Letters to the Editor
departments
Construction Dangers Noted
Colorado Springs, Co.
At a recent building officials meeting here in Colorado, a discussion of fire ratings of structures brought to the foreground the article by Captain Gary Collins entitled “Fire Exposes Weaknesses of Architectural Design.” The gist of the discussion and its connection to the article came about through an observation that metal truss plates expand out of the wood under fire conditions and can collapse on firemen.
This fire prevention captain seemed to be surprised that buildings can be constructed of Type V-N construction and, having no limitations on materials used, that architecturally they can use wood paneling and decorative wood siding. A Type V building is made of combustible materials and with a no-hour rating should not be expected to resist fire spread at all. We have become accustomed to having single family residential construction contain 1/2 inch sheetrock over most of the walls because they are easier to finish. The sheetrock could be replaced with wood paneling or left wide open in this occupancy, and meet the code requirements.
I don’t know of any tests in the past on unprotected metal-plated wood trusses in an attempt to obtain an hourly rating — nor do I ever expect it to happen. Heavy construction has been touted as the combustible construction that will hold you up while it is on fire. Light-weight wood trusses were never intended to replace heavy timber construction. In order to have any rating they must be covered with other fire resistive materials and together these materials may constitute a fire resistive assembly.
It should be required of the fire suppression people that they understand the various types of construction for structural integrity under fire conditions. The two most commonly misunderstood types of construction apparently have been Type V-N (combustible-unprotected) and Type II-V (non-combustible unprotected.) We lost one fireman on the roof of a Type V, no-hour apartment three or four years ago, and could have lost another, but for the circumstances.
The fire prevention bureau of each community should be able to extend themselves beyond the use hazard area and pass on information about building types — especially those that under the code (or otherwise) are in danger of collapse under fire conditions.
Perry C. Tyree, P.E.
Regional Buildings Official
