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Castleman File: American Petroleum Institute w/c = with cover letter or memo If DATE = 0, undated CD-ROM Document #:API ^ DATE j/ published article from trade journal __ published advertisements __ newspaper article __ published government report __ government inspection results __ unpublished or internal report __ unpublished presentation from conference __ letter __ memorandum __ industry warning labels __ industry sales literature __ industry recommended practices __ meeting minutes (with attachments) __ membership list BC notes idit&ual Staff ARTHUR L. RICE Editorial Director RALPH E. TURNER Editor ANDREW W. KRAMER Managing Editor CHESTER R. EARLE Associate Editor RICHARD H. MORRIS ' Engineering Editor On leave with U. S. Army Air Forces Published Monthly by TECHNICAL PUBLISHING CO. 53 W. JACKSON BLVD. CHICAGO 4, ILL. KINGSLEY L. RICE, President EDWIN C. PROUTY, Vice President WALTER PAINTER, Vice President ARTHUR L. RICE. Treasurer CHARLES S. CLARKE, Secretary JOHN O. AARVOLD, Prod. Mgr. 1. 1 Advertising Representatives CHICAGO: Charles S. Clarke Richard A. Patterson S3 W. Jackson Blvd., Chicago 4, 111. Harrison 0824 ` NEW YORK: John A. Kershaw Graybar Bldg., New York 17. N. Y. Caledonia 5-3779 PHILADELPHIA: H. G. Wilds 121 Waverly Road, Wyncote, Pa. Ogontz 1066 CLEVELAND: A. H. Van Duyn 627 Union Commerce Bldg. Cleveland 14, Ohio Cherry 1377 SAN FRANCISCO: Roy M. McDonald 564 Market St. San Francisco A, Calif. Garfield 8966 LOS ANGELES: Roy M. McDonald 541 S. Spring St. Los Angeles 13, Calif. Madison 6272 WASHINGTON, D. C. c/o Business News Service 10 Independence Ave. POWER PLANT ENGINEERING toHtenti, September. 194% VOLUME 48--NUMBER 9 Cover: Systematically designed boiler room control panel for a utility power plant. Photo, courtesy, Leeds & Northrop Co. Front Lines.................................................................. . ............ 77 What Leaders Say......................................................... ............ 75 Super-Gadget ............................................................... ............ 76 With the Editors ........................................................... ............ 77 Shasta--Key to Central Valley .................................... By M. H. Kight .............78 Modern Equipment Aids System Savings ................... By A. C. Monteith ............. 12 Power in the Aircraft Industry.................... ................ .......... 86 Causes of Turbine Vibrations ...................................... By Ralph E. Turner ....____ 88 Fuel Economy In Heating Philadelphia Schools ........ By Allen J. Johnson ............. 90 How Steam is Released in Water-Tube Boiler Drums By Max H. Kuhner ............. 92 Polarized Light Servo-System ..................................... ............. 95 insulation--How to Install It ....................................... ............. 96 The Practical Engineer & Electrician ........................... .............. 101 News From the Field ................................................... .. ............ 152 Obituaries ................................ .................................... ..... ........158 Coal Segregation in Boiler Plants--Correction ....... .............. 166 New Equipment............... .......-.............. -..........-.... ...........168 Manufacturers' News............. ,............. ....................... ________180 Manufacturers' Personals................. ........ ............... _............................ 184 New Engineering Books ............ .. .186 Power Plant Construction News . ..200 Contents ef back issues of Power Plant Engineering wiR be found in Industrial Arts Index on file la Public Ubrarias. . Copyright 1944, by Technical Publishing Co. Published monthly bj urn Technical Publi.Mnj Co.. t tl Wt Jubin Bld.;aolcM* 4. UL, V. . A. fcbocrlptlan prion. R.N n par. Ibtowd u mad dui nuttnr Swumhw INSULATION- How to Install It Preparation of surface, details of installation, application of finish, for mineral wool blankets, blocks, insulating cement and pipe insulation for heated industrial equipment The following data on how to install various types of in sulating materials represent recom mended practice at the present time. They form the major portion of a re cently-published standard on this sub ject issued by the National Bureau >t>f Standards, U. S. Department of Com merce; the work was undertaken at the instance of the Industrial Mineral Wool Institute. The recommendations have been approved by a large number of users anil manufacturers, have just been issued as Commercial Standard CS 117-44, and are effective for new pro duction from May 25, 1944. It is to be understood that the set ting up of these standards is a purely voluntary effort, on the part of all those interested, to establish minimum stand ards, avoid misunderstandings