5.
Ease of egress.
6.
External weather conditions.
7.
Tank roof level atmospheric test results.
7.3.5.3
It is petroleum industry practice to classify open
top floating roofs when they are within 5 feet of the top of the
tank as non-confined spaces, provided that none of the
requirements for classification as confined space exist. (See
ANSI/API Standard 2015 and API 2026 for additional infor-
mation.)
7.3.6
Floating Roof Hazards
Employers (owners/operators and contractors) and entry
supervisors shall be familiar with the potential hazards of
entering upon floating roofs and establish and implement
appropriate procedures, including but not limited to, the fol-
lowing (see API 2026 for additional information):
7.3.6.1
A qualified person shall initially evaluate the physi-
cal condition of the floating roof by visual examination
through openings in the fixed roof of internal and covered
open top tanks or from the top of the stairway, platform or
wind girders of open top tanks.
7.3.6.2
Entry supervisors, qualified persons and entrants
shall recognize that physical obstructions, defective roof
areas and panels and liquid product or water on top of the
roof may be difficult to detect because of restricted visibility.
7.3.6.3
When preplanning tank cleaning, employers (own-
ers/operators or contractors) shall provide sufficient notice to
allow for descent onto the floating roof to set legs to be made
when the roof is at the highest level that provides space for
safe entry. This will maximize natural ventilation and mini-
mize descent and climbing time.
7.3.6.4
Descent onto open top and covered open top float-
ing roofs is usually by means of a moveable stairway on
larger tanks and a vertical ladder on smaller tanks. Descent
onto internal floating roofs is usually by means of a vertical
ladder.
7.3.6.5
Open top and covered open top floating roofs are
usually well constructed and unless corroded or otherwise
defective, will support the weight of personnel. Many internal
floating roofs are of light construction, and walking on the
roof surface can be hazardous unless limited to areas desig-
nated for that purpose.
7.3.6.6
When descending upon floating roofs that were not
designed 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 a
greater area of the floating roof.
7.3.6.7
Prior to emptying the tank, the roof support legs
and sleeves through the roof shall be examined (to the extent
possible) by a qualified person for corrosion or other defects
to determine their ability to support the roof. Anti-rotation
guidepoles and devices shall also be checked to assure proper
function. Temporary roof support may be necessary until legs
are repaired or replaced.
