Hydrants required to serve any apartment buildings or portions thereof which are more than 150 feet from a public right-of-way shall be increased to 300 feet; provided, that the building is fully sprinkled with an approved sprinkling system as specified in National Fire Protection Association Pamphlet No. 13 and equipped with an approved automatic fire detection system as specified in National Fire Protection Association Pamphlet No. 72. (Ord. 3174 § 1(C), 1977.)