The executive consider the term “fire-resisting” more applicable for general use, and that it more correctly describes the varying qualities of different materials and systems of construction intended to resist the effect of fire for shorter or longer periods, at high or low temperatures, as the case may be, and they advocate the general adoption of this term in place of “fire-proof.”
Further, the executive, fully realizing the great variations in the fire-resisting qualities of materials and systems of construction, consider that the public, the professions concerned, and likewise the authorities controlling building operations, should clearly discriminate between the amount of protection obtainable or, in fact, requisite for different classes of property. For instance, the city warehouse filled with highly inflammable goods of great weight requires very different protection from the tenement house of the suburbs.
The executive are desirous of discriminating between fire-resisting materials and systems of construction affording temporary protection, partial protection, and full protection against fire, and to classify all building materials and systems of construction under these three headings. The exact and definite limit of these three classes is based on the experience obtained from numerous investigations and tests, combined with the experience obtained from actual fires, and after due consideration of the limitations of building practice and the question of cost.
The executive’s minimum requirements of fire-resistance for building materials or systems of construction will be seen from the standard tables appended for—
I. Fire-resisting floors and ceilings,
II. Fire-resisting partitions,
III. Fire-resisting doors,
but they could be popularly summarized as follows:—
(a) That temporary protection implies resistance against fire for at least three-quarters of an hour.
(b) That partial protection implies resistance against a fierce fire for at least one hour and a half.
(c) That full protection implies resistance against a fierce fire for at least two hours and a half.
The conditions under this resistance should be obtainable, the actual minimum temperatures, thickness, questions of load, and the application of water can be appreciated from the annexed tables by all technically interested, but for the popular discrimination—-which the executive are desirous of encouraging—the time standard alone should suffice.