11 minute read
HISTORICALLY SAFE
It is important in any building to get the emergency and exit lighting right, but it is even more imperative to do so when you are dealing with an historic or listed structure. Historic England’s Geraldine O’Farrell outlines some important dos and don’ts
Historic buildings and structures come in many shapes, sizes and grades and they require lighting designers and engineers to take different approaches when working on them, especially in the context of designing, specifying and installing emergency lighting systems.
This article outlines the different listing grades, what type of approach when it comes to emergency lighting is most appropriate, and the difficulties that designers can face when working on such buildings.
INTRODUCTION When considering an emergency lighting and exit signage installation in a historic building, it is unlikely that a conventional approach will result in an acceptable design. Listed buildings can be very challenging as there is no ‘one solution fits all’, as there is no such thing as a typical historic building.
Listed structures can vary from Tower Bridge to Battersea Power Station, from a medieval chapel to Dover Castle, from a palace to a warehouse and from one room to many. Every one of them could be, and often is, graded the same and each is as important as the other, as they all form a part of our nation’s rich heritage.
If working with England’s historic buildings is unfamiliar, then the listing system may also be confusing. So, to recap, what is a listed or scheduled building and what does each category mean?
UNDERSTANDING LISTED BUILDINGS The general principles to listing are that all buildings constructed before 1700 are listed, but they must survive in something like their original condition. Also, structures automatically listed are those built between 1700 and 1850.
In addition to these, special attention is paid to buildings from the period after the Second World War, in other words 1945. Listing is not normal for buildings and structures less than 30 years old to be considered as they have not yet ‘stood the test of time’.
There are three grades of listing currently employed. The first and highest grade is Grade I (Grade one). These make up about 2.5% of the approximately 500,000 listed buildings in England.
These are rare and categorised as being of ‘exceptional interest’. There are only about 12,500 of them left and we lose a few every decade to fire, flood, neglect and other unforeseen disasters.
Grade I listed buildings include such iconic buildings and structures as:
• St Paul’s Cathedral • The Monument • Admiralty Arch • Clifton Suspension Bridge • Burghley House • The Bank of England • The Lloyd’s Building • Rom Skatepark, Hornchurch, east London
The next listing is Grade II* (Grade two star). These are specified as being ‘important buildings of more than special interest’. These account for 5.8% of the total, which equates to around 29,000. They include such buildings and structures such as:
• London Underground Headquarters, including St James Park Underground Station • The Royal Fusiliers War Memorial • The bust of Nelson Mandela outside Royal Festival Hall • Dr Johnson’s House in London EC4 • Temple Bar • Liverpool Street, London Underground signal box
The final listing consists of the remainder of the 500,000 buildings or structures all listed at Grade II (Grade two).
These are classified as being of ‘special interest’ and this is the most likely grade for a heritage home-owner, for example. However, just to complicate things further, a building can be classed as a ‘Scheduled Monument’ and yet also be listed. Scheduling is the oldest form of heritage protection and began in 1913.
This designation cannot be applied to an ecclesiastical building or to an inhabited dwelling unless the person living there is employed as a caretaker. Buildings in use for non-residential purposes can be scheduled. Where this applies it is the scheduled monument statutory scheme that takes precedence.
HISTORY OF EXIT SIGNAGE Having clarified what listing and scheduling mean and the rarity of each, let’s very briefly look at the history of exit signage.
The first exit signs were used at the turn of the 20th century (in about 1911) following a very serious fire in an American factory. The system employed the now obsolete incandescent lamp.
Prior to the installation of electric lighting there was no easy way of providing emergency or exit signage. If you are ever lucky enough to find an early example of exit signage, try to record and retain it in situ, as early examples of building services are rare and are as important in their own right as the rest of the history of a building. Further guidance on how best to go about this can be found on the CIBSE Heritage Group website, www.hevac-heritage.org/ It is now common practice to consider emergency lighting and exit signs for any building used or visited by the public who, being unfamiliar with the internal space, may need assistance to safely make their way out of the building in the case of mains failure or emergency.
TEMPORARY EMERGENCY LIGHTING So, when a historic building is used in such a context, and it has been established that this form of lighting is required, a designer should follow this up by asking a series of questions.
The most important of these should be: ‘is permanent emergency lighting needed?’.
Examples of the sort of free-standing emergency lighting that can often work in a heritage or historic setting
The answer to this is often ‘no’, especially when public events are only sporadically held at the building in question.
For example, many listed churches are only occasionally used as musical or theatre venues and the associated cost, physical intervention to the historic fabric or the visual impact of an emergency and exit signage installation cannot therefore be justified or often afforded.
It is perfectly legitimate in this scenario to have simple free-standing, plug-in or solar-powered, floor-standing LED units providing the escape lighting.
These can be brought in on an ‘as-needed’ basis. These units can also incorporate running man signs if required. They can be made as sophisticated as required, the ones shown in the images above, for example, are for a highly ornate interior but they can be a simple wooden frame.
On top of this, it must be taken into account that some listed buildings have no electrical supply and still use gas lighting or candles.
