Document 99J66Oe5kBDmnkzOozMrM0Jn3

SRafl.:-:: aslfsilfm BfcSiMaSafc^a^aBaglgjnMnaMi^graMIM^ INSULATION WEATHERPROOF SEALING PROCEDURE PROJECT 1295 The original Adipic Acid Project (9098) had equipment pieces insulated and storediover twelve (12) months before being placed into service. For various reasons rainwater leaked into the insulation systems, which deteriorated the insulation and corroded the metal jackets. The current project (1295) has similar storage time; however, we are following this pro cedure to insure quality workmanship and to prevent costly rework. The major differences between the two systems are as follows; 1. Project 1295 is using calcium silicate insulation instead of unibestos. Calcium silicate insulation has greater resistance to water. Also a mixture of rainwater and calcium sili cate will not form as corrosive a salt that will corrode the metal jacket as unibestos. 2. Single and double "Z" _laps are being employed on Project 1295 instead of the single laps used on Project 9098. These "Z" laps are orientated to form a water-tight seal even when the equipment is stored in the horizontal position. DU 015229 DUP 0827180 PROCEDURE PROJECT 1295 PAGE TWO APRIL 15, 1975 3. Stainless steel bands are being installed on 12" centers; instead of 18" centers as used on the old project. This provides.a tighter joint; therefore, the use of sheetmetal screws can be kept to a minimum. The band tags are installed using 1/8" pop rivets instead of sheetmetal screws. 4. Insulation joints are being sealed with a double layer of weatherproof sealant and reinforced with a layer of. fiberglass. The old method used one layer of foamseal with no reinforcing. Foster GPM and Foster Elastalor sealants; which are now being used, are better sealants than the old foamseal. Foamseals become brittle and crack after six (6) months of service while the Foster sealants do not. 5. The large, field-erected tanks are sealed at the bottom with a 2" thick foamglass insulation block. This keeps moisture from seeping up through the base. 6. The jacket material presently used is an epoxy-coated, (both sides) 16 mill, aluminum metal, with a paper moisture barrier glued to the inside, employing a waterproof, 3 mill, layer of polyethylene. The old jacket material was not epoxy-coated on the inside and the paper moisture barrier was glued to the inside with a water-soluble glue. 7. Inspections are being made every two (2) weeks to ensure that these joints are tight and the caulking has not cracked on any of the insulated pieces of equipment. DUP 0827181 DU 015230 PROCEDURE PROJECT 1295 = - PAGE THREE - APRIL 15, 1975 Outlined below are the procedures to be followed for insulating the three major types of vessels for weather protection. I. SEALING INSULATION ON SMALL VESSELS (REFER TO FIG. I) A. After the insulation block has been installed, joints at the reinforcing bands, etc. are caulked with a layer of white Foster GPM sealant and (Glassfab) reinforcing. B. The 3' or 4' wide metal jacket is then installed around the tank in bands. Three sections are required to make up a complete band. The first section installed is one with "z" laps on both ends. This section is orientated on the tank; as to provide a water-tight seal. The next sec tion is installed with a single "Z" lap. The last section is installed with open ends. Small stainless steel bands are then installed on 12" centers. This procedure is repeated until the entire tank is covered. C. The joints are then caulked a second time with Foster Elastalor Sealant #9544. D. The tank insulation is then inspected every two (2) weeks. II. SEALING INSULATION ON FIELD-ERECTED TANKS (REFER TO FIG.II) A. A 2" thick foamglass block is installed around the tank base to prevent moisture from seeping up into the calcium silicate block. B. After the block has been installed the metal jacket is then installed in bands around the tank. DUP 0827182 DU 015231 PROCEDURE PROJECT 1295 PAGE FOUR APRIL 15, 1975 (continued) Four sections are required to complete a band around the tank. Two sections with "Z" laps on both ends are installed 180 apart, and two sections with open ends are fitted between the "Z" laps. C. The insulation and inspection are the same as outlined in Procedure I. III. SEALING INSULATION ON COLUMNS (REFER TO FIG. Ill) A. The jacket is installed on the columns in the same manner as outlined in Procedure I. B. Sealing around the "T"-shaped stiffening rings is different. On top of the stiffening ring, block insulation is installed to completely fill the void between the ring and the column plate. This area is then caulked with Foster GPM seal ant and with glassfab reinforcing. The metal jacket is then installed over and around the flange on stiffening ring. (Refer to Sketch III for details). The joints are then caulked again with the Foster Elastalor Sealant. Underneath the stiffening rings the insulation is sealed in the same manner as outlined in Procedure I. The columns are then inspected every two (2) weeks. DUP 0827183 DU 015232 KisifciiaiggBjKf easiaaiiiJK.. eiIsb: mmmyaH DUP 0827184 -- E 1 cvaIi O N ------ FIG- I - PRE-INSUU-VESSELLAYING DOU/N DU 015233 DUP 0827185 FIG n - LARGE VERTICAL TANK DU 015234 DUP 0827186 infig, - t-bar stiffener ring DU 015235 A-D. $J)$6LE ~ S'7 TO: E.XHUCKINS [INHERING DEPARTMENT fVIERS BUILDING FROM: M. F. HENNESSEY, JR. Name VICTORIA Plant Appendix A CORROSION OF PIPING AND EQUIPMENT UNDER THERMAL INSULATION 1. How many failures caused by corrosion of metal from the outside have been observed on insulated piping or equipment? Include only instances where pipe or equipment had to be replaced or repaired because there was a leak or crack in the metal which originated from the outside under insulation. NUMBER OF FAILURES THAT OCCURRED Within a Year of Turnover Piping Equipment Tv - Unprimed Stainless Steel 3 More Than One Year After Turnover Piping Equicme: 4 3 2; Keeping water out of the insulation would prevent corrosion of carbon steel; however, more rigorous control techniques during and after application of insulation could be costly. Priming of all carbon steel would offer protection against corrosion prior to startup, but this protection would diminish with time after exposure to elevated temperature. Priming would be an added cost; however, it has been common practice to prime carbon steel equipment. In your judgment, do the problems which you have observed justify any of the following: a. Protective coating or priming for carbon steel pipe before insulating. Yes b. More rigorous control measures during application and to minimize inleakage of water (See Appendix C). Yes DUP 0827187 3. Other comments or observations related to this matter; include results of recent inspections? H. E. Huckins June 1976 See Attached Comments DU 015236 2- - Carbon Steel Equipment - Primer 1. NH3 Sphere - wrong type insulation - a water absorbing styrofoam - stayed wet. Insulation replaced - no corrosion. 2. 2 NH3 Storage Tanks - Diamine Area - Plate coil severely corroded and developed leaks (not primed). Vessel was primed but "Unibestos used on cold service - vessel stayed wet. Sandblasted, primed and reinsulated. Stainless Steel Piping (Replaced) 1. About 50 feet lO'Vpipe - NRD - 1st year 2. About 150 feet 2" to 4" pipe - NRD - 1st year 3. Stainless steel instruments lines - H2 - 1st year. Stainless Steel Equipment (Vessels painted with "Thermalox 70" prior to insulating.) 1. PAK Storage Tank - Op. 14 Wall 6-76 2. Adipic Acid Holdup Tank - Op.4 Well and FIoojh 2-75 3. RML Tank - Op. 15 Wall 3-75 M. F. Hennessey, Jr. Victoria Plant DU 015238