§ 1090.1415 - Survey program plan design requirements.

§ 1090.1415 Survey program plan design requirements.

The survey program plan must include all the following:

(a) Number of surveys. The survey program plan must include 4 surveys each calendar year that occur during the following time periods:

(1) One survey during the period of January 1 through March 31.

(2) One survey during the period of April 1 through June 30.

(3) One survey during the period of July 1 through September 30.

(4) One survey during the period of October 1 through December 31.

(b) Sampling areas. The survey program plan must include sampling in all sampling strata during each survey. These sampling strata must be further divided into discrete sampling areas or clusters. Each survey must include sampling in at least 40 sampling areas in each stratum that are randomly selected.

(c) No advance notice of surveys. The survey program plan must include procedures to keep the identification of the sampling areas that are included in the plan confidential from any participating party prior to the beginning of a survey in an area. However, this information must not be kept confidential from EPA.

(d) Gasoline and diesel retail outlet selection.

(1) Gasoline and diesel retail outlets to be sampled in a sampling area must be selected from among all gasoline retail outlets in the United States that sell gasoline with the probability of selection proportionate to the volume of gasoline sold at the retail outlet. The sample of retail outlets must also include gasoline retail outlets with different brand names as well as those gasoline retail outlets that are unbranded.

(2) For any gasoline or diesel retail outlet from which a sample of gasoline or diesel was collected during a survey and was reported to EPA under § 1090.1410(e), that gasoline or diesel retail outlet must be included in the subsequent survey.

(3) At least one sample of a product dispensed as E15 must be collected at each gasoline retail outlet when E15 is present, and separate samples must be taken that represent the gasoline contained in each storage tank at the gasoline retail outlet unless collection of separate samples is not practicable.

(4) At least one sample of a product dispensed as diesel fuel must be collected at each diesel fuel retail outlet when diesel fuel is present. Samples of diesel fuel may be collected at retail outlets that sell gasoline.

(e) Number of samples.

(1) The number of retail outlets to be sampled must be independently calculated for the total number of gasoline retail outlets and the total number of diesel fuel retail outlets. The same retail outlet may represent both a gasoline retail outlet and a diesel fuel retail outlet for purposes of determining the number of samples.

(2) The minimum number of samples to be included in the survey program plan for each calendar year is calculated as follows:

Where:

n = Minimum number of samples in a year-long survey series. However, n must be greater than or equal to 2,000 for the number of diesel samples or 5,000 for the number of gasoline samples.

Z_α = Upper percentile point from the normal distribution to achieve a one-tailed 95% confidence level (5% α-level). For purposes of this survey program, Z_α equals 1.645.

Z_β = Upper percentile point to achieve 95% power. For purposes of this survey program, Z_β equals 1.645.

ϕ₁ = The maximum proportion of non-compliant outlets for a region to be deemed compliant. This parameter needs to be 5% or greater (i.e., 5% or more of the outlets, within a stratum such that the region is considered non-compliant).

ϕ₀ = The underlying proportion of non-compliant outlets in a sample. For the first survey program plan, ϕ₀ will be 2.3%. For subsequent survey program plans, ϕ₀ will be the average of the proportion of outlets found to be non-compliant over the previous 4 surveys.

F_a = Adjustment factor for the number of extra samples required to compensate for samples that could not be included in the survey (e.g., due to technical or logistical considerations), based on the number of additional samples required during the previous 4 surveys. F_a must be greater than or equal to 1.1.

F_b = Adjustment factor for the number of samples required to resample each retail outlet with test results reported to EPA under § 1090.1410(e), based on the rate of resampling required during the previous 4 surveys. F_b must be greater than or equal to 1.1.

Su_n = Number of surveys per year. For purposes of this survey program, Su_n equals 4.

St_n = Number of sampling strata. For purposes of this survey program, St_n equals 3.

(3) The number of gasoline samples that also need to be tested for aromatics, olefins, and distillation parameters under § 1090.1410(c)(2) must be calculated using the methodology specified in paragraph (e)(2) of this section without the F_a, F_b, and Su_n parameters.

(4) The number of samples determined under paragraphs (e)(2) and (3) of this section must be distributed approximately equally among the 4 surveys conducted during the calendar year.

(f) Laboratory designation. Any laboratory that the independent surveyor intends to use to test samples collected as part of the NFSP must be approved annually as part of the survey program plan approval process in § 1090.1400(a). In the survey program plan submitted to EPA, the independent surveyor must include the following information regarding any laboratory they intend to use to test samples:

(1) The name of the laboratory.

(2) The address of the laboratory.

(3) The test methods for each fuel parameter measured at the laboratory.

(4) Reports demonstrating the laboratory's performance in a laboratory crosscheck program for the most recent 12 months prior to submission of the survey program plan.

(g) Submission. Survey program plans submitted under this section must be approved annually under § 1090.1400(a).