save energy by insulating pipe components

8/2/2019 Save Energy by Insulating Pipe Components

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THE OFFICIALJOURNALOFTHE NATIONAL INSULATION ASSOCIATION

JANUARY2012

PLUS:

Isulti Pipe Compoets to Se Eed Moe

Isultios Pepetul Sustibilit

Set Issues o Isultio Cotctos d Distibutos

GO GREEN

DONT

A LOT OF GREEN TO

PEND

$

Asse

enin


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2 www.insulationoutlook.com

In most mechanical and boiler rooms,

pipes and ttings such as elbows and

tees are insulated with conventional

pipe insulation. However, in the authors

experience, the components (valves,

strainers, pressure regulators, etc.) are

either only partially insulated or totallyuninsulated (bare). This lack o proper

insulation wastes energy, creates a health

and saety issue (i.e., hot components

can cause burns), and produces unnec-

essary carbon dioxide emissions, and, in

unventilated mechanical rooms, the resulting high air tem-

peratures create a stressul work environment.

In this article, well explore simple solutions to improper

insulation and a means o estimating the energy savings.

Ee Sis b IsultiThe National Mechanical Insulation Committee has recently

developed a simple calculator or the Mechanical Insula-

tion Design Guide (MIDG) that is available at www.wbdg.

org/design/midg_design_echp.php. The MIDG is part o the

National Institute o Building Sciences Whole Building

Design Guide (WBDG).

This web-based calculator enables users to calculate

energy savings rom bare and insulated pipes and fat sur-

aces. It is based on Standard ASTM C680 and has been

validated or accuracy.

To demonstrate how this calculator can be used or evalu-ating the impact o insulating a pipe component, lets run an

example problem. Consider a 6 in. NPS pipe carrying 350F

(177C) steam, operating ull time, in a 90F (32C) room

with 0 mph wind, and evaluating it with berglass pipe insu-

lation with all-service jacket and a cost multiplier o 1.0 (this

term reers to a multiplier or the calculators deault value

o the installed cost per lineal oot o the insulation mate-

rial, which is the sum o the insulation material and labor to

install costs. These values must be assumed or obtained rom

an insulation contractor). We obtain

the ollowing results rom the calculator

(Figure 1).

The screenshot shows that or natural

gas costing $10 per MMBtu, with only

1 in. (25.4 mm) o insulation, we obtain

a predicted payback o about 3 monthsor an annual return o 462 percent. In

act, the cost o uel saved per lineal oot

(LF) is the cost per LF with 0 in. o insu-

lation minus the cost per LF with 1 in.

(25.4 mm) o insulation = $136/LF

$16.25/LF = $119.75/LF. This represents an 88 percent heat

loss reduction, a signicant savings under any circumstance.

Likewise, the last column shows CO2emissions are predicted

to be reduced by 0.74 0.09 = 0.65 metric tons annually per

LF o pipe.

What does this mean or a 6 in. NPS gate valve with anANSI rating o 300 (i.e., rated or 300 psi)? ASTM C1129-

89 (2008), Standard Practice or Estimation o Heat Savings

by Adding Thermal Insulation to Bare Valves and Flanges,

includes Table 1, which gives bare valve surace area values or

a range o pipe sizes and ANSI pressure ratings.

For this particular valve, the bare surace area is given as

9.71 t2 (0.90 m2), a signicant surace area o bare, hot steel.

Put into terms o equivalent LF o bare 6 in. NPS pipe, that

works out to 5.6 LF. I we assume that the insulated gate valve

has the same 5.6 LF o insulation surace area o 1 in. (25.4

mm) thick insulation on a 6 in. NPS pipe, then the annualvalue o our energy savings or this gate valve can be estimated:

Predicted annual energy savings = 5.6 LF $119.75/LF

= $670.60

Predicted annual emissions savings = 5.6 LF 0.65

MT/year/LF = 3.64 metric tons.

Thats $670.60 in annual energy savings or a single 6

in. NPS gate valve. And, i we assume that the installed cost

b Isulti Pipe Compoetso Stem d Hot Wte

Distibutio SstemsBy Gordon H. Hart, P.E.

