Roof Air Rising Of An Ammonia Storage Tank At KPIC
Roof air rising of an ammonia storage tank at Kermanshah Petrochemical Industries Co. (KPIC) H.Akbari1, G.Khaneh zarin2, S.Gheasi3, M.Siahkamari4 1.inspection department of KPIC, h.akbari@kpic.ir, 2. Inspection department of KPIC, gh.khanehzarin@kpic.ir,3. Construction engineer of NDEC, S.Ghiasi@ndec.ir, 4. Construction engineer of KPIC, m.siahkamari@kpic.ir Abstract Kermanshah Petrochemical Industries Co. (KPIC) is constructing a new ammonia storage tank at Kermanshah, Iran. The new tank with capacity of 16,796 m3 has been designed according to API 620 ANNEX R. This tank has two shells (inside diameter r 38m, outside diameter 40 m, height 16,610 mm). Present report explains procedure of roof air rising of the mentioned tank that was conducted by KPIC, NDEC (Namavaran Delvar Engineering Co.) and HEDCO (Hampa Energy Engineering and Design Co) (height of air rising 15,350 mm). After assembling the roof on the outer tank bottom, it was led to final position using air rising method. Air rising procedure allows most of the roof erection work to be constructed at a low elevation, resulting in a high quality roof as well as limiting personnel exposure to dangerous heights. Assembling procedure of the roof and suspended deck After installation of the outer bottom plate simultaneously with the installation of the outer shell, deck plates installed on bottom plates and after checking their dimension, welding procedure initiated. After completion of the deck assembly and welding, central ring was assembled on a temporary column and by means of temporary support around the internal circumference of the shell, ring girder and all of rafters and gusset plates were erected and welded. Afterwards, roof plateβs installation commenced according to sketch plate erection and then roof plates welded to each other. At the next step, hanger clips on the rafter, girder and stiffener of deck, were installed and finally suspended deck hanger was erected (see fig.1). Also six nozzles were cut and then welded on roof plates on proper positions.
Fig1. Installation of rafter structures and roof plate Necessary accessories for air rising In order to perform air rising correctly, some preliminaries shall be implemented comprising installation and welding of compression bar at top of the last shell course, installation of levelling cables, sealing system, preparing and installation of manometers, installation of blowers and etc. Fig 2 shows a schematic view of all necessary items that shall be supplied prior to starting the operation.
Fig2. A schematic view of all accessories for air rising. Leveling cables After installation, fit-up and welding of the compression bars, sixteen temporary supporting arms were erected on compression bar for installation of levelling cables. Cable levelling system was installed to assist roof stabilization as it travelled from bottom of the tank to its final top position. The end of levelling cables were connected to supporting arms and annular plates of outer bottom plates by drilling the roof plate (see fig 3). Each wire pulled toward the bottom plate (500 mm away from the shell of the tank) and stretched by each turnbuckle until the tension reached to 1,000 kgf, the tension load was checked by using resonant frequency method, according to the following formula: πΊπΊ F 12L ππ ( ) 29 times per 10 second π·π· Where: F frequency of vibration L free length of leveling wire (16m) S pre-tension load (1000 Kgf) G gravity acceleration (9.8 m/s2) D wire mass (1.1 kg/m)
Temporary supporting arm Leveling cable Two cables from two opposite temporary lugs End connection to annular plate A view of arrangement of leveling cables at center of the tank Fig 3. A schematic view of leveling cables.
