Document ID: chunk:federal_register_of_legislation:F2015L02109:body:0:p30
Version: federal_register_of_legislation:F2015L02109
Segment Type: other
Provision Reference: 
Character Range: 87685–90672

to settle, and Ptarget is the targeted fill pressure after the temperature settles.
3.1.3.                        The container is filled to a minimum of 95 per cent of the targeted fill pressure and allowed to settle (stabilize) prior to conducting the crash test.
3.1.4.                        The main stop valve and shut-off valves for hydrogen gas, located in the downstream hydrogen gas piping, are in normal driving condition immediately prior to the impact.
3.2.                              Enclosed spaces
3.2.1.                        Sensors are selected to measure either the build-up of the hydrogen or helium gas or the reduction in oxygen (due to displacement of air by leaking hydrogen/helium).
3.2.2.                        Sensors are calibrated to traceable references to ensure an accuracy of ±5 per cent at the targeted criteria of 4 per cent hydrogen or 3 per cent helium by volume in air, and a full scale measurement capability of at least 25 per cent above the target criteria. The sensor shall be capable of a 90 per cent response to a full scale change in concentration within 10 seconds.
3.2.3.                        Prior to the crash impact, the sensors are located in the passenger and luggage compartments of the vehicle as follows:
(a)             At a distance within 250 mm of the headliner above the driver's seat or near the top centre of the passenger compartment;
(b)            At a distance within 250 mm of the floor in front of the rear (or rear most) seat in the passenger compartment; and
(c)             At a distance within 100 mm of the top of luggage compartments within the vehicle that are not directly affected by the particular crash impact to be conducted.
3.2.4.                        The sensors are securely mounted on the vehicle structure or seats and protected for the planned crash test from debris, air bag exhaust gas and projectiles. The measurements following the crash are recorded by instruments located within the vehicle or by remote transmission.
3.2.5.                        The test may be conducted either outdoors in an area protected from the wind and possible solar effects or indoors in a space that is large enough or ventilated to prevent the build-up of hydrogen to more than 10 per cent of the targeted criteria in the passenger and luggage compartments.

4.                                    Post-crash leak test measurement for a compressed hydrogen storage system filled with compressed hydrogen
4.1.                              The hydrogen gas pressure, P0 (MPa), and temperature, T0 (°C), are measured immediately before the impact and then at a time interval, Δt (min), after the impact.
4.1.1.                        The time interval, Δt, starts when the vehicle comes to rest after the impact and continues for at least 60 minutes.

4.1.2.                        The time interval, Δt, shall be increased if necessary in order to accommodate measurement accuracy for a storage system with a