Order of Merit Third Class (2009) Isaak Sigal (Russian: Исаак Яковлевич Сигал; Ukrainian: Ісаак Якович Сігал; born 31 March 1927, Vinnytsia, Ukraine) is a Ukrainian scientist in the field of fuel combustion and protection of the atmosphere from industrial pollution.

Professor Isaak Yakovlevitch Sigal holds a position of chief of department of the Gas Institute of NASU (National Academy of Science of Ukraine).

He is well known by a broad circle of experts for his monograph “Air Protection During Fuel Combustion”, and its second edition (combined print run of the two editions — 12 thousand copies) and pioneering articles on nitrogen oxide formation in the following magazines: Heat Power Engineering, Industrial Energy Engineering, Power Plant Engineering, Gas Industry (Moscow), Echo Tech and Energy Conservation (Kyiv), and others.

Specialized gas boilers TVG (now KVG) and other ones, with the productive capacity of 4...10 MW, developed under his supervision, deliver heat to residential quarters with the population of 9 million people.

In 1998, Isaak Sigal was granted the honorary title of Honored Scientist and Engineer of Ukraine.

1960—1965 — special gas water-heating boilers TVG (and their modification, KVG) with the productive rate of 4..10 MW.