insulation

Chevron Specification IRM-MS-1381-K

THERMAL INSULATION FOR HOT LINES, VESSELS, AND EQUIPMENT

Commented Copy - Not for Vendor/Contractor Distribution

March 1995 Page 1 of 24

SPECIFICATION IRM-MS-1381-K


NOTE: This document is the "Commented" version of Specification IRM-EG-1381. The

comments, based on Company experience, provide background for the requirements

stated in the Specification. These comments are for Company use only, not for

distribution to Vendors/Contractors.

Copies of the EG Specification (without comment) are available in both hard copy

(paper) and electronic (MS Word for Windows) format. To order, contact CRTC

Technical Standards at either (510) 242-7232 or -7241. Copies of the MS Specification

are available only electronically. To order, contact CRTC Technical Standards at (510)

242-7241.




Page 2 of 24 March 1995

Job Specification Instructions

This specification gives requirements for the installation of insulation for hot vessels and piping. It

focuses on the technical requirements and does not contain contractual or project-specific information.

Those details are left to you.

The Contractor usually chooses the insulation material in most locations. We have restrictions on

material selection for some locations, and this specification and Standard Drawing GD-N99993 set

material temperature limits. If you wish to select the insulation material, guidelines are given in Section

200 of the Insulation and Refractory Manual. For additional information on calculating the economic

thickness, refer to Section 300 of the manual.

The Standard Drawings, except GD-N99993, are provided to supplement the specification. They show

typical details but contain few technical requirements. They do not replace the specification or stand

alone.

The specification contains references to "N" insulation numbers found on Standard Drawing GD-

N99993. The insulation item numbers refer to insulation materials and accessories acceptable to the

Company. An attempt was made to specify materials and accessories available through worldwide

distributors; however, some local installers may not be able to provide a specific vendors product. A

vendors alternate product may be acceptable and we suggest comparing technical data to decide if the

product is acceptable.

The different piping systems and equipment to be insulated should be listed on Standard Form IRM-EF-

630 along with any requirements for specific types of insulation to be used.





CONTENTS

1.0 SCOPE .................................................................................................................................4

2.0 MATERIALS........................................................................................................................4

2.1 Acceptable Materials ..............................................................................................................4

2.2 Insulation ...............................................................................................................................4

2.3 Stainless Steel ........................................................................................................................5

2.4 Weather Jacketing...................................................................................................................5

2.5 Weather Jacket Attachment Fixtures.........................................................................................6

2.6 Storage of Materials................................................................................................................7

3.0 GENERAL INSTALLATION REQUIREMENTS ...............................................................7

3.1 Condition of Surfaces to Be Insulated.......................................................................................7

3.2 Insulating Cement and Bore Coatings .......................................................................................7

3.3 Valve Bodies, Flanges, and Manways.......................................................................................8

3.4 Double-Layer Insulation ..........................................................................................................8

3.5 Weather Jacketing...................................................................................................................8

3.6 Insulation Interference ...........................................................................................................10

4.0 SPECIFIC REQUIREMENTS FOR PIPING ....................................................................10

4.1 Applicable Drawings and Forms ............................................................................................10

4.2 Insulation Requirements ........................................................................................................11

4.3 Weather Jacket Requirement..................................................................................................14

4.4 Insulation for Traced Lines ....................................................................................................16

5.0 SPECIFIC REQUIREMENTS FOR VESSELS, COLUMNS,

AND HEAT EXCHANGERS..............................................................................................18

5.1 Applicable Drawings and Forms ............................................................................................18

5.2 Insulation Requirements ........................................................................................................18

5.3 Weather Jacket Requirements ................................................................................................20

6.0 SPECIFIC REQUIREMENTS FOR MISCELLANEOUS EQUIPMENT .........................23

6.1 Applicable Forms .................................................................................................................23

6.2 Protection of Mechanical Equipment ......................................................................................23

6.3 Plastic Insulation...................................................................................................................23

7.0 INSPECTION ....................................................................................................................24

8.0 FORMS AND DRAWINGS ................................................................................................24





1.0 SCOPE

This specification covers the requirements for insulating hot surfaces on vessels, heat exchangers,

piping, and equipment using conventional types of insulation such as calcium silicate, mineral wool,

fiberglass, or cellular glass. This specification does not include storage tank insulation,

polyurethane foam insulation, the insulation of equipment operating at temperatures below ambient,

or the insulation of furnaces and buildings.

1.1 The equipment to be insulated and the insulation item number are listed on the attached Form

IRM-EF-630.

2.0 MATERIALS

2.1 Acceptable Materials

Standard Drawing GD-N99993, Standard Insulation Item Numbers, shows materials

acceptable to the Company. Other materials may be used only with the written approval of

the Company. Materials referenced in this specification as "N" item numbers are found on

Drawing GD-N99993.

2.2 Insulation

2.2.1 All insulation materials shall be asbestos-free. There shall be some indelible

indicator, such as color, on the insulation that identifies it as asbestos-free, so that

workers on subsequent repairs can readily identify insulation, at any location, as

being asbestos-free.

Comment 2.1 Standard Drawing GD-99993 lists common acceptable insulating materials

and accessories. We typically allow the Contractor to choose the insulation material

provided it meets the temperature requirements of the service. However, you may choose to

specify the material for particular needs (i.e., CalSil in areas of high foot traffic). For

additional information on material selection criteria, see Section 100 of the Insulation and

Refractory Manual.

2.2.2 All materials shall be new

2.2.3 Insulation material for all applications shall be capable of meeting ASTM C-795 for

leachable chloride ion content. All mastics, cements, and other material used with

insulation for austenitic stainless steels shall contain less than 100 ppm leachable

chlorides.

Comment 2.2.3 Insulation must be low in chlorides to help prevent chloride

cracking of the stainless steel as well as general corrosion of carbon steel if the





insulation becomes wet. Most common insulating materials meet this requirement so

it is not overly restrictive.

2.2.4 Insulation materials shall be used only within the temperature limits specified in

Drawing GD-N99993.