and pro vide a basis for certifying quality of ma terial and installation. The U. S. Depart ment of Commerce has no regulatory power to enforce them and the Bureau of Standards merely acts as an unbiased co-ordinator through which all inter ested 'parties can agree on the prac tices found most satisfactory to all. The standards are written in the form of specifications, which can be incorporated in agreements when de sired or can be referred to, and the original text of the standards has been largely retained here. However, the following represents only a portion of *A copy of CS 117-44 may be obtained without charge upon written request to the Industrial Mineral Wool Institute, 441 Lexing ton Avenue, New York 17, N. Y., or from the Superintendent of Documents, U. S. Government Printing Office, Washington, D. C.. for 10 cents per copy. , Fig. I.--Method of securing mineral wool blanket! on curved turfdcit. A, Bare surface; B, No. 9-gage galvanizedwire girdles pulled tight around curved surfaces, spaced 4 ft on centers; C, blankets affix*d to No. 9-gage girdles with No. 16-gage galvanized hairpin wires, 12 in. on centers; D, banket insu'at'on with expanded lath side exposed; E, blanket edges laced with No. 16-gage galvanized wires; F, blankets secured with Yi- or K*in. gal vanized bands spaced approximately 8 in. on centers. the standards and anyone desiring to use them should obtain a complete copy* ,, The standards begin with a discus sion of the requirements for the com position of insulation, its thermal con ductivity, denoted by k, in Btu per hr per sq ft per deg per 1-in. of thickness and the maximum temperature limits to be recommended by- the manufactur ers for various classes of insulation. These data are summarized in Table I. The standard sizes noted are subject to tolerances discussed in the text. Most of the above points are primarily of concern to manufacturers but many Tabla I.--Types, conductivities, desses end sixes of mineral wool products Typea k at *F mean temperature Maximum temperature limit mo 100 400 Class F 01X68 0.41 0.47 003 f....... 1C....... 1,000 1,200 t to 0 in. tbiok by 34 In. wide by 48 in. or 88 in. long. (A....... 000 1 to 4 In. thick by 6 In. or 12 in. wide Q.9Q o. 0.M fC..... 1,300 by 18 in. or 86 la. km*. 1X2....... 1,000 0.70 0.76 a 80 1,200 1,800 ^Packaged in 10-lb. bags. Fig. 2. Alternate method of affixing mineral wool blankatx A, Bare surface; B, punched clip an gles welded to sur face, spaced 8 ft on horizontal centers; HC, blankets hung tem porarily from angles with'No. 32-^age gal vanized wires; D, blanket insulation 1 in. thicker than out standing leg of angle: blanket secured with l/t- or K*in. gal vanized bands space approximately 8 in. on centers. must also be taken into account by en gineers who write specifications. The standards provide that certain charac teristics of the material are to he de termined by ASTM test methods read ily- available in published form. The following represents recom mended installation requirements, based upon long experience, for maximum service in the use of mineral wool products for insulating heated indus trial equipment. Auxiliary Material Finishing cements may be used to provide a smooth, hard surface over insulating materials in locations not subject to excessive moisture or abra sion. Table II--Molded-type pipe insulation Thicknesses s for standard-weight steel-pipe sizes Pipe size Standard thickness Nominal Actual 0. D. Double standard thickness fa. Vi H l iIRN S W t 8H 4 4M 1 6 7* 6 tv 10 11 v 12 14 and up in. 0.840 1.060 1.315 1.660 1.000 1875 2.875 8.500 4 000 4.600 8,000 8.663 6.635 7.625 8.62S 0.635 ia?60 U. 760 11750 in. J4 U {4 14 H m. m. in. mi nt w 11 m 1H IX 1H m iw iw in. IN IN IN IN IN 2)(. IK. 2Me 2Ht 2N 8M 2H 2H 2M 2H 2IHH 2Vi 8 8 Pipe insulation (blanket-type). Ml 047 063 Pipe Insulation (molded-type). 0.42 0.46 060 1,000 1,200 000 1,200 1 to 4 In. thick by 24 in. long fabri cated to lit 2 in. and larger pipe. H to 4 in. thick by 36 in. long to fit H to 12 in. and larger steel pipe .sizes. sin addition to the thicknesses specified above, roolded-type pipe insulation may be manufactured in thicknesses of 1, tti, 2, 2H. S, and 4 in. for all nominal pipe sizes. b These pipe sixes are no longer listed as standard for steel pipe, Simplified Practice Recommendation R57-X2, 96 September, 1944 --POWER PLANT ENGINEERING -- Chicago, III. Fig. 3 Alternate method of affixing mineral wool blankets on flat surfaces. A, Bare surface; B, No. 9-gage galvanized wires of specified length welded perpendicular to sur face. spaced approximately 8 in. on centers; C, blankets impaltd on No. 9-gage galvanized wires with expanded-lath side exposed; D, No. 9*gage galvanized wires bent up and pressed into the blankets; blanket edges laced with No. 16- gage galvanized wires. Asphaltic weatherproof finish may be used to provide a