Coffee Break Training: Hazardous Materials: Aboveground Flammable and Combustible Liquid Tank Emergency Venting - Part 9: Vent Sizes [open pdf - 507KB]
"The Coffee Break Training series has emphasized the importance of adequate venting for flammable and combustible liquid tanks to prevent catastrophic failures under fire conditions and tank collapse during routine filling and draining. In many instances, emergency venting is provided through pressure relieving devices such as weighted cover style emergency vents, loose manhole covers, rupture or burst disks, remote-actuated relief devices, or other pressure relieving equipment that may be used in place of pressure relieving tank designs. Although less recognized, in legacy installations the weak roof-to-shell seam construction technique may be used as emergency venting. Remember that in double-walled tanks, equal capacity venting must be provided for both the primary tank and the secondary containment vessel."
Coffee Break Training - Fire Protection Series No. FP-2013-9
United States Fire Administration: http://www.usfa.fema.gov/