A material which, in the form in which it is used in CONSTRUCTION, will not ignite and burn when subjected to fire. However, any material which liberates flammable gas when heated to any temperature up to 1380 degrees Fahrenheit for five minutes shall not be considered noncombustible. No material shall be considered noncombustible which is subject to increase in combustibility beyond the limits established above, through the effects of age, fabrication or erection techniques, moisture, or other interior or exterior atmospheric conditions. Local Law 13-1987.