The Water Boiling Test, Repeatedly

In my opinion, the WBT* cannot be used, especially in the lab, to improve a biomass cook stove because all of the important field variables are not represented.

A successful cook stove needs to be evolved from field tests, as we did in Southern India for the Shell Foundation. Cooks in eighteen villages kept on changing the Rocket stove until it was acceptable, useful, and even likable. It took a while but it was a lot of fun and a great introduction to Southern India!

The WBT, with severely limited variables, can be useful in the lab for international comparisons of stove performance. The same pots, same amount of water, same fuel, same procedures and protocols limit the confounding variables in an attempt to isolate the stove as the reason for perceived differences.

As we did in India, both field and lab data can inform stakeholders. The successful stove has to please cooks, retailers, distributors, etc. and, at the same time, meet project goals such as reducing adverse health effects. We used the WBT in the lab and the CCT* in the field. Marketing tests, as suggested by Baldwin (1987) were very important, as well. We learned right away that the stove had to cost ~$5 to capture sustainable market share.

The lab based WBT is best used to inform researchers how stoves might be improved. Then, iterations in prototypes are tried in the field including cost, weight, color, height, firepower, fuel used, etc, etc.

This combined use of the WBT, CCT, and KPT* for stove development was suggested in the International Stove Standards, (1985). 

*Water Boiling Test “The Water Boiling Test (WBT) is a simplified simulation of the cooking process. It is intended to measure how efficiently a stove uses fuel to heat water in a cooking pot and the quantity of emissions produced while cooking.” – The Water Boiling Test Version 4.2.3

*Controlled Cooking Test “The controlled cooking test (CCT) is designed to assess the performance of the improved stove relative to the common or traditional stoves that the improved model is meant to replace. Stoves are compared as they perform a standard cooking task that is closer to the actual cooking that local people do every day.” – CCT version 2.0

*Kitchen Performance Test “The Kitchen Performance Test (KPT) is the principal field–based procedure to demonstrate the effect of stove interventions on household fuel consumption.” -KPT version 3.0

Find out more about testing protocols at cleancooking.org/protocols/