1、Designation: C1129 17Standard Practice forEstimation of Heat Savings by Adding Thermal Insulation toBare Valves and Flanges1This standard is issued under the fixed designation C1129; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 The mathematical methods included in this practiceprovide a calculational procedure for estimating heat lo
3、ss orheat savings when thermal insulation is added to bare valvesand flanges.1.2 Questions of applicability to real systems should beresolved by qualified personnel familiar with insulation sys-tems design and analysis.1.3 Estimated accuracy is limited by the following:1.3.1 The range and quality of
4、 the physical property data forthe insulation materials and system,1.3.2 The accuracy of the methodology used in calculationof the bare valve and insulation surface areas, and the qualityof workmanship, fabrication, and installation.1.4 This procedure is considered applicable both forconventional-ty
5、pe insulation systems and for removable/reuseable covers. In both cases, for purposes of heat transfercalculations, the insulation system is assumed to be homog-enous.1.5 This practice does not intend to establish the criteriarequired in the design of the equipment over which thermalinsulation is us
6、ed, nor does this practice establish or recom-mend the applicability of thermal insulation over all surfaces.1.6 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are
7、not considered standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prio
8、r to use.2. Referenced Documents2.1 ASTM Standards:2C168 Terminology Relating to Thermal InsulationC450 Practice for Fabrication of Thermal Insulating FittingCovers for NPS Piping, and Vessel LaggingC680 Practice for Estimate of the Heat Gain or Loss and theSurface Temperatures of Insulated Flat, Cy
9、lindrical, andSpherical Systems by Use of Computer ProgramsC1695 Specification for Fabrication of Flexible Removableand Reusable Blanket Insulation for Hot Service2.2 ASTM Adjuncts:3ADJC0450A Recommended Dimensional Standards forFabrication of Thermal Insulating Fitting Covers for NPSPiping and Vess
10、el Lagging2.3 American National Standards Institute Standard:ANSI B16.5 Fittings, Flanges, and Valves43. Terminology3.1 DefinitionsFor definitions of terms used in thispractice, refer to Terminology C168.3.2 Symbols:1This practice is under the jurisdiction of ASTM Committee C16 on ThermalInsulation
11、and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition approved March 1, 2017. Published March 2017. Originallyapproved in 1989. Last previous edition approved in 2012 as C1129 12. DOI:10.1520/C1129-17.2For referenced ASTM standards, visit the ASTM website, www
12、.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from ASTM International Headquarters. Order Adjunct No.ADJADJC0450A. Original adjunct produced in 1976. Adjun
13、ct last revised in 2002.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was deve
14、loped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.1 The followin
15、g symbols are used in the development ofthe equations for this practice. Other symbols will be intro-duced and defined in the detailed description of the develop-ment. See Fig. 1 and Fig. 2.AB= outer surface area of the bare valve or flange (does notinclude the wheel and stem of the valve), ft2(m2).
16、AI= surface area of the insulation cover over the valve orflange, ft2(m2).C = distance from the center-line axis of the pipe (to whichthe valve is attached) to the uppermost position of thevalve that is to be insulated (recommended to bebelow the gland seal), ft (m).DF= the valve flange and the bonn
17、et flange outer diameter(assumed equal), ft (m).DP= the actual diameter of the pipe, ft (m).LV= overall length of the valve, flange to flange, ft (m).T = thickness of the valve flange and of the bonnet flange,ft (m).qB= time rate of heat loss per unit area from the bare valveor flange surface, Btu/h
18、ft2(W/m2).qI= time rate of heat loss per unit area from the insulationsurface, Btu/hft2)(W/m2).QB= time rate of heat loss from the bare valve or flangesurface, Btu/h (W).QI= time rate of heat loss from the insulated surface, Btu/h(W).4. Summary of Practice4.1 The procedures for estimating heat loss
19、used in thispractice are based upon standard steady-state heat transfertheory as outlined in Practice C680 (or programs conforming toit such as 3E Plus5). Practice C680 and 3E plus are used toestimate the heat loss per unit surface area for the particularconditions and for all configurations, both b
