Reed, Bob G027: Ventilated improved pit (VIP) latrines The addition of a vent pipe to a simple pit latrine is one way of reducing the nuisance of flies in the cubicle if the cubicle is kept clean and dark. This type of latrine is called a ventilated improved pit (VIP) latrine. There are a number of designs to suit different situations but they all work in much the same way. This guide describes how they work and presents various designs and design details. KVIP;Latrines;Pour flush latrines;Ventilated improved pit latrines (VIP);VIPP;VIPs;Spiral VIP latrine 2018-02-12
    https://repository.lboro.ac.uk/articles/online_resource/G027_Ventilated_improved_pit_VIP_latrines/9582083