Page 499 - Construction Waterproofing Handbook

LEAK INVESTIGATION AND DETECTION 13.15
amount of H atoms, the equipment is capable of providing an accurate reading of the amount
of water in each specific grid of area tested. This can be useful in narrowing the search of the
leakage problem.
All this equipment is useful in detailing the extent of moisture entrapped or present in
the substrate, but cannot pinpoint the actual cause for water infiltration. The equipment
must be used in conjunction with a visual inspection of the actual substrate conditions and
appropriate water testing to verify the actual cause of water infiltration. There are tech-
niques available and adopted from other industries that can assist in pinpointing leakage
that is not capable of being visually inspected. This includes fiber-optic endoscopes.
Endoscopes have a tiny camera attached to the end of a flexible cable that permits
the probe to be inserted directly into envelope components with minimal or no damage.
The camera relays the picture back to a portable viewing station that can be adapted to
tape the inspection on a video (VCR) format. The tape can then be viewed later, comparing
it with the construction documents in addressing the leakage problem.
This equipment can be used to inspect the inter-wythe of a masonry wall without
removing the outer masonry units to gain access for inspection.
Other envelope components that are multilayered can be accessed by the probe with
minimal destructive damage, including curtain walls and their anchoring and natural stone
facades applied with metal supports.
It is possible that the endoscope can be used to inspect below-grade exterior surfaces
without necessitating the complete removal of backfill or other landscaping. Small bore
holes adjacent to the envelope can be made, then lowering the probe into the hole. If nec-
essary, the hole can be flushed with water to remove soil and debris from the substrate
prior to the endoscope inspection.

TEST RESULTS

As the test progresses, all procedures and results should be documented for review. If the
test is to be used as evidence in legal situations, videotaping can be used to document test
procedures and results. Once an area begins to leak, the test should be stopped until water
infiltration stops, then retested immediately to certify the leakage.
The documentation of the tests does not complete the leak detection process. All infor-
mation gathered, from the initial leak reports to the test results, should be accumulated and
compiled for further investigation. All written documentation, pictures, and recordings
including video should be used together to verify the exact causes of the leakage and reme-
dial planning.

INVESTIGATION

Testing does not necessarily confirm the cause of leakage, as it may only have isolated the spe-
cific area where the envelope has been breached. This area, though, may include several dif-
ferent envelope components, transition, or termination detailing, or involve divertor systems.
To fully understand the cause of leakage and make appropriate remedial decisions, including