Arrangement of air blowers The necessary air for operation was supplied by two blowers that were erected on temporary plate of the shell. One of these blowers was main and the second was standby. Standby blower operated by one generator separately (see fig 4). Fig 4. Installation of blowers on temporary shell. The capacity of these blowers was 500 ππ3 ππππππ at 350 Necessary air rate also calculated as below: Q (ππ ππππ π΄π΄π΄π΄ . D2 4 V) Q' D Diameter of the tank V Rising speed Max 0.15 m/min Q' Percent of leakage volume from the sealed portion 30% (Based on experiences) Q { ππ (402/4)} 0.15 30% 245 m3/min The required air rising pressure also was calculated simply by estimation of weight of the roof, deck and all of rafters, girder and their accessories that was about 280 ton. Hence, the necessary pressure for air rising could be calculated as below: P W/ ( ππ.D2/4) 1.1 280 1000 9.807 / (3.1415 402/4) 1.1 2403 pa Based on the capacity of the blowers, rising velocity of the roof was equal to 140 mm 150 mm. Therefore, the estimated time to reach the final position of the roof was calculated as follows:
Required time βππππππβπ‘π‘ ππππ ππππππππππππ οΏ½οΏ½π£π£π£ ππππ ππππππ ππππππππππππ 15,350/150 102 Minutes Sealing system arrangement To prevent air leakage during air rising process, all the gaps needed be sealed. Thus, a sealing system was designed to prevent escaping of the air between the roof and the shell. In addition, all of positions that were prone the air leakage were identified and sealed using adhesive tape or plaster. To seal the space between the roof and shell, temporary bent plates were designed and fastened to the end of roof plates. Then, temporary seals consisting of polyethylene sheets and pre-assembled wire mesh were erected on temporary bent plates using nuts and bolts (see fig 5). Fig 5. A schematic view of sealing system between shell and roof. Arrangement of measuring equipment A measuring system for recording the levelness of the roof structure was installed at four positions using four meter tapes along the shell (0 , 90 , 180 , 270 ) to control the levelness. All data were measured at the same time. For this purpose, four persons were present on deck plates during lifting the roof. These persons had separate walkie-talkies. Commander should receive data from each person every 5 minutes to record the roof slope. During lifting the roof, maximum tolerance for levelness of the roof was five mm. finally the roof raised successfully without any problem.
Installation a meter to control of levelness of the deck along the shell plate at four points Fig 6. Arrangement of meters along the shell. Arrangement of manometers The inside pressure of the tank should be checked during air rising. So three manometers were installed around the tank. The first, near the blowers, the second, on the roof and the third, on the last course of the shell. Three persons checked the inside pressure of the tank using mentioned manometers. According to calculations, inside pressure of the tank was kept at 20 mm H2O. 20 mm H2O
Fig7. A view of manometer that installed near the blower. Preparation for roof fixing work Necessary tools were arranged for the angular alignment of the roof, such as levers, jacks, jigs, tools and welding equipment around the top of roof for fit-up and welding of roof to compression bar. In addition, ten welders were arranged around the compression bar for fixing and welding the roof to compression bar. Pre-air rising Prior to actual rising operation, the pre-air rising of the roof was performed up to 40 cm, Fig 8, to check the following conditions: Deck 40 cm BOTTOM PLATE Fig 8. Pre-air rising the roof Floating pressure and maintaining pressure. Opening ratio of blower damper and current value. Slope of the roof, seal gap between temporary roof and outer shell and movement of the roof. Sealing condition between roof and shell. Preparation of workers. Checking the roof balance. In case of witnessing any imbalance, correction was performed by applying some weight on the suspended deck. (Maximum tolerance for roof imbalance was 50 mm). The deck plate annular were used to balance the roof of the tank. Ensuring that the roof is in its stable state, and also checking the state of sealing material after the roof was put down on the temporary roof support. Preβair rising performed successfully, air leakage was identified in some areas and were sealed accordingly with adhesive tape and plaster (see fig 9).
Roof plate Sealing the temporary plate with plaster Fig 9. Sealing some positions with plaster Roof Air rising Air rising of the roof started and continued as per below procedure: Starting two blowers simultaneously. Checking the levelness of the roof as it started to rise. Slowing down the rising speed at the top 1000 mm of the height. Rising stopped at the top 200 mm of the height and rotation, alignment and also the centre of the roof were checked using meter tapes in random points. Rising continued slowly until the roof touched the compression bar. Foremen checked the entire compression bar along the circumference before starting any pinning of the roof. After reaching to final position, the roof was fixed by using lugs and channels that already had been arranged around the tank. Then, compression bar connected to the roof by applying tack welds.