SavIng EnErgy


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January 2012 3

Input Information

o custom removable/replaceable (R/R) insulation blankets

is twice as much as 5.6 LF o preormed pipe insulation on

this 6 in. NPS pipe, the payback is still 6 months. I we

were to use an insulation kit to make the R/R blanket, on

site, based on experience, I estimate that the installed costwould only be about 20 percent greater than that or con-

ventional pipe insulation. Thereore, the predicted payback

would only be about 3.6 months. Regardless o the exact

assumed installed cost value, the payback would only be

several months.

A more conservative case would be or heat distribution

piping system carrying hot water, at 180F (82C), rom a

urnace that operates only hal o the year, or 4,380 hours

per year (Figure 2).

Going to ASTM C1129, Table 1, or a 6 in. NPS, ANSI

150 rated valve, we nd a surace area o 7.03 t2 (0.65 m2);

this is equivalent to 4.05 LF o bare 6 in. NPS pipe. Using

Figure 2 or values o energy use or bare pipe and pipe insu-

lated with 1 in. (25.4 mm) o berglass insulation, we canestimate the value o the annual energy savings:

Predicted annual energy savings = 4.05 LF ($17.43/

LF $2.35/LF) = $61 per year.

Predicted annual emissions reduction = 4.05 LF

(0.10 0.01) MT/yrLF = 0.36 metric tons.

While not nearly as impressive as that or the hotter valve

that carries 350F (177C) steam year-round, the savings

Fiue 1: Fom the MIDg clculto, this is pitouto 6 i. nPS, anSI 300 ted te le ci350F (177C) stem e-oud. note tht the educ-tio i het loss pe LF o the fst ich o fbelssinsulation is 1343 160 = 1,183 Btu/hLF, represent-

i bout 88 pecet eductio i het loss. Thelue o the ul ee sis pe LF is pedictedto be $136.00 $16.25 = $119.75/LF. note tht othe ssumed cost multiplie o 1.0, the istlled costpe LF is $25.91 o 1 i. thick peomed fbelsspipe isultio. I the uthos opiio, this is lidumbe o tht tpe o isultio.

Fiue 2: Fom the MIDg clculto, the pedictedsimple pbck o 1 i. o fbelss isultio is 21moths. Ee thouh this is much ete th the3-moth pbck we oud o stem with 350F(177C) opeti tempetue o ull-time opetio

(i.e., 8,760 hous pe e), usi 1 i. o fbelssisultio o this 180F (82C) hot pipe tht olopetes hl the e (i.e., 4,380 hous pe e) isstill impessiel shot (i.e., less th 2 es).

1. Length o Piping Run, t 1

2. Select Pipe Size, NPS 6

3. Operating Temperature, F 350

4. Ambient Temperature, F 90

5. Wind Speed, mph 0

6. Select Insulation Fiberglass (0F to 450F)

7. Installed Cost Multiplier 1.00

8. Emittance o Surace 0.90 - All Service Jacket

9. Expected Useul Lie o Insulation System, yrs 10

10. Operating Hours per Year 8320

11. Efciency o Fuel Conversion, % 80

12. Select Fuel Natural Gas

13. Cost o Fuel, S/Mc 10

Thickenss

(inches)

0

0.5

0.751

1.5

2

2.5

3

3.5

4

Surface

Temp (F)

349

150

NA128

116

109

106

103

101

99

Heat Loss

(Btu/h)

1343

205

NA160

116

91

77

68

60

55

Cost of

Fuel ($/yr)

$136.00

$25.29

NA$16.25

$11.77

$9.21

$7.84

$6.90

$6.07

$5.57

Installed

Cost ($)

$0.00

$23.40

NA$25.91

$28.42

$32.27

$37.25

$38.57

$43.15

$47.23

Payback

(months)

NA

3

NA3

3

3

3

4

4

4

Annual

Return

NA

473%

NA462%

437%

393%

344%

335%

301%

276%

CO2

Emissions

(MT/yr)

