Sanitary Accommodation Scales for Large Shopping Malls

The architectural sanitary accommodation as an essential component of building sanitation system is examined from the perspective of a maximum probable waiting time of a user in order to get the desired service from the appliance. This paper reports the probable demands on the sanitary accommodations derived from the observations on the use of washrooms in a large shopping mall of Hong Kong. Specifically, arrival rates of the washrooms and service time for the users are surveyed. The arrival rates in various peak periods are examined in order to calculate the probable waiting time of users at certain probability of occurrence with a simple queuing model. Expressions for the waiting time at some levels of service were derived for the shopping mall. Scales of the provisions based on the probable waiting time are proposed and compared with those determined from the limiting failure rate of 1 %, and the existing scales for shopping malls. The proposed procedure offers flexibility to design sanitary accommodations to meet the various service standard described by the probable waiting time of users for the appliance.