Fuel Systems

Appendix A — Fuel System Standard

18.0 — Lab Examination No. 14
Fire Test of Fuel System Components cont'd

183.590 Fire Test cont'd

18.3 Test

18.3.1 This procedure shall be used to perform a fire test on fuel system components, such as but not limited to, fuel strainers, fuel pumps, fuel filters, and any other components specified in section 183.590. The three fuel system components identified above may be tested either in a fire chamber or as installed on the engine.

18.3.2 Visually inspect the component to be tested. Review the results of the Receiving Inspection and verify that the component is acceptable for testing.

18.3.3 Verify the applicability of this purpose to the component being tested before proceeding.

18.3.4 Fire Chamber Test

18.3.4.1 Mount and secure the component in a fire chamber as shown in the Test Schematic, Paragraph 18.2, and similar to a typical boat installation. Connect an inlet and outlet copper line to the component.

18.3.4.2 Connect the other end of the inlet line to a 3-way, 2-position valve and fuel supply tank as shown in the Test Schematic.

Note:
Although a 3-way valve has been shown in the Test Schematic, any equivalent combination of valves may be used to accomplish the same result.

18.3.4.3 Connect the outlet line to a shutoff valve over a receiving tank as shown in the Test Schematic (not applicable to carburetors).

18.3.4.4 Position an 8-1/2 in. x 14 in. x 1-1/2 in. (21.6 cm x 35.6 cm x 3.8 cm) (approximate) fuel pan directly under the test component. The bottom of the test component shall be 9 ±1 in. (22.9 ±2.5 cm) above the liquid surface of the fuel. The perimeter of the fuel pan shall extend beyond the vertical projection of the perimeter of the component being tested.

18.3.4.5 Two thermocouples shall be positioned even with the lowest point of the test component, one on each side, within one inch (2.5 cm) of the component, as shown in the Test Schematic. The thermocouple shall be capable of measuring 1200°F (648°C) at a remote station.

18.3.4.6 With all control valves in the closed position fill the fuel supply tank with a quantity of pump gasoline (regular) sufficient to fill the test system (approximately 2 or 3 gal, (7.6 or 11.4 l)). Closed position for the three-way valve is in the vent position.

18.3.4.7 Open the tank shutoff valve, the 3-way valve, and the discharge shutoff valve and allow a sufficient amount of gasoline to flow through the test setup to insure the system has been bled of all air and that the test component is filled with gasoline. Some components may have to be electronically or mechanically operated momentarily to accomplish this.

18.3.4.8 With the system full of gasoline close the discharge shutoff valve and perform a visual leak check of the system. There shall be no leakage of gasoline. Then close (vent position) the 3-way supply valve. In this position the fuel supply tank is isolated and the test component is vented to the atmosphere.

18.3.4.9 Remove the fuel pan from the fire chamber and fill it with technical grade or better heptane to a depth sufficient to burn for at least 2-1/2 min. (approximately 1/2 in. (1.3 cm)). Carefully replace the fuel pan (no spillage allowed) back into the fire chamber in the proper position. Measure the height from the bottom of the test component to the liquid surface. This height shall be 9 ±1 in. (22.9 ±2.5 cm).

18.3.4.10 Verify that the system is ready for the test and that all safety precautions are in effect. A CO2 fire extinguisher or equivalent should be ready.

18.3.4.11 Place the Pyrex glass shield into position and secure it.

18.3.4.12 With all personnel at a safe distance from the fire chamber ignite the heptane in the fuel pan through one of the vent holes using a three-foot (0.9 m) torch and allow it to burn for 2-1/2 min. It is desirable to continually record the temperatures encountered during the burn period, however, in no case should the recording interval exceed five seconds. During the 2-1/2 min., one temperature indication of at least 1200°F (648°C) shall be required at one of the two positions. Record the highest temperature observed during the test. Visually monitor the test system during the burn period for any indication of gasoline leakage. No leakage is allowed.

Note:
Even though leakage is observed during this part of the test, the rest of the test shall be accomplished to verify the actual point of leakage is in the component and not part of the test setup.

18.3.4.13 After 2-1/2 min. of burn time, extinguish the fire with CO2 or other suitable means. Do not disturb the test component or discharge the CO2 directly on the component.

18.3.4.14 Immediately after the fire has been extinguished, open the discharge shutoff valve and then the 3-way supply valve. Gasoline may not flow from the discharge part immediately, depending on the component being tested, the temperature and the degradation resulting from the fire. Close the discipline shutoff valve after there is a steady flow of gasoline. Leave the 3-way supply valve open and verify that the level of gasoline in the fuel supply tank is 36 ±1 in. (91 ±2.5 cm) above the inlet line to the fire chamber. Add pump gasoline (regular) as necessary.

18.3.4.15 Perform a visual check of the test component and the inlet fittings. There shall be no leakage of gasoline. If any indication of leakage is observed, the test component shall be rejected. If no leakage is observed, the test component shall be deemed acceptable according to the requirements of this procedure.

Note:
A leakage of 5 oz. In 2-1/2 minutes is allowed from the fuel pump, filter, strainer, and fuel line combined.

18.3.4.16 Secure the test system as required and safe the area.

18.3.5 Installed Test

18.3.5.1 Fuel pumps, fuel filters and fuel strainers may be tested as installed on the engine, either singularly or all at the same time.

18.3.5.2 Position the engine in a level position in a container. The container shall be large enough to permit the perimeter of the top surface of the heptane to extend beyond the vertical projection of the perimeter of the engine.

18.3.5.3 Verify that the component (or components) to be tested is full of gasoline. The system may have to be operated momentarily to accomplish this.

18.3.5.4 Remove, de-energize or disconnect all potential sources of ignition (fuel and electrical).

18.3.5.5 Pour a quantity of heptane sufficient to burn for 2-1/2 min. over the components to be tested with the excess being caught in the container under the engine. In addition, the quantity shall be sufficient to cover the entire bottom area of the container for the entire test. To meet this requirement, the container bottom should be as flat and level as possible.

18.3.5.6 The heptane shall be ignited at all locations and allowed to burn for 2-1/2 minutes. Visually monitor the test system during the burn period for any indication of gasoline leakage. No leakage is allowed. Extinguish the fire with CO2 or other suitable means. There is no minimum temperature requirement for this test.

18.3.5.7 Perform a visual leak check of the test component(s) as soon as the fire has been extinguished. There shall be no leakage of gasoline. If any indication of leakage is observed, the test component shall be rejected. If no leakage is observed, check for leak in accordance with Paragraph 18.3.4.14.

18.3.5.8 Secure the test system as required and safe the area.

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