Material Conditions Series Part 3: Spalls

December 16, 2014

Each week we’re bringing you an in-depth look at one of the standard conditions we encounter and document during inspections of buildings and civil structures. 

Part 3: Spalls

Incipient spall in concrete

Incipient spall in concrete

Spalling is the mechanism by which shear stresses within masonry or concrete force pieces of the material to break away. This process is sometimes referred to as bursting. The resulting piece of loose material is called a spall. Incipient spalls are not yet fully-formed. Bonded spalls are fully formed, but remain attached to the surrounding masonry, typically by mortar or sealant. Missing spalls may expose metal anchors or other ferrous embedments.

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Bonded brick spall held in place by sealant

Spalling is a mechanical action that can have various root causes. Water infiltration causes spalling through the destructive action of freeze-thaw cycles. The use of inappropriate repair materials or mortars can cause spalling by introducing a material with a different rate of thermal expansion than the adjacent material. When reinforcing steel, metal anchors, lintels or embedments are exposed to moisture, the rust that forms expands in volume, forcing apart the masonry or concrete in which it is located. Natural flaws in stone; manufacturing defects in brick, concrete or terra cotta; poor design (for example, too-narrow masonry joints); or improper installation (such as wood shims left in place) can also contribute to spalling.

Cramp spall in limestone due to rusted steel anchor

Cramp spall in limestone due to rusted steel anchor

Next in this series: Efflorescence and Leached Salts

Click here to see previous posts in this series.


Material Conditions Series Part 2: Crazing

December 9, 2014

Each week we’re bringing you an in-depth look at one of the standard conditions we encounter and document during inspections of buildings and civil structures. 

Part 2: Crazing

Crazing is a pattern of fine hairline cracks along the surface of a material, sometimes appearing in a net-like or web-like pattern. Crazing in concrete is also known as “map cracking” or “alligatoring”.

Crazing in concrete

Crazing in concrete

Crazing can occur when the surface of cast or poured concrete cures or dries more quickly than the interior. In glazed terra cotta, crazing can be a result of manufacturing defects and glaze/body incompatibility, or in response to water infiltration after installation. Crazing does not usually require a repair treatment.

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Crazing in a glazed terra cotta tile

Next in this series: Spalls

Click here to see previous posts in this series.


Material Conditions Series Part 1: Cracks and Crack Systems

December 5, 2014

Each week we’re bringing you an in-depth look at one of the standard conditions we encounter and document during inspections of buildings and civil structures. 

Part 1: Cracks and Crack Systems in Masonry

Crack system through joints in brick

Cracks of varying degrees of severity are almost always found during investigations of stone, brick, concrete and terra cotta building materials. Cracks can be limited to a single masonry unit, or can occur as crack systems through multiple units, through the mortar joints only, or through both units and joints. Severe crack systems can reach horizontally across entire facades, or can extend vertically for many floors. Crack systems that follow the masonry joint diagonally are often called “step cracks”.

293-67 Stone_Crack System units 2013-8

Crack system through units in granite

The forces that cause cracking in masonry and concrete have a variety of causes, including thermal expansion, water infiltration and freeze-thaw stresses, faulty design or installation, inappropriate repairs and repointing, and settlement. Patterns and directions of cracking can give clues to the underlying causes. Repair in the near future is recommended for most cracks and crack systems.

Severe crack through a terra cotta unit

Severe crack through a terra cotta unit

Next in this series: Crazing


The Quarterly – November 2014

November 25, 2014

Check out our November 2014 Quarterly newsletter.

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What’s The Difference Between ANSI and OSHA?

November 18, 2014

Twice a year, Vertical Access representatives attend meetings of the ANSI Z359 committee to assist in the creation and modernization of fall protection standards.  The ANSI Z359 suite of standards addresses just about all forms of fall protection equipment (harnesses, carabiners, lanyards, fall arrestors, etc) and associated work practices (rope access, rescue, management of fall protection programs, etc).  Before and after these meetings, we often field questions on the difference between ANSI and OSHA.  This article provides a brief overview of the two organizations and the documents they produce.

ANSI-word-cloudFounded in 1918, the American National Standards Institute is a not-for-profit organization dedicated to promoting “voluntary consensus standards.”  Those three words, “voluntary”, “consensus” and “standards” succinctly describe the documents that ANSI produces.  ANSI’s primary mission is to facilitate standards that, when adhered to, set a level of quality and safety across an entire industry.  These standards address everything from mold remediation, to transportation of nuclear materials, to bakery equipment and digital encryption.   The standards are consensus based because they are written and agreed upon by many members across the entire applicable industry: manufacturers, end users, testing laboratories, etc.  Lastly, the standards are voluntary in that ANSI has no enforcement power.

Technically speaking, ANSI itself does not develop standards.  Instead, ANSI develops and administers the procedures by which other organizations can create the actual standards.  ANSI will then accredit committees formed by other organizations and ultimately approve their documents as American National Standards.  These independent organizations are referred to as the secretariats to the ANSI accredited committees.  For example, the American Society of Safety Engineers (ASSE) acts as the secretariat to the ANSI Z359 Committee, the committee that Vertical Access serves on to create fall protection standards.

