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THE LESSONS OF HISTORY

FOCUS ON: DOORS AND WINDOWS

One of the many challenges we face when working with listed buildings is how to reconcile the requirements of current building regulations and fire legislation with historic doors, at the same time seeking to maintain detail and character.

For example, at Methodist Central Hall, completed and dedicated in 1912 and sited in the heart of Westminster, we were faced with a building of limited fire compartmentation, as many of the foyers, corridors and staircases are interconnected. Of particular concern was the Great Hall, the main place of worship, which is also used for conferences and lectures during the week. It is on the third floor and accommodates over 2,000 people. The doors from the Great Hall discharge into side corridors and the front foyer, from which various staircases descend to street level. Overall, there was a lack of separation between the various circulation parts. Glass panels to the doors offered little fire resistance and floor springs made it possible to hold the doors open, potentially allowing the passage of smoke and fire.

The fire-strategy report that we commissioned identified the need to upgrade the doors of the Great Hall and also provide separation between the side corridors and the foyer by putting in new fire screens between the various exit doors and the escape staircases.

The stiles and rails of the oak doors of the Great Hall were 50mm thick, but it was the thinner portions of the raised and fielded panels that posed problems with fire resistance.

Working with Sealmaster of Pampisford, we specified a thin intumescent veneered product known as Fireface Plus, which could be glued on to the thin portion of the panels, without obscuring mouldings or having to dismantle the doors. The product also had the advantage of being reversible in the future.

The veneer face was carefully stained and, where appropriate, grained to match the oak.

To improve smoke and fire separation, the edges of the doors were rebated and Sealmaster's smoke and intumescent strips inserted, the carrier of which was specially bronzed. We replaced the float glass of the doors with fireresistant glass by Schott Glass, bedded in intumescent tape, with the oak quadrant beads reused and repolished.

As it was desirable for all the Great Hall doors to have the ability to be held open and maintained as double swing doors, we specifi ed Dorma hold-open floor springs with an interface with the firealarm system. The control panels for multiple pairs of doors are in adjacent store rooms. Many of the original engraved floor-spring cover plates survived, and these were cleaned, polished and reinstated.

Specialist contractor Antique Bronze replicated missing pull handles and other components. All the bronzework, including the original bronze crosses over the glass panels, was hand patinated to a rich lustre.

One issue to resolve was how to avoid the usual fire-door signage, which can disfigure so many historic interiors. Fortunately, we agreed with the local authority that hand-painted signage, undertaken by Kevin Glashier, would be acceptable if applied to the oak mid rails in a contrasting colour. Thus, with the exception of the new signage, the overall appearance of the doors is as originally intended, but all the doors have upgraded fire resistance. They will close gently in response to a fire-alarm signal, but can be held open when required.

To separate the side corridors from the front foyer, we designed a series of contemporary detailed bronzed steel frames with maximum glazing of Pyran fire-resistant glass by Schott Glass, with pairs of wide oak glazed doors, polished to match the colour of the historic doors. These are fitted with hold-open Dorma floor springs with a link to the fire system. The door edges were fitted with Sealmaster smoke and intumescent edge seals.

Considerable damage had occurred to many of the oak cross-corridor doors of the west-wing offices. This was due to difficulties with wheelchair access, as well as damage from catering and chair trolleys, which was not surprising since the pairs of doors are only 1,400mm wide.

Automating the doors resolved this issue, with a system supplied and fitted by Woodwood (Door Controls) of Chelmsford. This comprises a remote compressor unit (serving multiple doors) that provides air, via a smalldiameter hose, to open the doors gently and silently. The top openers and the air hose were contained within a new surface-mounted transom.

Each pair of doors is operated by a wireless push pad, sited adjacent to the doors, which has the advantage of being surface mounted, avoiding chasing of plaster as there are no cables, and can be located at any height or position. In order to maintain the hierarchy of ironmongery between 'front and back of house' areas, bronze push pads with a disability logo infilled white are fitted to the frontof-house areas, and brass infilled black is used elsewhere.

All of these doors, along with dozens to the offices, were also upgraded with Sealmaster products as noted above. The painted doors were finished with Dulux oil eggshell paint from the Heritage range.

The conversion of the old bank hall to a new chapel scheme also posed a challenge.

The large, 4m-high, singleglazed windows to the east and south caused heat loss and furthermore meant that noise from traffic and tourist buses disturbed the desired peace of the space.

It would not have been acceptable to replace the original window frames with new integral double-glazed units, so we designed large secondary glazing panels of powder-coated steel frames with laminated glass. The frames are hinged to allow inward opening for cleaning.

The large space between the original window and the new unit maximises sound resistance and reduces double reflection issues when one views the building from the exterior.

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