Hoses vacuum conditions

The foreman failed to appreciate the frail nature of these standard low-pressure tanks. Many low-pressure tanks are designed for positive pressures of just 8 or 10 inches of water (2 to 2.5 kPa gauge) and just 3 or 4 inches of water (3/4 to 1 kPa) vacuum. Using a hose to modify the system addressed the immediate problem of dissolving any alcohol fumes, but the presence of the hose routed to a drum containing water created a situation in which the tank could be damaged by positive pressures and vacuum conditions well beyond its design specifications. 

Some liquids might create an ignitable froth layer (5-1.3.1), although mist accumulation will be offset under conditions where there is periodic suction of air through the hose, it is possible to specify a vacuum tmck tank with MAWP > 50 psig, sufficient to contain a deflagration beginning at up to... 

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