Comment 2.2.4 We limit fiberglass to 450F because the insulation can sag if the

binder burns. Manufacturers rate fiberglass higher than our limit. We rate calcium

silicate, mineral wool, and perlite to 1100F. Above this temperature, ceramic fiber

is required. Cellular glass is specified up to 350F even though manufacturers rate

it to 900F. For applications between 350F and 900F, a specially-fabricated,

single-layer cellular glass product is available. However, we do not have any

experience with it and have not fully reviewed its technical merits to recommend the

product in this specification. Additionally, there are pre-fabricated insulation

systems (weather jacket is laminated to insulation) which have been used in arid

locations. These systems offer potential cost savings but we have not reviewed fully

their technical merits to include in this specification. Experience at one location has

shown that the quality of the systems varies considerably and the poor quality

systems have failed.

2.2.5 Manville/Schuller, Thermo-12 is the preferred insulation where calcium silicate is

specified. The preferred insulation on stainless steel is perlite silicate for added

corrosion protection.

Comment 2.2.5 The Thermo-12 calcium silicate has reduced breakage. The perlite

silicate has a high rate of leachable inhibitors to reduce corrosion of the substrate.

Perlite silicate is also moisture resistant.

2.3 Stainless Steel

Throughout this specification, the term "stainless steel" shall mean an austenitic stainless steel

such as Type 304.

2.4 Weather Jacketing

2.4.1 Aluminum sheet with corrosion/moisture barrier of 40-pound Kraft paper and 3 mil

polyethylene, Childers or RPR process, or approved equal. Temper shall be in the

range of H14 through H19, conforming to ASTM B209. Preformed aluminum weather

jacket for pipe elbows shall be 1100 dead soft alloy with the corrosion/moisture

barrier.

Comment 2.4.1 The Kraft paper and polyethylene protects the aluminum from

corrosion on the underside where moisture will condense. We have seen severe

aluminum corrosion where the weather jacket was not coated. Copper content





should be limited to 0.40 because aluminum alloys containing more than that are

not as corrosion resistant. Change 1-mil polyethylene to 3-mil since 1-mil has pin

holes which leads to corrosion of the jacket from the inside by the caustics in the

insulation. The cost difference is small. Changed the aluminum specification to

agree with market availability.

2.4.2 Mastic weathercoating shall be used only where metal Weather jacketing is not

feasible and within the limitations of Section 3.5. Emulsion-type mastic coatings are

preferred (N208). Solvent-base mastic coatings shall be used only with written

approval of the Company, and shall be considered only when weather conditions at

the time of application would not permit satisfactory curing of emulsion-type

materials.

Comment 2.4.2 Mastic coatings are only intended for irregular-shaped areas

which cannot be jacketed with metal.

2.4.3 Stainless steel, Galvalume AZ-60 steel, or coated carbon steel shall be used where

fire-resistant weather jacket is specified. Do not use galvanized jacketing on stainless

steel pipe and equipment.

Comment 2.4.3 Aluminum has a low melting point and is not considered "fire-

safe." Use the alternate metal weather jackets where fire protection is a major

concern. Stainless steel is preferred but galvanized steel and coated carbon steel

are acceptable too. They do not have the corrosion resistance and so may become

"unsightly" with time. In the event of a fire, zinc in the galvanizing will cause stress

cracking of stainless steel. Substituted Galvalume AZ-60 for galvanized steel since

it is more resistant to environmental corrosion and is readily available from

insulation distributors.

2.5 Weather Jacket Attachment Fixtures

2.5.1 Fixtures shall be stainless steel, except that sheet metal screws, pop rivets and stud

caps may be aluminum (0.40% maximum Cu). Clips used to support weather jacket

panels and bands (S- and J-clips, Details 9 & 10 on GD-N99995) shall be 0.040-inch

minimum thickness stainless steel. Pop rivets (N342) shall be of the type where the

mandrel is retained after setting.

Comment 2.5.1 Stainless steel is the standard available material for attachment

fixtures.

2.5.2 Threaded welding studs shall be 1/4-inch diameter, unless otherwise specified, and be

of solid stainless steel, or composite with stainless steel at the exposed end and

carbon steel at the welding end.





Comment 2.5.2 The composite stud is preferred because its more easily welded to

carbon steel and has the improved atmospheric corrosion resistance of stainless

steel.

2.6 Storage of Materials

All insulation and necessary materials shall be protected from moisture during storage and

installation. Wet insulation is unacceptable and must be replaced with dry materials.

Comment 2.6 Wet insulation has extremely poor insulating value and it dries slowly even

in service at high temperatures.

3.0 GENERAL INSTALLATION REQUIREMENTS

3.1 Condition of Surfaces to Be Insulated

3.1.1 All surfaces to be insulated shall be clean and dry.

Comment 3.1.1 Surface must be dry to prevent the insulation from absorbing

water.

3.1.2 Contractor shall prime surfaces operating below 200F with Coating System 1.4 per

COM-EG-4743. No coating is required for surfaces operating at higher temperatures.

Comment 3.1.2 Some locations have experienced severe corrosion just above

external stiffening rings on vessels operating below 200F. The rings dam up water

which then saturates the insulation and corrodes the steel. It is critical that the

primer coating be applied here. Also, consider drilling holes in the ring to allow

water to drain.

3.1.3 No insulation shall be installed until completion of any stress-relieving and chemical

cleaning and after hydrotest inspection and release in writing.

Comment 3.1.3 One does not want to remove new insulation either for repairs or

because the hydrotest water soaked the insulation at a leak.

3.2 Insulating Cement and Bore Coatings

All voids (not straight through voids) and cracks in insulation shall be filled with an insulating

cement (N202). The side of cellular glass insulation exposed to the hot metal surface shall be

coated with a bore coating (N454) in severe vibrating systems and systems where the

substrate has been painted for corrosion protection.





