NYC FGC 503.5.6.1 Chimney Lining

Chimneys shall be lined in accordance with NFPA 211.
Exception: Where an existing chimney complies with Sections 503.5.6 (INSPECTION CODE) through 503.5.6.5 (SMOKE TEST CODE) and its sizing is in accordance with Section 503.5.5 (SIZING CODE), its continued use shall be allowed where the appliance vented by such chimney is replaced by an appliance of similar type, input rating and efficiency.