(Adopted 4/18/72, Renumbered 5/89)

I. Definition: Orchard Heater means any article, machine, equipment, or other contrivance burning any type of fuel, or charcoal briquettes or similar substances burned by an open flame, capable of being used for the purpose of giving protection from frost damage. For the purpose of this Rule, "Orchard Heater" shall include heaters used for frost protection for orchards, vineyards, field crops and truck crops. The contrivance commonly known as a wind machine is not included.

II. No new orchard heater produced or manufactured shall be sold for use against frost damage after January 1, 1971, unless it has been approved by the State Air Resources Board.

III. No person shall use any orchard heater after January 1, 1973, unless it has been approved by the State Air Resources Board or does not produce more than one gram per minute of unconsumed solid carbonaceous material.

IV. It shall be unlawful to sell, or offer to sell for frost protection any orchard heater which does not comply with Rule 421 III.

V. All orchard heaters shall be maintained in reasonable clean condition, good repair and working order. Whenever orchard heaters are burning they must be adequately attended and supervised to maintain the condition, adjustment and proper operation of the orchard heaters.

VI. It shall be unlawful for any person, for the purpose of frost protection, to burn any rubber, rubber tires, or other substance containing rubber, or to burn oil or other combustibles.