.1.1. Water boiling test (WBT)
This is a lab-based test, designed to explore the basic features of stove performance under controlled setting. It is also useful in the field, to determine whether the stove building is as per design criteria or not. Many organizations all over the world have used revised VITA-1985 WBT protocols, for example, WBT versions of NPIC and NISP [54] and [48]. The WBT test protocol, which is originally for wood stoves, is also suitable for charcoal stoves with some modifications [31], [32] and [70]. In 2003, WBT was revised to include “Excel spreadsheets” to help users with calculations [84]. Recently, the latest version of WBT, Version 4, was open for public comment, and was still under review. A corrected version of the WBT data calculation spreadsheet 4.1.2 is now available [85]. The WBT protocol consists of the three phases: “High power cold start”, “High power hot start” and “Low power”. Results from the first two phases are useful to find the difference in stove performance, from the cold and hot start. Similarly, results of last two phases are useful to find the difference in stove performance, between low power and high power operation. Features like simplicity, ease of conduction and quick to do procedures make WBT most widely used testing protocol; accounting for 73% of all the tests performed on cookstoves [86]. However, controlled conditions and performance by trained technicians gives only a gross estimate of actual household cooking, and is not useful to predict field performance. Taylor [87] gives a detailed discussion of the shortcomings of WBT. Table 1 provides additional important information for the protocol.