ASTM C1129-89(2001)

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

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/reusable 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 the standard. The SI units in parentheses are provided for information only.
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: 31-Dec-2000
• ICS: 23.040.60 - Flanges, couplings and joints
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.30 - Thermal Measurement

Relations

• Replaces: ASTM C1129-89(1994)e1 - Standard Practice for Estimation of Heat Savings by Adding Thermal Insulation to Bare Valves and Flanges
• Effective Date: 01-Jan-2001
• Replaced By: ASTM C1129-89(2008) - Standard Practice for Estimation of Heat Savings by Adding Thermal Insulation to Bare Valves and Flanges
• Effective Date: 01-Dec-2008
• Referred By: ASTM C1695-22 - Standard Specification for Fabrication of Flexible Removable and Reusable Blanket Insulation for Hot Service
• Effective Date: 01-Jan-2001

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: C 1129 – 89 (Reapproved 2001)
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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Thermal Insulation Fitting Covers for NPS Piping, Vessel
Lagging, and Dished Head Segments
1.1 The mathematical methods included in this practice
C680 Practice for Determination of Heat Gain or Loss and
provide a calculational procedure for estimating heat loss or
theSurfaceTemperaturesofInsulatedPipeandEquipment
heat savings when thermal insulation is added to bare valves
Systems by the Use of a Computer Program
and flanges.
C1094 Guide for Removable Insulation Covers
1.2 Questions of applicability to real systems should be
2.2 American National Standards Institute Standard:
resolved by qualified personnel familiar with insulation sys-
ANSI B16.5 Fittings, Flanges, and Valves
tems design and analysis.
1.3 Estimated accuracy is limited by the following:
3. Terminology
1.3.1 Therangeandqualityofthephysicalpropertydatafor
3.1 Definitions—For definitions of terms used in this prac-
the insulation materials and system,
tice, refer to Terminology C168.
1.3.2 The accuracy of the methodology used in calculation
3.2 Symbols:—The following symbols are used in the de-
of the bare valve and insulation surface areas, and
velopment of the equations for this practice. Other symbols
1.3.3 The quality of workmanship, fabrication, and installa-
willbeintroducedanddefinedinthedetaileddescriptionofthe
tion.
development. See Figs.1 and 2.
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
A = outer surface area of the bare valve or flange (does
B
2 2
calculations, the insulation system is assumed to be homog-
notincludethewheelandstemofthevalve),ft (m ).
enous.
A = surface area of the insulation cover over the valve or
I
2 2
1.5 This practice does not intend to establish the criteria
flange, ft (m ).
required in the design of the equipment over which thermal
C = distance from the center-line axis of the pipe (to
insulation is used, nor does this practice establish or recom-
which the valve is attached) to the uppermost posi-
mend the applicability of thermal insulation over all surfaces.
tionofthevalvethatistobeinsulated(recommended
1.6 The values stated in inch-pound units are to be regarded
to be below the gland seal), ft (m).
as the standard. The SI units in parentheses are provided for
D = the valve flange and the bonnet flange outer diameter
F
information only.
(assumed equal), ft (m).
1.7 This standard does not purport to address all of the
D = the actual diameter of the pipe, ft (m).
P
safety concerns, if any, associated with its use. It is the L = overall length of the valve, flange to flange, ft (m).
V
T = thicknessofthevalveflangeandofthebonnetflange,
responsibility of the user of this standard to establish appro-
ft (m).
priate safety and health practices and determine the applica-
q = timerateofheatlossperunitareafromthebarevalve
bility of regulatory limitations prior to use. B
2 2
or flange surface, Btu/h·ft (W/m ).
2. Referenced Documents
q = timerateofheatlossperunitareafromtheinsulation
I
2 2
surface, Btu/h·ft)(W/m ).
2.1 ASTM Standards:
Q = time rate of heat loss from the bare valve or flange
C168 Terminology Relating to Thermal Insulation B
surface, Btu/h (W).
C450 Practice for Prefabrication and Field Fabrication of
Q = time rate of heat loss from the insulated surface,
I
Btu/h (W).
ThispracticeisunderthejurisdictionofCommitteeC16onThermalInsulation
and is the direct responsibility of Subcommittee C16.30 on Thermal Measurement.
Current edition approved June 30, 1989. Published August 1989. Available from American National Standards Institute, 11 W. 42nd St., 13th
Annual Book of ASTM Standards, Vol 04.06. Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1129 – 89 (2001)
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
calculates the surface coefficients (if not entered directly), the
insulationresistance,thebaremetalheatlossperunitarea,and
FIG. 1 Equation 1 for a Bare Valve,A =[D (L +2L +(C −D /
B P V F P
V the insulation surface heat loss per unit area. The rate of heat
2 2
2)−6T)+1.5(D −D )+6D T]p
F P F
loss per unit area is computed by Practice C680 for the
appropriate diameter. For bare gate valves, the particular
surface area can be taken from a look-up table. Table 1 gives
these areas for typical (ANSI Class 150, 300, 600, and 900)
flanged gate valves and flanges. If these valves are not
considered sufficiently accurate, they can be calculated using
Eq 1 (see Fig. 1) and Eq 2 (see Fig. 2). Similar equations can
be developed for other types of valves and flanges. For the
insulation, the outer surface area may be obtained from the
insulation fabricator or contractor.
FIG. 2 Equation 2 for a Bare Flange,A =[D 5. Significance and Use
B P
F
2 2
(L +2L −4T)+(D −D )+4D T]p
V F F P F
5.1 Manufacturers of thermal insulation for valves typically
express the performance of their products in charts and tables
4. Summary of Practice
showing heat loss per valve. These data are presented for both
4.1 The procedures for estimating heat loss used in this bare and insulated valves of different pipe sizes,ANSI classes,
