1

Type of storage tank

a. External floating roof

Possible

Possible

Possible

b. Internal floating roof

Impossible

Possible in some cases

Possible

c. Dome tanks

Impossible

Impossible

Possible

2

Available number of entry points

Ranges from 3 to 10 depending of tank diameter

Depends on required accuracy

No entry points at all

3

Type of crude oil

Light, Medium, Heavy: sometimes if this oil is heated, because of limitations on viscosity

Any type of crude oil

Any type of crude oil

4

Time of tool installation

Can range from 30 to 40 minutes on one entry point

10 - 15 minutes on one entry point

No installation time

5.

Time of inspection

5 - 6 minutes for one entry point

5 - 6 minutes for one entry point

Approximately 30 minutes for 50 m

6

Presence of personnel on roof

Yes

Yes

No personnel on the roof

7

Number of personnel on the roof

Max 3 operators

One operator

No personnel

8

Detection of intermediate layers

Not possible

Possible to get detail information om all intermediate layers

Possible to get the information of all intermediate layers

9

Tank in/out of operation

In operation

In operation

Does not matter

10.

Potential accuracy of measured volume

±5% (requires following many conditions and needs additional information).

±8% for 20 entry points, ±10% for 15 entry points

18% - 38%. Can be reduced to 14% - 24%