std cc/sec approx. = approx. bubble equivalent
10-1 = 1 cc/10 sec
10-2 = 1 cc/100 sec
10-3 = 1 cc/hour
10-4 = 1 cc/3 hours
10-5 = 1 cc in 24 hours
10-6 = 1 cc/2 weeks
10-7 = 3 cc/year
10-8 = 1 cc/3 years
10-9 = 1 cc/30 years
10-10 = 1 cc/300 years
10-11 = 1 cc/3000 years
*Note : Experimental data indicate that no visable water will leak when dry air, at the same pressure, will leak at a rate as great as 1 x 10-4 cc/sec. To be on the safe side, it is believed that enclosures which are to contain liquids, such as water or oil, should have no leaks at rated pressure which are larger than 1 x 10-5 standard cc of air per sec. Helium leakage in volume is about the same as air and refrigerant R12 for leaks of approximately 1 x 10-6 standard cc/sec. For leaks smaller than 1 x 10-6, the volume of helium leakage will be somewhat greater than air through the same physical leak at the same pressure difference.