water-tight pro tective finish over insulating materials Fig. 4. Application of mineral wool blanket insulation on curved surfaces. A, Bare surface; B, No. 9-gage galvanizedwire girdles spaced 4 ft on centers; C. blanket insulation 2 ft by 8 ft, wired to girdles; D. blanket edges laced with No. 16-gage galvanized wires; E, y,~ or 14-in. galvanized bends .paced approx:mately 8 in. on centers; P, two or more bands at top; G, insulating cement: H, 1-in. gal vanized wire netting secured in place with No. 16-gage galvanized wires; I, finishing cement or asphaltic finish. Fig. 5. Application of mineral wool block insulation on curved surfaces A, Bare surface; B, mineral wool blocks ap plied with joints staggered; C, 'A- or ti-in. gal vanized bands spaced approximately 8 in. on cen ters; D, 1-in. galvanized wire netting secured in place with No. 16-gage galvanized wires; E, insu lating cement; F, 1-in galvanized-wire netting secured in place with No. 16-gage galvanized wires; G, finishing cement or asphaltic finish. Table III--Recommended minimum insulation thicknesses The insulation thicknesses listed in this table are recommended for indoor locations; for outdoor location increase insulation thickness not less than 'A in. For under ground application, thickness may be decreased V, in. when specified. Temperaturc F Up to 300 .. 300 to 500 . 500 to 700 . BLANKET INSULATION Thickness In. ... iy. ... 2 Tempera- Thick- turc ness F in. 700 to 900 ... .. 2 y. 900 to 1,100 .. .. 3 1,100 to 1.200 .. 3 y. rtr* INSULATION Blanket-type Thktaees Ifeldod-typa Thicknoos i i SLOCK INSULATION Tempera- Thick* ture ness F in. Up to 200 .... .. i 200 to 400 ... .. iy. 400 to 500 ... .. 2 500 to 600 ... .. 2'A 600 to 700 ... .. 3 700 to 900 ... .. 3V, 900 to 1,100 ,. .. 4 1,100 to 1,300 .. 4 y. 1,300 .............. .. 5 ' INSULATING CKMENTl Tempera- Thick- ture ness F in. Up to 200 .......... 1 200 to 400 ........ * i y, 400 to 500 ........ 2'A 500 to 600 ........ 3 600 to 700 ........ 3 '/2 700 to 900 ........ 4 900 to 1.100___ 4pS 1,100 to 1,300 .. 5 1,300 to 1,600 .. 5 yi 1,600 .................. b'A 1 Usually applied over blankets and blocks 16 In. thick as a base coat for desired finish. For built-up applications on irregular sur faces, thicknesses inay bo used up to tbs prac tical limit. Temperature Pipes Pipes Pipes 2 In. to 4 in. to fn. 4 in. In. endup Temperature Pins below 2 In. Pipes Pipes 2 in. to 4 In. and 4 In. up / ~ 250 to 850.................... 850 to 450 . 450 to *50 550 to 650 . .. . . 050 tn 750 . 750 to 000 1,050 to 1,200.............. in. 1 i 1 1 iu 2 j 2H in. i 1 1 JU %iH" t 2U in. 1 1 m m 2' s tH z 4 V Up to 275...'........... Btd........... 8td........... *76 to *50.................. ...do../.... ...do.......... 850 to 425................ 1H".......... 425 to 500.................. IH".......... IT............. 500 to 600.................. 2"............. Dbl.ztd... 000 to 760.................. *14".......... H".......... 750 to 900.................. 900 to 1,050 _............ 9\2,, 8 ............. M".......... 1,060 to 1,200............. *H".......... Btd. IH". **'. Dbl. std. Do. r. 4TM 4K". insulation. Ollier factors that deter sion, freezing, or fire; and personal i i | \ in locations where excessive moisture or abrasion are encountered or wher ever else specified within its tempera ture limit. This asphaltic finish shall mine insulation thickness are the main tenance of precise temperature control; protection against damage by corro safety of workmen. The insulation thicknesses to be ap plied for various operating conditions consist of a fibrated asphalt emulsion, which, for weatherproofing purposes, Fig. 6. Application of min shall be applied to a - minimum dry thickness of % in. Miscellaneous accessory materials!, such as adhesives, attachment devices, canvas, paper, metal fabrics, asbestoscement sheets, roofing felt, paint, sheet metal, etc., shall be of a type and qual ity satisfactory for use in the applica tions hereinafter described. Application (General) Selection of the economical thick ness of mineral wool insulation to be eral wool block* on flat or rectangular surfaces - Sketch 1: Application where insulation thickness is greater than stiffener he:ght. A. bare surface; B, stiffener ribs; C, mineral wool blocks; 1), No. 16-gage galvanized reinforcing wires or H*n. gal vanized bands applied over blocks; E, corner bead secured over blocks at corners with No. 16-gage galvanized wires; F. insulating cement; G, 1-in. gal vanized wire netting stretched tightly over insulatin'* cement and wired In place; H, finish ing cement or asphaltic finish. installed is governed largely by the Sketch 2: Enlarged details Operating temperature maintained, ibe cost of heat delivered, the number of showing application of corner bead. Ai mctai duct* b, min eral wool blocks; C, No. 16- hours operated per year, and by the gage