API 575 Practice Questions and Answers correct

API 575 Practice Questions and Answers correct Who may use API RP 575? Anyone desiring to use API RP 575 may do so. API RP 575 covers: maintenance and inspection of atmosphere and low-pressure storage tanks. The generic meaning for atmosperic pressure is up to but not exceeding _______ ibf/in2 gage pressure. 2.5 The exterior surface of the tank bottom is known as the : bottom- side. When describing the amount of product the tank can hold, it is referred to as: shell capacity The pressure on the surface of a confined liquid caused by the vapors of that liquid is known as: vapor pressure A device that protects atmospheric storage tanks by maintaining the pressure difference between the tank vapor space and the outside atmosphere to just a few ounces per square inch is called : a pressure vacuum vent. The most common type of atmospheric storage tank is the fixed : cone-roof tank. An older style of a floating roof has only a single deck without pontoons. It has no reserve buoyancy and is susceptible to sinking in service. This type of floating roof is known as a: pan type. Fixed cone-roof tanks may typically be up to _______ in diameter and _________in height. 300 feet,64 feet Fixed cone - roof tank roofs ( diameter greater than 60 feet) are usually supported by: internal structural members The purpose of a geodesic dome is to: reduce product vapor loss or to eliminate the need to drain rainwater from the roof . A tank with an annular- pontoon floating roof that has a geodesic dome is considered to be : an internal floating roof tank. A low pressure storage tank operates between: 2.5 and 15 ibf/15 2 Reducing the incidence of leaking petroleum storage tanks is a priority goal for the : petroleum industry What condition poses an immediate hazard for a petroleum storage tank? holes in either the liquid or vapor space Atmospheric storage tanks are generally inspected to determine the: physical condition and rate of deterioration The prime cause of deterioration of steel storage tanks is: corrosion If you find cinders presents in the pad of a tank,which of the following would you suspect? it is a possible source of corrosion if sulfur compounds and moisture are present. During the inspection of a tank, a section of the bottom is removed .Several globs of clay are found in the pad. Which of the following would you suspect ? pitting corrosion could exist at each point of contract (electrolytic corrosion) A tank that is supported above grade on a ringwall has its bottom exposed to elements .As an inspector, what would you do to prevent possible bottom corrosion? The ringwall to tank area should be sealed to prevent moisture accumulation & corrosion . During an external inspection of a tank, the inspector notices that the soil is at or just above the grade line of the tank on the south side . What should he do? Require removal of soil & check the tank shell in the area for corrosion . An atmospheric storage tank in a humid environment is located adjacent to a series of heaters that burn high sulfur fuel gas.The prevailing winds cause the heater gases to contact the tank often.What type of problem would you suspect? Atmospheric corrosion-damage to coating . The occurrence of internal corrosion of a storage tank depends on the ________of the tank and the _______of the construction. contents ,materials Internal corrosion of an atmospheric storage tank in the vapor zone is usually caused by: hydrogen sulfide vapor,water vapor , or oxygen , or a combination of all three. Internal corrosion of an atmospheric storage tank in the area covered by stored liquid , the corrosion is most commonly caused by: acid salts, hydrogen sulfide , or other sulfur compounds. A horizontal AST is inspected externally . The tank is supported on three saddle type supports. Where would you suspect significant corrosion to occur ? In the saddle to tank interface Where is one of the most likely points and one of the potentially most critical points for a crack to occur in a large storage tank? The lower shell to sketch plate or annular plate weld. What type of failure is characterized by sudden loss of tank contents and extensive damage to equipment in the vicinity of the tank( little or no loss of metal thickness throughtout the tank)? Brittle Fracture Settlement of a tank due to compaction or movement of soil under the tank foundation can cause: mechanical deterioration What would be the expected problem encountered with a water draw off on a floating roof tank if an internal elbow or the internal pipe develops a leak ? The leak will allow product to escape or possibly water to leak into the product. If a pan type (single deck)floating roof has a plugged water draw off, what could be the most likely consequence ? The roof could sink during or after a rain. The purpose of similar service methodology for estimation of tank corrosion rates is: establish how long a tank in similar service can operate without leaking due to corrosion . What API document provides requirements for inspection frequency? API Std 653 The application of___________procedures to set inspection intervals may results in longer orshorter inspection intervals. risk based inspection Internal inspections should be scheduled, when possible, when the tank is out of service due to: operational reasons An AST was built. and put in service 1990.The minimum thickness of the bottom course was 0.35 inch. The bottom course was constructed using a 0.5 inch thick plates. The tank was not inspected again until 2006. The thickness of the bottom course was measured and found to be 0.42 inch. Determine the corrosion rate and the calculated remaining life of the tank. 0.005"/yr and 14 years . An AST went into service in 2000. The bottom course was constructed using a 0.9375 inch thick plates The minimum required thickness of the tank 's bottom course was calculated to be 0.875" . The tank was recently inspected in 2011 and the actual thickness of the bottom course was measured to be 0.89 " . Determine calculated remaining life of the tank. 3.47 yrs An AST was place into service in 2000. It's bottom course original thickness was 1.00". It was recently UT'd 2010 and the bottom course thickness was found to be 0.92". What is the corrosion rate? 0.00727"/yr An AST was built in 2001 with an original thickness of 1.125" in it' s bottom course. It was recently UT'd in 2010 and the same course's thickness was 1.11". It's calculated t min is 0.999". What is it's remaining life(round to two decimal places ) ?? 