Mayor's Office memo re: DEP meeting, Mar 2002

NYC 9/11 Public Portal Document

Friday 15 of Mar 2002, Mayor Office ->718 595 4544 Page 22 of 29

Requirements and Performance Standards Removing Applied Paint (Signage) from Masonry

1.. Requirements

General: All work related to historic buildings shall comply with the Secretary of the Interior's Standards for the Treatment of Historic Properties. Treatment approaches will be in the "gentlest means possible," and all r,•:ethods should be material and building specific. Removal of Applied Paint (signage) from masonry should be done as soon as possible. Programs for the removal cf applied paint from historic building fabric shall be developed on a case-by-case basis with regard to each building and all associated building materials. Harsh treatments and inappropriate cleaning methods, including abrasive cleaning and certain chemical applications, can permanently damage significant historic building fabric and character-defining features. Traditional abrasive applications such as "sand-blasting" and hig'ti-pressure water cleaning shall not de used.

H. Performance Standards

Qualified Contractor(s)/Consultant(s): A qualified professional such as a historic preservation or a building conservation expert shall be consulted to develop an appropriate removal program for each building. A qualified contractor or building conservator, experienced in the removal of applied paint (signage) and cleaning of historic buildings shall be used to perform work.

Testing: Prior to the removal of applied paint, identify the paint type and the substrate to which the paint is applied. Identification of the paint type and substrate material (e.g. stone, cast stone, brick, terra cotta) combined with professional interpretation of test results will aid in the determination of the most appropriate removal method. After a cleaning program is selected, the method shall be tested and evaluated by a qualified professional prior to application. Each building and building material shall be assessed and tested prior to developing and implementing cleaning programs. It is expected that several methods of removal will be tested before an appropriate removal method is found.

WTC Sloe Specific Considerations:

o Masonry surfaces shall be free of dust prior to implementing a removal program. It is possible, based upon composition of the particulates generated by the disaster, that the dust and/or debris on the facade may chemically react with applications and masonry substrate during the cleaning process, creating deposits that • it cause problems to the building over time. Dust and debris deposited on buildings should be tested and, if determined necessary, properly removed prior to the application of water or liquid cleaning agents. (see Performance Standards for Cleaning Masonry Exteriors).

o The Applicant should ensure that potential disaster related damages to the building which may include, but are not limited to, openings in building facades, dust on building materials, cracks, open mortar joints, and weakened or damaged materials are identified by a qualified professional prior to cleaning the facade. Precautions should be taken prior

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NYC-WTC 000093809