N.1. System installation.

A minimum of 6 nozzles shall be installed in a test location for evaluation purposes. Hoses shall be selected to anticipate maximum customer usage and efficient observer interaction. The test nozzles shall not fail to operate as designed for the duration of the evaluation.

N.2. Dispenser measurement accuracy.

Prior to the field examination of a vapor recovery system, the dispenser meters for the test nozzles shall be tested and adjusted, if necessary, to be within maintenance tolerance.

N.3. Performance accuracy - primary and secondary shut-off devices.

N.3.1. Test method.

Examination of the test nozzles shall be performed with a field compliance test unit as specified in subsection S.2.

Note: Two or more test units will expedite the examination significantly.

N.3.1.1. Test procedure - primary shut-off device.

N.3.1.1.1. Initial test.

Dispense fuel into the test unit with each nozzle. All nozzles shall shut off automatically at any delivery flow rate as the test unit becomes full as specified in subsection S.1.1.(a).

N.3.1.1.2. Override test.

After the initial primary shut-off device activates, dispense enough additional fuel into the test unit to immerse the nozzle primary shut-off sensing mechanism in liquid. Record the dispenser indicator gallons.

Make 10 additional consecutive override attempts duplicating a range of customer usage and record the new indicated gallons. All 10 attempts shall result in automatic nozzle shut off before the dispenser volume indicator increases more than the ¹/₁₀ gallon limit as specified in subsection T.1.1. The 10 override attempts shall be performed on a minimum of 6 nozzles, each tested a minimum of 3 times during this examination.

N.3.1.2. Test procedures - secondary shut-off device (if equipped).

Introduce sufficient fuel into the vapor return line (approximately ¹/₁₀ gallon or 375 milliliter) to block the return of vapors through the line. Hold in place a “U-shaped” configuration of the fuel discharge hose at a level lower than the nozzle to concentrate the liquid. Make a minimum of 10 attempts to dispense fuel into an empty test unit. Record the dispenser indicator gallons before and after each attempt. (Balance-type nozzles must make their intended tight seal at the fill pipe opening.) The nozzle shall shut off automatically before the dispenser volume indicator increases more than the ³/₁₀ gallon limit for each attempt as specified in subsection T.1.2. This procedure shall be performed on a minimum of 6 nozzles.

Notes: (1) The test unit must be empty initially to insure liquid does NOT interact with the primary shut-off device sensing mechanism. (2) For some hose configurations, introducing additional fuel into the vapor return line during the test procedure may be necessary. Introduced liquid can be returned to storage by building vapor line pressure produced by this procedure.

N.4. Delivery accuracy - 150 vehicle test.

N.4.1. Test method.

Compliance with delivery accuracy requirements shall be based upon data recorded for at least 150 vehicles while observing customers fueling (self-serve) with the test nozzles under normal field conditions.

N.4.2. Test procedure.

Install a transparent trap, or other suitable means, between each nozzle and dispenser outlet connection for the hose. Any liquid entering a vapor return line will be collected while observing the fueling operations. Then after each fueling, the liquid shall be drained into the trap, removed, and measured. Trap placement and observer actions shall produce the least possible interference with normal operations at the test location.

The liquid collected from both one individual delivery and the total of all individual deliveries shall not exceed the tolerances as specified in subsections T.3.(a) and T.3.(b), respectively.

The 150 or more vehicles shall be representative of California vehicles, including various sizes of passenger vehicles, vans, and trucks. This examination shall include varied fuel delivery rates and nozzle orientations plus complete and partial fills. The system may be retested if the Director by his own initiative, or at the request of the applicant, determines the test was not representative of field conditions.

N.5. Performance accuracy - assist system evaporation and volume change.

N.5.1. Test method.

An appropriate means (manometer, column gauge, etc.) shall be used to determine the inches of H₂O column vacuum for nozzles where the spout is booted and can form a closed seal around the vehicle filler neck. Excessive vacuum may result in artificial evaporation of customer fuel which would decrease the measured volume and also cause possible implosion of vehicle fuel tanks.

N.5.2. Test procedure.

Install the vacuum indicator at the nozzle or test unit. Record the value of the reading while the system is operating in a normal manner to determine if it is functioning within the -10 inches H₂O column vacuum limit as specified in subsection T.2.

N.6. Independent laboratory evaluation.

Pursuant to Section 41958 of the Health and Safety Code, type approval certification regarding recirculation shall include evaluations by Underwriters Laboratories (U.L.) or a similar independent laboratory selected by the Secretary. Reports required by other State agencies may be used to determine compliance with this section. The laboratory evaluation shall determine but is not limited to, proper secondary shut-off device operation for nozzles where the spout is booted and can form a closed seal around the vehicle filler neck with the primary shut-off device inoperable.