Petavel was born on 14 August 1873. He received his early training at University College, London, under Sir Ambrose Fleming, with whom he collaborated in his first published paper, on the alternating current arc. He then worked under Dewar for three years at the Royal Institution and Davy Faraday Laboratory, where he studied the thermal emissivity of platinum at high temperatures and pressures. In 1900 he was elected to the John Harling research fellowship, at Owens College, Manchester.
Jointly with RS Hutton, Petavel published outstanding papers on electric furnaces reactions under high pressure and the effects of pressure on arc spectra. He had interest in meteorology and aeronautics, and collaborated in an investigation on kite soundings as applied to upper-air temperatures.
He became chairman of the Aerodynamics Advisory Committee during the 1914-1918 war, a post he held until 1925. He was a member of the general board of the National Physical Laboratory (NPL) from 1911 to 1916, and in September 1919 he was appointed its Director. During his 17 years as Director of NPL, Petavel devoted himself to maintaining and increasing the prestige of the Laboratory both nationally and internationally, and increasing its usefulness to various industries in Britain. He was elected Fellow of the Royal Society (FRS) in 1907 and was awarded the KBE (Knight Commander of the Most Excellent Order of the British Empire) in 1920.
Primary standard of light
He established the primary standard of light.
Combustion of gases
Petavel was an internationally acknowledged expert on the combustion of gases. Petavel designed the gauge for measuring pressures set up in exploding gaseous mixtures.
He also exercised a profound influence on the progress of aeronautical research in Great Britain. His enthusiasm for aeronautics led him to qualify as a pilot, an accomplishment which was not free from danger with the experimental aeroplanes of those days.
Petavel at Manchester
In 1901 Petavel became John Harling Research Fellow at Owens College and later Lecturer in Mechanics under Schuster at Manchester. Then in 1908 after Reynolds resignation Petavel became a Professor of Engineering and director of the Whitworth Laboratories at Manchester. Petavel's work at Manchester was chiefly concerned with standards of light, ventilation, structural stresses, the theory of gas engines, and aeronautics. Whilst Head of the Engineering Department, he developed into an internationally acknowledged expert on the combustion of gases and is a peripheral figure in the literature with regard to Wittgenstein's stay in Manchester. He encouraged Wittgenstein by providing a compressor from the Physics Department and also recommended him for a research studentship. He worked at the Owens College, Manchester for 15 years until 1919 when he was appointed as a Director of the national Physical Laboratory.