Document OyXQE3zKRg18n8bjkwkgyKvL

PLAINTIFF'S EXBmrr Mfg. Dept. Engr. Instruction SF**104 CHV-581 APPENDIX NO.III SAFETY INSTRUCTION SHEET - FIRED HEATERS ' FORM MFG. 600-3 ............. NO. SUBJECT DISCUSSION I to 31 Refer to Appendices I and II for the discussion. 32 TEST APPLIED NEW The tests applied new for both strength and leakage may be noted as those specified by the designing engineer and issued to the con struction forcer as the required tests. The strength test is governed by either (a) the cold test limitations of the terminal fittings or directly connected piping that can not be blinded off, or (b) by the stress being limited to 75# of the proportional limit of the material, i.e, the test pressure should not exceed (1.5) x (proportional limit) x (t)/O.D. The leakage test is usually between 2/3. of the strength test and a minimum of 1.5 times the cold equivalent of the safety valve'setting . . protecting the heater, . 33 LIMITED BY 34 BANK OR COIL Note the limitation for the specified test pressure as "tubes," "headers," "flanges," .etc. Give the location of the tubes and headers in the bank or coil as "convection," "radiant," "roof," "shock," etc. For the terminal fittings note as "inlet," "outlet," "crossover.," etc. 35 HEADER: TYPE The type of headers should be specifically designated where possible, for example "Key_____1900," etc. If type is no.t known designate by the general type as "mule ear," "breeck lock," "screw lock," etc. 36 DESIGN PRESSURE The operating pressure limit should be established as the maximum possible pressure that can be reached by any method of operation. The temperature should be the maximum for safe operation within the limitations of the equip- ment and material. 37 BASED ON Note the limiting features of the equipment at minimum thickness or other controling factor. The limitation may be the "tubes," "headers," "flange ratings," etc., with temperature limits restricted by "oxidation," "embrittlement," "graphitization," etc. CHEVBB _ 1? _ 0002699 Mfg. Dept. Engr. Instruction SF-104 NO*. SUBJECT 33 TEST PRESSURES 39 PRESSURE 40 TEMPERATURE FIRED HEATERS (Cont'd) DISCUSSION The routine test pressure for strength should - be as close as practicable to the Initial strength test, as these1 tests are applied-to test newly-rolled repair joints. A note should be added stating that the test pressure shall not exceed (l5l x (proportional limit) x (current minimum tube thickness)/o.D. The leakage test is a function of the strength as noted in "32" above, The pressure for calculating the minimum tube wall thickness should be taken as either of the following: (a) For low pressure-drop heaters, assume that the entire coil is protected by the safety valve on the top transfer line or on the vessel into which the furnace discharges, (b) For cracking, reforming, or similar heaters with appreciable coil pressure drop, take a different pressure for each bank or : section of the coil. These pressures are to be determined from the maximum inlet and outlet pressures and either the known or an assumed pressure drop through the coil. In assuming a pressure drop, remember that it will not be a ' straight line function of distance through the' coil, and this will be particularly true in a reformer or other heater where vaporization is appreciable, The temperatures used for calculating the minimum tube wall thickness should be the maximum allowable operating tube wall temperature. Different temperatures may be in dicated for radiant and convection tubes. Some judgment is required here on the part of the engineer, For example, if the fired heater is to operate with moderate outlet temperatures in the neighborhood of 7OO0F., it is usually a good idea to set the maximum temperature for carbon steel .tubes at about 100F. - 18 - CHEVBB 0002700 Mfg. Dept. Engr. Instruction SF-1G4 70. SUBJECT 41 MINIMUM THICKNESS 42 CORROSION ALLOWANCE FIRED HEATERS (Cont'd) DISCUSSION After establishing the pressure and'temperature, the minimum tube wall thickness shall be calculated according to the equation' tm = PD____ _ 2Sxl.33 where P Pressure, lbs. per square inch. D *= O.D., inches. S = Stress in lbs. per square inch for 1$ creep in 10,000 hours at the ma-x-tmum operating metal temperature. 