galvanized wire over frocks: D, corner b^d; E. No. effectiveness and applied cost of the 16-gage galvanized wires drawn through perforations in corner bead. tDuring the war emergency period, tome of the auxiliary material described m this standard may be considered critical. Wh*n such auxiliary materials are not available owing to Government order, an acceptable alternate material shall be. used. Sketch 3; Application where insulation thickness Is equal to or less than stiffener height. A. stiffener; B, miner* al wool blocks; C. insulating cement and specified finish bev eled back at rib. I rwt/i kirr nikiC. -- HI 97 Fig. 7. Application of minaral wool block* between structural support* A, bare surface; B, first layer of mineral wool block* against steel casing; C, second layer of blocks applied with all joints staggered; D, brick. shall not be less than those recom mended in Table III, unless otherwise approved by the purchaser. External surfaces of heated multi layer brick constructions shall be insu lated to a thickness no greater than that which will result in a safe temper ature gradient for all materials used in the composite construction. Expansion joints for insulation shall be provided on equipment operated at temperatures above 600 F, as specified by the insulation manufacturer or by the applying contractor. Adequate protection shall be pro vided to prevent the entrance of mois ture into the insulating material. Par ticular care shall be taken around open ings and connections. All mineral wool insulating products and accessory materials shall bfe in stalled in a neat, workmanlike manner in accordance with the following rec ommendations and subject to the ap proval of the purchaser. Blankat Insulation Preparation of surface--The surface to be insulated shall be carefully in spected and all loose rust, scale, or dirt removed and leaks or damage repaired. Suitable anchorage for the blankets shall be provided in the form of wire cables, nuts, clip angles, or No. 9-gagc galvanized wires, welded or otherwise, securely affixed to the surface on speci fied centers. Installation of blankets--On curved surfaces, blankets of specified thick ness as in Table III, shall be secured to the supports in the manner shown in Figs. 1, 2, and 4. On flat surfaces, blankets shall be applied with the expanded lath exposed as in Fig. 3. ' Application of finish--After the blankets arc in position and carefully secured, a %-in. layer of mineral wool insulating cement shall be applied. This coat shall be forced well.into the ex panded metal lath to form a strong key. Sufficient cement shall be applied to level off the surface. A second % -in. troweled coat of insulating or finishing cement shall be applied after the first coat has dried. Portland cement may be added to this coat to provide a harder finish. Insulation located indoors and not Fig. I. Application of mineral wool insulat ing cement on curved iteel surface*. A, cleaned bare surface; B. first coat of insu lating cement spotted on roughly by hand; C, sec ond coat of insulating cement; D, 1-in. galvanized wire netting; E, finishing cement or asphaltic finish. exposed to moisture or abrasion may be further finished as described below. (1) When specified, a 6- or 8-oz. canvas jacket shall be sewed or pasted smoothly in place. If sewed, stitches shall be spaced not more than ft in. apart, with seams located where least visible. (2) When specified, a layer of asphaltic weatherproof finish may be applied instead of canvas. After the second coat of cement has thor oughly dried, 1-in. galvanized wire Fig. 9. Application of mineral wool insulat ing cement on brick surfaces. A, brick wall; B, masonry nails spaced 8 to 12 in. on centers, extending approximately W in. from bricks; C, first coat of insulating cement ap plied nearly flush with nail heads; D, 1-in. gal vanized wire netting secured to nail heads; E. second coat of insulating cement; F, finishing cemnt or asphaltic finish. netting shall be stretched tightly over the surface and wired in place with No. 16-gage galvanized wire. Asphal tic finish shall then be applied suffi ciently thick (approximately A in. thick, wet) to provide a minimum dry thickness of % in., troweling it well into the wire netting. ~h<2) Fig. 10. Abovo--Application of blanket-type mineral wool pip* insulation on pipes A, hare pipe; B, blanket-type pipe insulation wrapped cir cumferentially around bare pipe; C, joints secured with No. 16-gage galvanized wires; D, insulating cement; E, asphaltic or other specified finish. Fig. II. Right--Application of bUnktMype minaral wool pipe Imuletion on Urge velvet end fittings A, bare fitting; B, blanket-type pipe insulation; C, joints secured with No. 16-gage galvanized wires; D, insulating cement or other specified finish. Fig. 12. Application of minaral wool sectional pipe insulation single-layer A. bare pipe; B, sectional pipe insulation; C, canvas jacket or other specified finish; D, metal bands Fig. 13. Application of mineral wool tagmantal pipe Insulation A, bare pipe; B, segmental pipe insulation; C, No. 16-gage galvanized wires; D, insulating cement when required; E, canvas jacket or other specified finish; F, metal bands. 