With its cost and time saving attributes, off-site modular construction has seen tremendous growth in the last few years. Andrew Dickinson of Hochiki Europe examines how the fire detection industry is reacting to this development and the benefits it offers.

Touted by some as the future of building, modular construction has seen a rapid growth in interest and popularity in recent times. Between 2003 and 2006 the off-site market grew from £2bn to £6bn and it’s not hard to see why – a shorter timeframe for construction, a more consistent level of quality, versatility of use, sustainability, and financial cost savings are just some of reasons why it has become better accepted and more readily available.

Innovation
According to research carried out by the Building Cost Information Service (BCIS) on behalf of the Royal Institute of Chartered Surveyors (RICS), only 63 per cent of site-based construction projects are delivered on time and only 49 per cent are delivered to budget. In light of these statistics it is no surprise that some industry experts are claiming that traditional methods are failing to meet the major challenges facing construction.

Offsite construction can mean improved build quality and reduced carbon emissions

While it is especially popular in the higher education, retail, hotel and defence sectors, modular buildings have a wide variety of uses, including camps, civilian and military housing, and industrial facilities. Modular buildings are also a perfect solution in remote and rural areas where conventional construction may not be reasonable, or even possible.

Concept
Central to its recent success is the realisation that modular construction does not necessarily result in buildings of a temporary nature. The materials used and methods of constructing them mean that they are built to extremely high standards in factory controlled conditions. The majority of today’s modular buildings have steel frames and a design life of 50 years. However, it is highly likely that they will last longer than that – longer in fact, than some, so-called permanent buildings constructed in traditional materials.

The component parts of a modular building can take one to three months to be developed but often take as little as a few weeks to assemble. Once they have been transported to the building site, a crane is brought in to put the modules together. Once assembled, modular buildings are essentially indistinguishable from typical site-built buildings.

The construction industry is looking to galvanise wider industry acceptance, with organisations such as BuildOffSite campaigning for greater uptake of off-site modular construction. BuildOffSite is an alliance of clients, developers, designers, contractors, manufacturers, suppliers, government, advisors and researchers. Its mission is to help create the mechanism which will enable the off-site industry to make its case more effectively by increasing awareness, informing and setting standards.

Green
The advantages of off-site modular construction include:

• Construction that exceeds Building Regulations requirements for air permeability, improving thermal efficiency for lower running costs and reduced carbon emissions (according to modular construction company, Yorkon)
• Up to 90%fewer vehicle movements to site (says building consultants, MTech)
• Material wastage reduced by up to 90% (according to the Government sponsored Waste & Resources Action Programme, WRAP)
• Project duration reduced by up to 50% for earlier handover and occupation (Yorkon)
• Safer, quieter and cleaner construction
• Improved build quality and reduced future maintenance
• Flexible buildings which can be expanded

As these points clearly demonstrate, there is a substantial green argument for off-site modular construction. Despite the current economic climate, the pressures on project costs have not diminished the appeal of green construction methods. Clients expect to see progress in the development of sustainable buildings and modular construction has a massive part to play in achieving this objective. For example, when focusing on whole life sustainability, modular construction can provide reductions of up to 50 per cent below the carbon emissions required to satisfy Part L of the Building Regulations.

Control
Fire detection and emergency lighting systems are particularly suited to the advantages of modular buildings, by reducing the need for laborious snagging, on-site testing and commissioning. They are also able to offer guarantees and assurances that the systems are fitted to the exact specifications laid down in the original design.

In fact, modularity is rapidly changing the way that fire detection systems are being implemented. Manufacturers are able to supply cables in pre-determined lengths with pre-fitted connectors which then plug into back-boxes that are pre-wired to fire system devices. This provides a pre-engineered, safe and quick installation which maximises efficiency and reduces device installation times by up to 80 per cent compared to traditional device installation methods.

A factory controlled environment improves overall quality because products and systems can be fully checked, tested and signed-off prior to being delivered on site. This method also means that the people working with particular products on a regular basis will be able to produce a higher quality fit-out.

Process
According to Chris Carvell, Commercial Director of TCS Fire Safety Services Ltd, and one of Hochiki’s partners: “Although different to traditional systems, specifying and installing a modular fire detection system is far from complicated”. Currently TCS is working on two modular projects in Bradford.

Cabling and installation time can be dramaticlally reduced in modular construction projects

He continues: “The installation process begins with a site visit to verify the positions of all of the fire detection equipment based on the fire system design. At this stage specific cable lengths between system devices are measured and recorded. Once the site survey is complete the various cable lengths and types can be specified, and the types of units and detection devices needed are ordered. The cables for the project can then be delivered direct to site if required”.

As with a traditional cabling system, modular fire detection system cables should be installed and clipped to comply with industry standards. The cable assemblies have a colour coded ‘in’ and ‘out’ end which should be correctly located by the installer in line with the system diagram. Excess cable length for ceiling mounted devices can be formed into a helix and secured with metal ties to the installation fabric.

The use of loop test lead assemblies allows the cables to be quickly linked together to facilitate cable testing. This cuts down on time on site when compared to traditional wiring, which would have to be stripped and terminated into connector blocks.

At final fix, with the cables brought through the ceiling or wall, the loop test lead assemblies can be removed and then stored for future use. The cables are then plugged directly into the specially manufactured device back boxes before they are fitted into the pre-cut holes in the fixing surface. One innovative manufacturer’s cable plugs and mounting back boxes have been mechanically designed and colour-coded to prevent mis-mating, thus eliminating the risk of wiring error. Once the unit is located into the fixing cavity the fixing screws are tightened and the relevant fire detection device can be secured ready for commissioning. One producer has created the ‘Rotalock’ mechanism which has been specially designed to lock flush fit back boxes into place.

Installing the detectors on a modular system is a great deal quicker than with a traditional system and rather than installing one device, it is quite possible to install six or seven within the same timeframe using modular fire cabling.

In summary
Off-site modular construction represents a step-change in how buildings are designed and built. Labour is the biggest cost on a modern project, so anything that can reduce this while enhancing the quality of the finished installation is welcomed. This means that the common practice of having a range of tradespeople on-site will also change and working methods will have to adapt accordingly. However, for the client this means enhanced quality, more efficient working practices, and significant time and money savings.

Rather than being a quick fix to get the industry through these tough recessionary times, off-site modular construction is here to stay and will only grow in popularity. The triple benefits of faster project turnaround, greater efficiency and financial savings that are recognised by the fire detection and emergency lighting sectors are being experienced elsewhere. The future is undoubtedly modular and once presented with the facts, clients are recognising its advantages.

For further information please contact Hochiki Europe on 01634 266566, email: emarketing@hochikieurope.com or visit www.hochikieurope.com, or Chris Carvell at TCS Fire Safety Services Ltd on 0844 8484580, email: c.carvell@tcs-org.co.uk