66.46 yrs The chart in figure 32 in API RP 575 shows the hypothetical corrosion rate for the top course of an AST. When should the tank top course reach its limiting thickness? approximately August of 1976 What type of inspection provides another means of establishing suitability for continued service ? Risk based inspection Fitness-for-Service evaluation (FFS) deals primarily with the evaluation of _______that can affect the remaining service life of an AST. defects and flaws After all required permits are obtained for an internal inspection of a tank, what are the first checks an inspector makes prior to entering ? Make a visual inspection of overhead parts and roof before entering. Who should be informed when personnel are working on the inside of a tank ? Personnel working in the vicinity of the tank. External ladders and stairways of AST's should be examined carefully for corroded or broken parts. The condition of the ladder or stairway parts may be checked by visual inspection and by: sounding. An inspector finds a low area in a platform floor plate that holds water, what is the quickest solution to this problem? Drill a small drain hole in the area. AST foundations should be checked for: settlement with a surveyor's level. Name three ways to check for wooden supports for small tanks or wooden walkways etc. hammer,scraper,and ice pick The condition of anchor bolts can usually be determined by visual inspection. Name three other methods of assessing the condition of anchor bolts hammer test,remove nuts,and UT Grounding connections on tanks should be visually checked for corrosion at the point where they enter the earth and at the mechanical connection to the tank. If any doubt exists about the condition of the ground, its resistance can be checked. The total resistance from the tank to the earth should not exceed approximately_____________. 25 ohms Paint blisters (film coating blisters ) most often occur: on the roof and on side of the tank receiving the most sunlight. When checking an insulated tank,careful inspection should be made around all nozzles and around the saddles of horizontal tanks.A few samples may also be removed for checking. These samples should be taken from: the shaded side of the tank. Why should inspectors exercise great care when inspecting the roof of an insulated tank? The roof plates may not be strong enough to support the inspector. An inspector is checking the tank shell on the outside of a tank.He notices soil collected around the bottom of the shell. What should he do? Remove soil from the area and check for external corrosion. In obtaining shell measurements, special attention should be given to the upper______ of uncoated shells of floating roof tanks. A higher rate of corrosion may occur in this area because of exposure to corrosion from both sides . 2 feet Coatings may affect UT readings.What should be done? The examiner should compensate for them . If evidence of cracking is found on the weld of a wind girder to the tank shell,the inspector should throughly clean the area and check it with: MT or PT If caustic is stored in a tank , the tank should be checked for evidence of damage from: possible cracks caused by caustic embrittlement A storage tank is used to store a product that must be kept warm (150+ degrees F). The product has a high concentration of caustic and stress corrosion cracking is suspected because of caustic embrittlement .Where would you look for cracks ? Check around connections for the internal heating units or coils. While internally inspecting the shell of an atmospheric storage tank the inspector shines his flashlight approximately parallel with the shell surface . He notices shadows which he at first thinks are pits. When he checks closer, he finds that they are small blisters. What type of attack would cause the blisters? Hydrogen blistering Deformations on a tank shell may be measured by: Place a straight edge lengthwise against the vertical shell and measure the depth or height. A riveted or bolted tank should have a number of random selected rivets or bolts checked for tightness.How is this done? lightly tap rivet / bolt laterally & hold a finger against the opposite side in contact with the plate. If a fixed cone roof of a tank is suspected of being extremely thin, what precaution should an inspector take to facilitate his inspection( beside using safety belts with attachments )? Use planks ( or plywood sheeting ) to span at least two roof rafters . Why should you not hammer test the roof of a tank during an in- service inspection ? Scale may dislodge from the roof and contaminate the product in the tank. What occasionally plugs tank flame arrestors( and pressure vacuum valves)? Bees and mud daubers. Flame arresters should be opened and the screens or grids should be visually inspected for cleanliness and corrosion at what interval? The interval for inspection should be appropriate for each case. What are common problems found with pressure- vacuum vents and breather valves? plugging of the discharge side screen and build up of solids on the pallets Tunneling beneath a tank for external bottom inspection should be avoided because: use of UT, MFL, & robotic inspection provides better information w/o disturbing the foundation What size coupons (according to API RP 575) should be cut from an out-of-service tank to check for roof and rafter corrosion? 1 foot X 1 foot