Smoke Bomb Air Leakage Testing
The following is extracted from a Richmond Refinery Engineering Guideline included in Appendix E.
Smoke testing should be performed at the beginning of a turnaround before the furnace has been opened. This will allow time to repair identified leakage during the shutdown. If large leaks are found, the furnace should be retested after initial repairs because many small leaks may have been obscured. A test should also be done after major refractory repairs and furnace modifications have been made.
1. Schedule the time and date of the smoke test. Notify any appropriate environmental authorities.
2. Assign an operator to work with the Maintenance and Inspection team during the smoke test. Operations should make the necessary control moves to complete the test (e.g., close dampers, start forced draft blower, etc.). On larger furnaces more operators may be needed to help with the leak identification and preparation of the furnace.
3. Seal the furnace as necessary to complete the test. Inspection doors and burner openings can be sealed with tape or other suitable material. If the closed damper leaks by too much, the stack may also have to be covered or sealed.
4. Provide and install a blower, such as an air-driven manway blower.
5. Supply smoke bombs and spray paint cans. Use enough smoke bombs to produce a smoke volume 10 to 20 times the furnace volume. A 5-minute bomb will produce 100,000 cubic feet of smoke.
6. Assign personnel to help identify leaks with spray paint.
1. Issue spray paint cans to the operators, mechanics, and inspectors doing the test. Assign an area to each person with instructions to spray all visible leaks within their areas.
2. Attach the smoke bomb(s) to the blower suction and CAUTIOUSLY light the bomb(s). Start the blower and adjust as necessary to achieve positive pressure of 0.10 to 0.20 inches of water. This will ensure adequate pressure to blow smoke through leaks.
3. Identify the leaks with spray paint. If you are unable to identify an area where smoke is coming from, use your hand or a light rag to detect air flow.
1. Fill or repair holes using ceramic fiber caulking.
2. Paint over original leak-identifying paint with a color matching the color of the furnace.