Abstract 

Inspiration

The Problem

The Outline of a Solution

The Main Cooling System and its Essential Elements

The Fluid Pressure

Headers and Downcomers

Natural or Assisted Circulation

Isometric Outline of the Main Structure Cooling System

Isometric Outline of a Protected Room

Some General Conditions

References

There are many parts in any building that need a fire protection but cannot be easily made of shapes with appropriate internal channels. Such parts should be collected in one or several protected rooms that are separated from remaining volumes of the building by appropriate cooled shields. The latter shall include at least one row of tightly spaced tubes that prevent an excessive penetration of radiation of flames or of other hot substances to the inside of the protected room. A reasonably tight box, made essentially of steel plates, shall be placed between the said row(s) of tubes and the outside border of any of said protected room(s). A controlled temperature and a pressure slightly higher than in surrounding spaces shall be maintained inside every protected room in order to prevent penetration of any gases from the outside. The inside atmosphere should preferably consist of an inert gas, e.g. carbon dioxide or nitrogen, unless the protected room shall remain accessible by persons without respirators.

The thermal shield described above greatly facilitates the objectives of the usual solid barrier. In particular, this shield will always keep the temperature of the inside surface of the barrier near the temperature of the outside surface of the risers, whereby the latter will always remain quite near the temperature of the water flowing inside. In such situation, the solid barrier needs neither absorb all the heat that hits its outside surface nor keep the temperature of its inside surface at a level acceptable for the steel structures. Instead, it is adequate and useful if the solid barrier restricts the steady state heat flow rate between both its surfaces. This latter objective can be achieved over such periods of time as the cooling systems operates correctly, i.e. unlimited in favorable cases.