Post proof of that statement. AFAIR, that only concerns systems that hold
50 pounds or more.

"Technician

Any person who performs maintenance, service, or repair that could
reasonably be expected to release class I (CFC) or class II (HCFC)
substances from appliances, except for MVACs, into the atmosphere.
Technician also means any person performing disposal of appliances,
except for small appliances, MVACs, and MVAC-like appliances, that
could be reasonably expected to release class I or class II
refrigerants from appliances into the atmosphere.

Appliance

Any device which contains and uses a class I (CFC) or class II (HCFC)
substance as a refrigerant and which is used for household or
commercial purposes, including any air conditioner, refrigerator,
chiller, or freezer. EPA interprets this definition to include all
air-conditioning and refrigeration equipment except that designed and
used exclusively for military purposes.

Small appliance

Any of the following products that are fully manufactured, charged, and
hermetically sealed in a factory with five pounds or less of
refrigerant: refrigerators and freezers designed for home use, room air
conditioners (including window air conditioners and packaged terminal
air conditioners), packaged terminal heat pumps, dehumidifiers,
under-the-counter ice makers, vending machines, and drinking water
coolers.

MVAC-like appliance

Mechanical vapor compression, open-drive compressor appliances used to
cool the driver's or passenger's compartment of a non-road vehicle,
including agricultural and construction vehicles. This definition
excludes appliances using HCFC-22.

http://epa.gov/ozone/title6/608/608defns.html#appliance

"Technician Certification

EPA has established a technician certification program for persons
("technicians") who perform maintenance, service, repair, or disposal
that could be reasonably expected to release refrigerants into the
atmosphere. The definition of "technician" specifically includes and
excludes certain activities as follows:

Included:

- attaching and detaching hoses and gauges to and from the appliance to
measure pressure within the appliance;

- adding refrigerant to (for example "topping-off") or removing
refrigerant from the appliance

- any other activity that violates the integrity of the MVAC-like
appliances, and small appliances.

.... Technicians are required to pass an EPA-approved test given by an
EPA-approved certifying organization to become certified under the
mandatory program. Section 608 Technician Certification credentials do
not expire."

"Refrigerant Sales Restrictions

Since November 14, 1994, the sale of refrigerant in any size container
has been restricted to technicians certified either under the program
described in Technician Certification above or under EPA's motor
vehicle air conditioning regulations. The sales restriction covers
refrigerant contained in bulk containers (cylinders or drums) and
pre-charged parts."

http://epa.gov/ozone/title6/608/608fact.html

AFAIK the "50 pound rule" refers to various service and record
keeping requirements where servicing unit at or above this size, for
example:

"Owners of equipment with charges of greater than 50 pounds are
required to repair leaks in the equipment when those leaks together
would result in the loss of more than a certain percentage of the
equipment's charge over a year. For the commercial and industrial
process refrigeration sectors, leaks must be repaired when the
appliance leaks at a rate that would release 35 percent or more of the
charge over a year. For all other sectors, including comfort cooling,
leaks must be repaired when the appliance leaks at a rate that would
release 15 percent or more of the charge over a year."

"Technicians servicing appliances that contain 50 or more pounds of
refrigerant must provide the owner with an invoice that indicates the
amount of refrigerant added to the appliance. Technicians must also
keep a copy of their proof of certification at their place of
business."

"Owners of appliances that contain 50 or more pounds of refrigerant
must keep servicing records documenting the date and type of service,
as well as the quantity of refrigerant added."

http://epa.gov/ozone/title6/608/608fact.html

The EPA takes this stuff very seriously:

http://epa.gov/ozone/enforce/index.html

As always, if I'm in error, I welcome corrections.

Michael Thomas
Paragon Home Inspection, LLC
Chicago, IL
mdt@paragoninspectsDOTcom
847-475-5668