N.Y.C. Admin. Code § 24-127: § 24-127 Expiration of work permits.

(a) In newly constructed buildings, a work permit shall expire if the installation is not completed within one year from the date of issuance of the work permit or if work on the installation under the work permit is suspended for more than ninety days.

(b) In existing buildings, a work permit shall expire if the installation or alteration is not begun within ninety days from the date of issuance of the work permit or if the work of the installation or alteration is suspended for more than thirty days or if the installation or alteration is not completed within six months.

(c) Extensions may be granted for a period of not more than six months per extension, provided that an application for an extension shall be made at least thirty days prior to the expiration of the work permit.

(d) An expired work permit shall be reinstated if it is filed within one year of the expiration date of the work permit. If an application for reinstatement is not filed within one year of the expiration date of the work permit, then a new application shall be filed with the department.