was delivered in an exemplary manner. We fully meet the acoustician’s specifications and always aimed to provide an exceptional service throughout the project.

Expanding Scope: Energy Centre Floating Floors and Extract Fan Frames
The initial project scope to isolate rooftop extract fans expanded to include the energy centre. Here, we installed two 200 mm thick FS Sprung Concrete Jack-Up Floating Floors for the main air source heat pumps, which each weighed 12 tonnes.

Due to the extensive size of the 10-meter-long inertia bases that would otherwise be required, constructing floating floors was deemed the lower-cost and more compact solution. Additionally, two smaller 100 mm thick floating floors were provided for other pumps on the mezzanine, along with a small inertia base for another pump on the ground floor. On the mezzanine level, a strict weight limit of 5kN/m² was the driving factor behind the 100mm thick floors as opposed to a conventional thicker steel frame inertia base design.

In addition to the pumps, three steel frames were required for the main extract and supply ductwork fans on the mezzanine level. The structural soffit above was not designed with the capability to support these loads, therefore floor mounted steel frames were required.

The tallest of these fans was positioned 4.8m above the floor, and all the frames were designed in collaboration with both the client and the ductwork supplier to ensure suitability for mounting and maintenance requirements. The two main extract fans weighed approximately 300kg each, while the supply fan had a weight of approximately 200kg. 50mm deflection spring hangers, Mason type 30N-B were supplied to support the fans off the steel frames.

Off-Site Fabrication and Installation Process
The fabrication and delivery of the rooftop evaporators steel frames was managed by our team, including custom extended baseplates for waterproofing, as requested by the main contractor. All materials were packed on bespoke pallets and craned into their designated positions on the rooftop.

Following a strict on-site installation procedure, Mason UK first marked and installed all baseplates, then fixed and levelled the appropriate spring mounts before attaching the column legs. Each frame was assembled on the roof around the plinths, lifted into position by the site crane and lowered carefully onto the column legs then bolted in place. Constructing the frames involved manual handling of all steel members, requiring exceptional team coordination and effort.

After completing the frame construction, the extract fan banks were lifted into place, and Mason UK returned to tension all the spring mounts, ensuring that each frame was properly floating and performing as per the design requirements.

For the Energy Centre floating floors, we followed our tried and tested methodology for installing the floating floors which were over jacked after curing by a carefully calculated amount to give the correct final air gap after equipment placement.

The extract and supply fan steel frames were installed by first fixing all column legs in place before working to a careful lifting plan using a combination of genie lifts and MEWPs to fix all upper column sections followed by the cross members at the top.

Conclusion
This project exemplifies Mason UK’s capabilities in delivering a comprehensive vibration isolation solution for a mixed-use development that combines luxury apartments with modern, well-furnished council flats. From the initial design and engineering to manufacturing, on-site installation, and final quality assurance, we provided a complete turnkey service.

Our expertise in designing custom solutions, manufacturing high-quality components, and ensuring rigorous installation procedures enabled us to deliver a system that met stringent acoustic and structural specifications. The personal involvement of our Senior Project Engineer, Tom, further emphasised our commitment to maintaining the highest standards, ensuring exceptional quality and customer satisfaction.