2009 Ashrae Hof Chapter 4 Equation 48 -pg 4.21-- Site

[ W = 0.62198 \cdot \fracp_wp - p_w ]

However, is:

[ W = \frac0.62198 \cdot \phi \cdot p_wsp - \phi \cdot p_ws ] 2009 ashrae hof chapter 4 equation 48 -pg 4.21--