The picture above shows an external floating roof with the roof legs in the high position in this position there is typically about 6 of space between the floor and roof.
Landing legs on a floating roof tank.
The floating roof must be provided with landing legs that are designed to support the external floating roof under a uniform design load of at least 25 psf api 650 appendix c 3 10.
This decreases the size of the vapor space and corresponding losses.
Internal floating roof tank is known as internal floating roof storage tank floating roof oil tank internal floating plate storage tank and internal floating plate oil tank etc.
A design requirements 1 rim seals.
Poor tank turnaround practices with inadequate checking of roof supports.
The leg sock are designed to prevent product loss caused by vapors escaping from floating roof support legs.
Another option to consider includes reconfiguring the tank bottom to eliminate the presence of a heel after the discharge pump loses suction.
However when the tank is emptied to the point that the roof lands on deck legs there is a period where the roof is not floating and.
Therefore the only time a roof should be set down on its legs is when the tank is to be taken out of service.
Floating roof landing losses21 when using floating roof tanks the roof floats on the surface of the liquid inside the tank and reduces evaporative losses during normal operation.
There was a fatality on a large diameter floating roof tank when a contractor died under the weight of the roof plates which collapsed on him.
The length of the legs must be adjustable from the top of the roof and the legs must be notched or perforated at the bottom to provide drainage.
Can be installed while tank is in service.
An ifr shall be equipped with one of the seal configurations listed in paragraphs a 1 i a through a 1 i c of this section.
When emptying floating roof tanks landing the legs will create a vapor space above the liquid thus causing air to be drawn in through the roof seals.
I internal floating roof.
The owner or operator who elects to use a floating roof to comply with the requirements of 63 1062 shall comply with the requirements in paragraphs a through e of this section.
The resulting atmosphere may be in the flammable range.
Landing a floating roof on low legs is an excellent and easy way to lower emissions during rvp landings.
The roof rises and falls with the liquid level in the tank.
Compatible for 100 aromatics.
Failures of floating roof primary and secondary seals foam filled or liquid filled have been a significant concern.
The roof leg is pinned through the sleeve in this position prior to landing the roof to do maintenance inside the tank.
Can be used with either u type or t bar leg handles.
Seams are factory welded.
The leg sock provide the following features.
