(Boilers, sewer maintenance access for people with) manholes, manhole (A hole, usually with a cover, through which a person may enter a sewer, boiler, drain, or similar structure.) Manhole: one often cover with a pore, a person may access Pai Road, boilers, water pipes, as well as including an internal channel telecommunications, cable television weak wells used by large bridge maintenance and so on. Manholes are installed on top of the tank safety emergency ventilation devices, usually associated with fire, mechanical breathing valve supporting the use, both to avoid accidental causes sharp when overpressure or vacuum tank, tank damage and accidents, and Fire safety has played a role in protecting the safety device of the tank, especially suitable for the storage of materials to atmospheric nitrogen tank dome cap. Emissions have constant pressure, constant pressure inhalation, opening and closing a flexible, secure Fire, compact structure, good sealing performance, safety and reliability. Manhole into the emergency relief manholes, manhole explosion Fire breathing, tank top manhole, tank wall manholes and manhole with a core. Manhole generally consists of 304,316L stainless steel or carbon steel produced. Manhole been molded products, the diameter is usually 600mm. Manhole center from the floor general for 750mm. Facilitate staff in installation, cleaning, maintenance and out of the tank or ventilation. Non-metallic tanks in tank top manhole, manhole metal tank located under the most laps in the tank wall board. Most of the hole with a diameter of 600mm, the center from floor 750mm, for tank cleaning or maintenance personnel with access to the tank, also known as the door. Access to clean tanks moment exploited holes lighting and ventilation. Vertical tank capacity is set from 1 to 2 individual holes 5000m3 below, 5000m3 located above two individual holes. Installation of manholes should be separated out of the oil pipeline is not greater than 90 °. When people have just one hole, it should be placed on top of the tank opposite the aperture; when set two individual holes, one located opposite the aperture, and the other should be separated by at least the first 90-hole individual °. Manholes should be located near the right side out of a pipe, and try to make the hole is on the tank room door closed for personnel access, maintenance and ventilation taken over by tanks.