Comment 3.2 Air gaps increase heat loss. Cellular glass has a rough surface which can

progressively abrade away if placed on a severely vibrating line. Bore coating creates a

smooth insulation surface to prevent abrasion. Insulation cement is not a substitute for

insulation. It has a poor K value and a short service life. Cellular glass without a bore

coating can destroy a paint system where expansion and contraction takes place.

3.3 Valve Bodies, Flanges, and Manways

All carbon steel or low alloy valve bodies, pipe flanges, manways, and exchanger body

flanges that operate at temperatures up to 750F shall be insulated. Flanges operating above

750 will be insulated only if specified by the Company. Stainless steel flanges shall be

insulated only if they wont get hotter than 400F. Flexible, reusable insulation covers, as

defined in Specification IRM-EG-4197, shall be used except for screwed and welded

fitting/valves where permanent insulation is preferred.

Comment 3.3 The temperature limit for carbon steel and low alloy flanges is to prevent

creep of the B7 studs. Above 750F, the studs may elongate enough to cause a leak. The

temperature limit for stainless steel is based on increased stress from the differential

thermal expansion between a stainless steel flange and carbon steel studs. See section 150

of the Insulation and Refractory Manual for more information on the design and insulation

of hot flanges.

3.4 Double-Layer Insulation

For metal temperatures above 650F, double-layer insulation shall be used, except on piping 1

inches and smaller. Double-layer insulation on horizontal piping may be required at lower

temperatures where open joints or heat loss cannot be tolerated. Regardless of temperature,

for insulation thickness greater than 3 inches, double-layer insulation shall be used. Insulating

material used for both layers shall be capable of withstanding the maximum metal

temperature, unless otherwise approved by the Company.

Comment 3.4 Insulating materials shrink as they are heated. We require double-layer

insulation where thickness would cause a single layer to crack or contract and separate

from the metal. The second layer prevents through-thickness gaps. Expansion joints on

horizontal piping do not compensate for open joints. Therefore, double-layer insulation

provides the only means to prevent excessive heat loss or hot spots where temperature

control is critical.

3.5 Weather Jacketing

3.5.1 Piping and equipment shall be weather jacketed with aluminum sheet, except as

indicated in Sections 3.5.2, 3.5.3 and 3.5.4.





3.5.2 Mastic weathercoat (N208) may be used on surfaces of complex shapes, where not

prohibited by paragraph 3.5.3 of this specification. It shall be used only on calcium

silicate, perlite and cellular glass insulation and where the surface temperature of the

insulation will not exceed 180F. Emulsion-type weathercoating shall not be applied

when atmospheric precipitation or condensation may wet the finished surface within

24 hours after application.

Comment 3.5.2 Mastics should only be applied to rigid insulation because it is

difficult to apply to "flexible" insulation and can more easily crack in service.

3.5.2.1 The mastic weathercoat shall be constructed as follows for most applications:

a. Apply a layer of finishing cement (N203) over the insulation to provide a

smooth, even surface.

b. Apply a tack coat of mastic (N208) by trowel, brush or spray.

c. While still wet, embed with glass fabric (N215). Lap joints 2 inches.

d. Apply finish coat of mastic immediately following the set of tack coat,

while still damp (N208) to completely cover fabric. The total dry film

thickness shall be a minimum of 1/8 inch.

On large fittings and equipment (insulation OD greater than 12 inches) or

vessel heads, use poultry mesh (N330) in place of glass fabric. Poultry mesh

shall be laced with wire (N349) and stapled (N340) with edges tightly

together. Apply tack coat of mastic flush with the wire mesh. Apply finish

coat of mastic immediately following the set of tack coat, while still damp.

Total dry film thickness shall be minimum 1/8 inch or as specified by the

mastic manufacturer. Any exposed poultry mesh shall be recoated.

Comment 3.5.2.1 Poultry mesh is stronger and more durable than glass

fabric. Thus it is used on larger applications where strength is more

critical. Provide more detailed method of applying mastic per the

manufacturers guideline which should improve the life of the system.

Replaced black wire with stainless steel wire to match the stainless mesh

and eliminate corroding.

3.5.3 Within 25 feet of furnaces, weather jacket shall be fire-resistant and insulation shall

be calcium silicate, perlite or cellular glass. Weather jacket on piping and equipment

shall be stainless steel, Galvalume AZ-60 steel, or coated steel, rather than aluminum.

Flammable weathercoating shall not be used. The Company will specify where

fire-resistant weather jackets are required for other equipment.





Comment 3.5.3 Rigid insulation is preferred where fire resistance is important.

Rigid insulation will better withstand any mechanical loads imposed on it in a fire.

Replaced galvanized steel with Galvalume AZ-60 steel for improved corrosion

resistance and readily available from insulation distributors.

3.5.4 For offshore facilities, stainless steel (N219) weather jacking shall be used in lieu of

aluminum.

Comment 3.5.4 Experience on offshore platforms has shown aluminum to pit

rapidly in this environment. Stainless steel is specified to prevent premature

corrosion failure.

3.5.5 Weather jacketing shall prevent entry of liquid water into the insulation under all

normal weather conditions. The following are examples of unacceptable Weather

jacketing techniques: upward-facing overlaps in aluminum weather jacket which

collect rather than shed water run-off, unsealed or unflashed gaps where weather

jacket is penetrated by structural members or nozzles, and lack of weathertight

end-seals where the pipe insulation terminates.

3.5.6 Troweling, rolling or applying mastics, adhesives, caulking compounds, tape or

exterior finishes shall not be performed below 40F or in wet weather.

Comment 3.5.6 Added precautionary note to maintain good practices and prevent

failure.

3.6 Insulation Interference

Where insulation interferes with support structures or equipment, coordinate installation with

Owners Construction Representative. Where interference requires reduction of the insulation

thickness, the weather barrier still shall be complete and continuous.

Comment 3.6 The integrity of the weather barrier must be maintained at the expense of

insulation thickness. An unreliable weather barrier will cause the entire insulation system to

fail.

4.0 SPECIFIC REQUIREMENTS FOR PIPING

4.1 Applicable Drawings and Forms

Piping shall be insulated in accordance with Form IRM-EF-630 and Drawing GD-N99783.

