This bulletin reports the research on two separate PVRC projects (97-04 and 97-09) on external bending moments on gasketed bolted flanged joints. This work is part of an experimental and analytical program to investigate the effect of the external bending moment on the integrity and leakage of a bolted joint and to develop a new or alternative procedure for use in the ASME design rules for bolted flanged joints. This bulletin is the third in a series covering the tests in the program. The first in the series is published in WRC Bulletin 450, which reports the test results on NPS 4 Class 150 weld-neck and lap joint flanges. The second in the series is published in WRC Bulletin 461, which covers tests using a full size 16 Class 300 flanged joint. Part 1 of this bulletin covers an experimental study on the effect of bending moments on two different type of flanges: Class DN 200 ISO PN 50 (NPS 8 Class 300) and Class DN 40 ISO PN 50 (NPS 1 ½ Class 300). The objective of the tests is to determine the effect of increasing and decreasing bending moments on gasket tightness and bolt loads. Different gasket materials are tested; non asbest's fiber sheet material, graphite sheet material, PTFE and Spiral Wound gaskets. The general conclusion that can be drawn from the test results is that the effect of bending moments on the leakage behavior of these tested joints is not significant.