Code of Federal Regulations Title 40. Protection of Environment § 40.449.2 General definitions

The following definitions apply to this part:

Aircraft deicing fluid (ADF) means a fluid (other than hot water) applied to aircraft to remove or prevent any accumulation of snow or ice on the aircraft. This includes deicing and anti-icing fluids.

Airfield pavement means all paved surfaces on the airside of an airport.

Airside means the part of an airport directly involved in the arrival and departure of aircraft, including runways, taxiways, aprons, and ramps.

Annual non-propeller aircraft departures means the average number of commercial turbine-engine aircraft that are propelled by jet, i.e., turbojet or turbofan, that take off from an airport on an annual basis, as tabulated by the Federal Aviation Administration (FAA).

Available ADF means 75 percent of the normalized Type I aircraft deicing fluid and 10 percent of the normalized Type IV aircraft deicing fluid, excluding aircraft deicing fluids used for defrosting or deicing for safe taxiing.

Centralized deicing pad means a facility on an airfield designed for aircraft deicing operations, typically constructed with a drainage system separate from the airport main storm drain system.

COD means Chemical Oxygen Demand.

Collection requirement means the requirement in § 449.11 for the permittee to collect available ADF.

Defrosting means the removal of frost contamination from an aircraft when there has been no active precipitation.

Deicing mean procedures and practices to remove or prevent any accumulation of snow or ice on:

(1) An aircraft;  or

(2) Airfield pavement.

Deicing for safe taxiing means the application of ADF necessary to remove snow or ice to prevent damage to a taxiing aircraft.

FAA Advisory Circular means a guidance document issued by the FAA on methods, procedures, or facility design.

Heating degree day means the number of degrees per day the daily average temperature is below 65 degrees Fahrenheit. The daily average temperature is the mean of the maximum and minimum temperature for a 24–hour period. The annual heating degree day value is derived by summing the daily heating degree days over a calendar year period.

Normalized Type I or Type IV aircraft deicing fluid means ADF less any water added by the manufacturer or customer before ADF application.

Primary Airport means an airport defined at 49 U.S.C. 47102 (15).