Lines 36 inches in diameter and over shall be insulated as a vessel. The specific thickness of

insulation does not include Weather jacketing.





4.2 Insulation Requirements

4.2.1 Insulation shall be calcium silicate, expanded perlite, or cellular glass preformed pipe

insulation. Mineral wool and fiberglass insulation shall be used only when specified

by the Company. Manville/Schuller Thermo-12 is the preferred insulation where

calcium silicate is specified. The preferred insulation on stainless steel is perlite

silicate for added corrosion protection.

Comment 4.2.1 Recent project experience showed that non-rigid insulation such as

fiberglass and mineral wool was easily damaged from construction activity. The

weather jacket was an "eyesore" where it had been bent and crushed. Other

concerns about damaged weather jacket are that it may allow water to more easily

penetrate to the insulation and the insulation is less efficient if crushed. If these are

not a concern for a specific area, then non-rigid insulation is acceptable. The

Thermo-12 Calcium silicate has reduced breakage. The perlite silicate has a high

rate of leachable inhibitors to reduce corrosion of the substrate. Perlite silicate is

also moisture resistant.

4.2.2 Insulation, 12 inches OD and less, shall be secured with 18-gage stainless steel wire

(N349). Larger diameters shall be secured with stainless steel straps (N336). On

double-layer insulation where insulation diameter exceeds 14 inches, the outer layer

shall be secured with -inch x 0.015-inch stainless (N336) steel straps instead of

wire. Regardless of diameter, cellular glass insulation shall be secured with straps

(N336).

Comment 4.2.2 The increased strength of the wire is important for large

diameters to insure the wire can hold the increased weight of insulation. On large

diameters of double-layer insulation, the straps are recommended because the wire

can more easily cut through the insulation while tightening it down. Replaced

galvanized steel wire with stainless since the galvanized steel wire causes a

problem when radiographing the pipe through the insulation system.

4.2.3 Insulation shall be secured on 9-inch centers.

Comment 4.2.3 Nine inches is considered an optimum for long-term performance.

4.2.4 Longitudinal joints of single-layer insulation and longitudinal and circumferential

joints of double-layer insulation shall be staggered (i.e., adjacent joints shall not

align).

Comment 4.2.4 Good practice is to not align joints, to minimize heat loss and to

provide an integrated construction for support.





4.2.5 Insulation on vertical piping shall have ring supports with an expansion joint as

indicated (Detail 3, GD-N99783) installed at the bottom of the pipe run and above

interruptions in the pipe run such as at flanges and valves. However, their maximum

spacing shall be:

Pipe Operating Temperature (F) Maximum Ring Spacing (ft.)

0-360 21

361-400 18

401-480 15

481-560 12

461-1200 9

Support rings are not required for vertical rises less than six feet when measured from

the bottom of a pipe run or from a support at an interruption.

Comment 4.2.5 Support rings allow the pipe to carry the weight of the insulation.

Rings are placed at interruptions to prevent the insulation from resting on flanges,

etc. Overall spacing is determined by weight. An expansion joint is part of the

system.

4.2.6 Expansion joints on horizontal straight pipe are not recommended. Where insulation

gaps, hot spots on the jacketing or excessive heat loss cannot be tolerated install

double-layer insulation with staggered joints per Section 4.2.4.

Comment 4.2.6 Expansion joints on horizontal pipe is deleted since they do not

compensate nor adjust to the extreme difference of measurement caused by an

expanding line and a shrinking insulation. It would be necessary to install an

expansion joint at every three foot section of pipe insulation.

This cannot be justified. Therefore, double-layer insulation is the recommended

method to overcome excessive insulation gaps.

4.2.7 Where specified, welded or screwed fittings and valves, 1 inches and smaller shall

be insulated with calcium silicate or perlite silicate pipe cover, or fibrous blanket to a

thickness of the adjacent insulation. Weather coating shall be per paragraph 3.5.2.1

only if aluminum weather jacket is impractical.

Comment 4.2.7 Added paragraph 4.2.7 for guidance on insulating small fittings

and valves.

4.2.8 Where specified, welded or screwed fittings and valves, 2 inches or larger, shall be

fabricated with calcium silicate insulation to a thickness of the adjacent insulation.

Insulate elbows with commercially molded or routed 2-piece fitting covers of perlite





silicate or calcium silicate as required. On sizes which are not commercially available

and the fitting covers are fabricated from pipe insulation, use thickness equal to that

of the pipe insulation. Mitered fitting covers shall have the proper number of miters

to provide clearance for the metal covers. Some rasping of the miters is acceptable.

The joints on the mitered fittings shall be true and tight. Perlite silicate fitting covers

may be used with calcium silicate piping sections. Pipe bends shall be insulated with

preformed insulation mitered segments. Insulation securement shall be per paragraph

4.2.2. Each segment shall be secured with not less than one wire/band. Factory cast

2-piece elbows shall be secured with wire/band on centers equivalent to the maximum

preformed insulation segments.

Comment 4.2.8 Added paragraph 4.2.8 for guidance on insulating large fittings

and valves.

4.2.9 Personnel protection (above 140F):

a. Insulate piping systems if less than 7 feet above or 3 feet from the edge of a

platform or walkway.

b. Tracer loops will be insulated for personnel protection. Double wrap loop

with aluminum foil (N249). Wrap loop with inch tempmat (N212) and

secure with 18 gauge stainless steel wire (N349). Spiral wrap with 2 inch

glass fiber tape (N244) overlapping 1 inch to provide two glass fiber tape

(N244) overlapping 1 inch to provide two layers of tape. Secure tape with

stainless steel wire (N349). Apply mastic (N208) to 1/8 inch dry film

thickness.

c. Where required by drawings, galvanized, 1 inch flattened, 16 gauge, expanded

metal (N245) will be used.

d. Valves and flanges requiring insulation for personnel protection shall be

insulated with conventional system in lieu of removable covers.

Comment 4.2.9 Added paragraph 4.2.9 for guidance on insulating where

personnel protection is required.