20、are and insulated.4.2 The procedures for estimating surface areas used in thispractice are based on standard geometric logic: for a bare valveor flange, the contours of the metal surface are considered. Foran insulated valve or flange, the fabricated shape of the finishedinsulation system is conside
21、red.4.3 Data Input:4.3.1 Total bare surface area and total insulation surfacearea of the valve or flange,4.3.2 Service and ambient temperatures,4.3.3 Wind speed,4.3.4 Surface emittance values4.3.5 Insulation thickness and type, and4.3.6 Number of service hours per year.4.4 System DescriptionInsulati
22、on thickness, insulationtype, bare valve or flange surface emittance, insulation surfaceemittance.4.5 AnalysisOnce input data is entered, the programcalculates the surface coefficients (if not entered directly), theinsulation resistance, the bare metal heat loss per unit area, andthe insulation surf
23、ace heat loss per unit area. The rate of heatloss per unit area is computed by Practice C680 for theappropriate diameter. For bare gate valves, the particularsurface area can be taken from a look-up table. Table 1 andTable 2 give these areas for typical (ANSI Class 150, 300, 600,and 900) flanged gat
24、e valves and flanges. If these valves are notconsidered sufficiently accurate for the particular valves orflanges being considered, those areas can be calculated usingEq 1 (see Fig. 1) for bare flanges and Eq 2 (see Fig. 2) for baregate valves. Similar equations can be developed for other typesof va
25、lves and flanges. For the insulation on the valves and theflanges, the outer surface area can be obtained either fromTable 3 and Table 4 for insulation thickness up to 4 in. or fromthe insulation fabricator or contractor.5. Significance and Use5.1 Manufacturers of thermal insulation for valves typic
26、allyexpress the performance of their products in charts and tablesshowing heat loss per valve. These data are presented for bothbare and insulated valves of different pipe sizes, ANSI classes,insulation types, insulation thicknesses, and service tempera-tures.Additional information on effects of win
27、d velocity, jacketemittance, bare valve emittance, and ambient conditions arealso required to properly select an insulation system. Due to theinfinite combination of pipe sizes, ANSI classes, insulationtypes and thicknesses, service temperatures, insulation covergeometries, surface emittance values,
28、 and ambient conditions,it is not possible to publish data for each possible case.5Available from the North American Insulation Manufacturers Association for afree download. http/:www.pipeinsulation.org.FIG. 1 Equation 1 for a for the Surface Area of Bare Valve, ABV=DP(LV+2LF+(C DP/2)6T)+1.5(DF2 DP2
29、)+6DFT (Ref.3)FIG. 2 Equation 2 for the surface area of a Bare Flange, ABFDP2LF+(DF2DP2)/2+2DFTC1129 1725.2 Users of thermal insulation for piping systems facedwith the problem of designing large systems of insulatedpiping, encounter substantial engineering costs to obtain therequired thermal inform
30、ation. This cost can be substantiallyreduced by both the use of accurate engineering data tables, orby the use of available computer analysis tools, or both.5.3 The use of this practice by the manufacturer, contractor,and users of thermal insulation for valves and flanges willprovide standardized en
31、gineering data of sufficient accuracyand consistency for predicting the savings in heating energyuse by insulating bare valves and flanges.5.4 Computers are now readily available to most producersand consumers of thermal insulation to permit use of thispractice.5.5 The computer program in Practice C
32、680 has beendeveloped to calculate the heat loss per unit length, or per unitsurface area, of both bare and insulated pipe. With values forbare valve or flange surface areas, heat loss can be estimated.By estimating the outer insulation surface area from aninsulation manufacturers or contractors dra
33、wings, the heatloss from the insulation surface can likewise be calculated bytaking the product of heat loss per unit area (from programsconforming to Practice C680) and the valve or flange insulationsurface area.The area of the uninsulated surfaces also will needto be considered.5.6 The use of this
34、 practice requires that the valve or flangeinsulation system meets either Specification C1695 forremoveable/reuseable or the Adjunct to Practice C4503forinsulation fabricated from rigid board and pipe insulation.6. Calculation6.1 This calculation of heat gain or loss requires thefollowing:6.1.1 The
35、thermal insulation shall be assumed to be homog-enous as outlined by the definition of thermal conductivity inTerminology C168.6.1.2 The valve or flange size and operating temperatureshall be known.6.1.3 The insulation thickness shall be known.6.1.4 Values of wind speed and surface emittance shall b
