A pressure vessel , comprising: a tank , including: i) a tank liner fabricated from thermoplastic material; ii) a valve fitting assembly ; and iii) an outer reinforcing layer disposed on the tank liner , the outer reinforcing layer defining at least a portion of an outer surface of the tank ; and a protective jacket adapted to surround and engage the tank , the protective jacket includes: i) an upper support rim defining a top aperture , wherein the valve fitting assembly extends through the top aperture , and said aperture creates a first airflow opening around the valve fitting assembly between the upper support rim and the valve fitting assembly ; ii) a lower support rim having a second airflow opening therethrough; and iii) a substantially cylindrical wall connecting the upper support rim to the lower support rim , the wall defining an inner surface disposed radially outwardly from the outer surface of the tank , the inner surface of the wall and the outer surface of the tank cooperating to define a flow channel in fluid communication with the first airflow opening and the second airflow opening , wherein the first and second airflow openings and flow channel are adapted to permit a convective flow to pass therethrough to facilitate heat transfer between the tank and an environment in which the pressure vessel is situated. a tank , including: i) a tank liner fabricated from thermoplastic material; ii) a valve fitting assembly ; and iii) an outer reinforcing layer disposed on the tank liner , the outer reinforcing layer defining at least a portion of an outer surface of the tank ; and i) a tank liner fabricated from thermoplastic material; ii) a valve fitting assembly ; and iii) an outer reinforcing layer disposed on the tank liner , the outer reinforcing layer defining at least a portion of an outer surface of the tank ; and a protective jacket adapted to surround and engage the tank , the protective jacket includes: i) an upper support rim defining a top aperture , wherein the valve fitting assembly extends through the top aperture , and said aperture creates a first airflow opening around the valve fitting assembly between the upper support rim and the valve fitting assembly ; ii) a lower support rim having a second airflow opening therethrough; and iii) a substantially cylindrical wall connecting the upper support rim to the lower support rim , the wall defining an inner surface disposed radially outwardly from the outer surface of the tank , the inner surface of the wall and the outer surface of the tank cooperating to define a flow channel in fluid communication with the first airflow opening and the second airflow opening , wherein the first and second airflow openings and flow channel are adapted to permit a convective flow to pass therethrough to facilitate heat transfer between the tank and an environment in which the pressure vessel is situated. i) an upper support rim defining a top aperture , wherein the valve fitting assembly extends through the top aperture , and said aperture creates a first airflow opening around the valve fitting assembly between the upper support rim and the valve fitting assembly ; ii) a lower support rim having a second airflow opening therethrough; and iii) a substantially cylindrical wall connecting the upper support rim to the lower support rim , the wall defining an inner surface disposed radially outwardly from the outer surface of the tank , the inner surface of the wall and the outer surface of the tank cooperating to define a flow channel in fluid communication with the first airflow opening and the second airflow opening , wherein the first and second airflow openings and flow channel are adapted to permit a convective flow to pass therethrough to facilitate heat transfer between the tank and an environment in which the pressure vessel is situated. <EOS>