Document zzXvGkoqkkv46vBM70aKrRLpn

HEATINC VENTILATING AIR CONDITIONING GUIDE 1940 -- i> CHAPTER 18. PIPE, FITTINGS, WELDING to 250 lb saturated steam working pressure, although most manufacturers also make valves for medium pressure up to 175 lb steam working pres sure. The more common types are gate valves or straightway valves, globe valves, angle valves, check valves and automatic valves, such as reducing and back-pressure valves. Gate valves are the most frequently used of all valves since in their open position the resistance to flow is a minimum. These valves may be Table 12. American Standard Dimensions of Steel Welding Neck Flanges for Steam Service Pressure Rating of 300 Lb per Sq In. (Gage) at a Temperature I of 750 F I secured with either a rising or a non-rising stem, although in the smaller sizes the rising stem is more commonly used. The rising stem valve is desirable because the positions of the handle and stem indicate whether the valve is open or closed, although space limitations may prevent its use. The globe valve is less expensive to manufacture than the gate valve, but its peculiar construction offers a high resistance to flow and may prevent complete drainage of the pipe line. These objections are of particular importance in heating work. Check valves are automatic in operation and permit flow in only one direction, depending for operation on the difference in pressure between Table 13. Standard Roughing-in Dimensions Angle Type Valves Nominal Pipe Gub k K l IK m 2 2K 3 3K 4 5 6 8 10 12 14 OD 16 OD 18 OD 20 OD 24 OD Dub. op Flange ThiceNZS3 OP Flg. Min. Dub. OP Hub 0Q X 3K m 4K 5K OK 6K 7K 8K 9 10 11 12K 15 17K 20 K 23 25K 28 30K 36 %6 IK K IK `Me 2K K 2K `Me 2K K 3Me 1 3`Me m 4K 5K IK 5K 1% 7 nu 8K m iok IK 12K 2 14K 2M 16K 2K < 19 2K 21 2 K 23M 2K 27% Hub Dum. Bboinnino op Chamfptb-C-d H 0.84 1.05 1.32 1.66 1.90 2.38 2.88 3.50 4.00 4.50 5.56 6.63 8.63 10.75 12.75 14.00 16.00 18.00 20.00 24.00 Length Thru Hub* Y 2Me 2K 2Ke 2Ke 2`Me 2K 3 3K 3Ke 3% 3K 3K 4K 4K 5K 5% 5K 6K 6M m Inside Duh. op Pipe Schedule 40e d Inside Dum. op Pipe Schedule 80 d J/ 0.62* . 0.551 0.82* 0.74f 1.05* 0.961 1.38* 1.28| 1.61* 1.50f 2.07* 1.94f 2.47* 2.321 3.07*- --2.901 3.55* 3.36t 4.03* 3.83 f 5.05* 4.811 6.07* 5.76f 7.98* 7.63 f 1_0.02* To Be Specified by Pur- To Be Speci- fied by Pur- chaser chaser Dum. op Bolt Circle No. Size OP op BOLT8 Bolts 2K 4 K 3K 4 K 3K 4 M 3K 4 M 4K 4 M 5 8K 5K 8 K 6K 8 K 7K 8 Vi 7K 8 Vi 9K 8 Vi 10M 12 Vi 13 12 K .15 K 16 1 17K 16 IK 20 kf 20 IK 22K 20 -1% 24% 24 IK 27 24 IK 32 24 IK All dimensions given in inches. A raised face of 14 in. is included in thickness offlange minimum and in length through hub. bThis outside surface of the welding end of the hub shall be straight or tapered at not more than 6 deg. Dimensions H and J correspond to the outside and inside diameters of pipe as given in AS/4 B36.10, 1939. Schedules 40 and 80. Purchaser's order must specify which of these two inside diameters is desired. dThese flanges are' regularly bored to match inside diameter of Schedule 40 pipe, but are bored to Schedule 80 pipe when so ordered. These diameters are identical with the diameters of what was formerly designated as Standard Weight Pipe of the corresponding sizes. fThese diameters are identical with the diameters of what was formerly designated as Extra-Strong Pipe of the corresponding sizes. 344 fin* OP Valve K K l IK IK 2 Tolerance Dimension A Steam and Hot Water Angle Valves and Union Elbowb Eppbctive Januabt 1.1926 Dimension a Modulating Valves Eppectivb January 1. 1926 2K 2K 2K 2K 33 3K 3K 3K 3K 4K 4K K K Dimension A Return Line Vacuum Valves Effective January. 1,1925 3K ..._____ _____ T---- - ........ -- All dimensions given 4n inches. Connecting ends shall be threaded and gaged as to threading according to the American (Taper) Pipe Thread Standard. Af>.A. No. B2--1919. The standardization of the Roughing-in Dimensions of Angle Steam and Hot Water, and Modulating Radiator Valves was made possible by the cooperation of the Manufacturers Standardization Society of the Valves and Fittings Industry. the two sides of the valve. The two principal kinds of check valves are the swing check in which a flapper is hinged to swing back and forth, and the lift check in which a dead weight disc moves vertically from its seat. Valves commonly used for controlling steam or water supply to radi ators constitute a special class since they are manufactured to meet heating system requirements. These valves are generally of the angle type and are usually made of brass. Graduations on the heads or lever handles are often supplied to indicate the relative opening of the valve in any position. Standard roughing-in dimensions for angle-type valves are given in Table 13. Automatic control of steam supply to individual radiators can be 345