Big Foot Systems has saved time and money for the contractors on the new Cromer and District Hospital in Norfolk with robust but lightweight rooftop supports. RAC reports
The £14.9m replacement of the original Cromer Hospital, which opened in 1932, sees accommodation for 14 departments in a two-storey building.
The design, by Purcell Miler Triton & Partners, required a significant number of air handling units and services on its flat roof.
However, the lightweight roof, built up of single ply membrane on top of insulation, meant any roof-mounted plant needed to be supported on a robust non-penetrative frame – to both avoid any damage to the roof membrane and to rule out the possibility of future leaks.
Main contractor Mansell Construction and M&E contractor Eyre Building Services also needed to ensure that the plant was not too heavy for the roof.
Eyre turned to Big Foot Systems for a solution. Big Foot visited the site to assess the installation and in collaboration with the contractor designed all the frameworks for the plant in 3D CAD and issued drawings for approval before the frames were manufactured. This enabled the client to visualise the project and make any necessary amendments before manufacture.
Once manufactured, the system was delivered flat packed, for simple assembly before the delivery of air handling units.
“The project at Cromer Hospital went exceptionally well,” says Richard Fryer, project director at Eyre Building Services. “The project involved installing external mechanical and electrical services on a Sarnifil roof. We were required to install 11 air handling units, four extract fans and nine condensing units together with pipework and electrical services.”
Eyre worked with Big Foot to design support systems for all plant and distribution services, including the acoustic isolation of the condensing units.
The primary support system was designed to carry the ductwork, pipework, electrical services and control panels. The system was rationalised to provide full access to maintain plant and the minimum obstruction to the roof area.
Big Foot’s supports avoided any penetration through the single ply roof, while working to the loading parameters. The support system also ensured that the plant will be easy to access for ongoing maintenance.
The Big Foot product portfolio provides complete, simple, safe and secure non-penetrative, prefabricated roof support systems, thereby avoiding the need for
time consuming and costly penetrations through the roof.
Big Foot notes that the systems’ modular nature and ease of installation simplifies project costing and programming, therefore reducing the need for complex, time consuming and expensive detailing. Along with being engineered, robust and repeatable, the systems allow for improved roof aesthetics, the company notes.
Installation on flat roofs
For air conditioning contractors, using traditional penetrative support systems on flat roofs may cause problems with roof integrity, resulting in thermal bridging, possible leaks, or potentially affecting roof warranty requirements, Big Foot cautions.
Further problems can arise if ac units are mounted on concrete slabs, wood or struts placed directly on a flat roof with a single ply membrane, since they can easily tear through the membrane, risking leaks.
Non-penetrative support frameworks mounted on anti-vibration mats provide a solution. These structures are configurable in that they can be adjusted in height, length and point load according to the demands of each individual project.
Big Foot Systems’ Light Duty and Heavy Duty modular framework systems are designed for retrofitting ac units and heavier cooling plant on flat roofs.
The Light Duty Range is non-penetrative, quick to install, robust and repeatable. Frame kits for most major manufacturers’ VRV/VRF units are available from stock. The range suits most applications including extract and supply fans, air conditioning, VRF units and AHUs.
The Heavy Duty Range is intended as a cost effective alternative to on-site construction concrete. One of the most popular products in the HD range is the Big Foot HD Cube, which provides an efficient and robust solution for supporting heavier services on flat roofs, making it ideal for the support of large packaged plant rooms, chillers and large AHUs.
The firm claims its non-penetrative systems are quick and easy to install, allowing plant to be sited on supports in as little as 10 minutes., without requiring costly penetrations through the roof for poured or pre-cast concrete plinths or steels.
Non-penetrative support systems also have the advantage of maintaining the integrity of the roof membrane, thereby avoiding thermal bridging and the potential for moisture ingress.
With lightweight roofs on the increase, load management becomes a vital consideration when installing plant, so Big Foot’s technical team uses Finite Element Analysis software to calculate load bearings and to offer custom-made where needed.