OSHA-word-cloudThe Occupational Safety and Health Administration  (OSHA) is a governmental agency that was created by Congress in 1971 as a subset of the Department of Labor.  Contrary to ANSI, OSHA’s mission is to assure safe working conditions for employees by “setting and enforcing standards”.  This enforcement aspect of OSHA is its primary distinction from ANSI.  Many OSHA regulations address similar topics as ANSI standards (e.g. fall protection), but where ANSI standards are voluntary, OSHA regulations are law.

ANSI standards, however, can be adopted by OSHA and become law in two primary ways.  Explicitly, OSHA can reference specific ANSI (or any other organization’s) standards in OSHA regulations.  This is referred to as “incorporation by reference”.  Implicitly, OSHA can require adherence to ANSI standards through the General Duty Clause, which states, “Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards…”  This clause allows OSHA to cite employers for hazardous conditions that are not directly addressed by OSHA, but are addressed by other industry standards.

To recap, ANSI is a private organization that creates voluntary standards, while OSHA is a regulatory government body that has the power to write ANSI standards into occupational law.


Can you identify this building? – Series No. 2

November 14, 2014

Test your knowledge of historic and iconic buildings in the U.S. (and beyond!) in this series of “guess the building” blog posts.

Series No. 2: The “Cathedral of Presbyterianism”

A very modern grotesque was spotted high up on this nineteenth-century church with an impressive address. Some of the badly-deteriorated original stone carvings were replaced in the 1990s, which is when we suspect this fellow appeared. It may be a self-portrait by the stonecarver, a tradition that dates back to the construction of medieval cathedrals in Europe.

This brownstone church is often referred to as the “Cathedral of Presbyterianism.” The iconic hotel in the background is another good clue! Where is it? Scroll down for the answer.

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5th ave

 

Answer: Fifth Avenue Presbyterian Church, New York City. Completed in 1875, the church was designed by Carl Pfeiffer and is the largest Presbyterian sanctuary in Manhattan. Across the street is the 1904 St. Regis Hotel, also pictured above.

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Don’t miss another architectural challenge: subscribe to our blog by signing up with your email address in the sidebar. Click here to see all of the posts in this series.

Photos by Vertical Access.


Highlights from the 2014 APT Conference

November 14, 2014

Last month, Evan Kopelson, Berta de Miguel and Kristen Olson traveled to Quebec City for the annual conference of the Association for Preservation Technology International. APT is a cross-disciplinary member organization promoting the best technology for conserving historic structures and their settings¹. The theme of this year’s conference was métissage, or the fruitful encounter of differences.

Chateau Frontenac

The Monument to the Faith statue and fountain with the Chateau Frontenac behind.

The conference was held at the Fairmont Le Château Frontenac, an iconic historic hotel situated on a high cliff overlooking the Saint Lawrence River. The hotel is located within the fortified walls of the old city, the most intact example of a colonial walled city north of Mexico and a UNESCO World Heritage Site. Against this spectacular backdrop, the APT conference offered a chance to hear from preservation professionals engaged in all types of work around the globe. Over 600 people were in attendance, with four simultaneous presentation tracks exploring a variety of preservation and conservation topics. Presentations included case studies ranging from traditional mud-brick buildings to modern and even postmodern structures, and from the application of technology to characterize material properties to management strategies for academic campuses and national parks.

Evan Kopelson describes Vertical Access’ investigation of the Sibley Hall Dome.

VA Partner Evan Kopelson, along with Janet Null of Argus Architecture & Preservation, P.C. presented Sibley Hall Dome: Integrating Investigative Techniques to Diagnose and Preserve an Iconic Steel Roof. The presentation examined the cross-disciplinary approach and investigative techniques used by the project team to understand the condition of the dome and to determine appropriate treatments. As part of the team for the conceptual design phase, VA used industrial rope access to perform a hands-on investigation of the dome, built in 1902 to connect the existing east and west wings of Sibley Hall on the campus of Cornell University. VA used an ultrasonic thickness gauge to measure the thickness of the dome’s sheet metal cladding, and employed live-feed video to discuss connection details with project team members in real time. Moisture testing at the interior of the dome confirmed condensation as the cause of corrosion in limited areas. Hands-on inspection showed the structure and cladding of the dome to be in good shape overall, and the information gathered during the investigation led the project team to recommend a conservative repair treatment that will preserve much of the dome’s original fabric.

Lower Town

Place Royal in Quebec City’s Lower Town

The conference was packed with activities, but we found a little bit of time to explore Vieux Quebec, walking among 17th and 18th century buildings in the Lower Town and touring the Cathedral-Basilica of Notre-Dame de Quebec. One of the highlights was getting to know our tablemates and deciding as a group which dessert to bid on during the Student Scholar Dessert Fundraiser auction.

The pear tart created by the Chateau Frontenac's pastry chef was amazing!

The pear tart created by the Chateau Frontenac’s pastry chef was amazing!

Funicular

A narrow street in the Lower Town leading to the Funicular.

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Ceramic plaques identify historic buildings in the Lower Town.

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Many of the shops in the Lower Town have whimsical signs like this one.

Chateau at night

The Place d’Armes and Chateau Frontenac at dusk.

We’re looking forward to APT’s 2015 conference in Kansas City, Missouri!

To learn more about APT, visit www.apti.org. 

Vertical Access was proud to be a Conference Premier Sponsor for APT’s 2014 conference.

1 Paraphrased from apti.org.


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