98 September, 1944--POWER PLANT ENGINEERING -- Chicago, III. Insulation located outdoors or ex posed to moisture or abrasion shall be protected by one of the methods de scribed below. (1) After .the cement has thor oughly dried, 1-in. galvanized wire neitjng shall be stretched tightly over tlie surface and wired in place with No. 16-gage galvanized wire. Asphal tic finish shall then be applied suffi ciently thick (approximately 54 in. thick, wet) to provide a minimum dry thickness of 5fs in., troweling it well into the wire netting. (2) When specified on smooth regular surfaces, the cement and asphaltic coatings may be omitted, and the surface weatherproofed in stead with a sheet-metal jacket. The sheet-metal jacket shall be no lighter than No. 28 gage, single or double galvanized, suitably anchored to the surface. Seams shall be lapped 2 in. against the weather and secured with metal screws, or provided with a locked or flange-crimped joint or otherwise sealed, to prevent the entry of moisture. After providing for ex pansion and contraction of the metal jacket, it shall be secured in place with ^-in. or Y~in. galvanized metal bands, machine-stretched and crimped, on specified centers. Block Insulation Preparation of surface--The surface to be insulated shall be carefully in spected and all loose rust, scale, or dirt shall be removed and leaks or damage repaired. Brick surfaces shall be made true and even. Suitable anchorage or support for the blocks shall be provided when re quired, by securely affixing wire cables, nuts, dip angles, or rods to the sur face on specified centers. Installation of blocks--On curved surfaces, blocks of specified thickness (see Table III) shall be applied using staggered joint construction as shown in Fig. S. On flat surfaces, blocks shall be ap plied by the methods shown in Fig. 6. When blocks are installed between brick or other structural supports, the anchors, insulating cement, and other finish shall be omitted. See Fig. 7. Finish is to be applied by the same methods given above for blanket insu lation. Insulating Cement (Built-up Applications) Preparation of surface.--The sur face to be insulated shall be carefully inspected and all loose rust, scale, or dirt removed and leaks or damage re paired. Paint or grease shall be re moved with a caustic solution which shall then be washed off with water. Anchorage for the insulating ce ment stiall be provided as required, In the form of clip angles, nuts, rods, or masonry nails of proper size. Addi tional support is recommended for insulating cement applied on light-gage metallic surfaces, or when surface ex pansion and contraction is excessive. When possible, the surface to be insulated shall be kept hot to facilitate drying. . - Installation of insulating cement-- Insulating cement shall be mixed with clean fresh water to troweling consist ency before application. On curved or fiat steel surfaces, in sulating cement of specified thickness (see Table III) shall be built up in sepa rate coats not greater than Ys in. thick as in Fig. 8. (1) A reinforcing layer of 1-in. galvanized-wire netting shall be ap plied between every second coat of insulating cement, stretched tightly over the dry cement and securely wired in place with No. 16-gage gal vanized wire when: (a) the total in sulation thickness specified is greater than 1 in., (b) the cement is to be applied to the underside of equip ment, (c) the insulated equipment will be subjected to vibration. On heated brick surfaces, insulating cempnt shall be applied as in Fig. 9. If the insulated surface is to be weatherproofed, No. 16-gage galvan ized hairpin wires shall be affixed to the nail heads and permitted to extend through the second layer of insulating cement to provide anchorage for the weatherproof finish. Application of finish--Insulating ce ment located indoors and not exposed to moisture or abrasion shall be fin ished, when specified, with a 54-in. troweled coat of finishing cement. Portland cement may be added to pro vide a harder finish. (1) When specified, a 6- or 8-oz canvas jacket shall be sewed or pasted smoothly in place. If sewed, stitches shall be spaced not more than 54 in. apart, with seams located where least visible. (2) When specified, a layer of asphaltic weatherproof finish shall be applied instead of canvas. After the cement has thoroughly dried, 1-in. galvanized wire netting shall be stretched tightly over the surface and wired in place with No. 16-gage gal vanized wire. Asphaltic 'finish shall then be applied sufficiently thick (ap proximately 