practice are based upon standard steady-state heat transfer insulation types, insulation thicknesses, and service tempera-
theory as outlined in Practice C680 (or programs conforming tures.Additionalinformationoneffectsofwindvelocity,jacket
to it). This practice is used to estimate the heat loss per unit emittance, bare valve emittance, and ambient conditions may
surface area for the particular conditions and for all configu- alsoberequiredtoproperlyselectaninsulationsystem.Dueto
rations. the infinite combination of pipe sizes,ANSI classes, insulation
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) .
C 1129 – 89 (2001)
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 RunPracticeC680foreitherahorizontaloravertical
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 C 680 for the Insulated Valve or
and consistency for predicting the savings in heating energy
Flange—Since Practice C680 is designed to calculate heat
use by insulating bare valves and flanges.
loss for insulated flat surfaces and for pipes, it is necessary to
5.4 Computers are now readily available to most producers
treat the insulated valve as an insulated pipe. It is recom-
and consumers of thermal insulation to permit use of this
mendedthatthediameterofthepipe,towhichthevalvefits,or
practice.
thediameteroftheflangesbeselectedforthecalculation.Input
5.5 The computer program in Practice C680 has been
thesameambientairtemperatureandwindspeedasin6.1and
developed to calculate the heat loss per unit length, or per unit
estimate the insulation surface emittance. For a removable
surface area, of both bare and insulated pipe. With values for
insulation cover, this would be the emittance of the fabric or
bare valve or flange surface areas, heat loss can be estimated.
metal jacket. For conventional insulation, this is either the
By estimating the outer insulation surface area from an
emittance of that material or of the jacketing, if jacketing is
insulation manufacturer’s or contractor’s drawings, the heat
used. The value of heat loss per unit insulation surface area is
loss from the insulation surface can likewise be calculated by
designated q.
I
taking the product of heat loss per unit area (from programs
6.4 Surface Area of the Bare Valve or Flange—Fig. 1 gives
conforming to Practice C680) and the valve or flange insula-
a diagram of a gate valve with the dimensions D , L , T, L ,
P V F
tionsurfacearea.Theareaoftheuninsulatedsurfacesmayalso
D , and C as indicated. Eq 1 (see Fig. 1) gives a method for
F
need to be considered.
estimating the surface area of valves, and Eq 2 (see Fig. 2)
5.6 The use of this practice requires that the valve or flange
givesamethodforestimatingthesurfaceareaofflanges.Table
insulation system meets Guide C1094 and Practice C450,
1 gives the results of calculating the surface area for 2-in.
where applicable.
through 36-in. NPS gate valves forANSI classes of 150, 300,
600 and 900. The value of a bare valve or flange is designated
6. Calculation
A .
B
6.1 This calculation of heat gain or loss requires the
6.5 Surface Area of the Insulated Valve or Flange—The
following:
estimationoftheouterinsulationsurfaceareaisbestperformed
6.1.1 The thermal insulation shall be assumed to be homog-
by the manufacturer or the insulation contractor. This surface
enous as outlined by the definition of thermal conductivity in
areawilldependonthedimensionsofthevalveorflangebeing
Terminology C168.
insulated, the thickness of the insulation, and the extent of
6.1.2 The valve or flange size and operating temperature
coveragetoeithersideofthevalveorflange.Thispracticedoes
shall be known.
not recommend a specific method for arriving at this area,
6.1.3 The insulation thickness shall be known.
which would be designated as A.
I
6.1.4 Values of wind speed and surface emittance shall be
6.6 Calculation of Bare Valve or Flange Heat Loss—This
available to estimate the surface coefficients for both the bare
value is determined by taking the product of the bare valve or
surface and for the insulation.
flange heat loss per unit surface area and of the bare surface
6.1.5 Thesurfacetemperatureineachcaseshallbeassumed
area. It will be designated as Q :
B
to be uniform.
Q 5 q A (1)
B B B
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
6.7 Calculation of Insulated Valve or Flange Heat Loss—
estimated from drawings or field measurements.
This value is determined by taking the product of the insulated
6.1.8 PracticeC680orothercomparablemethodologyshall valve or flange heat loss per unit surface area and of the
be used to estimate the heat loss from both bare and insulated
insulation outer surface area. It would be designated as Q:
I
surfaces.
Q 5 q A (2)
I I I
6.2 Estimation of Rate of Heat Loss from the Bare
6.8 Calculation of Heat Loss Savings—This value is deter-
Surface—Since Practice C680 needs to perform iterations in
mined by taking the difference between the values of heat loss
calculating heat flow across an insulation surface, an uninsu-
for the bare and the insulated valve or flange. It would be
lated surface must be simulated. To do this, select a thin
designated as Q :
B-I
insulation(withathicknessof0.02in.(0.5mm))andathermal
curve giving a high thermal conductivity. It is recommended Q 5 Q 2 Q (3)
B2I B I
C 1129 – 89 (2001)
7. Report extreme environmental conditions. This may not be necessary
if the piping system is located indoors in a controlled environ-
7.1 The results of calculations performed in accordance
ment, but it is strongly advised if located outdoors. For
withthispracticemaybeusedtoestimateheatlosssavingsfor
example, the greatest heat loss savings would occur for a cold
specific job conditions, or may be used in general form to
ambient temperature with a strong wind; the least savings
present the effectiveness of insulating valves or flanges for a
would occur for a hot ambient temperature with no wind. Use
particular product or system. For the purpose of decision
of these calculations, along with a calculation based on design
making, it is recommended that reference be made to the
conditions, will give maximum and minimum values of heat
specific constants used
...