This seminar gives an overview of methods used for the determination of recommended heat gains and diversity factors for different office equipment in the ASHRAE Fundamentals Handbook tables. In particular, the effects of a number of tested pieces of equipment as well as the interval duration for data reduction are investigated. Analysis on the effect of the different number of tested pieces of equipment and averaging interval on the diversity factor is also discussed. Recommendations for minimum equipment count for determining diversity factors as well as recommendations for future work are given.