Construction
1.1. Equipment
A combination color CCTV pipeline survey system
with, a cable distance counter, circumferential laser ring
projection system and measurement software shall be used to
perform a measurement survey of new or existing lines as
directed by the Florida Department of Transportation. The
equipment and software used must be tested and approved by a
recognized independent testing group and include a tested
certified accuracy of 0.5% or better and a repeatability of
0.12% or better. References for the equipment calibration are
ASTM E 691 and ASTM E 177.
Equipment meeting or exceeding the calibration criteria and with the ability to perform specification requirements as defined in Section 430-4.8 and 430-4.8.1 of the Specifications will be acceptable for use on FDOT projects.
1.1.2. Procedure
The measurement survey shall be accomplished
using a CCTV color pipe inspection system as specified above. To
determine the representative diameter of a given pipe, select a
cross-section, in the pipe, evenly spaced between two points 10
feet apart. The selected section should be in the barrel (away
from collar or junction) and defect free. Measure the internal
diameter at the section. Take at least 4 measurements at the
selected cross section. Ignore the section if the variance in
measurements is too high and the section appears non-circular.
Average the four (4) diameters and round to the nearest 1mm to
arrive at the representative diameter of that line. If the pipe
deformation is too great to make the above measurements then the
pipe diameter as shown on the as built drawings may be used for
the generation of the required reports.
A lens distortion calibration chart shall be
imaged by the survey camera and recorded on the survey DVD in an
MPEG2 format for 15 to 20 seconds. The measurement software
shall include a lens distortion correction capability to assure
the measurement accuracy regardless of the survey camera used.
A calibration target shall be imaged by the
survey camera and recorded on the survey DVD in an MPEG2 format
for 15 to 20 seconds. The measurement software shall have the
capability to reference and calibrate to this target assuring
unlimited accurate report processing of the recorded survey.
Equipment with the ability to directly measure
pipe diameter are not required to perform the measurement survey
noted above provided reports generated from laser inspection
gives direct measurements.
The survey system with laser ring projection head shall be placed into the pipe. The laser projection head shall be positioned, in relationship to the camera, so that the laser ring fills minimum 75% of the monitor screen height and the alphanumeric cable distance display does not interfere with the laser ring image. The camera and laser projection head shall be moved through the pipe at a speed not to exceed 30 feet per minute. The color video image, from the camera, shall be recorded on the survey DVD in an MPEG2 format.
