1、Designation:C112989(Reapproved 2008) Designation: C1129 12Standard 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 a
2、doption or, in the case of revision, 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 practice provide a calculat
3、ional procedure for estimating heat loss or heatsavings when thermal insulation is added to bare valves and flanges.1.2 Questions of applicability to real systems should be resolved by qualified personnel familiar with insulation systems designand analysis.1.3 Estimated accuracy is limited by the fo
4、llowing:1.3.1 The range and quality of the physical property data for the insulation materials and system,1.3.2 The accuracy of the methodology used in calculation of the bare valve and insulation surface areas, and 1.3.3Thethequality of workmanship, fabrication, and installation.1.4 This procedure
5、is considered applicable both for conventional-type insulation systems and for removable/reuseable covers.In both cases, for purposes of heat transfer calculations, the insulation system is assumed to be homogenous.1.5 This practice does not intend to establish the criteria required in the design of
6、 the equipment over which thermal insulationis used, nor does this practice establish or recommend the applicability of thermal insulation over all surfaces.1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI uni
7、ts that are provided for information only and are not considered standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine
8、 the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C168 Terminology Relating to Thermal InsulationC450 Practice for Fabrication of Thermal Insulating Fitting Covers for NPS Piping, and Vessel LaggingC680 Practice for Estimate of the Heat Gain or Loss
9、and the Surface Temperatures of Insulated Flat, Cylindrical, and SphericalSystems by Use of Computer ProgramsC1094Guide for Flexible Removable Insulation Covers 1695 Specification for Fabrication of Flexible Removable and ReusableBlanket Insulation for Hot Service2.2 ASTM Adjuncts:3ADJC0450A Recomme
10、nded Dimensional Standards for Fabrication of Thermal Insulating Fitting Covers for NPS Piping andVessel Lagging2.3 American National Standards Institute Standard:ANSI B16.5 Fittings, Flanges, and Valves43. Terminology3.1 DefinitionsFor definitions of terms used in this practice, refer to Terminolog
11、y C168.3.2 Symbols: The3.2.1 The following symbols are used in the development of the equations for this practice. Other symbols will be introduced1This practice is under the jurisdiction ofASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal Me
12、asurement.Current edition approved Dec.May 1, 2008.2012. Published February 2009.July 2012. Originally approved in 1989. Last previous edition approved in 20012008 asC112989 (2001).(2008). DOI: 10.1520/C1129-89R08.10.1520/C1129-12.2For referencedASTM standards, visit theASTM website, www.astm.org, o
13、r contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.3Av
14、ailable from ASTM International Headquarters. Order Adjunct No. ADJADJC0450A. Original adjunct produced in 1976. Adjunct 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.1This document is not an ASTM
15、standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all
16、cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and defined in the detailed description of the development. See Figs. 1 and 2
17、.AB= outer surface area of the bare valve or flange (does not include the wheel and stem of the valve), ft2(m2).AI= surface area of the insulation cover over the valve or flange, ft2(m2).C = distance from the center-line axis of the pipe (to which the valve is attached) to the uppermost position of
18、the valve thatis to be insulated (recommended to be below the gland seal), ft (m).DF= the valve flange and the bonnet 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
19、and of the bonnet flange, ft (m).qB= time rate of heat loss per unit area from the bare valve or flange surface, Btu/hft2(W/m2).qI= time rate of heat loss per unit area from the insulation surface, Btu/hft2) (W/m2).QB= time rate of heat loss from the bare valve or flange surface, Btu/h (W).QI= time
20、rate of heat loss from the insulated surface, Btu/h (W).4. Summary of Practice4.1 The procedures for estimating heat loss used in this practice are based upon standard steady-state heat transfer theory asoutlined in Practice C680 (or programs conforming to it). This practice is used to estimate the
21、heat loss per unit surface area forthe particular conditions and for all configurations. (or programs conforming to it such as 3E Plus5). Practice C680 amd 3E plusare used to estimate the heat loss per unit surface area for the particular conditions and for all configurations, both bare andinsulated
22、.5Available from the North American Insulation Manufacturers Association for a free 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)+6DFT p(Ref.3)FIG. 2 Equation 2 for the surface area of a Bare Flange,ABF=DP(2L
23、V+2LF4 T)+ (DF2 DP2)/2+42DFT pC1129 1224.2 The procedures for estimating surface areas used in this practice are based on standard geometric logic: for a bare valve orflange, the contours of the metal surface are considered. For an insulated valve or flange, the fabricated shape of the finishedinsul
24、ation system is considered.4.3 Data Input:4.3.1 Total bare surface area and total insulation surface area of the bare valve or flange,4.3.2 Service and ambient temperatures,4.3.3 Wind speed,4.3.4Surface emittances,4.3.4 Surface emittance values4.3.5 Insulation thickness and type, and4.3.6 Number of
25、service hours per year.4.4 System DescriptionInsulation thickness, insulation type, bare valve or flange surface emittance, insulation surfaceemittance.4.5 AnalysisOnce input data is entered, the program calculates the surface coefficients (if not entered directly), the insulationresistance, the bar
26、e metal heat loss per unit area, and the insulation surface heat loss per unit area. The rate of heat loss per unitarea is computed by Practice C680for the appropriate diameter. For bare gate valves, the particular surface area can be taken froma look-up table. Table 1 gives these areas for typical
27、(ANSI Class 150, 300, 600, and 900) flanged gate valves and flanges. If thesevalves are not considered sufficiently accurate, they can be calculated using Eq 1 (see and Table 2 give these areas for typical(ANSI Class 150, 300, 600, and 900) flanged gate valves and flanges. If these valves are not co
