Nondestructive Testing (NDT) Services
Vertical Access specializes in the application of many different types of nondestructive
testing methods as part of our investigations in order to better preserve historic structures while
being able to deliver superior information.
Borescopes and Fiber-Optic Camera
A borescope is an optical device consisting of a rigid or flexible
tube with an eyepiece on one end, and a lens on the other end.
A remote object is illuminated by a light source and an internal
image formed by the objective lens is relayed to the eyepiece,
which magnifies the internal image and presents it to the viewer's
eye. Vertical Access utilizes a variety of borescopes with rigid and
flexible tubes as well as ones with a 0° (straight ahead) and 90°
direction of view. The borescope allows the user to see behind
the façade and requires only a small hole to be drilled. A video
camera can be attached to the borescope unit to provide recorded
documentation of the conditions behind the façade.
Vertical Access owns and operates another fiber-optic diagnostic
tool called the "See Snake" for the investigation of internal leaders,
drain pipes, ductwork, cavity walls, crawl spaces, and other
locations where human access is not possible. This rugged device
consists of a miniature video camera with wide-angle lens and
built-in light source attached to 200 feet of heavy duty fiber-optic
cable. A built-in odometer records the total distance that the
camera travels to assist in locating areas of deterioration.
Infrared Thermography (Thermal Imaging)
Infrared thermography measures emitted and reflective heat
coming from an object. This closely corresponds with the
temperature of that object; the hotter it is, the more heat it will
emit to its surroundings. It can be very useful in building
inspections to be able to "see" the heat emanating from a building.
Water, for example, will heat up and cool down at a slower rate
than the rest of a building façade. This makes it possible to view
where there may be water infiltration using a thermal imager
because wet areas appear as a different color on the image, whereas
a visible light image will not show the temperature differences.
Steel rebar and relieving angles in a fašade will similarly change
temperature at a different rate than the surrounding material and
therefore be distinguishable in a thermal image. Vertical Access
has a FLIR B40 thermal imager that can enhance our condition
Shown on the left are two thermal images and a corresponding
visible light image of the same area of a building wall. The first IR
image was taken on the morning of a warm day. The structural
framing of the building is visible in the image. The second IR
image was taken the following day after a rain storm. A darker
area above the floor framing is visible, a likely indication of
moisture infiltration behind the brick masonry.
Ultrasonic Thickness Gauge
Ultrasonics can be used to determine the thickness of a solid
material, such as a metal or plastic. An ultrasonic thickness
gauge has a probe that couples to the material and then sends
an ultrasonic pulse through the material. When that pulse
hits a boundary in the material it gets reflected back. Based
on specific material properties and the time delay between
when the pulse is sent and then received, it is possible to
determine the thickness of that material. Vertical Access uses
a StressTel TM1-CD Ultrasonic Thickness Gauge in order
to determine the existing thickness of solid materials such as
copper cladding. To calibrate the instrument and quantify
the amount of total section loss, an initial measurement is
taken on a non-exposed piece of copper to get a reading on the
original thickness, and then a piece of copper with a known
thickness is measured to calibrate the thickness gauge.
Wall Tie Locator and Rebar Locator
Vertical Access uses a Protovale Imp Wall Tie Locator to
quickly find embedded steel, including both mild steel
and non-ferrous metals. This is very useful in detecting the
presence or absence of wall ties, relieving angles and other
pieces of structural metal behind the façade.
Vertical Access also owns a Proceq Profometer 5, a compact,
lightweight instrument specifically used for detecting rebar in
concrete. The Profemeter is used to detect reinforcement and
mesh, measure their cover depth and determine bar diameter.
Download the Nondestructive Testing
Mike using a borescope at Dulles State Office Building in Watertown, NY.
Warm day ...after rain
Visible light image
Dave using an ultrasonic thickness gauge at the Cathedral Bailica of Saints Peter and Paul in Philadelphia.
Kent using the wall tie locator at Buffalo City Hall
Evan using the Profometer 5 at St. Frances de Sales Church in Philadelphia.