Sometimes, and the way to find out is arithmetic rather than judgement by eye. Natural ventilation depends on openings that are genuinely open, at both high and low level, with a path between them. A room with a single door that is kept shut for temperature control is not naturally ventilated, whatever the drawing says.
Compare the gas volume of your worst credible release against the free volume of the room and the air change rate you can actually demonstrate. A store holding a single 50 litre vessel in a large room with a permanently open louvre may be adequately served. A basement, an internal room, a lift lobby or a cupboard converted into a store rarely is, and those are exactly the places vessels tend to end up as laboratories run out of space.
Where the calculation fails, mechanical extract taken from low level is the usual fix, because the cold vapour sits low. Interlocking the fan with the oxygen monitor is common practice.
Two points get missed in practice. Ventilation openings must not be blocked by later building work or stacked boxes, and a door closer defeats the assumption that the door provides the ventilation path.
