(b) Component description. The following components will be used in sampling and analytical systems for testing under the regulations in this part.

(1) Flowmeters FL1, FL2, FL3, and FL4 indicate the sample flow rate through the analyzers.

(2) Low range hydrocarbon analyzer.
(3) Carbon monoxide analyzer.
(4) Carbon dioxide analyzer.

(5) High range hydrocarbon analyzer. (6) Pressure gauges P1, P2, and P3 indicate the analyzer sample pressure.

(7) Needle valves N1, N2, N3, and N4 regulate sample flow rate to the analyzers.

(8) Needle valves N5, N6, N7, N8, N9, and N10 regulate the flow rates of N. and normalizing gases to the analyzers.

(9) Ball valves V1, V2, and V3 for directing either sample or calibration gases to the analyzers.

(10) Needle valves N11, N12, N13 regulate the sample flow rate through the bypass network.

(11) Flowmeters FL5, FL6, and FL7 indicate the flow rate through the bypass system.

(12) Pumps P1, P2, and P3 for pulling sample from source.

(13) Filters F1, F2, and F3 remove contaminants from sample prior to analysis.

(14) Ball valves V4, V5, and V6 for directing sample to the analyzer or directing air in the reverse direction as a blackflush.

(15) Toggle valves V8, V9, V10, and V11 for draining condensate traps and refrigerated bath.

(16) Traps T1, T2, and T3 for condensing water vapor and cooling exhaust sample.

(17) Ball valve V7 for diverting air to low HC analyzer during periods of high hydrocarbon response.

(18) Needle valve N14 for regulating air flow to low hydrocarbon analyzer during purge conditions.

(19) Thermometer for indicating bath temperature.

(20) Refrigerated water bath for condensing water vapor and cooling exhaust sample.

(21) Sample line from vehicle to analysis system.

(22) Sample probe to extract exhaust gas sample from terminus of vehicle exhaust system.

(23) Ball valve V12 for directing N, to hydrocarbon analyzers.

§ 85.82 Sampling and analytical system (fuel evaporative emissions).

(a) Schematic drawings. (1) The following figures (Figures 2, 3, and 4) are flow diagrams of typical evaporative loss collection applications.

(i) Canister-300±25 ml., cylindrical container having a length to diameter ratio of 1.4±0.1. An inlet tube, 5/16-inch ID and 1-inch long is sealed into the top of the canister, at its geometric center. A similar outlet tube is sealed into the wall 1/4-inch from the bottom of the canister. The canister is designed to withstand an air pressure of 2 p.s.i., when sealed, without evidence of leaking when immersed in water for 30 seconds.

(ii) Activated carbon-meeting the following specifications:

Surface area, min. (N, 1,000 square meters BET method).1

Adsorption capacity,

min. (carbon tetrachloride).

per gram.

60 percent, by weight.

let tubes is prevented through the use of wire screens of 0.7-mm. mesh or wads of loosely packed glass wool. The canister is closed immediately after filling and the carbon is allowed to cool while the trap is vented through a drying tube via the unclamped outlet arm.

(iii) The trap is sealed and weighed after cooling and the weight, to the nearest 0.1 gram, is inscribed on the canister body. Within 12 hours of the scheduled test, the weight of the trap is checked and if it has changed by more than 0.5 gm., it is redried to constant weight. This redrying operation is performed by passing dry nitrogen, heated to 275° F., through the trap, via the inlet tube, at a rate of 1 liter per minute until checks made at 30-minute intervals do not vary by more than 0.1 percent of the gross weight. The trap and its contents are allowed to cool to room temperature, while vented through a drying tube via the outlet arm, before use.

equipment.

(2) Auxiliary collection (i) Drying tube-transparent, tubular body 3/4-inch ID, 6 inches long, with serrated tips and removable caps.

(ii) Desiccant-indicating variety, 8 mesh. The drying tube is attached to the outlet tube of the collection traps to prevent ambient moisture from entering the trap. It is prepared by filling the empty drying tube with fresh desiccant using loose wads of glass wool to hold the desiccant in place. The desiccant is renewed when three-quarters spent, as indicated by color change.

