Heartsaver First Aid Part I Progress Indicator: Question 4 of 22 4.  If a portable foam machine is used for fire protection at a mine, it shall have a water supply capable of delivering: Choices: 25 GPM at 25 PSI 30 GPM at 30 PSI 50 GPM at 50 PSI None of the above; foam machines cannot be part of the fire protection package.