Ministry of Home Security, the Admiralty, the War Office, the Air Ministry, the Ministry of Aircraft Production, the Ministry of Supply and the Ministry of Defence and Glanville found that defence matters accounted for up to 70% of the department's work. Glanville also acted as an advisor to the Air Ministry and the Ministry of Aircraft Production on the construction of concrete runways and specialised airfields. The latter included "Prefabricated Bituminised Surfacing" (PBS) made from bitumen-impregnated hessian laid over steel mesh which could act as a runway surface over swampy or otherwise difficult ground. These PBS airstrips had a service life of around four months and were easily transportable, in the course of the war 60 million square yards of PBS were manufactured in the UK, US and India. The soil section of the BRS, assisted by Glanville, was also responsible for the assessment and categorisation of European beaches prior to the Normandy Landings. The soil section, which Glanville set up, was particularly useful to the war effort with soil analysis impacting aircraft and tank designs. Glanville had a particular interest in explosives and he helped Edward Terrell of the Admiralty's DMWD develop a stone-chip-and-bitumen protective plating "plastic armour" which was installed on the bridges and gun positions of most allied merchant vessels. The RRL was asked to test samples of plastic armour against machine-gun bullets by the Department of the Inspector of Anti-Aircraft Weapons and Devices in August 1940. The material supplied proved unsatisfactory but Glanville recommended that the fine grit used in the samples be replaced by larger stone particles. Revised samples, with an additional backing of thin steel plate, performed well under test. A programme of works in the field was then approved at a 25 August conference. RRL testing showed that armour containing the strongest stones performed best and that it worked well in a wide range of temperatures making the armour suitable for deployment in the North Atlantic winter or the Red Sea. It was also proved that the armour provided protection against incendiary devices. Glanville was named on the patent for the material, alongside Terrell in September 1940. Work to armour ships began just one month after the RRL began its investigations, beginning with the SS Empire Frost, which was then under construction in Glasgow. Later research produced armour suited to protection against cannon shells and shrapnel. Plastic armour, and the related "Plastic Protection