5.Ease of egress.6.External weather conditions.7.Tank roof level atmospheric test results.188.8.131.52It is petroleum industry practice to classify opentop floating roofs when they are within 5 feet of the top of thetank as non-confined spaces, provided that none of therequirements for classification as confined space exist. (SeeANSI/API Standard 2015 and API 2026 for additional infor-mation.)7.3.6Floating Roof HazardsEmployers (owners/operators and contractors) and entrysupervisors shall be familiar with the potential hazards ofentering upon floating roofs and establish and implementappropriate procedures, including but not limited to, the fol-lowing (see API 2026 for additional information):184.108.40.206A qualified person shall initially evaluate the physi-cal condition of the floating roof by visual examinationthrough openings in the fixed roof of internal and coveredopen top tanks or from the top of the stairway, platform orwind girders of open top tanks.220.127.116.11Entry supervisors, qualified persons and entrantsshall recognize that physical obstructions, defective roofareas and panels and liquid product or water on top of theroof may be difficult to detect because of restricted visibility.18.104.22.168When preplanning tank cleaning, employers (own-ers/operators or contractors) shall provide sufficient notice toallow for descent onto the floating roof to set legs to be madewhen the roof is at the highest level that provides space forsafe entry. This will maximize natural ventilation and mini-mize descent and climbing time.22.214.171.124Descent onto open top and covered open top float-ing roofs is usually by means of a moveable stairway onlarger tanks and a vertical ladder on smaller tanks. Descentonto internal floating roofs is usually by means of a verticalladder.126.96.36.199Open top and covered open top floating roofs areusually well constructed and unless corroded or otherwisedefective, will support the weight of personnel. Many internalfloating roofs are of light construction, and walking on theroof surface can be hazardous unless limited to areas desig-nated for that purpose.188.8.131.52When descending upon floating roofs that were notdesigned to support the weight of personnel, employers (own-ers/operators or contractors) shall provide a lightweight mate-rial to be used by the entrant(s) to spread the weight over agreater area of the floating roof.184.108.40.206Prior to emptying the tank, the roof support legsand sleeves through the roof shall be examined (to the extentpossible) by a qualified person for corrosion or other defectsto determine their ability to support the roof. Anti-rotationguidepoles and devices shall also be checked to assure properfunction. Temporary roof support may be necessary until legsare repaired or replaced.