B038 Public sanitary provision

Provisional scales of sanitary accommodation in public toilets

Brief:

Sanitation is one of the essential facilities in buildings. The unit of sanitary accommodation required in some public toilets is currently calculated at a failure rate of providing immediate service to meet the user demands. As a user is very likely to feel anxious about the time needed to get to the service desired, the waiting time would probably be a better criterion for specifying the unit of sanitary accommodation required in toilets for large spaces. In this study, a procedure of determining the probable user waiting time for an appliance in a public toilet is proposed based on a queuing theory. A simple queuing system for water closets and washbasins was developed by the measured waiting time from experiments. The corresponding probability of queuing for a specific appliance/service was determined. For average waiting times of 1 s and 10 s, the number of appliances required was calculated and compared with the current one in common use. Applied examples with input parameters, including the user arrival rate and appliance service time for the users, derived from the observation of the use of washrooms in a large shopping mall in Hong Kong were illustrated. This procedure offers flexibility for the design of sanitary accommodation to meet various service standards in terms of the probable user waiting time for different appliances.

Further information:

Wong LT, 2006. Provisional scales of sanitary accommodation in public toilets, The 32nd CIBW062 International Symposium of Water Supply and Drainage for Buildings, 18-20 September, National University of Science and Technology (NTUST), Taipei, Taiwan, Section H4, pp. 1-8.