Final answer:
The use of a delivery hose assembly for unloading liquefied compressed gases is prohibited if the equipment cannot handle the extreme temperatures and pressure changes required for safety. Rigid containers have air gaps to allow for expansion and contraction, and delivery hoses must be compatible with the gas and properly insulated to prevent structural failure.
Step-by-step explanation:
Conditions that prohibit the use of a delivery hose assembly for unloading liquefied compressed gases involve safety measures to prevent accidents due to the unique properties of these gases. When unloading liquefied compressed gases like liquefied natural gas (LNG) or liquefied petroleum gas (LPG), it is critical to use equipment that can handle extreme temperatures and pressure changes.
Problems arise when containers are not properly designed to manage the expansion and contraction of these gases. For instance, if you cap a tank tightly to prevent overflow, the container might still leak or burst because constricting the expanding gas is equivalent to compressing it, and gases, like liquids and solids, resist compression with significant force.
To prevent rupturing, rigid containers for compressed gases have air gaps allowing for expansion and contraction without undue stress. Similarly, during transportation, LNG typically stored at about -162°C in double-walled, vacuum-insulated containers, emphasizes the need for specialized containers that can manage low temperatures and the high pressure of compressed gases.
Delivery hose assemblies must also be equipped to deal with these conditions, and if they cannot, their use is prohibited due to the potential risk of leaks, ruptures, or other forms of structural failure.
In addition, if the delivery hose is not constructed of materials compatible with the gas being unloaded, or isn't adequately insulated, it may lead to safety risks, including fire or explosions caused by the high flammability of the gases involved. Regular inspection and maintenance of hose assemblies are essential to ensure their integrity and safe operation during the unloading of liquefied compressed gases.