36、eavailable to estimate the surface coefficients for both the baresurface and for the insulation.6.1.5 The surface temperature in each case shall be assumedto be uniform.6.1.6 The bare surface dimensions or area shall be known.6.1.7 The outer surface area of the insulation cover can beestimated from
37、drawings or field measurements.6.1.8 Practice C680 or other comparable methodology shallbe used to estimate the heat loss from both bare and insulatedsurfaces.TABLE 1 Calculated Surface Areas of Bare Valves using Eq 1 (Ref3)ANSI ClassNPS, in.150 300 600 900ft2(m2)ft2(m2)ft2(m2)ft2(m2)2 2.21 (0.205)
38、2.94 (0.273) 2.94 (0.273) 5.20 (0.483)212 2.97 (0.276) 3.51 (0.326) 3.91 (0.363) 6.60 (0.613)3 3.37 (0.313) 4.39 (0.408) 4.69 (0.436) 6.50 (0.604)4 4.68 (0.435) 6.06 (0.563) 7.64 (0.710) 9.37 (0.870)6 7.03 (0.653) 9.71 (0.902) 13.03 (1.210) 15.80 (1.468)8 10.30 (0.957) 13.50 (1.254) 18.40 (1.709) 23
39、.80 (2.211)10 13.80 (1.284) 18.00 (1.672) 26.50 (2.462) 32.10 (2.982)12 16.10 (1.496) 24.10 (2.239) 31.90 (2.964) 41.90 (3.893)14 22.80 (2.118) 32.50 (3.019) 39.70 (3.688) 48.20 (4.978)16 27.60 (2.564) 39.30 (3.651) 50.50 (4.691) 57.00 (5.295)18 31.70 (2.945) 49.40 (4.589) 59.80 (5.555) 69.70 (6.475
40、)20 37.70 (3.502) 59.10 (5.490) 71.30 (6.624) 24 49.10 (4.561) 83.50 (7.757) 95.10 (8.835) 30 72.20 (6.707) 123.30 (11.46) 141.70 (13.6) 36 107.30 (9.968) 164.00 (15.24) 199.00 (18.49) TABLE 2 Calculated Flange Pair Surface Areas using Eq 2Bare surface areas in square feet (square meters) for ANSI C
41、lasses 150, 300, 600, and 900NPS, in.150 300 600 900ft2(m2)ft2(m2)ft2(m2)ft2(m2)2 0.71 0.066 0.84 0.078 0.88 0.081 1.54 0.1433 1.06 0.099 1.32 0.122 1.36 0.127 1.85 0.1724 1.44 0.133 1.83 0.170 2.23 0.208 2.64 0.2456 2.04 0.190 2.72 0.252 3.60 0.334 4.37 0.4068 2.92 0.271 3.74 0.348 4.89 0.454 6.40
42、0.59510 3.68 0.342 4.80 0.446 6.93 0.643 8.47 0.78712 5.01 0.465 6.34 0.589 7.97 0.740 10.43 0.96914 6.15 0.571 7.90 0.734 9.16 0.851 11.59 1.07716 7.19 0.668 9.25 0.859 11.49 1.067 13.34 1.23920 9.40 0.873 12.50 1.161 15.18 1.411 19.12 1.77624 11.82 1.099 16.23 1.507 19.30 1.793 28.18 2.618C1129 17
43、36.2 Estimation of Rate of Heat Loss from the Bare SurfaceSince Practice C680 needs to perform iterations in calculatingheat flow across an insulation surface, an uninsulated surfacemust be simulated. To do this, select a thin insulation (with athickness of 0.02 in. (0.5 mm) and a thermal curve givi
44、ng ahigh thermal conductivity. It is recommended that Type 1 beselected for which the following constants are assigned: a =10Btuin.hft2F (1.44 W/mc), b = 0, and c = 0. 3E Plus has thecapability of calculating heat loss from bare surfaces so thisstep is unnecessary.6.2.1 Run Practice C680 or 3E Plus
45、for either a horizontal ora vertical pipe of the appropriate diameter, inputing theambient air temperature, wind speed, and bare valve surfaceemittance. Unless information is available for estimating thebare valve surface emittance, it is suggested that a value of 0.9be selected. Select output in un
46、its of heat loss per unit surfacearea. This value of heat loss per unit bare surface area isdesignated qB.6.3 Use of Practice C680 for the Insulated Valve orFlangeSince Practice C680 is designed to calculate heat lossfor insulated flat surfaces and for pipes, it is necessary to treatthe insulated va
47、lve as an insulated pipe. It is recommended thatthe diameter of the pipe, to which the valve fits, or the diameterof the flanges be selected for the calculation. Input the sameambient air temperature and wind speed as in 6.1 and estimatethe insulation surface emittance. For a removable insulationcov
48、er, this would be the emittance of the fabric or metal jacket.For conventional insulation, this is either the emittance of thatTABLE 3 Calculated Insulated Gate Valve Surface AreasTable 3A - 150 psi gate valves - insulated Surface Area, sf (sm) for four different insulation thicknessesNPS, in. 1 in.
49、 25 mm 2 in. 51 mm 3 in. 76 mm 4 in. 102 mm2 4.21 0.392 4.64 0.43 6.31 0.59 8.25 0.773 5.24 0.487 5.73 0.53 7.30 0.68 9.30 0.864 7.15 0.664 7.72 0.72 8.60 0.80 10.60 0.996 9.67 0.898 10.29 0.96 11.70 1.09 14.18 1.328 12.49 1.160 12.29 1.14 15.89 1.48 17.26 1.6010 15.03 1.396 15.85 1.47 17.41 1.62 19.99 1.8612 20.80 1.932 21.58 2.01 23.39 2.17 25.50 2.3714 24.50 2.276 25.27 2.35 27.29 2.54 29.33 2.7216 33.27 3.091 34.30 3.19 36.64 3.40 39.07 3.6320 38.66 3.592 39.63 3.68 41.98 3.90 48.01 4.4624 45.98 4.272 46.97 4.36 49.50 4.60 52.12 4.84Table 3B - 300
