<small-title />
<!-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->
{|width="100%"
|}
<br>
----
<br>[[Image:Icon_double_ventilated_improved_pit.png |right|95px80px]]
'''The Double VIP has almost the same design as the [[Single Ventilated Improved Pit|Single VIP]] with the added advantage of a second pit that allows the technology to be used continuously and allows for safer and easier emptying.'''
}}
===Adequacy===
The Double VIP is more appropriate than the [[Single Ventilated Improved Pit|Single VIP]] for denser, peri-urban areas. The material is manually emptied (it is dug out, not pumped out), so vacuum truck access to the pits is not necessary. The users can remove the pit material after a sufficient resting time of one or more years even though the treatment processes in the pit are not complete and the material is not entirely hygienic. The Double VIP technology will only work properly if the two pits are used sequentially and not concurrently. Therefore, an adequate cover for the out of service pit is required. Double VIPs are especially appropriate when water is scarce and where there is a low groundwater table. They should be located in an area with a good breeze. They are not suited for rocky or compacted soils (that are difficult to dig) or for areas that flood frequently.
===Health Aspects/Acceptance===
The Double VIP can be a very clean, comfortable and well accepted sanitation option, in some cases even more so than a water-based technology. However some health concerns exist:
* Health risks from flies are not completely removed by ventilation.
===Maintenance===
To keep the Double VIP free of flies and odours, regular cleaning and maintenance is required. Dead flies, spider webs, dust and other debris should be removed from the ventilation screen to ensure a good flow of air. The out of service pit should be well sealed to reduce water infiltration and a proper alternating schedule must be maintained.
===Field experiences===
{|style="width: 70%; text-align: justify; background-color: #f5f5f5;"
|[[Image:rsr 474.jpg|thumb|none|200px|<font size="2"><center>Project 474</center></font>|link=http://www.akvo.org/rsr/project/474/]]
|}
===References===
* Mara DD. (1984). The Design of Ventilated Improved Pit Latrines (UNDP Interreg. Project INT/81/047). The World Bank+ UNDP, Washington. (A good reference for detailed Double Pit VIP design information.)
* The World Bank (1986). Information and Training for Low-Cost Water Supply and Sanitation (UNDP Project INT/82/002). The World Bank, Washington.
===Acknowledgements===
{{:Acknowledgements Sanitation}}
