The information has arrived & it's very detailed and has been of great use.
A Summary of the summary:
ConstructionThe store was over SB, B, G & 4 upper floors. Floor area based on frontage 76ft x 196ft
It comprised of the original store area from 1919 & altered in 1936 and an extension built in 1959.
The original building had a steel framed construction without protection, unsupporting walls and timber floors and joists with plaster ceilings directly applied to the timber. Floors were further lined with decorative timber blocks, plastic tiles or carpeting
The extension was similar, except that the steel frame and beams were encased in concrete to give 2hrs FR for external columns & beams and 1hr FR for internal beams & columns. where new & old columns were side by side, both were encased in concrete. Floors were of 1hr FR concrete with similar lining of tiles to the original.
StairsAn escalator opened through all floors with no protection or fire shutters.
Two stairs were present at opposite ends of the floor.
In the original wing a 3'6" timber staircase originally unenclosed, but in 1956 enclosed using 3" x 2" timber studding and 6mm plywood sheeting to each face sprayed with fire retardant. (It was planned to replace the stair with a concrete stair with brick enclosure in the near future). The stair had self closing doors at each level, but these were fitted with cabin hooks and were regularly hooked open for ventilation. Another factor was that the whole stair was not enclosed as a shaft - each flight was separately enclosed so that you had to travel across each open floor space for a few metres to reach the next enclosed flight down.
The second stair was a 4' concrete stair fully enclosed as a shaft in brick with self closing doors at each landing onto the main shop floor.
ShaftsA brick lift shaft capable of accommodating three lifts was included - two lifts with imperforate metal doors were within, the third part of the shaft had been converted to storerooms with timber flooring. In one cormer a similar brick shaft contained a goods lift with imperforate metal doors.
A brick services shaft and small apertures for cables and ventilation ducting was also present.
Internal divisionFloors were open plan and where subdivisions were present for stockrooms, fitting rooms, etc they were timber stud and plywood with glazing & plastic cladding where required and were to false ceiling level only.
false CeilingsThe false ceiling was added in 1956 throughout the store suspended by timber battens to 2'6" depth (3'6" on the 3rd floor to accomodate water and waste pipes from the 4th floor kitchen). 2' x 2' "Whitelite" fibreboard tiles were used, with fire retardant finish to the underside only. At intervals plastic troughs for light fittings were present.
At the end of the store where the ventilation ducting and grilles were fitted the ceiling was 12" lower and of incombustible Burgess acoustic tiles (perforated 24swg zinc coated steel with rockwool padding). Timber planks remained above to allow workmen access.
ElectricalThrough these ceilings ran power cables and from each floors distribution board was fed by 0.6 sq in twin core, paper insulated, lead lined, steel armoured cables. MICC was used from the floor's board to individual sockets and fittings, etc.
Active fire PrecautionsFire AlarmNo fire alarm in the modern sense was fitted. However each floor had a single 240v motorised bell (two to the 4th floor to cover the kitchen) connected to a switch in the telephone exchange in the nearby Hendersons Admin building (connected via an underground tunnel). The exchange had to be rung from the stores internal phones to enable the bells to be sounded & an external call made to the Fire Brigade.
As part of modernisation an AFA 240V fire alarm system was being fitted with heat detectors to all floors and the larger 3rd floor ceiling void connected to the already in service system in the Admin block to share it's GPO link to Hatton Garden Fire Station. Unfortunately the fire occurred 1 week before it's commissioning.
Fire FightingThe transformer room for the store was in the nearby Admin block & had a CO2 system (but all the doors were vented without asbestos curtains & so had no integrity). Other than that a suitable quantity of 2 gallon break bottle Soda acid and water/gas extinguishers & 2 gallon water buckets were located through the store. The kitchen had a 2 gallon Chemical Foam & an asbestos blanket, the lift motor rooms two 5lb CO2's
Emergency lightingA 110V central battery system was provided covering the whole premises on local circuit failure
Training & Fire DrillNo fire training or instruction was given. No fire procedure existed even in a rudimentary form. This applied across the chain that owned Hendersons (House of Fraser) despite similar chains having such in place.
The FireWednesday 22nd June 1960, after 1400.
Approximately 100 staff & 100 customers in the premises
The twin core Cabling from the distribution board at the North of the floor above the false ceiling began to arc internally or similar and in any event built up a large amount of heat that caused the frame of the false ceiling to ignite by radiation, and rapidly spreading throughout the whole false ceiling (the material of these tiles and supporting battens was dried out and already warm from high temperatures in the store due to the ventilation system being partly out of order - this is why the stair doors were hooked open).
Conditions in the void soon led to flashover into the wooden fire stair, rendering it impassible to those on the 4th floor.
Between 1414 & 1420 molten lead from the cable showered down the service shaft to the 1st floor where workmen were laying lino in the switchroom. One went up to the upper floors as they thought it was a welder and wanted them to stop as the lino was being scorched. At 1420 the fire was discovered by 3rd floor staff and the General Manager (GM) who first heard a crackling and then saw flames through the holes in the acoustic tiles.
The GM rang the switchboard in the Admin block & told them to call 999. He then used the first of 9 water extinguishers. (all were ineffective as the jet splashed back off the tiles). The switchboard rang back & asked if the fire bells were to be activated. The GM said yes & the bells sounded throughout the building without any premature failure (as in other fires).
Several other staff & workmen helped with extinguishers and the GM went down to meet the FB. Orderly evacuation of the 1st & 2nd floors was in progress. He went back up the the 3rd, noticing burning droplets from the tiles falling down the escalator shaft. The floor was rapidly smoke logging and he told remaining staff to escape. He was going to check the 4th, but with the worsening fire and the arrival on the 3rd floor of firemen decided to leave the job to the FB.
Around this time the fire had flashed over, with false ceiling collapse causing the 3rd floor to become well alight and trapping several people on the 4th.
5 people had to escape onto a ledge through windows, including ventilation engineers who had been trapped after taking time to go back into the store to shut off the one working ventilator as smoke was being drawn through it. All were rescued by either TL or crawling to adjoining buildings save one who slipped and fell onto the canopy at ground level suffering fatal injuries.
10 people died from smoke inhalation as they had gone to the stair knocked out by the flashover & couldn't make the alternative in time.
5 Pump Escapes, 15 Major Pumps, 5 TLs, 1 Control Unit, Emergency Tender, & Hose Layer used 65 hydrants, 11 jets, 5 TL monitors, 6 twin jets & 1.5 million gallons of water over 3.5 hrs were used to control the fire
Firefighting was defensive as the spread of smoke and then flame forced firefighters out of the building within the first 10-15 minutes of te fire starting.
A partial internal collapse occurred during the fire & at one point bulging in the unsupporting walls threatened external collapse onto fire fighters.
ironyOnly a week or so later a fire occurred in the Admin block of Hendersons. Due to the AFA fire detection system the alarm was quickly raised and the premises evacuated in 3 minutes and due to the protected stairways, concrete floors and frame cladding, the fire was limited in spread and controlled with no loss of life or injury