54 in. thick, wet) to pro vide a minimum dry thickness of % in., troweling it well into the wire netting. Insulating cement located outdoors, or exposed to moisture or abrasion, shall be finished with an asphaltic weatherproof finish. (1) A 54-in. coat of finishing ce ment shall be applied when specified, to which Portland cement may be added to provide a harder finish. (2) After the cement has thor oughly dried, 1-in. galvanized wire netting shall be stretched tightly over the surface and wired in place with No. 16-gage galvanized wire. Asphaltic finish shall then be applied sufficiently thick (approximately 54 in. thick, wet) to provide a minimum dry thickness of 54 in., troweling it well into the wire netting. (See Figs. 8 and 9.) BUnk*t-typ* Pip* Insulation Installation on pipes--Blanket-type pipe insulation of specified thickness (sec Table III) shall be applied on pipes and long radius bends of 2-in. diameter or greater. (1) Before applying, the insulation shall first be formed roughly to fit the pipe. Pipe insulation shall be spaced a sufficient distance from flanges to permit removal of the bolts when flanges are opened. Adjacent lengths shall be butted closely to- Fig. 14. Application of minoral wool block insulation to larga fittings. A, pipe huulstion; B, Mock insulation; C. No.' 16gage galvanized wires; D. insulating cement or other specified finish. troweling it weil into the wire netting. (3) When a roofing-felt finish is specified it shall be smooth-surface asbestos asphalt-saturated, weighing not less than SS lb per roll of 108 iq ft. Seams shall be lapped at least 2 in. against the weather and when =;i specified, shall be sealed with lap ce ment. The roofing-felt jacket shall then be secured in place with copper wires or galvanized bands spaced on specified centers. Blanket-type pipe insulation located outdoors or exposed to moisture or abrasion shall be weatherproofed as i described below. !. (1) Pipes, valves, flanges, and fit- ings shall be finished with a sheet- metal jacket, roofing-felt, or aspaltic finish, as specified, (a) Sheet-metal jackets shall be no lighter than No. 28 gage, single or double galvanized. Seams shall be lapped 2 in. against the weather and secured in place with l/2- or f$-in. galvanized metal bands, machinc- stretched and crimped, on specified centers. (b) When a roofing-felt finish is specified it shall be smooth-surface asbestos asphalt-saturated, weighing not less than SS lb per roll of 108 sq ft, applied as above. (c) Pipes, valves, flanges, and fit tings may be finished with asphaltic finish when specified, applied as above. Molded-Type Pipe Insulation Installation on pipes.--Molded-type mineral wool pipe insulation of speci fied thickness (see Table 111) shall he Fig. 17. Application of moldad-typa mineral wool pips insulation to flanges and fittings applied in sectional or segmental form, A, sectional pipe insulation; B, No. 16-gage galvanized wires or galvanized bands; C. sectional or segmental pipe insulation; D. insulating cement or other specified finish. of single- or double-layer construction, as specified. At flanges, pipe cover gether and laced with No. 16-gage (2) Blocks of a thickness Y> in. ing shall be spaced a sufficient distance galvanized wire. The ends of wire less than the insulation on adjacent from the flanges to permit easy re loops shall be bent over and pressed piping shall be carefully fitted and moval of bolts when flanges are opened. into the insulation to leave no sharp wired securely in place. A 'A -in. coat (1) Adjacent pieces of sectional projections. (See Fig. 10.) of insulating cement shall then be pipe insulation shall be butted closely (2) When specified, blanket-type pipe insulation shall be furnished with an integral galvanized-metal applied, troweling it well into the cracks between adjacent blocks. Application of finish--Blanket-type together and banded in place. (See Fig. 12.) (2) Segmental pipe insulation jacket. It shall be applied snugly around the pipe and bolted along the flanged longitudinal joint. No fur pipe insulation located indoors and not exposed to moisture or abrasion shall be finished as described below. (See should be secured in place with sepa rate loops of No. 16-gage galvanized wire, spaced on 8- to 12-in. centers, ther finish is required. Fig. 10.) depending on the pipe size and (1) Pipes, valves, flanges, and fit insulation thickness. Ends of wire Installation on valves, flanges, and tings shall be finished, when speci loops shall be bent over and pressed fittings--Valves, flanges, and fittings 6 in. in diameter or larger shall be insu lated with blanket-type pipe insulation of thickness equal to insulation on ad jacent piping. The insulation shall be formed to fit by cutting it along the circumferential edges, then secured in fied, with a canvas jacket sewed or pasted over a layer of flameproof