0.74

0.14

NA0.09

0.06

0.05

0.04

0.04

0.03

0.03

Results

Input Information

1. Length o Piping Run, t 1

2. Select Pipe Size, NPS 6

3. Operating Temperature, F 180

4. Ambient Temperature, F 90

5. Wind Speed, mph 0

6. Select Insulation Fiberglass (0F to 450F)

7. Installed Cost Multiplier 1.00

8. Emittance o Surace 0.90 - All Service Jacket

9. Expected Useul Lie o Insulation System, yrs 10

10. Operating Hours per Year 4380

11. Efciency o Fuel Conversion, % 80

12. Select Fuel Natural Gas

13. Cost o Fuel, S/Mc 10

Thickenss

(inches)

0

0.5

0.751

1.5

2

2.5

3

3.5

4

Surface

Temp (F)

180

110

NA102

98

96

95

94

93

93

Heat Loss

(Btu/h)

327

68

NA44

32

25

21

19

17

15

Cost of

Fuel ($/yr)

$17.43

$3.61

NA$2.35

$1.71

$1.34

$1.14

$1.01

$0.89

$0.82

Installed

Cost ($)

$0.00

$23.40

NA$25.91

$28.42

$32.27

$37.25

$38.57

$43.15

$47.23

Payback

(months)

NA

20

NA21

22

24

27

28

31

34

Annual

Return

NA

58%

NA58%

55%

49%

42%

41%

37%

33%

CO2

Emissions

(MT/yr)

0.01

0.02

NA0.01

0.01

0.01

0.01

0.01

0

0.

Results


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4 www.insulationoutlook.com

Fiue 3: Plte 14 om the 2006 Editio o the Nation-al Commercial and Industrial Insulation Standards

Manual (the MICa Mul). This isultio sstem,bicted om peomed pipe isultio, eectie-l isultes the le bod, boet, d pt o thestem. Howee, this tpe o isultio is ot wht weclssi s emoble/eusble isultio becusei the pocess o emoi it, the mteils usullbecome sufcietl dmed d he to be dis-cded.

rom insulating just one 6 in. NPS gate valve carrying 180F

(82C) hot water is still compelling. I we again assume the

installed cost o custom made R/R insulation is twice that o

preormed berglass pipe insulation, the payback would be

about 42 months. I using a modular insulation kit to makeR/R blankets, the installed cost would be about 20 percent

greater than that or pipe insulation. Thereore, the payback

would be about 2 years.

Are these energy savings a signicant portion o all the

space heating needs?

In a recent article,1 Chris Crall and Ron King reported on

their mechanical insulation survey or the State o Montana.

They surveyed mechanical rooms in 25 buildings that are

part o the state capital system in Helena, Montana, repre-

Photo 1: Seel be pipe compoets i buildis

mechicl oom eceie 380F (193

C) stem om cetl plt. about two doze simill be com-

poets e i this oom, esulti i wsted ee,uecess emissios o eehouse ses, mhot suces tht pose bu isk to mitecewokes, d witetime spce i tempetuetht is well oe 100F (38C), ceti stessulwok eiomet o those mitece wokes.

Photo 2: a be tee d te le e pt o stemdistibutio sstem i buildis mechicl oom;the stem is eeted b cetl stem plt.notice how es it is to ideti be compoets o

pipe distibutio sstems i mechicl ooms.

senting about 1.3 million t2 (121,000 m2) o buildings. The

authors ocused on identiying pipe components and equip-

ment, located in mechanical rooms and boiler rooms, that

were either bare or had severely deteriorated thermal insula-tion. They came up with a total o about 3,500 items. They

calculated the total annual savings rom insulating these com-

ponents would be about 6 billion Btu, or about 8 percent o

the total natural gas used to heat these 25 buildings annually.

Isulti Pipe CompoetsPipe components are oten uninsulated or two reasons:

1. They have convoluted shapes, which are more expensive

to insulate, and

2. They require periodic maintenance that involves remov-ing existing insulation or access.

Photos 1 and 2 show bare pipe components in several

buildings mechanical rooms. To insulate these dicult

shapes, one option is or the insulation contractor to crat

insulation pieces using preormed pipe insulation and then

install these over, or example, a gate valve; Figure 3 shows

how this can be done.

