However, there are various regulations concerning fire resistance, impact strength, permeability etc. with which they must comply. These requirements are set out in UN standard ECE R.34 Annex 5. RISE tests tanks against this standard and against the vehicle manufacturers' own requirements. The ECE R.34 tests are (in general terms) as follows:
Evaporative emission testing
This test measures the average permeation of petrol vapour over an eight-week period, by weighing the tanks and recording the loss of weight. During the test, the tanks are stored at a temperature of +40 °C in explosion-resistant areas.
The tanks are filled with water at +53 °C, and then subjected to an internal positive pressure of 30 kPa for five hours. The ambient temperature is also maintained
at 53 °C.
The tanks are filled with a glycol/water mixture and cooled to -40 °C, before being subjected to blows from a pyramid-shaped body with an impact energy of 30 Nm.
The tanks are filled with water at a temperature of +20 °C, and then placed in a test chamber for one hour at a temperature of +95 °C.
The tanks are filled with fuel to half their volume and exposed to a naked flame for two minutes.