File of correspondence mainly between Theatre Projects Consultants Ltd and various companies and consultants regarding sound insulating doors, safety curtains and smoke vents. Subjects covered include quotations and estimates; information on the equipment made by these companies and how they will meet the Theatre Projects Consultants Ltd's specifications, including descriptions, outline specifications and related sketches; invitations to tender and resulting tender documents and forms; issues with door 'D'; notes on sound reduction with attached acoustical research; the issue of drawings; and finishes and alterations.
Correspondents include Dreadnought Fireproof Doors (1930) Ltd; Geo W King Ltd; Acoustic Designers; Mole Richardson (Stage & Studio Engineering) Ltd; Hall Stage Equipment Ltd; Hall & Dixon Ltd; Denys Lasdun & Partners; Acoustical Investigation & Research Organisation; and Flint & Neill Ltd. The file also includes specifications for the safety curtain and fire and sound resistant doors (including Theatre Projects Consultants Ltd specification number 904/FS17 and number 904/FS10); sketch number DF 3145 'Elevation of Winch and Latching Gearr' by Geo W King Ltd; a series of 5 sketches by Hall Stage Equipment Ltd 'National Theatre Sound Insulated Doors'; a sketch by Hall Stage Equipment Ltd number E 3148 'Basic Construction For 35dB Average Sound-Insulating Door'. Original card folder disposed of. '04/5B3 New the National Theatre. (1) Sound Insulating Doors.' was written on the spine.