WALL WASHING!!!

THE WALL WASH TEST IS A PROCEDURE FOR WASHING SELECTED AREAS SUCH AS THE INTERIOR BULKHEADS, TANK BOTTOMS WITH AN APPROPRIATE WASH LIQUID; AND; SUBSEQUENTLY TESTING THE WASH A LIQUID FOR THE PRESENCE OF MATERIAL WHICH MIGHT CONTAMINATE THE CARGO TO BE LOADED.

WALL WASH TEST PROCEDURES CAN BE FOUND IN API MPMS CHAPTER 17, SEC 8, GUIDELINES FOR PRE-LOADING INSPECTION OF MARINE VESSEL CARGO TANKS.

EQUIPMENT:

PLASTIC GLOVES (FOR SKIN PROTECTION AND TO PREVENT CHLORIDE CONTAMINATION OF SAMPLE); EXPLOSION PROOF FLASHLIGHT, LABORATORY WASH BOTTLE, WALL WASH FUNNEL, WALL WASH COLLECTION BOTTLES, WITH POLY SEAL CAPS, SMALL, CLEAN PLASTIC BAGS, FOR RUST SAMPLES, SUFFICIENT WASH LIQUID (USUALLY REAGENT GRADE METHANOL), CLEAN WIPING RAGS.

THE MINIMUM AREAS TO BE WASHED ARE DETERMINATE BY THE FOLLOWING:

TANKS <3000 BBLS OR 500 M3 MUST BE MINIMUM 5 HRS; FROM 3000-6300 BBLS (500-1000M3) MINIMUM 7 AREAS AND > 6300 BBLS OR 1000 M3 AM MINIMUM OF SPOT AREAS OF 9 PLACES.

RECOMENDATIONS:

1.-DO NOT PERFORM WALL WASHES ON WET TANKS. REQUEST VESSEL'S PERSONNEL TO DRY TANKS.
2.-EACH WASHED AREA SHOULD BE ABOUT 3 FEET WIDE AND 6 FEET HIGH FROM THE BOTTOM OF EACH TANK. HIGHER AREAS THAT CAN BE SAFELY ACCESSED MAY ALSO BE WASHED.
3.-DISCOLORED PATCHES, TANK COATING BREAKS, OR EXPOSED SECTIONS ALL OTHER NON-TYPICAL AREAS ON THE TANKS WALLS OF TANKS FLOORS MUST BE NOTED ON THE REPORT AND TESTED AS FOLLOWS:

IN ANY AREA WHERE THE NON-TYPICAL AREA IS LESS THAN ABOUT 20% OF THE TOTAL SURFACE OF THE TANK, INCLUDE THE WALL WASHING WITH THOSE FROM THE REST OF THE TANK.

WHEN THE NON-TYPICAL AREA EXCEEDS 20% OF THE TANK SURFACE AREA, KEEP WALL WASHINGS FROM THESE AREAS IN A SEPARATE BOTTLE AND PERFORM SEPARATE ANALYSIS.

TANK BOTTOMS OFTEN DO NOT REQUIRE WASH TESTING. HOWEVER, IF WASH TESTING IS REQUIRED, USE BLOTTER METHOD OR FILTER METHOD.

FUNNEL METHOD:

POT ON PLASTIC GLOVES PRIOR TO STARTING TEST; RINSE WASH BOTTLE, FUNNEL, AND SAMPLE BOTTLE WITH A SMALL AMOUNT OF WASHING LIQUID; PLACE THE SPOUT OF THE FUNNEL INTO THE SAMPLE BOTTLE AND HOLD THE FLAT SIDE OF THE FUNNEL FIRMLY AGAINST THE SURFACE TO BE TESTED (CAUTION: TO AVOID POSSIBLE CONTAMINATION OF SAMPLES WITH SUSPENDED MATTER, CARE MUST BE TAKEN NOT TO SCRAPE ZINC TANK COATINGS WITH THE EDGE OF THE FUNNEL); USING THE WASH BOTTLE, SPRAY A STEADY STREAM OF THE WASHING LIQUID ON THE SURFACE OF THE TANK WALL, ABOUT 3 FEET ABOVE THE FUNNEL, WITH THE WASH BOTTLE HELD ABOUT 18 INCHES AWAY FROM THE WALL. ALLOW THE WASH LIQUID TO RUN DOWN THE WALL INTO DE FUNNEL AND INTO THE SAMPLE BOTTLE; CONTINUE SPRAYING UNTIL ABOUT 50 ML OF WASH LIQUID HAS BEEN USED; REPEAT THE STEPS UNTIL A SUFFICIENT QUANTITY OF WALL WASHING LIQUID HAS BEEN RECEIVED INTO THE SAMPLE BOTTLE FRO THE ENTIRE TANK. SAMPLES MUST ALSO BE TAKEN FROM HORIZONTAL PIPELINES, BAFFLES, DIVIDERS AND SUPERSTRUCTURES, RINSE THE INSIDE OF THE BOTTLE CAP WITH A SMALL AMOUNT OF WASH LIQUID AND PLACED SECURELY ONTO THE BOTTLE; PREPARE A BLANK SAMPLE; TAG EACH WALL WASH SAMPLE AND THE BLANK SAMPLE IMMEDIATELY TO AVOID LOSING THE IDENTITY OF THE SAMPLES; SUBMIT TO THE LAB FOR REQUIRED ANALYSIS; WALL WASH REPORTS SHOULD SPECIFY WHERE EACH WASH SAMPLE WAS TAKEN IN THE TANK.

AND REMEMBER THE MOST PRINCIPAL THING "NEVER ENTER ANY TANK W/O HAVING RECEIVED CONFINED SPACE ENTRY TRAINING.

SEE YOU!!!