paper, T,B-in. thick asbestos paper, or a |'4-in. coat of insulating or finishing cement. If sewed, stitches shall be spaced not more than kS-in. apart, with seams located where least vis into the insulation, leaving no sharp projections. Insulating cement shall then be troweled well into any cracks between adjacent segments. (See Fig. 13.) (3) Double-layer pipe insulation, either in sectional or segmental form, place by wiring the longitudinal joint. ible. shall be applied with circumferential I All cut edges shall be laced together with No. 16-gage galvanized wire and the ends of wire loops bent over and pressed into the insulation to leave no sharp projections. (See Fig. 11.) - (2) Pipes, valves, flanges, and fit tings may be finished with asphaltic finish when specified. A )4-in. coat of insulating or finishing cement shall be applied and when the cetnenf and longitudinal joints staggered, omitting the canvas jacket between layers. The first layer shall be wired in place with separate loops of No. 16-gage galvanized wire ypaccd As alternate applications on valves, has thoroughly dried, 1-in. galvan- , on 8- to 12-in. centers. The second flanges, and fittings, insulating cement ized-wire netting shall be stretched layer shall be applied snugly over or block insulation shall be used. lightly over the surface and wired in the first laver and secured in place. (1) Insulating cement shall be place with No. 16-gage galvanized (See Fig. 14.) built-up in }j-in. coats to a thickness wire. Asphaltic finish shall then be Installation on valve*, flange*, and equal to the insulation on adjacent applied sufficiently thick (approxi fitting*.--Valves, flanges, and fittings piping, by the same method as used mately XA in. thick, wet) to provide shall be covered with insulating cc- in Fig. 8. a minimum dry thickness of k4-in., (Continued on page 162) 100 September. 1944 --POWER PLANT ENGINEERING --Chicago, III. I ^^loDEHN methods of baffling boilers have reduced flue gas temperatures and draft losses, with a resulting increase in ef ficiency, capacity, economy of operation and ultimate saving ol fuel. Eneo Streamline Baffles are built gas tight and at any angle across the tubes, or interbank spaces, in all water tube boilers. The construction provides for easy removal of tubes and is a life time fob. The long sweeping curves promote the smooth rapid flow of gases over practically every square foot of the heating surface --gas passes are tapered in correct proportion to the contraction of the gas as it cools to maintain gas velocity. Bottle necks, dead gas spaces and soot pockets are eliminated with resulting better heattransfer and minimum draft-loss. Flexibility in design and construction permits baffles to be placed in the most effective position Instead of a convenient, location for easy installation. Since boilers differ as to site and location of superheaters, num ber of drums, location of damper, nature of fuel, use of arches, water walls, etc- the design of an Enco baffle for each boiler is an engineering study which requires, and gets, individual study. A bwfleff*4M boiler fcattfegfye* valuable fafarwaffoM which. "J t" J\ every eegleeer sheeU bave. Arfc for bulletin *W 44 It's frsoU,';1- M * #1 ^ rWVl'fr " ^ f v <,, ,, *" Vr ENGINEE jr-ti PRODUCED EXCLUSIVELY BY THE ENGINEER COMPANY Insulation-- How to Install It (Continued from page 100) ment, block insulation, or molded-type pipe insulation, as specified. (1) Insulating cement shall be built up in separate coats no greater than J4 in. thick, to a thickness equal to the insulation on adjacent piping by the method shown above for insulating cement and shown in Fig. 8. (See Fig. IS) (2) Blocks of a thickness 54 in. less than the insulation on adjacent piping shall be carefully installed on large fittings (approximately 4 in. and up in diameter) and secured in place with No. 16-gage galvanized wire. A 54-in. coat of insulating ce- , ment shall then be applied, troweling it well into the cracks between ad jacent blocks. (See Fig. 16.) (3) Molded-type pipe insulation . may be used to insulate flanged couplings. Rings of sectional pipe covering \y2 to 2 in. wide should be wired in place on each side of the flange, selecting an insulation thick ness that will provide an outside diameter equal to or greater than the flange diameter. A piece of sec tional pipe insulation long enough to covgr the flange should then he banded in place. (See Fig. 17.) Application of finish located in doors.