4.2.10 Instrument tubing insulate as per paragraph 4.2.9.b.

Comment 4.2.10 Added paragraph 4.2.10 for guidance on insulating instrument

tubing.

4.2.11 At flanged joints, stop the insulation 1 bolt length plus 1" to the back of each flange.

Do not bevel the insulation. See Detail 7 GD-N99783-5.





Comment 4.2.11 Provide specific information on clearance to prevent damage to

insulation while performing maintenance to the flanges. Common practice for bolt

clearance is to bevel the terminated insulation. However, the beveled portion of

insulation fails.

4.2.12 Piping specified shall be insulated individually. No "gang" insulation will be

permitted.

Comment 4.2.12 Multi-pipe vibration and movement will destroy the insulation.

Configuration makes insulating and sealing from moisture intrusion difficult.

4.2.13 Where possible, on pipe 10 inches and smaller, make provisions or indicate in the

pipe specifications to support all new lines outside the insulation jacket except where

guided supports or anchors are used. Support with a 180 degree, 10 gage galvanized

steel saddle (length to be 1.5 times the OD of the insulation) or equal. Secure the

saddle with stainless steel bands at each end. On hung pipe, use clevis hangers to

accommodate the saddle.

Comment 4.2.13 By supporting pipe outside the insulation system protrusions

through the insulation weather barrier are eliminated, thus, reducing possible

points of moisture entry to the insulation.

4.2.14 All insulation cuts for protrusions such as hanger, nozzles or nipples must be tightly

fitted. No gaps are permitted around these cutouts.

Comment 4.2.14 Tightly fitted insulation will reduce excessive heat loss.

4.3 Weather Jacket Requirement

4.3.1 Aluminum smooth roll jacket for applications up to and including 20 inches OD, the

jacket shall be minimum 0.016 inches thick (N242). Above 20 inches OD the jacket

shall be minimum 0.024 inches thick (N229). Use aluminum within the limitations of

Section 3.5.4 All jacketing shall be machine cut and curled.

Comment 4.3.1 16 mil aluminum jacketing is not suitable outdoors for long term

protection on large diameter piping. Exposure to elements and mechanical abuse

causes thinner aluminum to wrinkle, fishmouth and corrode. Corrugated aluminum

is prohibited since the corrugations on horizontal lines act as troughs and collect

moisture at the top which can seep through the circumferential jacket seam into the

insulation.

a. Use aluminum fitting covers on all fittings to the largest commercially

available size. For larger sizes install aluminum gore covers. Humped fitting

covers are not permitted except on screwed and socket welded fittings. Two





piece elbows (N246) and four piece elbows (N251), shall be fastened as

follows: 6 inch insulation OD and under with screws (N344). Greater than 6

inch insulation OD with rivets (N343). The cover seams shall overlap a

minimum of inch. Seal the seams with a bead of caulking sealant. All

fasteners securing heel shall be on no more than 6 inch centers. Elbow cover

seams shall be installed in a watershed fashion.

Comment 4.3.1 (a.) Metal el covers should be used whenever possible to

reduce source of moisture entry (fewer seams). Added four piece covers for

larger elbows. These were recently introduced by Childers Products Co.

Humped or Universal type covers create a cavity when used on long and

short radius elbows. The cover can be pushed in at the heel with very little

pressure, thus, a source of moisture entry. Greatest problem with metal

covers is improper sizes where the seams do not completely overlap. Tight

closure of seams are in some cases difficult to attain therefore seal with

bead of caulking. Cover seams installed in a non-watershed fashion will

collect moisture which will eventually seep into the insulation.

b. Gore type elbows shall be .024 inch, smooth, preformed aluminum segments

(N231) and fastened with rivets (N343). If stainless steel is used, use (N220)

and rivets (N352). Rivets shall be spaced equally at heel, throat, and sides.

Comment 4.3.1 (b.) Added paragraph 4.3.1 (b.) to provide detailed

information on metal gore systems.

4.3.2 Weather jacket shall be overlapped 2 inches longitudinally and circumferentially.

Longitudinal joints shall be staggered between the three oclock and nine oclock

positions. On horizontal piping, seal under the circumferential overlap with a

continuous bead of caulking sealant (N206).

Comment 4.3.2 The 2-inch overlap helps to prevent water penetration under windy

conditions. The rolled hem at the longitudinal seam helps make the joint water

shedding and stronger; it is standard practice. Deleted the rolled hem since this

application is unnecessary when jacketing is secured on 9-inch centers. Sealing the

circumferential lap will prevent moisture from migrating into the insulation which

has been experienced.

4.3.3 For insulation larger than 12 inches OD, secure jacket with 3/4-inch x 0.020-inch,

stainless steel straps (N334) with buckles (N335) on 9-inch maximum centers. For

insulation 12 inches OD and smaller use -inch x .015-inch straps (N336) and

buckles (N337).

Comment 4.3.3 Some suppliers feel 12-inch spacing for straps is satisfactory;

however, we prefer 9 inches for long-term service.





4.3.4 Install end caps at all insulation terminations. The preferred method of end capping is

shown on Details 6, 7, and 11 GD-N99783, insulation item numbers N232 and N233.

4 inch insulation OD and under, crimp without extended leg. Greater than 4 inch

insulation OD Pittsburgh seam with extended leg.

Comment 4.3.4 Where possible, end caps should have Pittsburgh seams with

extended legs for moisture protection.

4.3.5 Any gap or separation greater than 1/8 inch in the metal jacketing is not acceptable for

caulking and must be rejacketed at those locations. All penetrations in weather jacket

shall be caulked with a full bead of sealant (N206). Do not feather edge the bead of

sealant. Apply sealant to a clean, dry surface on the same day the jacket is installed

and at the recommended temperature range.

Comment 4.3.5 Wet insulation is usually caused by failed caulking at joints. The

proper application of a caulking sealant should last the life of the insulation system.

However, recaulking is usually the result of a poorly applied initial application.