These locations can use either solar-powered units, as described above, or photo-luminescent safety signage that provides 24 hours of bright illumination within five minutes of a change in normal lighting conditions.
Alternatively, as is used in some large listed houses that open at night for such events as ghost tours, an option is to have trained staff familiar with the internal layout who are on hand to guide visitors out. This arrangement will only comply with health and safety requirements however when there are sufficient numbers of staff, with the necessary knowledge, to provide the required ratio of staff to visitors. All hazards must have been identified beforehand.
‘wish for’ item and it will be available soon.
It will mean running man signage can be almost invisible within a heritage building’s internal space, and therefore is a welcome and valuable addition to the designer’s lighting armoury. I would be pleased to pass on any information about these new products to any interested parties, and my email address is at the end of this article.
Examples of discreet permanent emergency lighting exit and running man signage that may be appropriate for a heritage/historic building setting
PERMANENT EMERGENCY LIGHTING INSTALLATIONS Where listed churches are regularly used for non-ecclesiastical events and the church’s aim is to make the building a centre for community events (something that is on the increase), it may be cost effective and desirable to have a permanent emergency lighting installation in place. If this is the case, then it is important in a listed building interior to make this installation as discreet as possible. The best way of achieving this is to have integral emergency packs installed in the space lighting wherever possible. It is a good idea, too, to use discreet locations, such as low level and door reveals and non-conventional running man exit signage.
This can take the form of a non-standard design that suits the interior better or an exit sign that will only appear when there is a mains failure. The latter would be the ideal compromise as the sign will be invisible when not needed and illuminating the way out when it is.
New product development here in the UK now means this sort of exit sign is no longer a
INSTALLING EMERGENCY AND EXIT LIGHTING IN HISTORIC BUILDINGS When a decision to install emergency and exit signage has been made, before any work is carried out permission for these works must be gained from the local authority conservation officer. In the case of Grade I and Grade II* buildings this must be in consultation with Historic England. In the case of churches, a faculty (or the church law that grants a permissive right to undertake works to a church building or its content) must be applied for via the appropriate diocese.
It must be remembered that it is a criminal offence to undertake works to a listed building or scheduled monument without detailed written consent.
As well as dealing with the legislation, there are other issues that must be considered when working within a listed building. When installing any service into a heritage structure, you must adhere to the principles of reversibility – total reversibility if possible – so that no part of the installation leaves a permanent scar. This means methods such as only fixing into mortar joints and not the brick or stone and using mounting pattresses where needed to locate such fixing points.
At Historic England we support the use of modern technology and contemporary fittings that are an honest addition to a building’s interior.
A faux heritage lantern that pretends to be a historic fitting is unlikely to be suitable unless there are exceptional circumstances, for example where an existing lighting theme is being matched. Wherever possible, the use of low-energy LED lamps is encouraged.
Finally, remember, a conventional, strict adherence to British Standard guidance approach is unlikely to be met with favour, so come to a listed building project prepared to do some lateral thinking.
If ILP members wish to find out more about this topic, Geraldine is happy to be emailed on : geraldine.ofarrell@HistoricEngland.org.uk
Geraldine O’Farrell DipConHistEnv(RICS) BA(Hons) CEng FCIBSE FIET MSLL is senior building services engineer, Technical Conservation Team, at Historic England
Since 1837 the Sugg name has been synonymous with handmade heritage lanterns & flambeaux. William Sugg & Co Ltd, established in 1837, are the oldest gas and electric lighting manufacturer in the UK. Specialising in handmade bespoke exterior gas and electric lanterns and our world famous flambeaux gas features for the garden, as seen at the entrances to well-known landmark buildings and historic places of interest. Our craftsmen build bespoke products for you and can be tailored to your personal requirements. Our gas products are made in Sussex and are gas safe approved. William Sugg & Co Ltd, established in 1837, are the oldest gas and electric lighting manufacturer in the UK. Specialising in handmade bespoke exterior gas and electric lanterns and our world famous flambeaux gas features for the garden, as seen at the entrances to well-known landmark buildings and historic places of interest. Our craftsmen build bespoke products for you and can be tailored to your personal requirements. Our gas products are made in Sussex and are gas safe approved. Since 1837 the Sugg name has been synonymous with handmade heritage lanterns & flambeaux. William Sugg & Co Ltd, established in 1837, are the oldest gas and electric lighting manufacturer in the UK. Specialising in handmade bespoke exterior gas and electric lanterns and our world famous flambeaux gas features for the garden, as seen at the entrances to well-known landmark buildings and historic places of interest. Our craftsmen build bespoke products for you and can be tailored to your personal requirements. Our gas products are made in Sussex and are gas safe approved. William Sugg & Co Ltd, established in 1837, are the oldest gas and electric lighting manufacturer in the UK. Specialising in handmade bespoke exterior gas and electric lanterns and our world famous flambeaux gas features for the garden, as seen at the entrances to well-known landmark buildings and historic places of interest. Our craftsmen build bespoke products for you and can be tailored to your personal requirements. Our gas products are made in Sussex and are gas safe approved.