28、nsidered sufficiently accurate forthe particular valves or flanges being considered, those areas can be calculated using Eq 1 (see Fig. 1) and Eq 2 (see ) for bareflanges and Eq 2 (see Fig. 2). Similar equations can be developed for other types of valves and flanges. For the insulation, the outersur
29、face area may be obtained from the insulation fabricator or contractor. ) for bare gate valves. Similar equations can be developedfor other types of valves and flanges. For the insulation on the valves and the flanges, the outer surface area can be obtained eitherfrom Table 3 and Table 4 for insulat
30、ion thickness up to 4 in. or from the insulation fabricator or contractor.5. Significance and Use5.1 Manufacturers of thermal insulation for valves typically express the performance of their products in charts and tablesshowing heat loss per valve. These data are presented for both bare and insulate
31、d valves of different pipe sizes, ANSI classes,insulation types, insulation thicknesses, and service temperatures. Additional information on effects of wind velocity, jacketemittance, bare valve emittance, and ambient conditions mayare also be required to properly select an insulation system. Due to
32、the infinite combination of pipe sizes, ANSI classes, insulation types and thicknesses, service temperatures, insulation covergeometries, surface emittance values, and ambient conditions, it is not possible to publish data for each possible case.5.2 Users of thermal insulation for piping systems fac
33、ed with the problem of designing large systems of insulated piping,encounter substantial engineering costs to obtain the required thermal information. This cost can be substantially reduced by boththe use of accurate engineering data tables, or by the use of available computer analysis tools, or bot
34、h.5.3 The use of this practice by the manufacturer, contractor, and users of thermal insulation for valves and flanges will providestandardized engineering data of sufficient accuracy and consistency for predicting the savings in heating energy use by insulatingbare valves and flanges.5.4 Computers
35、are now readily available to most producers and consumers of thermal insulation to permit use of this practice.5.5The computer program in Practice C680 has been developed to calculate the heat loss per unit length, or per unit surface area,of both bare and insulated pipe. With values for bare valve
36、or flange surface areas, heat loss can be estimated. By estimating theTABLE 1 Calculated Surface Areas of Bare Valves using Eq 1 (Ref 3 )ANSI ClassNPS, in.150 300 600 900ft2(m2)ft2(m2)ft2(m2)ft2(m2)2 2.21 (0.205) 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 (
37、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) 23.80 (2.211)10 13.80 (1.284) 18.00 (1.672) 26.50 (2.462) 32.10 (2.982)12 16.10 (1.496) 2
38、4.10 (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)20 37.70 (3.502) 59.10 (5.490) 71.30 (6.624) 24 49.10 (4.561) 83.50 (7.757) 95.10 (8.8
39、35) 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) C1129 123outer insulation surface area from an insulation manufacturers or contractors drawings, the heat loss from the insulation surfacecan likewise be calculated by taking the product of heat loss pe
40、r unit area (from programs conforming to Practice5.5 The computer program in Practice C680 ) and the valve or flange insulation surface area. The area of the uninsulatedsurfaces may also need to be considered.5.6The use of this practice requires that the valve or flange insulation system meets Guide
41、 C1094 and Practice C450, whereapplicable. has been developed to calculate the heat loss per unit length, or per unit surface area, of both bare and insulated pipe.With values for bare valve or flange surface areas, heat loss can be estimated. By estimating the outer insulation surface area froman i
42、nsulation manufacturers or contractors drawings, the heat loss from the insulation surface can likewise be calculated by takingthe product of heat loss per unit area (from programs conforming to Practice C680) and the valve or flange insulation surface area.The area of the uninsulated surfaces also
43、will need to be considered.5.6 The use of this practice requires that the valve or flange insulation system meets either Specification C1695 forremoveable/reuseable or the Adjunct to Practice C4503for insulation fabricated from rigid board and pipe insulation.6. Calculation6.1 This calculation of he
44、at gain or loss requires the following:6.1.1 The thermal insulation shall be assumed to be homogenous as outlined by the definition of thermal conductivity inTerminology C168.6.1.2 The valve or flange size and operating temperature shall be known.6.1.3 The insulation thickness shall be known.6.1.4 V
45、alues of wind speed and surface emittance shall be available to estimate the surface coefficients for both the bare surfaceand for the insulation.6.1.5 The surface temperature in each case shall be assumed to be uniform.6.1.6 The bare surface dimensions or area shall be known.6.1.7 The outer surface
46、 area of the insulation cover can be estimated from drawings or field measurements.6.1.8 Practice C680or other comparable methodology shall be used to estimate the heat loss from both bare and insulatedsurfaces.6.2 Estimation of Rate of Heat Loss from the Bare SurfaceSince Practice C680needs to perf
47、orm iterations in calculating heatflow across an insulation surface, an uninsulated surface must be simulated. To do this, select a thin insulation (with a thicknessof 0.02 in. (0.5 mm) and a thermal curve giving a high thermal conductivity. It is recommended that Type 1 be selected for whichthe fol
48、lowing constants are assigned: a = 10 Btuin./hft2F (1.44 W/mc), b = 0, and c = 0. 3E Plus has the capability ofcalculating heat loss from bare surfaces so this step is unnecessary.6.2.1 Run Practice C680 or 3E Plus for either a horizontal or a vertical pipe of the appropriate diameter, inputing the
49、ambientair temperature, wind speed, and bare valve surface emittance. Unless information is available for estimating the bare valve surfaceemittance, it is suggested that a value of 0.9 be selected. Select output in units of heat loss per unit surface area. This value of heatloss per unit bare surface area is designated qB.6.3 Use of Practice C680 for the Insulated Valve or FlangeSince Practice C680is designed to calculate heat loss for insulatedflat surfaces and for pipes, it is necessary to treat the insulated valve as an insulated pipe. It is rec