Fig 10. Fixing the roof and compression bar After tack-welding the roof to compression bar and without decreasing the internal pressure, the circumferential welding process started. 10 cm on the area of T joints were left un-welded due to huge air leakage. At the final step, the blowers were shut-down and those remaining un-welded areas were welded entirely. The fixing jigs, seal and other air rising equipment were removed from the roof plate. The holes for the balancing cables on the roof were covered by using the same type plate as the roof and with the dimension of 100 100 10 mm. Fig 11 shows some different views of the roof during the air rising.
Fig 11. Different steps of the roof air-rising
Safety considerations prior to air rising Before initiation of air rising, all necessary items were checked as below: Checking all the tools and equipment for air rising Generators and air blower inspected prior to air rising process. Because of limitation caused by weather condition at rainy days and also maximum wind speed ππ at 14 , weather condition were checked several days before. π π Checking and confirming that all levelling cables were fully installed and connected. Checking that the temporary seals for tank were fully installed and taped. Ensuring that equal flow rate could be achieved for each blower.
o. (KPIC) is constructing a new ammonia storage tank at Kermanshah, Iran. The new tank with capacity of 16,796 m. 3. has been designed according to API 620 ANNEX R. This tank has two shells (inside diameter r 38m, outside diameter 40 m, height 16,610 mm). Present report explains procedure of roof air rising of th e mentioned tank
A low slope roof or flat roof has four parts such as roof deck, vapour retarder, insulation and roof membrane. The combination of these parts is known as roof assembly. 3.1 Roof Deck An entire roof system is held up by a roof deck. This is the base of roof assembly. Roo
1.1 Sloped Roof Eave 1.2 Sloped Roof Gable 1.3 Ridge Vent Detail 1.4 Roof Penetration 1.5 Sloped Roof at Chimney - Side 1.6 Cricket at Chimney 1.7 Chimney at Sloped Roof - 3D View 1.8 Roof Overhang at Exterior Wall 1.9 Sloped Roof at Dormer - Head Wall 1.10 Sloped Roof at Dormer - Side Wall 1.11 Valley Detail FLASHINGS 2.1 Roof Diverter .
Flat Roof Board 200 0.034 90 200 Flat Roof Board 250 0.034 100 250 Flat Roof Board 300 0.033 120 300 Flat Roof Board 350 0.033 140 350 Flat Roof Board 400 0.033 160 400 Flat Roof Board 500 0.033 190 500 Flat Roof Board HP 150 0.031 70 150 Example Point Load Calculation Air Handling Unit -2000kg Square Spacer Pads -300 x 300mm x 4No
of the green roof components. The distributions of the conventional roof and green roof were summed to obtain the total cost of installation for a new green roof with a new conventional roof. The mean difference between the cost of the green roof and the conventional roof is deο¬ned
38. roof access ladder with lockable roof scuttle - see reflected ceiling plan and roof plan for additional information - typ. 39. roof drain and overflow roof drain. connect roof drain to underground storm drain pipe per civil drawings, overflow roof drain to daylight. overflow roof drain to have cast bronz
Roof TilerβsWage RM 80.00/hours Cost Of Roof Tiles Per Hour RM 10.00 NosOf Roof Tiles Fixed Per Person Per Hour 95 pcs Cost Of Labour Per Piece Of Roof Tile RM 10.00 95 pcs RM 0.11 NosOf Roof Tiles Per M2 9.83 pcs Cost Of Labour Per Roof Square Of Roof Tiles 9.83pcs x RM 0.11 10
Roof Layout Plan. Roof Plan A roof plan is commonly drawn to a scale of 1/8 inch per foot or 1/16 inch per foot. A roof plan shows the shape of the roof, as well as roofing materials, underlayment and location of vents. Roof Plan A roof framing plan shows size and direction of the
CONTENTS 2 Introduction 4 Rising Stars in Artist Management 8 Rising Stars in Orchestra Leadership 13 Rising Stars in Presenting 18 Rising Stars in Communications/Public Affairs 22 Adventuresome Programming. Rising Stars in Education 28 Rising Stars in Radio and Recording 32
