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Abstract
The use of mechanical fasteners for securing membranes or booth insulation and membranes to the structural deck of low-slope roof systems is a common practice in the U.S. The fasteners have been observed to corrode in service in the presence of moisture. Depending on the extent of corrosion, loss of securement may result, making the roofing vulnerable to damage during high winds. Systematic studies to elicit the factors affecting the corrosion of fasteners in service have not been conducted. This paper presents the results of a study conducted to summarize available information on the corrosion issue and to identify research needed to correct problems. On the basis of the available information, it was not possible to estimate the extent of the corrosion problem. In particular, the incidence of loss of fastener securement due to corrosion could not be established because of the inaccessibility of installed fasteners within roofs. In reviewing factors affecting fastener corrosion, water was the only one that stood out on the basis of the information obtained. Uniform corrosion (rust on some or all of the surface) was the predominant type that inspectors have observed in service. Nevertheless, some evidence of localized corrosion processes (e.g., crevice corrosion) has also been observed. Both types of corrosion may lead to loss of fastener securement in service. The results of the study indicated that there are three major gaps in the knowledge base: evaluation test procedures for the corrosion resistance of fasteners are limited and need to be improved; a database on field performance of fasteners is lacking; and nondestructive diagnostic procedures for assessing the condition of in-place fasteners are not available. Research needed to overcome these limitations was identified.
The use of mechanical fasteners for securing membranes or booth insulation and membranes to the structural deck of low-slope roof systems is a common practice in the U.S. The fasteners have been observed to corrode in service in the presence of moisture. Depending on the extent of corrosion, loss of securement may result, making the roofing vulnerable to damage during high winds. Systematic studies to elicit the factors affecting the corrosion of fasteners in service have not been conducted. This paper presents the results of a study conducted to summarize available information on the corrosion issue and to identify research needed to correct problems. On the basis of the available information, it was not possible to estimate the extent of the corrosion problem. In particular, the incidence of loss of fastener securement due to corrosion could not be established because of the inaccessibility of installed fasteners within roofs. In reviewing factors affecting fastener corrosion, water was the only one that stood out on the basis of the information obtained. Uniform corrosion (rust on some or all of the surface) was the predominant type that inspectors have observed in service. Nevertheless, some evidence of localized corrosion processes (e.g., crevice corrosion) has also been observed. Both types of corrosion may lead to loss of fastener securement in service. The results of the study indicated that there are three major gaps in the knowledge base: evaluation test procedures for the corrosion resistance of fasteners are limited and need to be improved; a database on field performance of fasteners is lacking; and nondestructive diagnostic procedures for assessing the condition of in-place fasteners are not available. Research needed to overcome these limitations was identified.
Date
2/1989
2/1989
Author(s)
jWalter Rossiter Jr; Michael Streicher; Willard Roberts
jWalter Rossiter Jr; Michael Streicher; Willard Roberts
Page(s)
89
89
Keyword(s)
corrosion, durability, metallic fasteners; membrane attachment; research needs; securement
corrosion, durability, metallic fasteners; membrane attachment; research needs; securement