4.3.6 Weather jacket on vertical piping shall have S-clips to prevent telescoping of the

jacket. Lines up to 18 inches in diameter shall have two S-clips fabricated from 3/4

inch strapping (N334), spaced 180 degrees apart. Larger lines shall have four S-clips

90 degrees apart. Weather jacket straps shall be supported by screws (N344) under

the straps of the same number and spacing as S-clips. Strapping at the jacket overlap

shall be supported by the S-clips. Fabricate the S-clips for a 2 inch overlap.

Comment 4.3.6 Unnecessary to use special S-clips and J-clips on vertical piping.

The loads are small and the method indicated above is more cost effective.

4.4 Insulation for Traced Lines (Excluding Electric Tracing)

Traced lines shall be insulated with oversized insulation capable of withstanding maximum

tracing temperature as well as stock temperature. Do not notch the insulation to accommodate

the tracer. On large piping, stabilize the insulation to the pipe with shims constructed of

insulation.

4.4.1 Tracer shields shall be used in all cases. Shields shall be constructed of 28-gage

sheet steel (N222) and be secured with 14-gage wire (N332) on 12-inch centers.

Shields are not required within two feet of a flange or fitting. Galvanized steel

channels (N252) are available from HTM vendors.

Comment 4.4.1 The tracer shield secures the tracing to the pipe. This design

prevents the tracer from expanding into the insulation during operations.





4.4.2 Distinctive weatherproof markers shall be applied to the outside of the weather

jacket, at intervals of no more than ten feet, to mark the full length of the route of the

tracing. The type of marker used shall be approved by the Company.

Comment 4.4.2 This helps operators locate the steam source and steam traps for

each tracer.

4.4.3 For small steam tracer supply lines and steam trap condensate return lines,

pre-insulated tubing is preferred (N100). For proper sealing at connections use the

preinsulated tubing manufacturers fitting kits.

Comment 4.4.3 Pre-insulated tubing is cost-effective when compared to field

insulating small diameter tubing. The alternative insulation tape is not durable and

typically fails within a couple of years. Most failures on pre-insulating tubing occur

at poorly sealed connector points. Therefore, it is important to use the

manufacturers fitting kits rather than some field method.

4.4.4 Heat transfer medium (HTM) material is available in mastic and premolded. The

nonharding type is generally recommended where the temperature does not exceed

400F, since curing or drying is not required, has excellent heat transfer, easy to

remove, and requires no surface preparation. Follow HTM manufacturers

instructions for proper design heat transfer.

Comment 4.4.4 Added paragraph 4.4.4 on guidance with the application of HTM.

Improper selection and application of HTM can result in a under performed traced

system.

4.4.5 Heat tracing shall be located on pipe so as not to be between the pipe and the support

load.

Comment 4.4.5 Prevent damaging the tracer and/or the insulation.

4.4.6 Steam tracer connections or couplings shall be located out side the pipe insulation.

The tracer jumpers shall be sealed with a generous bead of high temperature caulking

compound where it protrudes from the weather barrier. Insulate jumpers as per

paragraph 4.2.9 (b).

Comment 4.4.6 Most steam leaks occur at the couplings. Should a leak occur

inside the insulation the entire insulation system would be destroyed before it is

detected.





5.0 SPECIFIC REQUIREMENTS FOR VESSELS, COLUMNS, AND HEAT EXCHANGERS

5.1 Applicable Drawings and Forms

Block insulation shall be applied in accordance with Form IRM-EF-630 and Drawing

GD-N99785. The specified thickness of insulation does not include weather jacketing. The

sidewall insulation shall be cut and scored to fit the shape and contour of equipment 10 feet

OD and less.

Comment 5.1 Adjoining insulation blocks must be completely butted together to reduce

excessive heat loss. The gaps on small equipment are usually excessive and the application

of insulation cement to fill the gaps is unacceptable. Insulation cement is not thermally

efficient and breaks apart from expansions.

5.2 Insulation Requirements

5.2.1 Heat exchanger shells less than 36 inches in diameter shall be insulated in the same

manner as piping, Section 4.0. All other vessels, columns and heat exchangers shall

be insulated according to Sections 5.2 and 5.3. The sidewall insulation shall be cut

and scored to fit the shape and contour of equipment 10 feet OD and less.

5.2.2 Calcium silicate, perlite, or cellular glass block insulation shall be used for the top

heads of vertical vessels and for the upper one-third of the circumference of

horizontal vessels, to support foot traffic. It is preferred that perlite silicate insulation

be used on stainless steel equipment heads. It is preferred to use engineered vessel

head segments on complex heads.

Comment 5.2.2 Rigid insulation better withstands foot traffic associated with these

areas. If foot traffic is not a concern, the requirement can be eliminated.

Recommend perlite silicate which contains a high rate of inhibitors for application

on stainless steel to prevent corrosion. Engineered vessel head segments are

available up to 20 feet in diameter and for all head configurations. They provide

excellent fit-up with reduced labor. Cement coated the head is unnecessary.

5.2.3 The shell block insulation shall be secured with 3/4-inch x 0.020-inch stainless steel

straps (N334) on 12-inch centers. Each strap shall have one buckle (N335) per

connection.

Comment 5.2.3 Straps on 12-inch centers are necessary to secure the blocks to the

shell. The stronger straps help insure that they can handle the loads from expansion

of the vessel at operating temperatures.

5.2.4 Circumferential joints shall be staggered on single-layer insulation. Circumferential

and longitudinal joints shall not align between layers of double-layer insulation.





Comment 5.2.4 Non-aligned joints helps insure a stronger insulation matrix (i.e.,

adjacent blocks support each other) and prevents gross gaps in the insulation. The

longitudinal joints should also not align on double-layer insulation.

5.2.5 When insulating vessel heads, insulation straps shall be attached to a support ring

(N501) centered on the head. Straps shall be spaced a maximum of 6 inches around

the ring so that each block is well fastened. Intermediate rings may be necessary to

prevent the straps from stacking. Straps shall not be carried completely around the

vessel head. The straps shall be tensioned in sequence to ensure a positive securing

of the insulation. Secure each head strap to one of the two tie-down straps below the

head weld line by alternating. The tie-down strapping shall be 1 1/4 inch x 0.020 inch

stainless steel (N353), Detail 3 on GD-N99785-6.