A second option is to use R/R insulation blankets. These

usually are custom made and require the abricator to send

someone to the site to measure the suraces, then design theR/R blankets, abricate the blankets in a shop, bring the

blankets to the job site, and install the blankets. Photo 3

(page 10) shows a custom R/R insulation blanket on a gate

valve. The photo shows that these blankets require a certain

amount o skill and training to design, abricate, and install

correctly. When done well, and in such a way that all the

bare suraces are insulated, this option results in insulation

that can be removed or maintenance or inspection and then

reinstalled airly quickly. The abrication o these blankets


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January 2012 5

can be done ollowing either a project-specic specication,

prepared by the architect or engineer, or ollowing the indoor

requirements section o industry standard ASTM C1695-10,

Standard Specication or Fabrication o Flexible Removableand Reusable Blanket Insulation or Hot Service.

Another option is to use a modular thermal insulation

blanket kit that meets ASTM C1695. This allows the con-

tractor to abricate and install R/R blankets on the job site

using standardized materials. In addition, using a kit avoids

the delay required o custom-made R/R blankets.

While a kit has a xed thickness, the rst inch o insula-

tion reduces heat loss by at least 88 percent and provides

the shortest payback (as the reader can see rom reviewing

payback values rom Figure 1 and Figure 2). Overall, a mod-

ular kit allows pipe components to be insulated easily andquickly. Modular insulation kits or R/R blankets, which

meet the indoor requirements section o ASTM C1695-10,

are commercially available. Photos 4 and 5 show how a mod-

ular insulation kit can be used to do this.

Coclusios d recommedtiosMany opportunities exist or energy savings in institutional

buildings that use district heating systems, with a mechani-

cal room or each building, or a boiler room where steam

or hot water is generated or heating each individual build-

ing. Typically, there are many heat distribution pipe compo-nents let either uninsulated or partially insulated. I you can

walk into a mechanical or boiler room and see bare steel on

operational heat distribution pipe and equipment compo-

nents, then thermal energy is being wasted. And, this ther-

mal energy waste can be corrected simply by insulating those

bare components.

In one study, insulating these components has been pre-

dicted to comprise 8 percent o buildings total uel use or

heating. Payback periods o less than 1 year, and even as

Photo 3: a emoble/eusble isultio blket o te le. While the boet is well isulted, thestem, betwee the boet d the hdle, ws letbe, d dditiol ee could lso be sed i itws isulted.

short as several months, are common when insulating these

previously bare components.

Estimates o the energy saved, payback, and reductions

o emissions can be made using the Mechanical Insulation

Design Guides heat loss calculator. This is part o the WholeBuilding Design Guide and was developed with assistance

rom the U.S. Department o Energy.

It is recommended that mechanical designers and acil-

ity owners/operators learn to survey their mechanical rooms

and boiler rooms or bare pipe components and equipment.

Although conventional, permanent types o insulation work

well, they do not normally provide easy accessibility or main-

tenance personnel. The author recommends using remov-

able/reusable insulation blankets or these components. The

blankets can be either custom-made or site-made using mod-

ular thermal insulation kits designed or this purpose.

References

1. Crall, C.P., R.L. King. 2011. Montana mechanical insulation energy

appraisal. Insulation Outlook(5). http://tinyurl.com/3zzt6yg.

Gordon H. Hart, P.E., is a consulting engineer at Artek Engineering, Shrews-

bury, Massachusetts.

2011 ASHRAE. Reprinted by permission fromASHRAE Journal (Octo-

ber 2011),www.ashrae.org.

Photo 4: a woke cuts pieces om 4 t x 8 t (1.2 mx 2.4 m) sheet om modul isultio kit. Oce cutto size, the isultos will use stips o hook d loopstee tpe, stpled to the pieces, to secue themoud the compoet bei isulted.

Photo 5: Two compoets om Photo 2 te beiull isulted usi modul theml isultio kit.


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