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e e e e Fire Resistance Ratings The following tables present for the information of building inspectors and other public officials, architects, engineers and others interested in fire safety in buildings, types of construction' which, provide fire resistance ratings of I, 1~, 2, 2~, 3 and 4 hours, as may be required by codes or regulations. The data cover. , Beam, girder and truss protectioI\s Ceiling constructions Column protections Floor and ceiling constructions Roof constructions Walls and partitions. ,_J .~ " :, ! I - The tables are set up in terms of minimum requirements (type, details ot construction and thickness of materials) for the specified fire resistance, and in such 'form as to fit the requirements for hours fire resistance given in building codes. Some constructions, such as brick walls and .certain column protections, have obtained test ratings higher than required by building codes, and hence higher than, indicated ~n the tables. For further data the original references, shown by numbers in parenthesis, should be consulted. The fire resistance rating of a wall or partition or floor and ceiling construc- tion is essentially the time in hours the construction will remain in place and prevent temperatures 011 the unexposed side from exceeding a certain amount when the construction is exposed to the standard test fire. The fire resistance rating of a column is the time in' hours the column will stay in place and carry its load. The usefulness of the assembly after the fire exposure is not taken into account, and damage to the assembly is not necessarily a factor in the rating. Ratings shown as "Based on Standard Fire Tests" are ratings derived from tests made. substantially in accord with the "Standard Methods of Fire Tests of Building Construction and Materials," ASTM E1l9. Grouped separately from ratings based on standard tests are estimated ratings of certain forms of construction which have been commonly recognized in building codes but for which standard test data have not been available. Such ratings have been included to fill some of the important gaps in the tables of ratings based on standard tests, so that building inspectors and other users of these tables would have some information to go by pending the time when more adequate test data become available. The data given under estimated ratings do not include details on attachment, but it is assumed that the protection will be securely attached in such a way that it will remain in place during fire exposure. The tables include the ratings shown in the January, 1956 Fire Protection Equipment List of Underwriters' Laboratories, Inc., and the Supplements thereto through October. Listings of Underwriters' Laboratories made since that date may include additional ratings. For data on any such ratings. see the latest issue of the Fire Protection Equipment List, which is published by Underwriters' Laboratories, Inc. annually with bi-monthly supplements. Attention is called to the fact that with ratings based on currently published listings by Underwriters' Laboratories, Inc., there is reasonable assurance that the listed materials will conform in weight, dimension, and quality to those which developed the original test rating, but that with other ratings the materials cur- rently available may not necessarily be the same weight, dimensions and quality as those which were originally tested and rated. Where an assembly is specified to be of noncombustible materials, care must be exercised in selecting from the tables only assemblies which are made of non- combustible materials. Analyzing Test Data. In judging and interpreting test results it is necessary to analyze carefully the test data if ratings therefrom are to be on a comparable basis. With many of the older fire tests the fire exposure differed to a considerable extent from the present standard fire exposure, and with many of the early floor fire tests top surface temperatures were not obsened. ' 1 . '. ., ,I n ( L r I I , . e