Comment 5.2.5 The "support ring" construction (Detail 3, GD-N99785) insures

each block will be fastened. Provide proper tensioning of the head straps and

indicate securement to the straps. Specify larger tie-down straps for additional

strength.

5.2.6 On equipment 4-0" diameter and greater operating above 400F a minimum of one

expansion spring (N341) per insulation strap shall be provided with an additional

expansion spring (N341) every 25 feet for both single- and double-layer construction.

Folded straps, corrugated straps, and similar tensioning devices which tend to relax

are not acceptable. Cut a pocket in the insulation for the expansion spring.

Comment 5.2.6 Expansion units maintain the strap tension when the vessel

diameter increases from thermal expansion. The diameter and temperature

requirements are based upon the diameter increase at operating conditions.

Calcium silicate and perlite insulation is very rigid. Therefore, all the expansion is

absorbed by the straps. This is true of small diameter equipment as well. A pocket

in the insulation will allow the expansion spring to move freely.

5.2.7 Expansion joints are not required on horizontal vessels. Where insulation gaps cannot

be tolerated specify double-layer insulation. Expansion joints on vertical equipment

shall be provided at every insulation support ring or stiffener ring. The 1 inch

expansion space below the support ring shall be packed with glass wool (N345).

Comment 5.2.7 Similar to piping (see Section 4.2.6), the insulation will shrink at

high temperatures so the joint prevents excessive heat loss through gaps. The

expansion joints on horizontal vessels were deleted simply because they do not

work. The expansion is distributed equally across the entire surface of the vessel

and will not be absorbed on 20 feet segments. The only way to compensate for the

expansion is to pack every insulation joint with glass wool. This method is to costly.





At elevated temperatures double-layer insulation with staggered joints is the only

solution. On vertical equipment the expansion joints as indicated will function since

the weight of the insulation will prevent intermediate gaps between the lower

insulation support and the above expansion joints.

5.3 Weather Jacket Requirements

5.3.1 Aluminum weather jacket shall have a thickness of 0.024 inch (N227). Stainless steel

and Galvalume AZ-60 steel sheeting shall be 0.010-inch thick (N219, N220). The

shells of vertical equipment shall be weather jacketed with 1 1/4-inch pitch corrugated

sheet (N227). It may not be practical to use corrugated sheeting on small diameter

equipment in which case use smooth roll jacketing (N229). The shells of horizontal

equipment shall be smooth roll jacketing (N229). Do not use corrugated jacketing on

horizontal equipment. All weather jacket for exposed heads shall use flat sheet

(N229). All circumferential seams on horizontal equipment shall be sealed with a

continuous bead of caulking sealant (N206) under the overlap.

Comment 5.3.1 The corrugated weather jacket is stronger and more rigid than

smooth jacket to resist mechanical loads associated with large diameter vessels.

Weather jacket for exposed heads commonly comes as flat sheet. The increased

sheet thickness provides additional strength for large diameter equipment.

Corrugated sheeting is difficult to install on small diameters. Sealing the

circumferential joint will prevent moisture migration to the insulation which has

been experienced. Changed galvanized to galvalume steel for added corrosion

resistance.

5.3.2 Weather jacket shall be secured with 3/4-inch x 0.020-inch stainless steel straps

(N334) on 18-inch maximum centers and at the circumferential overlap for corrugated

jacketing and on 9 inch maximum centers for smooth jacketing.

Comment 5.3.2 Eighteen-inch spacing is generally specified for vessels since the

corrugations provide mechanical support too. The circumferential lap must be

supported with a strap. Smooth jacketing require additional straps for support.

5.3.2.1 When specified by the Company using corrugating sheeting for high wind

areas, straps shall be on 12-inch maximum centers. Seams shall have rivets

(N342) on 6-inch centers instead of 9-inch centers where specified in Sections

5.3.4. and 5.3.7. Specify paragraph is for corrugated sheeting and indicate

cherry T type rivets for additional strength.

Comment 5.3.2.1 Where wind loadings are a significant concern (i.e., in

the hurricane regions of the Gulf coast), decrease the strap spacing for

more support. Pop rivet spacing is decreased for mechanical support as

well.





5.3.3 The circumferential and longitudinal laps in the weather jacket shall be a minimum of

3 inches when using the cross-crimp corrugated or smooth rolled sheet. The lap in the

1 1/4-inch pitch corrugated sheet shall be two corrugations.

5.3.3.1 Cut the metal jacket so that the vertical seams overlap at the center of the

nozzles. Where it is practical use metal collars or back-up strips secured by

pop rivets (N342).

Comment 5.3.3.1 This procedure may be standard practice; however, if

this is not done the result is a poor fit-up to the nozzle causing gaps for

moisture entry.

5.3.4 On vertical equipment, the circumferential lap of the weather jacket shall be

supported by S-clips. Each sheet shall have at least one clip in the center of the sheet

and one at the vertical lap. In addition, vertical laps shall be secured with pop rivets

(N342) on 9-inch centers. However, at least two vertical laps 180 degrees apart shall

not be riveted to allow for thermal expansion.

5.3.5 On vertical equipment, greater than 8 feet in diameter all straps shall be supported by

J-clips on 4-6" centers, except straps located at the circumferential laps.

Circumferential lap straps shall be supported by S-clips located per Section 5.3.4.

Comment 5.3.5 J-clips prevent the straps from sagging and prevent them from

twisting. At circumferential laps in the weather jacket sheet, S-clips are easy to

install and serve the same purpose as J-clips. On small diameter equipment the

straps can remain tight and in position without the need for J-clips.

5.3.6 To determine number of dual spring expansion units (N338) Detail 6, Drawing GD-

N99995 for use with weather jacketing straps the outside diameter of the insulation

and operating temperature must be known. Pretension all expansion springs by 1/4

inch to prevent sagging.

