Special glasses.
NYC Admin. Code § 27-647
in effect§ 27-647 Special glasses.
For types of glass other than single annealed sheet and plate glass, allowable maximum areas may be determined by multiplying values in table 10-7 by the appropriate multiplying factor listed in table 10-8.
TABLE 10-8
Multiplying Factors for Various Types of Glass
Glass Type Multiplying Factor
Full tempered 4.0
Heat strengthened 2.0
Factory-fabricated double glazing *1.5*
Laminated 0.6
Wired 0.5
Sandblasted or etched 0.4
* For asymmetrical units base strength on thinner lite.
Source: City of New York, Charter, Administrative Code and Rules (American Legal Publishing XML export, codelibrary.amlegal.com)URL: https://codelibrary.amlegal.com/codes/newyorkcity/latest/NYCadmin/0-0-0-51176Fetched: 10/24/2026