Monitoring and detection of small loose parts within commercial light-water cooled nuclear reactors has been required by regulation in the United States for about 20 years. This monitoring was originally complaint only with Nuclear Regulatory Commission (NRC) Reg Guide 1.133, REV 1, May 1981. The American Society of Mechanical Engineers (ASME) developed an Operations and Maintenance Standard, OM-12, addressing issues which the regulatory guide did not address. The regulatory guide was prepared prior to significant operating experience which began to unfold during the mid 1980's time frame. This paper reflects upon the history of development for the two standards. Based on available information it concludes that systems meeting the OM-12 requirements are more sensitive to impact-like-events based on a comparison of the detection sensitivities and alert set by each standard. Newer systems meeting OM-12 guidance are not prone to false alarm problems which plagued the first generation systems installed in response to issues discussed in Reg Guide 1.133.