Example: OD of Insulation = 12 feet

Circumference of Insulation = (12 feet) (3.1416) = 37.7 feet

Opr Temp = 800F Ambient Temp: Assume 50F

Expansion of Vessel (assume carbon steel) will be equal to =

0 82837 7

100

800 50

1002 34.

. ( ).

=

feet F Finches





Hence three dual spring expansion units will be required - place at 120 spacing

(equally spaced). In all cases there shall be a minimum of one expansion spring for

all applications.

Comment 5.3.6 Provide a more direct method to determine expansion spring

requirements.

5.3.7 On horizontal vessels, circumferential laps shall be sealed with a continuous bead of

caulking sealant (N206) and secured with banding (N334).

Comment 5.3.7 The S-clips on longitudinal laps and pop-rivets on circumferential

laps were deleted since they serve no purpose.

5.3.8 Aluminum weather jacket for exposed heads shall be "gore and crown" with laps

"beaded and crimped." Gores shall be overlapped a minimum of 3 inches. The

maximum width of the section shall be pre-determined to assure a tightly conformed

fit to the head. The number of gore sections shall be kept to a minimum. All laps

shall be secured with pop rivets on 4-inch centers and caulked with sealant (N206).

Comment 5.3.8 The weather barrier on the head of equipment requires detailed

installation instruction since this is the area where the majority of insulation

failures begin on equipment.

5.3.8.1 The edge of the segmental sections shall extend down over the shell jacketing

by a minimum of 4 inches. Do not pop rivet the gore section to the shell

jacketing. Install an aluminum beauty band with fabricated beads on both

edges at the overlap. Apply a continuous bead of caulking sealant at the top

beaded edge of the band. Secure the beauty band to the gore with pop rivets

on 6 inch centers and two 3/4 inch bands with breather springs.

5.3.8.2 Upon installation of the gore, install a center cover ring fabricated with

aluminum sheeting. The ring OD shall have a bead and overlap the gore.

Secure the ring with pop rivets on 6 inch centers and a bead of caulking.

Where a center head nozzles exist, cut the center cover ring for a tight fit at

the nozzles. Seal the joint at the nozzle with a full bead of caulking sealant.

5.3.9 When bottom head of vessel is fully enclosed by skirt (unexposed head), insulation

shall be weathercoated with 1/4-inch wet thickness hydraulic insulating cement

(N202) over poultry netting (N330) in place of metal weather jacket.

Comment 5.3.9 Unexposed heads are weathercoated with insulating cement since

the heads are not subject to atmospheric conditions or mechanical loads.





5.4 Heat exchanger flanges and manway flanges on insulated columns and vessels may be

insulated at COMPANYs option. Insulation, when required shall be flexible, reusable

insulation covers. Cold face and the hot face at 600F and below of insulation cover shall be

Teflon impregnated glass cloth.

Comment 5.4 Modified paragraph 5.4 to provide additional guidance. Flexible type

removable/reusable insulation covers have successfully been used for this application

providing the fabricator designs and fabricates the cover with suitable materials for

environmental and temperature exposure.

5.5 Nameplates and weep holes on reinforcing pads shall not be covered.

5.6 Each section of a double pipe exchanger shall be insulated as a single unit. Continuous

insulation around a multi-sectional unit is permissible only with written approval by the

Company.

Comment 5.6 "Continuous insulation" construction can change the design operating

conditions of the exchanger and thus is not allowed by the specification unless approved by

the Company.

6.0 SPECIFIC REQUIREMENTS FOR MISCELLANEOUS EQUIPMENT

6.1 Applicable Forms

Pumps, turbines and other miscellaneous equipment shall be insulated as indicated on Form

IRM-EF-630. Access shall be provided to pump and turbine glands and other points requiring

periodic maintenance.

Comment 6.1 One can not define how to insulate every piece of equipment due to the

irregular shapes. However, the principles stated throughout the specification still apply.

6.2 Protection of Mechanical Equipment

Working parts of turbines and other mechanical equipment shall be protected when insulation

is applied. Until all insulation materials, including cement or mastic, have been removed from

these parts, the scope of insulation work shall be considered incomplete.

6.3 Plastic Insulation

Plastic insulation (N202) shall be used on any surface which is not suited to block insulation.

The use of plastic insulation shall be kept to a minimum. This insulation has poor thermal

efficiency and therefore may have to be considerably thicker than the block insulation.

Insulation shall be applied on clean surfaces to recommended thicknesses. If a second layer is





required, greater than 1 1/2 inch plastic insulation shall be allowed to set and 1-inch by

20-gage galvanized hexagonal mesh (N330) applied over the entire plastic insulation surface

with butted joints laced together with No. 16-gage galvanized iron wire (N331) and secured to

the insulation with copper wire staples (N340). The insulation, when completely dry, shall be

weather jacketed.

Comment 6.3 Plastic insulation does not have the insulating properties of more

unconventional insulation and is not fire resistant. Therefore, its use should be limited to

locations where geometry prohibits any other type of insulation technique. Indicate poor

thermal properties of this material. This material requires a long period of time to dry and

must not trap moisture by installing the weather barrier too soon.

7.0 INSPECTION

The Company reserves the right to inspect the insulation prior to and after Weather jacketing. The

Contractor shall replace or correct any materials or installation which do not meet the requirements

of this specification and reference drawings.

8.0 FORMS AND DRAWINGS

The following forms and drawings are a part of this specification:

PIM-EF-565 Line Index

IRM-EF-630 Piping and Equipment Insulation Index

GD-N99783 Standard Insulation for Hot Piping

GD-N99785 Standard Insulation for Hot Vessels, Heat Exchangers and Hot Equipment

GD-N99993 Standard Insulation Item Numbers

GD-N99995 Standard Insulation and Aluminum Weatherproofing Details for Hot Tanks

IRM-EG-4197 Flexible Removable Insulation Covers

Comment 8.0 If Contractor is to prime surfaces per Paragraph 3.1.2, add COM-4743 to the list

in Section 8.0.

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