Effectively protecting historic buildings
From sprawling heritage sites which house our national treasures to townhouses which are home to multiple million pound flats in our major cities, the sheer number and variety of historic properties within the UK is huge. Here, Warren Moyle, Senior Product Support Engineer at Apollo Fire Detectors and Bill Jordan, Quality Manager at Firetecnics Systems, join forces to discuss the protection of these precious properties.
Protecting heritage properties is a complex challenge which must be taken seriously, with a number of factors to consider. Life safety should always clearly remain paramount to any system specification, but it’s a sad fact that any fire occurring in a historic building will most likely result in the loss of priceless and irreplaceable contents, as well as run the risk of structural damage and loss of architectural features.
But, as well as the usual need for early warnings of fire, designers of a fire detection system for a heritage property also need to take into consideration a host of other factors. One of the main considerations is the need to avoid false alarms, particularly as many of these heritage buildings are either tourist attractions which enjoy a high number of visitors or flat conversions which house a number of residents.
Old building challenges
The age of historic buildings lends itself to a number of challenges. Buildings of cultural heritage were constructed under different, if any, rules and often with no building or safety standards. Although most of them were originally built as homes, historic buildings are now used in many different ways. Many house a lot of modern equipment such as computer systems, generators and catering facilities.
Not only does this impact upon the fire detection systems used, but it means that considerable work needs to be undertaken by fire safety specialists to ensure that an effective fire evacuation strategy is in place.
The nature of heritage buildings means that they are often subject to maintenance works being carried out. Ironically, it is these works, often to preserve/repair a building, which can present risks that need to be factored into the design of a fire detection system. Hot works during maintenance and repairs, such as welding and soldering, present a major fire risk, particularly when used around combustible materials such as wooden beams, thatch, and old furnishings.
Another less critical, but still significant, issue is that of aesthetics, especially in buildings which have focussed on preserving the historical and archaeological integrity of their listed sites.
Firetecnics has a wealth of experience in balancing the fire protection needs of a site and ensuring compliance with insurance companies and/or building authority standards with the need to make its detection systems as unobtrusive as possible.
One of the most popular ways of ensuring this is by housing the most obvious of the system elements within specially designed housings. As an example, we recently worked on an old manor house where the owner was keen that the sounders within the library were as inconspicuous as they could be. To achieve this, we positioned these sounders within hollowed out old leather books – with their leather spines and matching height, the result was a totally hidden set of sounders, completely blended with their surroundings. Another client who owns a property near to Harrods commissioned an architect to build a pair of walnut cabinets – one houses his control panel, whereas the other is for his own use but the visual impact of both together is impressive. We’re currently exploring a similar option for a historic church where the fire brigade has ruled that the control panel must be positioned within the entrance, but doing so would spoil the look of this lovely old building.
Where logistics and budgets don’t allow for total concealment, there are a number of clever ways of making fire detection as discreet as possible. It’s an established fact that the human eye is automatically drawn up to the centre of a room, so by positioning elements in the corners of a room, rather than the middle, the visual impact is less noticeable. We also use techniques such as placing detectors above top picture rails, lining them up in even numbers by plaster detailing and positioning sounders behind the thick curtains that are often found in heritage properties. While more sounders are needed to effectively do the job, this cost is often justified by the aesthetic gain.
There’s also the need to be flexible and adopt a common sense approach within historic properties, while still meeting fire regulations. We worked on one old building which had been converted into flats and had a beautiful 200-year-old wooden door which, ideally, would have been a fire door. The owner of the building was obviously very keen to keep the door, so we used the very simple solution of placing a detector directly either side of it to maximise fire and smoke detection in its vicinity.
MCPs are probably the most challenging aspect as, by their virtue, they are the one element of a detection system which needs to be visible. Even in a converted house where residents are aware of what they need to do in an emergency, there still may be visitors to the building who need to know how to activate an alarm system, and within historic buildings which are open to the large number of public visitors, this visibility is even more crucial. While we can’t “hide” an MCP, it is certainly possible to blend them more into their surroundings – examples of this include mounting them on material which matches other aesthetic detailing in the property, such as brass plates, or even making a framed surround to make the contrast between the wall and the MCP less striking.
Identifying the best technical solution
Although the approach to historic building fire detection needs to be tailored to fit a range of specific criteria, the most popular product type Apollo specifies for such applications is a multisensor range such as our SOTERIA® collection which can be programmed to switch “smoke” sensors over to “heat” sensors at different times of the day.
The range uses new optical sensing technology, PureLight®, to detect smoke particles entering its chambers – a unique system marking a new stage in the development of advanced optical technology which increases the reliability of fire detection while resulting in fewer false alarms, making it ideal for the challenges often presented by heritage properties.
A number of other technical developments have been integrated into the SOTERIA® design, including an advanced technology chip sensor to significantly improve smoke detection and a sleek low profile design which means that less dust penetrates the outer casing. We have also designed the detectors to be less sensitive to any dust that does accumulate over long periods of time.
We have worked quite closely with English Heritage in the past and a lot of their sites are remote and in countryside settings, making them open to issues with bugs. The bug screen inside the SOTERIA® detector has been successful in keeping insects out of the optical chamber. Careful design of the optical chamber also ensures that any insect small enough to penetrate the mesh barrier has fewer opportunities to interrupt the operation of the smoke detector.
Another alternative for heritage buildings is our wireless intelligent XPander range of detectors. Wireless detectors are a great way of providing effective fire detection whilst minimising the presence of visible wires and cables in architecturally-sensitive buildings and avoiding invasive drilling. An example of XPander being specified for a heritage building can be seen in Exeter Cathedral. The building is one of the finest examples of Gothic architecture in the country, featuring the longest uninterrupted stretch of decorated vaulting in the world. Heritage Lottery Funding was secured to transform the upper floor of the cloisters into a dedicated space providing modern learning facilities, whilst retaining the historic legacy of the building. XPander was installed to provide fire detection as part of this programme of works without compromising the aesthetics of the ceiling.
From a manufacturer’s point of view,
it is also crucial that we work within our capabilities to ensure that we make our detection systems not stand out like a sore thumb and, from an installation and design perspective, that we strive to provide clever solutions to conceal and minimise a detection system’s visibility. With this in mind, it’s no wonder that it’s common to hold four or five site meetings with property owners, management companies and guardians before we even put pen to paper to provide designs and costings.
Each historic building is unique, and whilst we can’t advise on a “one size fits all” system, our many years of experience have shown that the best approach is often to opt for either the reliability and flexibility of a multisensor system, the discreet option of a wireless solution or, indeed, a combination of the two. By working closely together, Apollo and Firetecnics can continue to ensure effective fire detection, whilst remaining sympathetic to helping to maintain a building’s visual historical integrity.