Scope of application: The Type A/B low-light intensity barrier requirements that meet the requirements of ICAO standards and CAP168specificaions are suitable for Zone 1 and Zone 2 sites in explosive gas environments such as offshore oil production platforms tankers chemical tankers oil storage tanks etc and serve as a warning to aircraft for obstacles and facilities with a height of less than 45 meters and for use with medium-intensity obstruction lights when the height exceeds 45 meters。