(a) General. In determining, under the 13(a)(2) exemption, whether 75 percent of the establishment's sales are not for resale and are recognized as retail sales in the industry, sales to the ultimate consumer of liquefied-petroleum-gas, whether delivered in portable cylinders or in bulk to the customer's storage tanks, are recognized as retail in the industry if they meet all the requirements for such classification as previously explained in this subpart. The following are not recognized as retail:

(1) Sales in single lot deliveries exceeding 1,000 gallons;

(2) Sales made on a competitive bid basis (this term covers sales made pursuant to an invitation to bid, particularly sales to Federal, State and local governments; sales made in a like manner to commercial and industrial concerns and institutions are also included); and

(3) Sales for use in the production of a specific product in which the gas is an essential ingredient or principal raw material, such as sales of liquefied-petroleum-gas for the production of chemicals and synthetic rubber; and

(4) Sales of liquefied-petroleum-gas for use as truck or bus fuel and the repair and servicing of trucks and buses used in over-the-road commercial transportation (including parts and accessories for such vehicles).

(b) Sales or repairs of tanks. Sales or repairs of tanks for the storage of liquefied-petroleum-gas are recognized as retail in the industry, except: (1) Any tank exceeding 1,000 gallons in capacity; (2) any tank sold or repaired on the basis described in paragraph (a) (2) of this section or for the purposes described in paragraph (a)(3) of this section; and (3) sales in quantity larger than involved in the ordinary sales to a farm or household customer.

(c) Conversion units. Sales and installation of units for converting pumps, stoves, furnaces and other equipment and appliances to the use of liquefied-petroleum-gas, are recognized as retail sales except: (1) Sales of the installation of such conversion units which involve substantial modification of the appliance or equipment; (2) sales and installation of such units to be used in industrial machinery or equipment; (3) sales and installations made on the basis described in paragraph (a)(2) of this section or in quantity as described in § 779.327; and (4) sales and installation of such units for vehicles mentioned in paragraph (a) (4) of this section.