If they don't work, there's a risk that, number one, as we were discussing a bit earlier, you could have a reading that everything appears to be okay; or the controller could turn around and the monitor could show that the PPMs have gone above the acceptable level, but the alarm didn't go off.
Le cas échéant, il y a d'abord le risque, dont on a déjà parlé plus tôt, de lecture normale ou alors, en vérifiant sur le moniteur, on peut constater que le nombre de PPM est supérieur au niveau acceptable, mais que l'alarme ne s'est pas déclenchée.