Best practice for big projects
Much of the discussion around the advantages of chilled beams in recent years has focused on their energy efficiency performance. In many ways however, their sustainability features are only part of the overall picture, particularly in larger scale projects.
In recent years there has been a growing appreciation of the benefits of off-site construction. Factory assembly of chilled beams, for example, offers greater control of build schedules and the minimisation of risk, simplified construction processes, faster installation and commissioning times, and greater consistency of quality for the installed equipment.
In addition, constructing the chilled beam in the more easily controlled environment of a factory offers greater control over health and safety aspects, reduces site traffic, and streamlines the day-to-day management of the project.
These benefits increase exponentially with the size and complexity of the project.
The design phase offers numerous opportunities to exploit the benefits of chilled beams. Having the right methods of working in place from the outset can prevent profit margins from being eroded by ineffective communication and costly changes.
A common pitfall is that insufficient information is shared between parties at this stage, or that details are made available too late in the process to harness the potential time and cost savings. Often this is because the customer is not familiar with chilled beam installations, or is embarking on a larger project than they have worked on before. This need not be a problem however if the chilled beam supplier is invited to assist with collation of the information required.
Having secured the order for the chilled beams on a project, for example, we require ‘Construction Status’ information in the form of consultants mechanical and electrical drawings, specifications, architects layouts and details of other services to be incorporated within the chilled beams.
It is critical that we understand, from the outset, the site construction programme and any restraints that may affect the chilled beam design. We need to understand how beams are to be moved to the relevant floors i.e. whether they have to be moved in a goods lift of restricted size, as this may govern the maximum size of the chilled beam sections that can be supplied to site.
On receipt of this information we prepare floor layout drawings showing the beam section splits, luminaires, and any other elements to be incorporated. These have to be co-ordinated with any structural restraints such as downstand beams, columns and the position of services within the bulkhead to connect with the chilled beam, and sprinkler head positions where relevant.
The chilled beam layout drawings will be prepared in conjunction with the Chilled Beam Technical Schedule which details all aspects of the performance of the chilled beam. We then work with other suppliers and subcontractors to co-ordinate all elements required to be incorporated into the design.
Off-site manufacture at all levels works best where the customer has a single source of responsibility for every aspect of the finished product, from design concept through to installation. This minimises the risk of poor communication and leads to faster resolution of potential problems.
A professional chilled beam supplier will provide aspects of project management as part of their role. This is particularly valuable for multi-service chilled beams (MSCBs) where a single raft might contain a number of additional features such as luminaires, PIRs, smoke detection devices etc. Another important aspect is integration of equipment. A supplier with an extremely broad portfolio can be expected to supply products which are already proven to work effectively within a single assembly.
Some years ago we established a dedicated team (Trox Design Bureau) to project manage from design through to installation. The Trox Group has also extended its product portfolio to encompass virtually all components required for a complete air conditioning system from a single source.
It is also important to prove the design concept to the satisfaction of all of the relevant parties, well ahead of installation. Each chilled beam project will have a number of stakeholders which include the architect and consultant, to the main contractor and M&E contractor. Each of these may have a different perspective on aesthetics, performance and installation, and changes to the design in the later stages of projects can have a catastrophic effect on profit margins.
Facilities for proving design concepts varies according to the manufacturer. Trox for example has comprehensive testing facilities at its laboratories in Norfolk. If it is required, performance testing can take place to confirm outputs based on simulation of the actual site conditions including bulkhead details, window details, beam infill and ceiling finishes. On approval of the test proposal we organise and conduct the in-house test at our laboratory which will be witnessed and approved by the design team.
There are three test cells available for real room mock up tests, offering capability up to a room size of 9m x 6m. Height is adjustable between 2.0m to 4.0m with a 6m x 4m simulated glazing wall to simulate temperatures between 8°C and 38°C. The room also has a heavy duty computer floor system with 500mm under floor void to allow testing of floor mounted diffusers.
Off-site manufacture enables assembly to progress concurrently with other aspects of the construction project, without the constraints of weather and on-site bottlenecks. For large-scale projects in particular, however, it is vital to ensure that the supplier has sufficient capacity to meet the delivery schedules. The majority of contracts require customised designs. Large-scale projects can often demand multiple beam design, all customised, with different dimensions and features. A recent large new build project which we carried out, for example, involved around 6,000 different engineering drawings.
When choosing a supplier, look beyond the bottom-line price and ask for details of the company’s ability to combine high levels of customisation with high volume output.
Flexibility is also important. For example, in a recent project, we were able to accelerate the beam delivery programme, at the customer’s request, from a manufacture and delivery rate of 25 beams sections per day to 52 beams sections, delivering two full articulated lorries of product to site daily. This was made possible by recent investment in fully-automated production machinery.
In recent years, the most successful large scale projects have exploited techniques from outside our industry to streamline delivery of equipment to site. Supply chain approaches such as ‘Just In Time’ delivery did not originate in the construction industry, but the same approaches which the automotive industry developed for line-side delivery of components are proving extremely effective when applied to the delivery of chilled beams to site.
So to summarise, the sustainability credentials of chilled beams will continue to dominate discussions. When planning a project however, it pays to consider the bigger picture and to also exploit the practical and logistical advantages of this technology.