ASTM C1129-89(2008)

Standard Practice for Estimation of Heat Savings by Adding Thermal Insulation to Bare Valves and Flanges

SIGNIFICANCE AND USE
Manufacturers of thermal insulation for valves typically express the performance of their products in charts and tables showing heat loss per valve. These data are presented for both bare and insulated valves of different pipe sizes, ANSI classes, insulation types, insulation thicknesses, and service temperatures. Additional information on effects of wind velocity, jacket emittance, bare valve emittance, and ambient conditions may also be required to properly select an insulation system. Due to the infinite combination of pipe sizes, ANSI classes, insulation types and thicknesses, service temperatures, insulation cover geometries, surface emittances, and ambient conditions, it is not possible to publish data for each possible case.
Users of thermal insulation for piping systems faced 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 both the use of accurate engineering data tables, or by the use of available computer analysis tools, or both.
The use of this practice by the manufacturer, contractor, and users of thermal insulation for valves and flanges will provide standardized engineering data of sufficient accuracy and consistency for predicting the savings in heating energy use by insulating bare valves and flanges.
Computers are now readily available to most producers and consumers of thermal insulation to permit use of this practice.
The computer program in Practice C 680 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 from an insulation manufacturer's or contractor's drawings, the heat loss from the insulation surface can likewise be calculated by taking the product of heat loss per unit area (from programs conformi...
SCOPE
1.1 The mathematical methods included in this practice provide a calculational procedure for estimating heat loss or heat savings 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 design and analysis.
1.3 Estimated accuracy is limited by the following:
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
1.3.3 The quality of workmanship, fabrication, and installation.
1.4 This procedure 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 the equipment over which thermal insulation is 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 mathematical conversions to SI units 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 responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Nov-2008
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.30 - Thermal Measurement

Relations

• Replaces: ASTM C1129-89(2001) - Standard Practice for Estimation of Heat Savings by Adding Thermal Insulation to Bare Valves and Flanges
• Effective Date: 01-Dec-2008
• Replaced By: ASTM C1129-12 - Standard Practice for Estimation of Heat Savings by Adding Thermal Insulation to Bare Valves and Flanges
• Effective Date: 01-May-2012
• Referred By: ASTM C1695-22 - Standard Specification for Fabrication of Flexible Removable and Reusable Blanket Insulation for Hot Service
• Effective Date: 01-Dec-2008

