Windsor Castle after the fire

Citation

(1998), "Windsor Castle after the fire", Facilities, Vol. 16 No. 3/4. https://doi.org/10.1108/f.1998.06916cab.008

Windsor Castle after the fire

Windsor Castle after the fire

Five years after the fire at Windsor Castle, in November 1992, the reconstruction has been completed.

Oscar Faber's consultancy services were called on to design building services for over 100 rooms in the north-east section, which were damaged by the fire or by water, including several state rooms, three of the towers and extensive staff accommodation. Some sections have been painstakingly repaired, others rebuilt to new designs sensitive to the historical and cultural context.

This massive undertaking involved large numbers of experts, including contractors, consultants and specialist craftsmen, working in close co-operation. Oscar Faber were privileged to be selected as the mechanical and electrical engineering consultants. Our job was to provide modern building services in the rebuilt and repaired section of the castle, including heating, ventilation, lighting and public health services, and a new fire-fighting and detection system.

Installing services into an historic building is a tremendous challenge. There were only limited records or drawings of the original building or of alterations made over the centuries, and when work was under way, investigation revealed what lay within the fabric.

For services engineers, historic buildings present special difficulties. Installations are preferably invisible, but the miles of wiring, ducting and pipework required by today's sophisticated systems need a lot of space. Fire detectors are vital, but they must be unobtrusive, hidden behind the decoration and within the fabric of walls and ceilings. Thick stone walls and high vaulted ceilings provide very few opportunities for concealment without causing damage.

Another factor in this project was the need for consultation with the many organizations involved in the reconstruction and those responsible for running the complex building, in order to meet the needs of the royal household, state functions and the public who visit the castle every year.

Heating and ventilation

One of the main difficulties in installing the new heating and ventilating systems was finding suitable rooms large enough to accommodate the plant. We had to design the plant to fit into the available spaces. For example, the equipment for supplying hot water to the accommodation block only just fitted into the calorifier room.

Ventilating the great kitchen presented problems because the discovery and restoration of the old medieval roof, its lantern and its three-storey height made it difficult to conceal ducting. This has been overcome by housing ventilation plant in the restricted enclosures at each end of the lantern and making use of existing chimneys and flues for extract air.

Public health engineering

The water and drain pipes for the staff accommodation in the damaged Brunswick, Prince of Wales and Chester Towers were hidden behind panelling. Most had been destroyed by the fire and any that survived were damaged or did not meet current standards, and therefore had to be replaced. In addition, the plumbing for the newly-built accommodation had to be replanned and new drains installed. Digging new trenches presented problems, because drain runs had to be diverted around ancient buried stonework.

Electrical engineering

Here again, space for plant was at a premium and the main panel supplying power had to be specially designed to fit the room available. All cabling had to be routed through concealed wireways and risers supplying strategically positioned load centres and distribution boards.

Because there is a need for broadcasts from banquets and functions in St George's Hall and other state rooms, permanent sound, lighting and camera cabling has now been installed. Loudspeakers for the public address system are concealed in corbels in St George's Hall and microphone outlets are hidden in the floor.

Fire detection and fire-fighting systems

We have provided a new fire detection and warning system in the fire-damaged areas, fully addressable and conforming to BS5839 P1. This forms part of the overall network for the castle and is linked to the control centre at the castle fire station. The main control panel incorporates graphics displays so that the exact location of any alarm can be pinpointed. Audible alarms are initiated by electronic sounders, and in state rooms there is discreet visible warning by flashing lights.

There are more than 550 detectors in the system that serves the fire restoration area, installed in all accessible spaces, including broom cupboards and roof voids. A combination of point automatic smoke detectors is used or, in state rooms and areas of greater architectural importance, aspirators or infra-red beam detectors.

There are 14 aspirators systems, each with several heads and individual panels. A fan draws air through small-bore pipes with openings in the ceiling surface. Ingenuity was needed to select places to conceal aspirator heads, such as the roses of chandeliers and other plasterwork decoration. Particle size is measured by a laser, and the alarm sounds when larger smoke particles are found.

It is essential to minimize the number of false alarms, so the system is self-diagnostic: it can identify faults in any of the detectors before it gives a false signal. Particularly in the great kitchen, where smoke could cause a false alarm, a heat tape sensor was used, installed round the edge of the lantern. The detection system in St George's Hall can be monitored separately during banquets so that the large numbers of candles do not trigger the main alarm.

There is a hose reel system serving the rebuilt area, which includes a break tank and automatic pumps, and several dry risers are provided. There are also automatic suppression systems within the extract hoods in the kitchen.

The fire detection system is co-ordinated with other fire precautions designed by the architect. The overall focus is on compartmentation to reduce the potential for fire spread.

Concealing the services

As already indicated, the need to conceal services in rooms with architectural features placed great demands on the skills of the specialist conservation engineers of Oscar Faber. This is well illustrated in St George's Hall.

All the light sources were designed by Maurice Brill to be invisible. For example, he had one set of lights installed within the brackets half way up the wall to illuminate the "knights" standing on the brackets, and fibre optic projectors are concealed in the bosses supported from the new hammer beam roof. The fibre optic cables were concealed in the roof beams and above the new ceiling. Dimming equipment was concealed behind panelling and access to wiring is via a crawl-way above the ceiling.

The hall is also supplied with conditioned fresh air, from remote air-handling plant. Fan coil units in each window reveal provide local heating and cooling. Ducting and wireways are hidden within the floor, between the floorboards and the top of the barrel-vaulted ceiling of the undercroft below. Extract fans in the roof draw air out through a slot behind the decorative roof timbers.

In conclusion

Before starting on this project, Oscar Faber already had considerable experience of working in historic buildings, including the Royal Exchange, Tower of London and Palace of Westminster. But our part in the restoration of Windsor Castle has been our most exciting and demanding restoration project so far and we are proud to have been part of the team.

Further information from Bill 0'Neill on 0181-784 5986.