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HEATING VENTILATINC AIR CONDITIONING CUIDE 1944 generally used because it is simplest to install. Blanket type insulations are applied only to round or curved surfaces, and are secured with twine and lagged with sewed-on canvas. Semi-rigid type insulation, secured by adhesive, flat wire bands, and comer dips, is lagged with canvas only where exposed. Blanket type' insulation is at least 1 in. thick. The thickness of semi-rigid insulation is frequently selected in accordance with the values given in Table 2. Table 2. Duct Insulation Thickness for Use in Ships Application Thickness IN. Tempered air ducts in unheated spaces where a temperature differential greater than 35 F exists____ _____________________ _______ -................. C\^OoIlUd a<11i1r dUuUcUts9,, sauupuppliy; and e__x__h__a__u__s__t,p. assin^g through heated spaces.--............ Exposed ducts in heated* spaces, c---a---r---r--y-ing reheated a"Siirr.___ Concealed ducts carrying reheated air, adjacent structure exposed.. CLDoounnccctseeasaleeierdvadinuugucoutsnacluyaurthri^yeuinsisgpar--ce--eh--ei-n-a-----t--w-e-----d*h-,-ira-co--ih-rI,n,t_rhat_td_ef-,,jpyaHacerenltosctarutecdtu_r_e_n__o___t___e_._x...p....o....s.._.e_.d............... Exhaust ducts carrying hot gases (galley, forges, etc.), in living and working spaces-______ ____________ :--................................................... Supply ducts in machinery spaces and similar hot spaces, serving spaces other than the hot spaces through which they pass........ .......................... Heaters............................................................................................................. Ducts subject to excessive sweating............................................................... J4 1 a i lA None Vi Fans are seldom insulated. Preheaters are frequently located close to. the fresh air intake in order to conserve insulation, and' for the same reason zone reheaters are located as close to the zone as possible. Where a reheater serves only one space, the heater is commonly located in the space. BIBLIOGRAPHY The Ventilation of Ships, by R. McDonald (Journal of the Institution of Heating EngVineenetirlsat(iBonr) OancdtobAeirr, 1C9o3n9d).itioning of the S. S. Panama (_H_eating and Ventilating, SepAteirmCboenr,d1it9io3n9,inpg. 4th7e). New Mauretania (Heating, Piping and Air Conditioning, July, 193H9e, apt.in4g3,1)V. entilating and Air Conditioning on Shipboard, by J. H. Clarke (Heating, Piping and Air Conditioning, August, p. 467; September, p. 529;.October, p. 610, 1940). Care of Cargo at Sea, by O. D. Colvin, W. H. E. Hahne and M. R. Colby (Transactions. of the Society of Naval Architects and Marine Engineers; Part I, Vol. 46, 1938, p. 109; PaVrteInI,tilVaotiol.n49o,f1S9h4i1p,sp, .b2y0J8.).Dawson (Journal of The Institution of Heating and Venti lating Engineers, London, Vol. 10, June-July, 1942, No. Ill, p. 89). Modern Marine Engineers Manual, Vol. II, Sections 16 to 19, Inch Cornell Maritime . PreWssa, r1s9h4ip3. Ventilating, Heating and , Air Conditioning, by Comdr. T. H. Urdahl, U.S.N.R., and W. C. Whittlesey (A.S.H.V.E. Journal Section, Heating, Piping and AirStCaonnddairtdioizneindg,HFeeabtirnugarayn, d1V94e3n, tipla. t1in0g5).Equipment for Fighting Ships, by Comdr. T. H. Urdahl, U.S.N.R. and Lt. John Everetts, Jr., U.S.N.R. (Healing, Piping & Air CoDndeistiiognniinngg, JWualyr,sh1i9p43V, epn. t3il3a3ti)o. n with Standardized Equipment, by Comdr. T. H. Urdahl U.S.N.R. and W. C. Whittlesey (Heating, Piping & Air Conditioning, August, 1943, p. 419). 846 EMERGENCY WAR PRACTICES NFORMATION given in the Technical Data Section of The Guide I is based on standard and commonly accepted good practices. Due to war conditions. and in order to save critical materials for war service many substitutions in materials and changes in methods have been necessary. Recent changes in priority regulations have had a tendency to relax some of the restrictions that have been placed upon the use of some metals in producing heating and air conditioning equipment, but nevertheless it will undoubtedly be necessary to' continue the use of substitute materials wherever feasible during the emergency. > Regulations by the War Production Board have banned the manufacture,, installation and sale of heating, ventilating, air conditioning and re frigeration equipment of almost all kinds except for essential war and civilian use. Interpretation of the regulations discloses that all air conditioning for personal comfort is eliminated, and equipment for sup plying preference orders only can be made available. In this way, the most essential needs of the war program, by virtue of their high priority rating, have first access to whatever equipment is available. Provision has been made for securing materials to permit emergency repair-services to be rendered on existing.equipment. As amendments to . these orders are made from time to time to meet current needs, it is not feasible to include a list of these regulations but they are available at all regional and local offices of W. P. B. Whereas, there was a tendency at first to reduce ventilation standards as a means of saving fuel during the emergency, greater emphasis is now being placed upon intelligent operation of heating, ventilating, and air conditioning systems. Public attention is being directed to correction of fuel burning equipment and to the advisability of maintaining tem peratures at the minimum allowable value for reasonable comfort. The emphasis upon saving fuel is being continued in Government publicity, and consequently the engineer must continue to seek out ways .and means of accomplishing the necessary fuel economy in every type of plant as fuel is a weapon of war. 847