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1129 – 89 (Reapproved 2008)
Standard Practice for
Estimation of Heat Savings by Adding Thermal Insulation to
Bare Valves and Flanges
This standard is issued under the fixed designation C1129; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 The mathematical methods included in this practice 2.1 ASTM Standards:
provide a calculational procedure for estimating heat loss or C168 Terminology Relating to Thermal Insulation
heat savings when thermal insulation is added to bare valves C450 Practice for Fabrication of Thermal Insulating Fitting
and flanges. Covers for NPS Piping, and Vessel Lagging
1.2 Questions of applicability to real systems should be C680 PracticeforEstimateoftheHeatGainorLossandthe
resolved by qualified personnel familiar with insulation sys- Surface Temperatures of Insulated Flat, Cylindrical, and
tems design and analysis. Spherical Systems by Use of Computer Programs
1.3 Estimated accuracy is limited by the following: C1094 Guide for Flexible Removable Insulation Covers
1.3.1 Therangeandqualityofthephysicalpropertydatafor 2.2 American National Standards Institute Standard:
the insulation materials and system, ANSI B16.5 Fittings, Flanges, and Valves
1.3.2 The accuracy of the methodology used in calculation
3. Terminology
of the bare valve and insulation surface areas, and
1.3.3 The quality of workmanship, fabrication, and installa- 3.1 Definitions—For definitions of terms used in this prac-
tice, refer to Terminology C168.
tion.
1.4 This procedure is considered applicable both for 3.2 Symbols:—The following symbols are used in the de-
velopment of the equations for this practice. Other symbols
conventional-type insulation systems and for removable/
reuseable covers. In both cases, for purposes of heat transfer willbeintroducedanddefinedinthedetaileddescriptionofthe
development. See Figs.1 and 2.
calculations, the insulation system is assumed to be homog-
enous.
1.5 This practice does not intend to establish the criteria
A = outer surface area of the bare valve or flange (does
B
required in the design of the equipment over which thermal
2 2
notincludethewheelandstemofthevalve),ft (m ).
insulation is used, nor does this practice establish or recom-
A = surface area of the insulation cover over the valve or
I
mend the applicability of thermal insulation over all surfaces.
2 2
flange, ft (m ).
1.6 Thevaluesstatedininch-poundunitsaretoberegarded
C = distance from the center-line axis of the pipe (to
as standard. The values given in parentheses are mathematical
which the valve is attached) to the uppermost posi-
conversions to SI units that are provided for information only
tionofthevalvethatistobeinsulated(recommended
and are not considered standard.
to be below the gland seal), ft (m).
1.7 This standard does not purport to address all of the
D = thevalveflangeandthebonnetflangeouterdiameter
F
safety concerns, if any, associated with its use. It is the
(assumed equal), ft (m).
responsibility of the user of this standard to establish appro-
D = the actual diameter of the pipe, ft (m).
P
priate safety and health practices and determine the applica-
L = overall length of the valve, flange to flange, ft (m).
V
bility of regulatory limitations prior to use.
1 2
This practice is under the jurisdiction of ASTM Committee C16 on Thermal For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Insulation and is the direct responsibility of Subcommittee C16.30 on Thermal contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Measurement. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2008. Published February 2009. Originally the ASTM website.
approved in 1989. Last previous edition approved in 2001 as C1129–89 (2001). Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
DOI: 10.1520/C1129-89R08. 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 States.
C1129 – 89 (2008)
T = thicknessofthevalveflangeandofthebonnetflange,
ft (m).
q = timerateofheatlossperunitareafromthebarevalve
B
2 2
or flange surface, Btu/h·ft (W/m ).
q = timerateofheatlossperunitareafromtheinsulation
I
2 2
surface, Btu/h·ft ) (W/m ).
Q = time rate of heat loss from the bare valve or flange
B
surface, Btu/h (W).
Q = time rate of heat loss from the insulated surface,
I
Btu/h (W).
FIG. 2 Equation 2 for a Bare Flange,A =[D
B P
F
2 2
(L +2L −4T)+(D −D )+4D T]p
V F F P F
4.2 The procedures for estimating surface areas used in this
practicearebasedonstandardgeometriclogic:forabarevalve
or flange, the contours of the metal surface are considered. For
aninsulatedvalveorflange,thefabricatedshapeofthefinished
insulation 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,
4.3.4 Surface emittances,
4.3.5 Insulation thickness and type, and
4.3.6 Number of service hours per year.
4.4 System Description—Insulation thickness, insulation
type, bare valve or flange surface emittance, insulation surface
emittance.
4.5 Analysis—Once input data is entered, the program
FIG. 1 Equation 1 for a Bare Valve,A =[D (L +2L +(C −D /
B P V F P
V
2 2 calculates the surface coefficients (if not entered directly), the
2)−6T)+ 1.5(D −D )+6D T]p
F P F
insulationresistance,thebaremetalheatlossperunitarea,and
the insulation surface heat loss per unit area. The rate of heat
4. Summary of Practice
loss per unit area is computed by Practice C680 for the
4.1 The procedures for estimating heat loss used in this appropriate diameter. For bare gate valves, the particular
practice are based upon standard steady-state heat transfer surface area can be taken from a look-up table. Table 1 gives
theoryasoutlinedinPracticeC680(orprogramsconformingto these areas for typical (ANSI Class 150, 300, 600, and 900)
it). This practice is used to estimate the heat loss per unit flanged gate valves and flanges. If these valves are not
surface area for the particular conditions and for all configu- considered sufficiently accurate, they can be calculated using
rations. Eq 1 (see Fig. 1) and Eq 2 (see Fig. 2). Similar equations can
TABLE 1 Calculated Surface Areas of Bare Valves
ANSI Class
150 300 600 900
NPS, in.
2 2 2 2 2 2 2 2
ft (m)ft (m)ft (m)ft (m )
2 2.21 (0.205) 2.94 (0.273) 2.94 (0.273) 5.20 (0.483)
2 ⁄2 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) 23.80 (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)
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) .
C1129 – 89 (2008)
be developed for other types of valves and flanges. For the 6.1.5 Thesurfacetemperatureineachcaseshallbeassumed
insulation, the outer surface area may be obtained from the to be uniform.
insulation fabricator or contractor.
6.1.6 The bare surface dimensions or area shall be known.
6.1.7 The outer surface area of the insulation cover can be
