Start-to-FinishWith a SF and zero lag, the successor activity can finish on theprevious day or later than the predecessor activity starts whetherthe schedule is based on early times or late times. Because thepredecessor could start the next day of the successor’s finish,special care is required in the backward pass with SF:0, especiallywhen nonworking days are involved. The latest possible start timeof the predecessor is the next day of the successor’s LFT or, if itis a nonworking day, the next available working day. For example,as shown in Fig. 20, Activity B finishes at the end of Day5, thus its predecessors with SF:0 can start at the beginning ofDay 6, if it is a working day. However, since Activity A belongsto Calendar 2 and Day 6 is a nonworking day, Activity A can startat the beginning of Day 8.With a SF and positive lag, the successor can finish at the lagtime after or later than the predecessor starts. With this property,the latest possible start time of the predecessor is the next day ofthe successor’s LFT less the amount of the lag time counted byworking days on the predecessor’s calendar. For example, asshown in Fig. 21, the LFT of Activity B is the end of Day 5, thusits predecessors with SF:1 on Calendar 2 can start at the beginningof Day 3. Since Day 3 is working day on Calendar 2, ActivityA can start at that time.With a SF and negative lag, the successor can finish at the lagtime before or later than the predecessor starts. With this property,the latest possible start time of the predecessor is the next day ofthe successor’s LFT plus the amount of lag time counted byworking days on the predecessor’s calendar. For example, asshown in Fig. 22, the LFT of Activity B is the end Day 5, thus itspredecessors with SF:−1 on Calendar 2 can start at the beginningof Day 9 or earlier. Since Day 9 is a working day in Calendar 2,Activity A can start at that time.