--Molded-type pipe insulation lo cated indoors and not exposed to mois ture or abrasion shall be finished with a canvas jacket. (1) The factory-weight canvas jacket furnished shall be drawn tight, and smoothly pasted down at all side and end laps. Factory bands shall be applied, one binding the adjacent ends and one at the center of each section. (2) When extra-weight canvas jacket is specified, the factory-weight canvas and bands (if furnished) shall be omitted. The pipe insulation shall be enclosed in 40-lb rosin-sized pa per, over which the specified 6- or 8-oz canvas jacket shall be sewed neatly in place with stitches spaced not more than Ys in. apart, with seams located where least visible. Insulation on flanges, valves, and fittings located indoors or not exposed to moisture or abrasion shall be cov ered with a 54-in. coat of insulating or finishing cement. Portland cement may he added to provide a harder finish. (1) When specified, a 6- or 8-oz canvas jacket shall then be sewed or pasted neatly over the dry cement. Sewed canvas jackets on valves, flanges, and fittings shall be made continuous with the canvas on ad jacent piping by overlapping or blind stitching. . Application of finish located out doors.--Molded-type pipe insulation and fittings located outdoors or exposed to moisture or abrasion shall be pro vided with a weather-proof protective finish in the same general manner as specified for blanket-type pipe insula tion. 162 , / September, 1944 --POWER PLANT ENGINEERING -- Chicago, 111. r ' StuteUufoUtUe. HENSZEY DISTILLATION SYSTEM This Hensiey unit it compact and axtromaly officiant avaporator that pro* ducat adaquata supplies of trash water of highest quality and purity . . . an important item in certain manufacturing methods, food processing, chemi cal formulations, power production and human consumption. Hentxay Distillation Systems can be built iq any desired capacity from 3,000 to 50,000 pounds per hour in one single, compact unit. They can be fur nished with or without integral boilers. They can be fabricated from steal, stainless steal, monel, copper or combinations of the above to meet your purpose. Get to know more about these remarkable units--they may be the answer to an abundant low cost supply of pure water required in your post war plans'. . . or they may be the answer to an immediate war production problem now. ' HENSZEY CO., Depl. C 9, Watertown, Wis. *6 EFFECT EFFICIENCY with only * EFFECTS A remarkable achievement at design and performance! HENSZEY DISTILLATION SYSTEMS Continoous Blowdown Hoot Exchangers e Boiler food Regulators Toed Water Motors e Blow ladlcators # Proportioning Valves Guides for Peinfing When specified, insulation finishes shall be painted for identification pur poses in actordance with "Scheme for the Identification of Piping Systems," issued by the American Standards As sociation (A13--1928). The applica tion of paint should be deferred until the insulated equipment has been op erated at the design temperature for a sufficient length of time to thoroughly dry out all components of the installa tion. When weatherproof finish of the emulsified-asphalt type is to be painted, it should be primed with at least one coat of aluminum paint before applying lead-in-oil paint. Asphalt-base paint may be used directly over the asphaltic finish when a black color is specified. Canvas should be given at least one coat of glue size followed by two coats of lead-in-oil paint. Galvanized metal is not ordinarily painted immediately following application. If painting is re quired, it should be done in accordance with manufacturers' directions. Insu lating cements and finishing cements ordinarily dry to a light color, and may be painted with a nonpenetrating paint such as aluminum. Maintenance In order to maintain high thermal efficiency in conjunction with long in sulation life, the following recom mendations arc made: (a) Inspect all insulation jobs pe riodically, particularly those located outdoors or exposed to moisture, vibration, or abrasion. (b) When equipment is moved, or if for other reasons the finish of the insulation is damaged or becomes loose, repair or replace as required to prevent deterioration. (c) For advice on problems in connection with any specific insula . tion application, consult the manu facturer or the contractor who ap plied it. Polarized Light Servo-System (Continued /row /tiijc 95) A small d-c generator is attached to the shaft of the motor and its output voltage is applied through capacitor (Cj) between the grid and cathode of tube (2). The voltage (e) generated by this generator is proportional to the speed (w) of the secondary shaft. For the frequencies encountered the current through Ci, and therefore the voltage across the grid resistor of the tube (2), is proportional to and is therefore proportional to the acceleration of the shaft. Thus, the condition of balance of the two light beams is anticipated, and the system is stabilized .and remarkably free from the hunting or oscillation com monly experienced in servo systems. It will be noted that a single lamp is used as a light source for both beams of light so that any changes in the light output due to aging, darkening of the 164 September, 1944 --POWER PLANT ENGINEERING -- Chicago, III.