On a technical level, the original design, the Mark 1 has been built in many countries by a wide range of organizations including WHO, MSF, the British Council, UNICEF, the Salvation Army, and many individual mission and charity workers.

The design has generally worked well, but inevitably regular use in the field has identified weaknesses that were not evident in the original design tests. There have also been calls for slight design changes to meet particular requirements, for instance to use gaseous fuel in the Central Asia region, or to support longer chimneys to meet certain regulations in some countries...

Thus the designs have been subject to regular improvements and modifications. The present range of recommended models, the Mark 7, the Mark 8a and the Mark 9, are a means of identifying the drawings which resulted from these continuous modifications, and to avoid confusion no other models are shown on this website. It cannot be over-emphasized that these models are improvements on previous models.

There are now estimated to be over 1'000 De Montfort incinerators in Africa, Central Asia, East Europe, South Asia and South-East Asia. Some have been reported inoperative, mainly due to poor manufacture or operating procedures and maintenance. We have therefore added on top of a specific section on construction, some basic advice on Operation and Maintenance (O & M).