Except as otherwise specifically provided in this section, it
shall be unlawful to install, alter or extend a refrigerating system
without first having obtained a permit therefor from the Commissioner.
No permit shall be required for emergency or general service repairs
which require no permanent change in the equipment nor for a unit
system containing a maximum of 20 pounds of refrigerant nor for a
noncondensing refrigerating system using air as a refrigerant.
It shall be unlawful to use or permit the use of any such refrigerating
system until the Fire Commissioner has approved the same as meeting
the requirements of the New York Uniform Code.