To obtain a copy of a specific publication, users should contact the publication's publisher directly.
Abstract
The most frequently reported defect in EPDM single ply roofing systems is in field formed joints. The causes of these joint defects are largely unknown, but they ten to occur a short time after a roof is installed. The objectives of this research were: to determine the importance of the following materials and fabrication variables in causing joint failures: adhesive thickness, cure time, mechanical load, adhesive type and surface cleanness; to rank these variables as they affect the creep rupture life and strength of butyl adhered EPDM joints; and to determine the maximum peel stress which EPDM joints can sustain over their design life. From our results, cure time & level of clenness of the EPDM membrane have the greatest effect on joint strength; while the thickness of the adhesive and the magnitude of the mechanical load have the greates effect on a joint's creep rupture time-to- failure. Thus, the rankings of variables in creep rupture and short-time strength experimente were different and this difference should have important implications in standards writing and in establishing performance requirements for EPDM roofing joints. Creep rupture results were used in determining the maximum design stress that butyl and neoprene adhered EPDM joinats can sustain when loaded in peel. The maximum sustainable stress in only a small fraction (less than 5%) of the short time yield strength of a joint. Thus, efforts should be made to insure that the field formed joints are on ly subjected to small peel loads.
The most frequently reported defect in EPDM single ply roofing systems is in field formed joints. The causes of these joint defects are largely unknown, but they ten to occur a short time after a roof is installed. The objectives of this research were: to determine the importance of the following materials and fabrication variables in causing joint failures: adhesive thickness, cure time, mechanical load, adhesive type and surface cleanness; to rank these variables as they affect the creep rupture life and strength of butyl adhered EPDM joints; and to determine the maximum peel stress which EPDM joints can sustain over their design life. From our results, cure time & level of clenness of the EPDM membrane have the greatest effect on joint strength; while the thickness of the adhesive and the magnitude of the mechanical load have the greates effect on a joint's creep rupture time-to- failure. Thus, the rankings of variables in creep rupture and short-time strength experimente were different and this difference should have important implications in standards writing and in establishing performance requirements for EPDM roofing joints. Creep rupture results were used in determining the maximum design stress that butyl and neoprene adhered EPDM joinats can sustain when loaded in peel. The maximum sustainable stress in only a small fraction (less than 5%) of the short time yield strength of a joint. Thus, efforts should be made to insure that the field formed joints are on ly subjected to small peel loads.
Date
5/1990
5/1990
Author(s)
J Martin; E Embree; P Stutzman; J Lechner
J Martin; E Embree; P Stutzman; J Lechner
Page(s)
59
59
Keyword(s)
butyl adhesive; creep rupture life; EPDM; neoprene; seam; peel performance criteria;
butyl adhesive; creep rupture life; EPDM; neoprene; seam; peel performance criteria;