(iii) Collection tubing-stainless steel or aluminum, 16-inch ID, for connecting the collection traps to the fuel system vents.

(iv) Polyvinyl chloride (vinyl) tubing-flexible tubing, 546-inch ID, for sealing butt-to-butt joints.

(v) Laboratory tubing-air tight flexible tubing, 546-inch ID, attached to the outlet end of the drying tubes to equalize collection system pressure.

(vi) Clamps-Hosecock, open side, for pinching off flexible tubing.

(c) Weighing equipment. The balance and weights used shall be capable of determining the net weight of the activated carbon trap within an accuracy of +75 mg.

(d) Temperature measuring equipment. (1) Temperature recorder-multichannel, variable speed, potentiometric, or substantially equivalent, recorder with a temperature range of 50° F. to 100° F.

and capable of either simultaneous or sequential recording of the ambient air and fuel temperatures within an accuracy of +1° F.

(2) Fuel tank thermocouples-ironconstantan (type J) construction.

(e) Assembly and use of the activated carbon vapor collection system. (1) The prepared activated carbon trap, dried to constant weight, cooled to the ambient temperature and sealed with clamped sections of vinyl tubing is carefully weighed to the nearest 20 milligrams and the weight recorded as the "tare weight."

(2) A drying tube is attached to the outlet tube and the clamp released, but not removed. A length of flexible tubing, for pressure equalization, is connected to the other end of the drying tube.

(3) The inlet tube of the adsorption trap and external vent (s) of the fuel system will be connected by minimal lengths of stainless steel or aluminum tubing and short sections of vinyl tubing. Butt-tobutt joints will be made wherever possible and precautions taken against sharp bends in the connection lines, including any inanifold systems employed to connect multiple vents to a single trap.

(4) The clamp on the inlet tube of the trap will be released but not removed. Care shall be exercised to prevent heating the vapor collection trap by radiant or conductive heat from the engine.

(5) Upon completion of the collection sequence, the vinyl tubing sections on each arm of the collection trap will be clamped tight and the collection system dismantled.

(6) The sealed vapor collection trap shall be weighed carefully to the nearest 20 milligrams. This constitutes the "gross weight," which is appropriately recorded. The difference between the "gross weight" and "tare weight" represents the "net weight" for purposes of calculating the fuel vapor losses. § 85.83

Information to be recorded.

The following information shall be recorded with respect to each test:

(a) Test Number.

(b) System or device tested (brief description).

(c) Date and time of day for each part of the test schedule.

(d) Instrument Operator.

(e) Driver or Operator.

(f) Vehicle: Make-Vehicle identification number-Year-Transmission type-Odometer reading-Engine dis

Minimum storage temperature of the cylinders shall be 60° F.; minimum use temperature shall be 68° F.

(4) Compare values with previous curves. Any significant change reflects some problem in the system. Locate and correct problem, and recalibrate. Use best judgment in selecting curve for data reduction.

(5) Check response of hydrocarbon analyzer to 100 percent CO2. If response is greater than 0.5 percent full scale, refill filter cells with 100 percent CO2 and recheck. Note any remaining response on chart. If response still exceeds 0.5 percent, replace detector.

(6) Check response of hydrocarbon analyzers to nitrogen saturated with water at ambient temperature. Record ambient temperature. If the low-range instrument response exceeds 5 percent of full scale with saturated nitrogen at 75° F., replace the detector. If the high

range response exceeds 0.5 percent of full scale, check detector on low-range instrument, then reject if response exceeds 5 percent of full scale at 75° F.

(b) Daily instrument check: Allow a minimum of 2 hours warmup for infrared analyzers. (Power is normally left on continuously; but, when instruments are not in use, chopper motor is turned off.) The following should be done before each series of tests:

(1) Zero on clean nitrogen introduced at analyzer inlet. Obtain a stable zero on the amplifier meter and recorder. Recheck after test.

(2) Introduce normalizing gas and set gain to match calibration curve. In order to avoid a correction for sample cell pressure, normalize and calibrate at the same flow rates used for exhaust sampling. Normalizing or span gases: (See paragraph (a) (3) of this section for allowable variation.)