Fire-resistant floor structure

Claim 2

Apparatus for fireproofing an underfloor access chamber comprising: a metal cellular unit providing spaced-apart raceways for distributing electrical wiring; a covering layer of concrete having an upper surface; insert means forming an access chamber between said concrete and said cellular unit, said chamber having a bottom portion extending between adjacent raceways with inlet openings each communicating with one of said adjacent raceways, and having a top portion with an outlet opening providing access to said chamber from said upper surface; an unobtrusive resilient strip of fire-resistant material covering all of said bottom portion and obstructing said inlet openings; and slit means in said resilient strip for passing wiring between each raceway and said chamber without significantly deteriorating the obstruction of said inlet openings; whereby under fire conditions, said resilient strip shields said top portion from convection currents of hot gases which would normally pass through said inlet openings and from high temperature radiation emitted by hot surfaces of said bottom portion.

Claim 3

The apparatus defined in claim 1 including external fireproofing confronting the lower face of said cellular unit.

Claim 4

The apparatus defined in claim 1 wherein said strip is formed from a resilient foamed plastic.

Claim 5

The apparatus defined in claim 3 wherein said foamed plastic comprises foamed neoprene.

Claim 6

The apparatus defined in claim 1 wherein said strip is formed from flexible glass fiber mat.

Claim 7

The apparatus defined in claim 1, 3, 4 or 5 wherein the width of said resilient strip is greater than the width of said chamber, said resilient strip being compressed between confronting surfaces of said chamber and thereby retained in position.

Claim 8

An electrical wiring distributing floor structure including: a metal cellular unit providing plural cells, adjacent cells presenting spaced crests separated by a trough, each trough comprising a valley and confronting webs connecting said valley to said crests; a covering layer of concrete having an upper surface; insert means forming an access chamber between said concrete and said cellular unit, said chamber having confronting side walls cooperating with a valley segment and with web segments of said cellular unit to define a trough space; access means providing access to said chamber from said upper surface; inlet openings, one presented by each of said web segments; and an unobtrusive resilient strip of fire-resistant material including a central portion covering all of said valley segment, and opposite end portions, each covering all of one of said web segments and obstructing the inlet opening thereof; and slit means, one in each of said end portions, for passing electrical wiring between the adjacent cell and said chamber without significantly deteriorating the obstruction of said inlet openings; whereby under fire conditions, said resilient strip shields said top portion from convection currents of hot gases which would normally pass through said inlet openings and from high temperature radiation emitted by hot surfaces of said bottom portion.

Claim 9

An electrical wiring distributing floor structure including: a metal cellular unit providing plural cells, adjacent cells presenting spaced crests separated by a trough, each trough comprising a valley and confronting webs connecting said valley to said crests; a covering layer of concrete having an upper surface; insert means forming an access chamber between said concrete and said cellular unit, said chamber having confronting side walls cooperating with a valley segment and with web segments of said cellular unit to define a trough space; access means providing access to said chamber from said upper surface; inlet openings, one presented by each of said web segments; and an unobtrusive resilient strip of fire-resistant material including a central portion covering all of said valley segment, and opposite end portions, each covering all of one of said web segments and obstructing the inlet opening thereof; and slit means, one in each of said end portions, for passing electrical wiring between the adjacent cell and said chamber without significantly deteriorating the obstruction of said inlet openings; whereby under fire conditions, said resilient strip shields said top portion from convection currents of hot gases which would normally pass through said inlet openings and from high temperature radiation emitted by hot surfaces of said bottom portion.

Claim 10

The floor structure defined in claim 7 wherein each of said slit means extends from a terminal edge of the end portion toward said central portion.

Claim 11

The floor structure defined in claim 7 or 8 including external fireproofing confronting the lower face of said floor structure.

Claim 12

The apparatus defined in claim 7 or 8 wherein the width of said resilient strip is greater than the distance between said confronting side walls, said resilient strip being compressed between said confronting side walls and thereby retained in position.