5. Significance and Use
estimated from drawings or field measurements.
5.1 Manufacturers of thermal insulation for valves typically 6.1.8 Practice C680 or other comparable methodology shall
be used to estimate the heat loss from both bare and insulated
express the performance of their products in charts and tables
showing heat loss per valve. These data are presented for both surfaces.
bare and insulated valves of different pipe sizes,ANSI classes, 6.2 Estimation of Rate of Heat Loss from the Bare
insulation types, insulation thicknesses, and service tempera-
Surface—Since Practice C680 needs to perform iterations in
tures.Additionalinformationoneffectsofwindvelocity,jacket calculating heat flow across an insulation surface, an uninsu-
emittance, bare valve emittance, and ambient conditions may
lated surface must be simulated. To do this, select a thin
alsoberequiredtoproperlyselectaninsulationsystem.Dueto insulation(withathicknessof0.02in.(0.5mm))andathermal
the infinite combination of pipe sizes,ANSI classes, insulation
curve giving a high thermal conductivity. It is recommended
types and thicknesses, service temperatures, insulation cover that Type 1 be selected for which the following constants are
geometries, surface emittances, and ambient conditions, it is
assigned: a =10 Btu·in./h·ft ·F (1.44 W/m·c), b =0, and c
not possible to publish data for each possible case. =0.
5.2 Users of thermal insulation for piping systems faced
6.2.1 Run Practice C680 for either a horizontal or a vertical
with the problem of designing large systems of insulated
pipe of the appropriate diameter, inputing the ambient air
piping, encounter substantial engineering costs to obtain the
temperature, wind speed, and bare valve surface emittance.
required thermal information. This cost can be substantially
Unless information is available for estimating the bare valve
reduced by both the use of accurate engineering data tables, or
surface emittance, it is suggested that a value of 0.9 be
by the use of available computer analysis tools, or both.
selected. Select output in units of heat loss per unit surface
5.3 The use of this practice by the manufacturer, contractor,
area. This value of heat loss per unit bare surface area is
and users of thermal insulation for valves and flanges will
designated q .
B
provide standardized engineering data of sufficient accuracy
6.3 Use of Practice C680 for the Insulated Valve or
and consistency for predicting the savings in heating energy
Flange—SincePracticeC680isdesignedtocalculateheatloss
use by insulating bare valves and flanges.
for insulated flat surfaces and for pipes, it is necessary to treat
5.4 Computers are now readily available to most producers
theinsulatedvalveasaninsulatedpipe.Itisrecommendedthat
and consumers of thermal insulation to permit use of this
thediameterofthepipe,towhichthevalvefits,orthediameter
practice.
of the flanges be selected for the calculation. Input the same
5.5 The computer program in Practice C680 has been
ambient air temperature and wind speed as in 6.1 and estimate
developed to calculate the heat loss per unit length, or per unit
the insulation surface emittance. For a removable insulation
surface area, of both bare and insulated pipe. With values for
cover,thiswouldbetheemittanceofthefabricormetaljacket.
bare valve or flange surface areas, heat loss can be estimated.
For conventional insulation, this is either the emittance of that
By estimating the outer insulation surface area from an
material or of the jacketing, if jacketing is used. The value of
insulation manufacturer’s or contractor’s drawings, the heat
heat loss per unit insulation surface area is designated q.
I
loss from the insulation surface can likewise be calculated by
6.4 Surface Area of the Bare Valve or Flange—Fig. 1 gives
taking the product of heat loss per unit area (from programs
a diagram of a gate valve with the dimensions D , L , T, L ,
P V F
conformingtoPracticeC680)andthevalveorflangeinsulation
D , and C as indicated. Eq 1 (see Fig. 1) gives a method for
F
surface area. The area of the uninsulated surfaces may also
estimating the surface area of valves, and Eq 2 (see Fig. 2)
need to be considered.
givesamethodforestimatingthesurfaceareaofflanges.Table
5.6 The use of this practice requires that the valve or flange
1 gives the results of calculating the surface area for 2-in.
insulation system meets Guide C1094 and Practice C450,
through 36-in. NPS gate valves forANSI classes of 150, 300,
where applicable.
600 and 900. The value of a bare valve or flange is designated
A .
B
6. Calculation
6.5 Surface Area of the Insulated Valve or Flange—The
6.1 This calculation of heat gain or loss requires the estimationoftheouterinsulationsurfaceareaisbestperformed
following: by the manufacturer or the insulation contractor. This surface
6.1.1 Thethermalinsulationshallbeassumedtobehomog- areawilldependonthedimensionsofthevalveorflangebeing
enous as outlined by the definition of thermal conductivity in insulated, the thickness of the insulation, and the extent of
Terminology C168. coveragetoeithersideofthevalveorflange.Thispracticedoes
6.1.2 The valve or flange size and operating temperature not recommend a specific method for arriving at this area,
which would be designated as A.
shall be known.
I
6.1.3 The insulation thickness shall be known.
6.6 Calculation of Bare Valve or Flange Heat Loss—This
6.1.4 Values of wind speed and surface emittance shall be value is determined by taking the product of the bare valve or
available to estimate the surface coefficients for both the bare flange heat loss per unit surface area and of the bare surface
surface and for the insulation. area. It will be designated as Q :
B
C1129 – 89 (2008)
Q 5 q A (1)
calculated heat loss from the bare surface, in turn, is highly
B B B
dependentonthevaluesofvalveorflangeservicetemperature,
6.7 Calculation of Insulated Valve or Flange Heat Loss—
ambient temperature, wind speed, and surface area, with a
This value is determined by taking the product of the insulated
lesser dependence on surface emissivity.
valve or flange heat loss per unit surface area and of the
8.3 Sincetheservicetemperatureshouldbereasonablywell
insulation outer surface area. It would be designated as Q:
I
known, the person performing this estimation is advised to
Q 5 q A (2)
I I I
perform Practice C680 calculations on the bare surface under
6.8 Calculation of Heat Loss Savings—This value is deter-
extreme environmental conditions. This may not be necessary
mined by taking the difference between the values of heat loss
if the piping system is located indoors in a controlled environ-
for the bare and the insulated valve or flange. It would be
ment, but it is strongly ad
...