1.33 = is a factor applied to get the effect of the two dimensional stress in the tube wall caused by internal pressure. It represents the ratio between two dimensional creep stress and that determined by an ordinary tensile specimen in one direction only, which is the value, appearing in the literature. The recommended values of creep stress are'given in the Richmond Materials Laboratory report of \ November 20, 1946 entitled "Recommended Values of Creep and Rupture Strength." The minimum tube wall thickness in the case of fired heaters subjected to high pressure tests may be determined by the routine test stress in the tube being limited to 75$ of the pro portional limit for the material. When the minimum thickness is so limited, the basis should be clearly stated, in the asterisk note- -- as it may be desirable to reduce test pressures ' at a later date to obtain maximum service life for the tubes. In the event the calculated minimum thickness is less than 0.10", the minimum shall be established arbitrarily at 0.10". The above apply except where tube thickness requirements are mandatory as for power boilers in which case- the requirements of the State of California Boiler Safety Orders and the ASME Boiler Code govern. The corrosion allowance can now be determined by subtracting the minimum thickness calculated from 1ie tube wall thickness supplied. - 19 - CHEV BB 0002701 DATA AND OPERATING LIMITS SHEET.- FIRED HEATERS EQUIPMENT DATA SERVICE. MFR____ TUBE NUMBER IHG DIAGRAM DRAWINGS_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ TEST APPLIED NEK: STRENGTH LIMITED BY__________________ J2. 33 TUBES: LOCATION, i.e. BANK OR COIL ORDER NO. ._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ MATERIAL . _________________ SPEC. A GRADE _ HUK3ER _______ O.O.-WALL, AY. OR MIN.-LGTH.. HEADERS 4 FITTINGS: LOCATION ORDER NO. '______ MANUFACTURER. TYPE_______ _ MAT* L-HEADERS 4 PUIGS_________ MAT'L-HOLOIHG MSIBERS A SCREWS. INLETS,OUTLETS & CROSSOVERS: LOCATION FLANGE SIZE 4 RATING_________ FLANGE FACING _ ___________________ CROSSOVER SIZE 4 HEIGHT. Jl 34 3V NO. .YEAR BUILT. EXT. HEATING SURFACE .SQ.FT. .Pl____ LEAKAGE_____ -.3? psi__ Eras j- . /OVALS ENG. DEPT. -- ----------- -- OPRfl DEPT. . OPERATING LIMITS (CONSULT DESIGNS ENGINEER BEFORE EXCEEDING THESE LIMITS) DESIGN PRES.: INLET 36. Pi. F., OUTLET. BASED ON _ _ _ _ _ _ _ _ _ _ _ _ 3L MAX.ALL0H.TU8E HALL. TEMP.___ PJSJ.TEiCTED BY SAFETY VALVE ON TEST PRESSURES: STRENGTH____ 15" 38 psi. LEAKAGE. KKWE3 Till CNN ESS OF TUBES AND HEADERS AT PRESL 4 METAL TFMP. GIVEN TU3ES' V PRES. TPIP. HEADERS 36 psi 1__ _ - S.Y. SET AT 38_______ _ psi. psi. PRES. TEMP, 4l 42 32- 4o DATE *4n based on: SAFETY PRECAUTIONS REFER TO GENERAL SAFETY INSTRUCTION SHEETS ME-5IC2 Sheets I, 2, 3, 6, 7, FOR NOTES OH HAZARDS OF EQUIPMENT FAIL URE, KITH RECOMMENDATIONS FOR THEIR AVOIDANCE AND FOR .INSPECTIONS AMD TESTS. NOTE SELOU ANY SPECIAL HAZARDS, RECGMrIENDAT IOHS, IHSPECTIOHS, OR TESTS THAT ARE IMPORTANT FOR THE ABOVE EQUI FfttNT:_____________________ !----------------------------------------------------------------------------------------------------- :----------------------- .______ _____ j?sa.__. "CHEVBB"0002702 Mfg. Dept. Engr. ' Instr.SS'-ldJiFigure 8 jr SAFETY INSTRUCTION SHEET FIREO HEATERS (fif'flr'rv ) -- *- - fn --- " -Tr-L *Hrwm (Plant I 20 DWG. HO. _ Sheet of r, rt it i; u 4 I